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Jéhannet P, Heinsbroek LTN, Swinkels W, Palstra AP. Recent insights into egg quality and larval vitality of the European eel Anguilla anguilla. Gen Comp Endocrinol 2024; 354:114531. [PMID: 38670468 DOI: 10.1016/j.ygcen.2024.114531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 03/18/2024] [Accepted: 04/23/2024] [Indexed: 04/28/2024]
Abstract
To date, the eel industry still depends on wild-caught juveniles that are grown to marketable size. There is an urgent need to close the eel life cycle in captivity to make aquaculture independent of the natural population. With this artificial reproduction protocol, yolk-sac larvae can be produced but egg quality may be impaired. Low survival rates and high deformity rates are frequently observed during the first week after hatching. Over the past four years, we have conducted studies with the aim to optimize the artificial reproduction protocol, thereby focussing on increasing egg and larval quality. Weekly carp or salmon pituitary extract (PE) treatment was successfully replaced with recombinant gonadotropins (rGTHs) to mature female eels and produce larvae. 17α,20β-dihydroxy-4-pregnen-3-one (DHP) was replaced with upstream precursor progesterone (P) to induce the endogenous production of DHP by the female eel. DHP and P were found equally potent in inducing oocyte maturation and ovulation. The effects of antibiotics on larval survival and the occurrence of deformities were investigated. Antibiotic treatment increased survival and decreased the occurrence of deformities indicating bacterial infection as an important cause. A deformity determination key for young eel larvae has been developed that provides a framework of reference for larval deformities which will be instrumental with gaining insights on the reasons behind each larval deformity. These improvements of the artificial reproduction protocol and hatchery practices will contribute to the production of robust eel larvae that survive, grow and metamorphose into juveniles that will later be able to reproduce in captivity.
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Affiliation(s)
- Pauline Jéhannet
- Animal Breeding and Genomics, Wageningen University & Research, PO Box 338, 6700 AH Wageningen, the Netherlands.
| | - Leon T N Heinsbroek
- Wageningen Eel Reproduction Experts B.V., Mennonietenweg 13, 6702 AB Wageningen, the Netherlands
| | - William Swinkels
- Palingkwekerij Koolen BV, Hongarijesedijk 12, 5571 XC Bergeijk, the Netherlands
| | - Arjan P Palstra
- Animal Breeding and Genomics, Wageningen University & Research, PO Box 338, 6700 AH Wageningen, the Netherlands
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Palstra AP, Abbink W, Agbeti WEK, Kruijt L, Jéhannet P, Lankheet MJ. Heart Rate and Acceleration Dynamics during Swim-Fitness and Stress Challenge Tests in Yellowtail Kingfish ( Seriola lalandi). Biology (Basel) 2024; 13:189. [PMID: 38534458 DOI: 10.3390/biology13030189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 03/12/2024] [Accepted: 03/13/2024] [Indexed: 03/28/2024]
Abstract
The yellowtail kingfish is a highly active and fast-growing marine fish with promising potential for aquaculture. In this study, essential insights were gained into the energy economy of this species by heart rate and acceleration logging during a swim-fitness test and a subsequent stress challenge test. Oxygen consumption values of the 600-800 g fish, when swimming in the range of 0.2 up to 1 m·s-1, were high-between 550 and 800 mg·kg-1·h-1-and the heart rate values-up to 228 bpm-were even among the highest ever measured for fishes. When swimming at these increasing speeds, their heart rate increased from 126 up to 162 bpm, and acceleration increased from 11 up to 26 milli-g. When exposed to four sequential steps of increasing stress load, the decreasing peaks of acceleration (baseline values of 12 to peaks of 26, 19 and 15 milli-g) indicated anticipatory behavior, but the heart rate increases (110 up to 138-144 bpm) remained similar. During the fourth step, when fish were also chased, peaking values of 186 bpm and 44 milli-g were measured. Oxygen consumption and heart rate increased with swimming speed and was well reflected by increases in tail beat and head width frequencies. Only when swimming steadily near the optimal swimming speed were these parameters strongly correlated.
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Affiliation(s)
- Arjan P Palstra
- Animal Breeding and Genomics, Wageningen University & Research, 6700 AH Wageningen, The Netherlands
| | - Wout Abbink
- Animal Breeding and Genomics, Wageningen University & Research, 6700 AH Wageningen, The Netherlands
| | - Wisdom E K Agbeti
- Animal Breeding and Genomics, Wageningen University & Research, 6700 AH Wageningen, The Netherlands
| | - Leo Kruijt
- Animal Breeding and Genomics, Wageningen University & Research, 6700 AH Wageningen, The Netherlands
| | - Pauline Jéhannet
- Animal Breeding and Genomics, Wageningen University & Research, 6700 AH Wageningen, The Netherlands
| | - Martin J Lankheet
- Experimental Zoology Group, Wageningen University & Research, 6700 AH Wageningen, The Netherlands
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Jéhannet P, Palstra AP, Meijerhof M, Schipper H, Giménez IN, Dirks RP, Swinkels W, Heinsbroek LTN, Komen H. The induction of oocyte maturation and ovulation in the European eel ( Anguilla anguilla): in vitro and in vivo comparison of progesterone with 17α,20β-dihydroxy-4-pregnen-3-one. Front Physiol 2023; 14:1207542. [PMID: 37614755 PMCID: PMC10442833 DOI: 10.3389/fphys.2023.1207542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 07/13/2023] [Indexed: 08/25/2023] Open
Abstract
Ovulation in European eel is induced by injection of 17α,20β-dihydroxy-4-pregnen-3-one (DHP) as the maturation-inducing hormone (MIH). Female eels need to ovulate within 18 h after injection to release good quality eggs. Progesterone (P), as an upstream precursor of DHP, may promote endogenous DHP production and improve egg quality. The purpose of this study was therefore to compare treatment of P with DHP on batch level, in vitro, to determine dose-response effects, and in vivo, at a single dose. For the in vitro experiment, ovarian tissue was extracted and placed in culture plates containing hormone-free medium and media supplemented with the treatment: DHP at 1, 10 and 100 ng mL-1, or P at 10, 100 and 1,000 ng mL-1. At the start of incubation, the folliculated oocytes were sampled for histology, microscopy and qPCR. After incubation for 12 and 18 h, the oocytes were sampled for microscopy and qPCR analysis. For the in vivo experiment, females were either injected with DHP or P at a dose of 2 mg kg-1 to assess their effects on ovulation and reproductive success. At the moment of release, eggs were sampled for RNA sequencing to compare effects of DHP and P on the expression of genes involved in egg quality aspects. Remaining eggs were fertilized and larval viability was recorded. Both DHP and P were able to induce GVBD (DHP at 10 and 100 ng mL-1, P at 100 and 1,000 ng mL-1) in vitro. Expression of genes involved in oocyte maturation and ovulation was similar in vitro for both DHP and P treatments. Regarding the in vivo results, RNAseq results reflected similar DHP and P effects on the expression of genes involved in egg quality aspects. Females injected with either DHP or P ovulated, released eggs, and were equally able to produce larvae without any differences in reproductive success. Our results support the conclusion that DHP and P work equally well in vitro and in vivo. P is more attractive to apply as the price is 3,000 times lower than the price of DHP.
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Affiliation(s)
- Pauline Jéhannet
- Animal Breeding and Genomics, Wageningen University & Research, Wageningen, Netherlands
| | - Arjan P. Palstra
- Animal Breeding and Genomics, Wageningen University & Research, Wageningen, Netherlands
| | - Miriam Meijerhof
- Animal Breeding and Genomics, Wageningen University & Research, Wageningen, Netherlands
| | - Henk Schipper
- Experimental Zoology, Wageningen University & Research, Wageningen, Netherlands
| | | | - Ron P. Dirks
- Future Genomics Technologies B.V., Leiden, Netherlands
| | | | | | - Hans Komen
- Animal Breeding and Genomics, Wageningen University & Research, Wageningen, Netherlands
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Palstra AP, Bouwman LJ, Jéhannet P, Kruijt L, Schipper H, Blokland MH, Swinkels W, Heinsbroek LTN, Lokman PM. Steroid implants for the induction of vitellogenesis in feminized European silver eels (Anguilla anguilla L.). Front Genet 2022; 13:969202. [PMID: 36061169 PMCID: PMC9428156 DOI: 10.3389/fgene.2022.969202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 07/07/2022] [Indexed: 11/13/2022] Open
Abstract
Assisted propagation of the European eel will lead to a closed production cycle supplying the aquaculture industry with juvenile glass eels. Females require long-term weekly treatment with pituitary extract (PE), which is stressful and causes abnormalities in oogenesis. We tested the effects of 17α-methyltestosterone (17 MT), as potent androgen activating the androgen receptor, and 17β-estradiol (E2), as an inducer of vitellogenesis, to shorten the duration of PE treatment.Four groups of feminized eels were subjected to a simulated migration and subsequent injection with implants containing 17 MT (17 MT-group), E2 (E2-group) or 17 MT plus E2 (17 MT + E2-group) to test for synergistic effects, or without any steroids as controls (C-group). The effects of a 2-months treatment were investigated by determining the eye index (EI), hepatosomatic and gonadosomatic index (HSI and GSI, respectively), plasma steroid concentrations by liquid chromatography mass spectrometry (LCMS), gonadal histology, expression of androgen receptors a and b (ara, arb); estrogen receptor 1 (esr1); FSH receptor (fshr); vitellogenin receptor (vtgr) and aromatase (cyp19), and the required number of weekly PE injections to fully mature. For many parameters, both the 17 MT and E2 groups showed an increase vs. controls, with the 17 MT + E2 group showing a synergistic effect, as seen for EI, GSI (3.4 for 17 MT and for E2, 6.6 for 17 MT + E2), oocyte diameter and ara, arb and esr1 expression. Concentrations of almost all focal steroids decreased with simulated migration and steroid treatment. Only eels of the 17 MT-group showed increased expression of cyp19 and of fshr, while fshr expression increased 44-fold in the 17 MT + E2 group, highlighting that co-implantation is most effective in raising fshr mRNA levels. Specific for eels of the E2 groups were vitellogenesis-associated changes such as an increase of HSI, plasma E2, and presence of yolk in the oocytes. Steroid treatments reduced the duration of PE treatment, again synergistically for co-implantation. In conclusion, E2 is necessary to start vitellogenesis, but 17 MT has specific effects on cyp19 and fshr expression. The combination is necessary for synergistic effects and as such, steroid implants could be applied in assisted reproduction protocols for European eel to improve oocyte quality leading to the production of more vital larvae.
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Affiliation(s)
- Arjan P. Palstra
- Animal Breeding and Genomics, Wageningen University and Research, Wageningen, Netherlands
- *Correspondence: Arjan P. Palstra,
| | - Lotte J. Bouwman
- Animal Breeding and Genomics, Wageningen University and Research, Wageningen, Netherlands
| | - Pauline Jéhannet
- Animal Breeding and Genomics, Wageningen University and Research, Wageningen, Netherlands
| | - Leo Kruijt
- Animal Breeding and Genomics, Wageningen University and Research, Wageningen, Netherlands
| | - Henk Schipper
- Experimental Zoology Group, Wageningen University and Research, Wageningen, Netherlands
| | - Marco H. Blokland
- Wageningen Food Safety Research, Wageningen University and Research, Wageningen, Netherlands
| | | | - Leon T. N. Heinsbroek
- Animal Breeding and Genomics, Wageningen University and Research, Wageningen, Netherlands
- Wageningen Eel Reproduction Experts B.V, Wageningen, Netherlands
| | - P. Mark Lokman
- Department of Zoology, University of Otago, Dunedin, New Zealand
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Arechavala-Lopez P, Lankheet MJ, Díaz-Gil C, Abbink W, Palstra AP. Swimming Activity of Gilthead Seabream (Sparus aurata) in Swim-Tunnels: Accelerations, Oxygen Consumption and Body Motion. Front Anim Sci 2021. [DOI: 10.3389/fanim.2021.679848] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Acoustic transmitters equipped with accelerometer sensors are considered a useful tool to study swimming activity, including energetics and movement patterns, of fish species in aquaculture and in nature. However, given the novelty of this technique, further laboratory-derived calibrations are needed to assess the characteristics and settings of accelerometer acoustic transmitters for different species and specific environmental conditions. In this study, we compared accelerometer acoustic transmitter outputs with swimming performance and body motion of gilthead seabream (Sparus aurata L.) in swim-tunnels at different flow speeds, which allowed us to characterize the swimming activity of this fish species of high aquaculture interest. Tag implantation in the abdominal cavity had no significant effects on swimming performance and body motion parameters. Accelerations, cost of transport and variations on head orientation (angle with respect to flow direction) were negatively related to flow speed in the tunnel, whereas oxygen consumption and frequencies of tail-beat and head movements increased with flow speed. These results show that accelerometer acoustic transmitters mainly recorded deviations from sustained swimming in the tunnel, due to spontaneous and explorative swimming at the lowest speeds or intermittent burst and coast actions to cope with water flow. In conclusion, accelerometer acoustic transmitters applied in this study provided a proxy for unsustained swimming activity, but did not contemplate the high-energy cost spent by gilthead seabream on sustained swimming, and therefore, it did not provide a proxy for general activity. Despite this limitation, accelerometer acoustic transmitters provide valuable insight in swim patterns and therefore may be a good strategy for advancing our understanding of fish swimming behavior in aquaculture, allowing for rapid detection of changes in species-specific behavioral patterns considered indicators of fish welfare status, and assisting in the refinement of best management practices.
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Jéhannet P, Palstra AP, Heinsbroek LTN, Kruijt L, Dirks RP, Swinkels W, Komen H. What Goes Wrong during Early Development of Artificially Reproduced European Eel Anguilla anguilla? Clues from the Larval Transcriptome and Gene Expression Patterns. Animals (Basel) 2021; 11:ani11061710. [PMID: 34201077 PMCID: PMC8227761 DOI: 10.3390/ani11061710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/23/2021] [Accepted: 06/03/2021] [Indexed: 12/21/2022] Open
Abstract
Simple Summary Closing the life cycle of the European eel in captivity is urgently needed to gain perspective for the commercial production of juvenile glass eels. Larvae are produced weekly at our facilities, but large variations in larval mortality are observed during the first week after hatching. Although much effort has been devoted to investigating ways to prevent early larval mortality, it remains unclear what the causes are. The aim of this study was to perform a transcriptomic study on European eel larvae in order to identify genes and physiological pathways that are differentially regulated in the comparison of larvae from batches that did not survive for longer than three days vs. larvae from batches that survived for at least a week up to 22 days after hatching (non-viable vs. viable larvae). In contrast to earlier published studies on European eel, we conclude that larvae exhibit immune competency. Non-viable larvae initiated an inflammatory and host protection immune response and tried to maintain osmoregulatory homeostasis. As a perspective, microbial control and salinity reduction might benefit eel larvae in terms of lower mortality and improved development by lowering the costs of immune functioning and osmoregulation. Abstract In eels, large variations in larval mortality exist, which would impede the viable production of juvenile glass eels in captivity. The transcriptome of European eel larvae was investigated to identify physiological pathways and genes that show differential regulation between non-viable vs. viable larvae. Expression of genes involved in inflammation and host protection was higher, suggesting that non-viable larvae suffered from microbial infection. Expression of genes involved in osmoregulation was also higher, implying that non-viable larvae tried to maintain homeostasis by strong osmoregulatory adaptation. Expression of genes involved in myogenesis, neural, and sensory development was reduced in the non-viable larvae. Expression of the major histocompatibility complex class-I (mhc1) gene, M-protein (myom2), the dopamine 2B receptor (d2br), the melatonin receptor (mtr1), and heat-shock protein beta-1 (hspb1) showed strong differential regulation and was therefore studied in 1, 8, and 15 days post-hatch (dph) larvae by RT-PCR to comprehend the roles of these genes during ontogeny. Expression patterning of these genes indicated the start of active swimming (8 dph) and feed searching behavior (15 dph) and confirmed immunocompetence immediately after hatching. This study revealed useful insights for improving larval survival by microbial control and salinity reduction.
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Affiliation(s)
- Pauline Jéhannet
- Animal Breeding and Genomics, Wageningen University & Research, 6708 PB Wageningen, The Netherlands; (P.J.); (L.K.); (H.K.)
| | - Arjan P. Palstra
- Animal Breeding and Genomics, Wageningen University & Research, 6708 PB Wageningen, The Netherlands; (P.J.); (L.K.); (H.K.)
- Correspondence:
| | | | - Leo Kruijt
- Animal Breeding and Genomics, Wageningen University & Research, 6708 PB Wageningen, The Netherlands; (P.J.); (L.K.); (H.K.)
| | - Ron P. Dirks
- Future Genomics Technologies B.V., 2333 BE Leiden, The Netherlands;
| | | | - Hans Komen
- Animal Breeding and Genomics, Wageningen University & Research, 6708 PB Wageningen, The Netherlands; (P.J.); (L.K.); (H.K.)
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Palstra AP, Roque A, Kruijt L, Jéhannet P, Pérez-Sánchez J, Dirks RP. Physiological Effects of Water Flow Induced Swimming Exercise in Seabream Sparus aurata. Front Physiol 2020; 11:610049. [PMID: 33364981 PMCID: PMC7750471 DOI: 10.3389/fphys.2020.610049] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 11/17/2020] [Indexed: 11/25/2022] Open
Abstract
A longer on-land rearing period of Gilthead seabream Sparus aurata before transfer to sea-cages would allow the farmer to benefit from exercise-enhanced growth, resilience, and robustness as induced by increasing water flow in the tanks. In this study, the physiological effects of flow-conditioning were investigated by subjecting large groups of experimental fish to minimal flow or to flow regimes inducing swimming exercise at 1 or 2 body length (BL) s−1 for a period of 8 months (February–October) in 1,500 L tanks. Fish representing the three treatment groups were then used for: (1) a stress challenge netting test and plasma cortisol measurement (baseline, peaking, and recovery levels), (2) blood plasma measurements of glucose, triglycerides, lactate, cholesterol, growth hormone (GH), and insulin-like growth factor 1 (IGF1), and (3) heart and muscle gene expression of the GH and IGF1 receptors and the muscle transcriptome by deep RNA sequencing (RNAseq). Fish size after 8 months of flow conditioning was 92 ± 27 g body weight (BW) for fish under minimal flow, 106 ± 24 g BW (+15%) at 1 BL s−1, and 125 ± 27 g BW (+36%) at 2 BL s−1. Flow conditioning at 1 BL s−1 provided optimal conditions for growth and uniformity, but also stress (lowest baseline plasma cortisol), robustness (higher condition factor and larger hearts), and energy mobilization (increased plasma glucose). Although flow enhanced growth linearly with swimming speed, also the percentage of lordotic fish increased with exercise, particularly high for swimming at 2 BL s−1. The absence of important differences in plasma GH and IGF1, and expression levels of their receptors in heart and white skeletal muscle, indicated that other factors may be involved in growth enhancement. RNAseq of the white skeletal muscle showed upregulated expression of genes involved in muscle contraction, muscle development and its molecular regulation, and immune genes that may play a role in the muscle repair mechanism. An exercise regime of swimming at 1 BL s−1 can be considered as optimal for farming robust seabream although the increase of skeletal deformities should be avoided.
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Affiliation(s)
- Arjan P Palstra
- Wageningen University & Research Animal Breeding and Genomics, Wageningen Livestock Research, Wageningen, Netherlands
| | - Ana Roque
- IRTA-SCR, Sant Carles de la Rapita, Spain
| | - Leo Kruijt
- Wageningen University & Research Animal Breeding and Genomics, Wageningen Livestock Research, Wageningen, Netherlands
| | - Pauline Jéhannet
- Wageningen University & Research Animal Breeding and Genomics, Wageningen Livestock Research, Wageningen, Netherlands
| | - Jaume Pérez-Sánchez
- Nutrigenomics and Fish Growth Endocrinology Group, Institute of Aquaculture Torre de la Sal (CSIC), Castellon, Spain
| | - Ron P Dirks
- Future Genomics Technologies B.V., Leiden, Netherlands
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Palstra AP, Kals J, Böhm T, Bastiaansen JWM, Komen H. Swimming Performance and Oxygen Consumption as Non-lethal Indicators of Production Traits in Atlantic Salmon and Gilthead Seabream. Front Physiol 2020; 11:759. [PMID: 32733272 PMCID: PMC7358457 DOI: 10.3389/fphys.2020.00759] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 06/11/2020] [Indexed: 11/13/2022] Open
Abstract
The aim of this study was to investigate swimming performance and oxygen consumption as non-lethal indicator traits of production parameters in Atlantic salmon Salmo salar L. and Gilthead seabream Sparus aurata L. A total of 34 individual fish of each species were subjected to a series of experiments: (1) a critical swimming speed (Ucrit) test in a swim-gutter, followed by (2) two starvation-refeeding periods of 42 days, and (3) swimming performance experiments coupled to respirometry in swim-tunnels. Ucrit was assessed first to test it as a predictor trait. Starvation-refeeding traits included body weight; feed conversion ratio based on dry matter; residual feed intake; average daily weight gain and loss. Swim-tunnel respirometry provided oxygen consumption in rest and while swimming at the different speeds, optimal swim speed and minimal cost of transport (COT). After experiments, fish were dissected and measured for tissue weights and body composition in terms of dry matter, ash, fat, protein and moist, and energy content. The Ucrit test design was able to provide individual Ucrit values in high throughput manner. The residual Ucrit (RUcrit) should be considered in order to remove the size dependency of swimming performance. Most importantly, RUcrit predicted filet yield in both species. The minimal COT, the oxygen consumption when swimming at Uopt, added predictive value to the seabream model for feed intake.
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Affiliation(s)
- Arjan P Palstra
- Wageningen University & Research Animal Breeding and Genomics, Wageningen Livestock Research, Wageningen, Netherlands.,Wageningen Marine Research, Wageningen University & Research, Yerseke, Netherlands
| | - Jeroen Kals
- Wageningen Marine Research, Wageningen University & Research, Yerseke, Netherlands.,Wageningen University & Research Animal Nutrition, Wageningen Livestock Research, Wageningen, Netherlands
| | - Thijs Böhm
- Wageningen Marine Research, Wageningen University & Research, Yerseke, Netherlands
| | - John W M Bastiaansen
- Wageningen University & Research Animal Breeding and Genomics, Wageningen Livestock Research, Wageningen, Netherlands
| | - Hans Komen
- Wageningen University & Research Animal Breeding and Genomics, Wageningen Livestock Research, Wageningen, Netherlands
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Mes D, Palstra AP, Henkel CV, Mayer I, Vindas MA. Swimming exercise enhances brain plasticity in fish. R Soc Open Sci 2020; 7:191640. [PMID: 32218982 PMCID: PMC7029906 DOI: 10.1098/rsos.191640] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 12/04/2019] [Indexed: 06/10/2023]
Abstract
It is well-established that sustained exercise training can enhance brain plasticity and boost cognitive performance in mammals, but this phenomenon has not received much attention in fish. The aim of this study was to determine whether sustained swimming exercise can enhance brain plasticity in juvenile Atlantic salmon. Brain plasticity was assessed by both mapping the whole telencephalon transcriptome and conducting telencephalic region-specific microdissections on target genes. We found that 1772 transcripts were differentially expressed between the exercise and control groups. Gene ontology (GO) analysis identified 195 and 272 GO categories with a significant overrepresentation of up- or downregulated transcripts, respectively. A multitude of these GO categories was associated with neuronal excitability, neuronal signalling, cell proliferation and neurite outgrowth (i.e. cognition-related neuronal markers). Additionally, we found an increase in proliferating cell nuclear antigen (pcna) after both three and eight weeks of exercise in the equivalent to the hippocampus in fish. Furthermore, the expression of the neural plasticity markers synaptotagmin (syt) and brain-derived neurotrophic factor (bdnf) were also increased due to exercise in the equivalent to the lateral septum in fish. In conclusion, this is the first time that swimming exercise has been directly linked to increased telencephalic neurogenesis and neural plasticity in a teleost, and our results pave the way for future studies on exercise-induced neuroplasticity in fish.
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Affiliation(s)
- Daan Mes
- Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, Oslo, Norway
| | - Arjan P. Palstra
- Wageningen University and Research Animal Breeding and Genomics, Wageningen Livestock Research, Wageningen, The Netherlands
| | - Christiaan V. Henkel
- Department of Basic Sciences and Aquatic Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Ian Mayer
- Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, Oslo, Norway
| | - Marco A. Vindas
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
- Uni Environment, Uni Research AS, Bergen, Norway
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Jéhannet P, Kruijt L, Damsteegt EL, Swinkels W, Heinsbroek LTN, Lokman PM, Palstra AP. A mechanistic model for studying the initiation of anguillid vitellogenesis by comparing the European eel (Anguilla anguilla) and the shortfinned eel (A. australis). Gen Comp Endocrinol 2019; 279:129-138. [PMID: 30796898 DOI: 10.1016/j.ygcen.2019.02.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 02/19/2019] [Accepted: 02/19/2019] [Indexed: 12/20/2022]
Abstract
An inverse relation exists between the maturation stage at the start of the oceanic reproductive migration and the migration distance to the spawning grounds for the various eel species. The European eel Anguilla anguilla migrates up to 5-6000 km and leaves in a previtellogenic state. The shortfinned eel A. australis migrates 2-4000 km and leaves in an early vitellogenic state. In this study, we compared the early pubertal events in European silver eels with those in silver shortfinned eels to gain insights into the initiation of vitellogenesis. Immediately after being caught, yellow and silver eels of both species were measured and sampled for blood and tissues. Eye index (EI), gonadosomatic index (GSI) and hepatosomatic index (HSI) were calculated. Plasma 11-ketotestosterone (11-KT) and 17β-estradiol (E2) levels were measured by radioimmunoassay. Pituitary, liver and ovaries were dissected for quantitative real-time PCR analyses (pituitary dopamine 2b receptor d2br, gonadotropin-releasing hormone receptors 1 and 2 gnrhr1 and gnrhr2, growth hormone gh and follicle-stimulating hormone-β fshb; liver estrogen receptor 1 esr1; gonad follicle-stimulating hormone receptor fshr, androgen receptors α and β ara and arb, vitellogenin receptor vtgr and P450 aromatase cyp19). Silver eels of both species showed a drop in pituitary gh expression, progressing gonadal development (GSI of ∼1.5 in European eels and ∼3.0 in shortfinned eels) and steroid level increases. In shortfinned eels, but not European eels, expression of fshb, gnrhr1 and gnrhr2, and d2br in the pituitary was up-regulated in the silver-stage as compared to yellow-stage females, as was expression of fshr, ara and arb in the ovaries. Expression of esr1 in European eels remained low while esr1 expression was up-regulated over 100-fold in silver shortfinned eels. The mechanistic model for anguillid vitellogenesis that we present suggests a first step that involves a drop in Gh and a second step that involves Fsh increase when switching in the life history trade-off from growth to reproduction. The drop in Gh is associated with gonadal development and plasma steroid increase but precedes brain-pituitary-gonad axis (BPG) activation. The Fsh increase marks BPG activation and increased sensitivity of the liver to estrogenic stimulation, but also an increase in D2br-mediated dopaminergic signaling to the pituitary.
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Affiliation(s)
- P Jéhannet
- Wageningen University & Research Animal Breeding and Genomics, Wageningen Livestock Research, PO Box 338, 6700 AH Wageningen, The Netherlands
| | - L Kruijt
- Wageningen University & Research Animal Breeding and Genomics, Wageningen Livestock Research, PO Box 338, 6700 AH Wageningen, The Netherlands
| | - E L Damsteegt
- Department of Zoology, University of Otago, 340 Great King Street, PO Box 56, Dunedin 9054, New Zealand
| | - W Swinkels
- DUPAN Foundation, Bronland 12-D, 6700 AE Wageningen, The Netherlands
| | - L T N Heinsbroek
- Wageningen University & Research Animal Breeding and Genomics, Wageningen Livestock Research, PO Box 338, 6700 AH Wageningen, The Netherlands; Wageningen Eel Reproduction Experts B.V., Mennonietenweg 13, 6702 AB Wageningen, The Netherlands
| | - P M Lokman
- Department of Zoology, University of Otago, 340 Great King Street, PO Box 56, Dunedin 9054, New Zealand
| | - A P Palstra
- Wageningen University & Research Animal Breeding and Genomics, Wageningen Livestock Research, PO Box 338, 6700 AH Wageningen, The Netherlands.
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Jansen HJ, Liem M, Jong-Raadsen SA, Dufour S, Weltzien FA, Swinkels W, Koelewijn A, Palstra AP, Pelster B, Spaink HP, van den Thillart GE, Dirks RP, Henkel CV. Author Correction: Rapid de novo assembly of the European eel genome from nanopore sequencing reads. Sci Rep 2019; 9:7911. [PMID: 31114003 PMCID: PMC6529464 DOI: 10.1038/s41598-019-44275-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
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Affiliation(s)
| | - Michael Liem
- Institute of Biology, Leiden University, Leiden, The Netherlands
| | | | - Sylvie Dufour
- Muséum National d'Histoire Naturelle, Sorbonne Universités, Research Unit BOREA, Biology of Aquatic Organisms and Ecosystems, CNRS, IRD, UCN, UA, Paris, France
| | - Finn-Arne Weltzien
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Department of Basic Science and Aquatic Medicine, Oslo, Norway
| | | | | | - Arjan P Palstra
- Animal Breeding and Genomics Centre, Wageningen Livestock Research, Wageningen University & Research, Wageningen, The Netherlands
| | - Bernd Pelster
- Institute of Zoology and Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Herman P Spaink
- Institute of Biology, Leiden University, Leiden, The Netherlands
| | | | | | - Christiaan V Henkel
- Institute of Biology, Leiden University, Leiden, The Netherlands. .,University of Applied Sciences Leiden, Leiden, The Netherlands. .,Generade Centre of Expertise in Genomics, Leiden, The Netherlands.
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12
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Palstra AP, Mendez S, Dirks RP, Schaaf MJM. Cortisol Acting Through the Glucocorticoid Receptor Is Not Involved in Exercise-Enhanced Growth, But Does Affect the White Skeletal Muscle Transcriptome in Zebrafish ( Danio rerio). Front Physiol 2019; 9:1889. [PMID: 30692930 PMCID: PMC6339955 DOI: 10.3389/fphys.2018.01889] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 12/12/2018] [Indexed: 11/13/2022] Open
Abstract
Forced sustained swimming exercise at optimal speed enhances growth in many fish species, particularly through hypertrophy of the white skeletal muscle. The exact mechanism of this effect has not been resolved yet. To explore the role of cortisol, we first subjected wild-type zebrafish to an exercise protocol validated for exercise-enhanced growth, and showed that exercised zebrafish, which indeed showed enhanced growth, had higher cortisol levels than the non-exercised controls. A central role was therefore hypothesized for the steroid hormone cortisol acting through the Glucocorticoid receptor (Gr). Second, we subjected wild-type zebrafish and zebrafish with a mutant Gr to exercise at optimal, suboptimal, and super-optimal speeds and compared them with non-exercised controls. Exercised zebrafish showed growth enhancement at all speeds, with highest growth at optimal speeds. In the Gr mutant fish, exercise resulted in growth enhancement similar to wild-type zebrafish, indicating that cortisol signaling through Gr cannot be considered as a main determinant of exercise-enhanced growth. Finally, the transcriptome of white skeletal muscle tissue was analyzed by RNA sequencing. The results of this analysis showed that in the muscle tissue of Gr mutant fish a lower number of genes is regulated by exercise than in wild-type fish (183 vs. 351). A cluster of 36 genes was regulated by exercise in both wild-type and mutant fish, and in this cluster genes involved in transcriptional regulation and protein ubiquitination were overrepresented. Because these two processes appear to be regulated in both wild type and mutant fish, which both display exercise-enhanced growth, we suggest that they play an important role in the growth of muscles upon exercise.
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Affiliation(s)
- Arjan P Palstra
- Wageningen Marine Research, Wageningen University and Research, Yerseke, Netherlands.,Wageningen University & Research Animal Breeding and Genomics, Wageningen Livestock Research, Wageningen, Netherlands.,Institute of Biology (IBL), Leiden University, Leiden, Netherlands
| | - Silvia Mendez
- Wageningen Marine Research, Wageningen University and Research, Yerseke, Netherlands.,Institute of Biology (IBL), Leiden University, Leiden, Netherlands
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13
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Kavouras M, Malandrakis EE, Golomazou E, Konstantinidis I, Blom E, Palstra AP, Anastassiadis K, Panagiotaki P, Exadactylos A. Hox gene expression profiles during embryonic development of common sole. ANIM BIOL 2019. [DOI: 10.1163/15707563-17000123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
Common sole (Solea solea) aquaculture production is based mostly on wild-caught breeders. Recently, the successful reproduction of first-generation fish that were reared in captivity was accomplished. A consistent good quality and quantity of produced eggs throughout the year, and of next-generation broodstock, is important for reducing the overall cost of production. Hox genes play a pivotal role in normal embryonic development and alterations of their temporal expression level may be important for egg viability. Expression profile analysis of five hox genes (hoxa1a, hoxa2a, hoxa2b, hoxb1a and hoxb1b) involved in early embryonic development and of hoxa13a, which is involved in late stages, was carried out. Results revealed a premature and/or maternal expression of hoxa13a in sole embryos, and the detection of hoxa2a and hoxa2b genes as members of paralog group 2. Principal Component Analysis of hox gene expression in 54 ± 6 hours post fertilization embryos coming from wild-caught broodstock and a first-generation one reared in the hatchery, unveiled that these broodstocks are clearly distinct. In addition, their pairwise comparison revealed significant differences in the expression levels of hoxb1a and hoxb1b genes. Hox gene regulation during embryonic development could give valuable insight into rearing sole broodstocks with different origin in concert, and also into gaining a steady mass production of eggs, either in quality or quantity, all year round.
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Affiliation(s)
- Menelaos Kavouras
- 1Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fytokou Str., Volos, Greece
| | - Emmanouil E. Malandrakis
- 1Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fytokou Str., Volos, Greece
| | - Eleni Golomazou
- 1Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fytokou Str., Volos, Greece
| | - Ioannis Konstantinidis
- 1Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fytokou Str., Volos, Greece
| | - Ewout Blom
- 2Wageningen Marine Research, Wageningen University & Research, IJmuiden, The Netherlands
| | - Arjan P. Palstra
- 3Wageningen University & Research, Animal Breeding and Genomics, Wageningen Livestock Research, Wageningen, The Netherlands
| | | | - Panagiota Panagiotaki
- 1Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fytokou Str., Volos, Greece
| | - Athanasios Exadactylos
- 1Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fytokou Str., Volos, Greece
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Palstra AP, Kals J, Blanco Garcia A, Dirks RP, Poelman M. Immunomodulatory Effects of Dietary Seaweeds in LPS Challenged Atlantic Salmon Salmo salar as Determined by Deep RNA Sequencing of the Head Kidney Transcriptome. Front Physiol 2018; 9:625. [PMID: 29910738 PMCID: PMC5992350 DOI: 10.3389/fphys.2018.00625] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 05/09/2018] [Indexed: 02/03/2023] Open
Abstract
Seaweeds may represent immuno-stimulants that could be used as health-promoting fish feed components. This study was performed to gain insights into the immunomodulatory effects of dietary seaweeds in Atlantic salmon. Specifically tested were 10% inclusion levels of Laminaria digitata (SW1) and a commercial blend of seaweeds (Oceanfeed®) (SW2) against a fishmeal based control diet (FMC). Differences between groups were assessed in growth, feed conversion ratio and blood parameters hematocrit and hemoglobin. After a LPS challenge of fish representing each of the three groups, RNAseq was performed on the head kidney as major immune organ to determine transcriptomic differences in response to the immune activation. Atlantic salmon fed with dietary seaweeds did not show major differences in performance in comparison with fishmeal fed fish. RNAseq resulted in ∼154 million reads which were mapped against a NCBI Salmo salar reference and against a de novo assembled S. salar reference for analyses of expression of immune genes and ontology of immune processes among the 87,600 cDNA contigs. The dietary seaweeds provoked a more efficient immune response which involved more efficient identification of the infection site, and processing and presentation of antigens. More specifically, chemotaxis and the chemokine-mediated signaling were improved and therewith the defense response to Gram-positive bacterium reduced. Specific Laminaria digitata effects included reduction of the interferon-gamma-mediated signaling. Highly upregulated and specific for this diet was the expression of major histocompatibility complex class I-related gene protein. The commercial blend of seaweeds caused more differential expression than Laminaria digitata and improved immune processes such as receptor-mediated endocytosis and cell adhesion, and increased the expression of genes involved in response to lipopolysaccharide and inflammatory response. Particularly, expression of many important immune receptors was up-regulated illustrating increased responsiveness. NF-kappa-B inhibitor alpha is an important gene that marked the difference between both seaweed diets as Laminaria digitata inhibits the expression for this cytokine while the blend of seaweeds stimulates it. It can be concluded that the inclusion of seaweeds such as Laminaria digitata can have important modulatory effects on the immune capacity of Atlantic salmon resulting in a more efficient immune response.
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Affiliation(s)
- Arjan P Palstra
- Wageningen Marine Research, Wageningen University & Research, Yerseke, Netherlands.,Department of Animal Breeding and Genomics, Wageningen Livestock Research, Wageningen University & Research, Wageningen, Netherlands
| | - Jeroen Kals
- Wageningen Marine Research, Wageningen University & Research, Yerseke, Netherlands.,Department of Animal Nutrition, Wageningen Livestock Research, Wageningen University & Research, Wageningen, Netherlands
| | - Ainhoa Blanco Garcia
- Wageningen Marine Research, Wageningen University & Research, Yerseke, Netherlands
| | | | - Marnix Poelman
- Wageningen Marine Research, Wageningen University & Research, Yerseke, Netherlands
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15
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Graziano M, Benito R, Planas JV, Palstra AP. Swimming exercise to control precocious maturation in male seabass (Dicentrarchus labrax). BMC Dev Biol 2018; 18:10. [PMID: 29649968 PMCID: PMC5897932 DOI: 10.1186/s12861-018-0170-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 04/08/2018] [Indexed: 01/19/2023]
Abstract
Background Male European seabass, already predominant (~ 70%) in cultured stocks, show a high incidence (20–30%) of precocious sexual maturation under current aquaculture practices, leading to important economic losses for the industry. In view of the known modulation of reproductive development by swimming exercise in other teleost species, we aimed at investigating the effects of sustained swimming on reproductive development in seabass males during the first year of life in order to determine if swimming could potentially reduce precocious sexual maturation. Methods Pre-pubertal seabass (3.91 ± 0.22 g of body weight (BW)) were subjected to a 10 week swimming regime at their optimal swimming speed (Uopt) in an oval-shaped Brett-type flume or kept at rest during this period. Using Blazka-type swim tunnels, Uopt was determined three times during the course of the experiment: 0.66 m s− 1 at 19 ± 1 g BW, 10.2 ± 0.2 cm of standard length (SL) (week 1); 0.69 m s− 1 at 38 ± 3 g BW, 12.7 ± 0.3 cm SL (week 5), and also 0.69 m s− 1 at 77 ± 7 g BW, 15.7 ± 0.5 cm SL (week 9). Every 2 weeks, size and gonadal weight were monitored in the exercised (N = 15) and non-exercised fish (N = 15). After 10 weeks, exercised and non-exercised males were sampled to determine plasma 11-ketotestosterone levels, testicular mRNA expression levels of genes involved in steroidogenesis and gametogenesis by qPCR, as well as the relative abundance of germ cells representing the different spermatogenic stages by histological examination. Results Our results indicate that sustained swimming exercise at Uopt delays testicular development in male European seabass as evidenced by decreased gonado-somatic index, slower progression of testicular development and by reduced mRNA expression levels of follicle stimulating hormone receptor (fshR), 3-beta-hydroxysteroid dehydrogenase (3βhsd), 11-beta hydroxysteroid dehydrogenase (11βhsd), estrogen receptor-beta (erβ2), anti-mullerian hormone (amh), structural maintenance of chromosomes protein 1B (smc1β), inhibin beta A (inhba) and gonado-somal derived factor 1 (gsdf1) in exercised males as compared with the non-exercised males. Conclusions Swimming exercise may represent a natural and non-invasive tool to reduce the incidence of sexually precocious males in seabass aquaculture.
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Affiliation(s)
- Marco Graziano
- Department of Physiology and Immunology, School of Biology, University of Barcelona, Diagonal 643, 08028, Barcelona, Spain.,Wageningen Marine Research, Wageningen University & Research, Korringaweg 5, 4401, NT, Yerseke, The Netherlands
| | - Raul Benito
- Department of Physiology and Immunology, School of Biology, University of Barcelona, Diagonal 643, 08028, Barcelona, Spain.,Wageningen Marine Research, Wageningen University & Research, Korringaweg 5, 4401, NT, Yerseke, The Netherlands
| | - Josep V Planas
- Department of Physiology and Immunology, School of Biology, University of Barcelona, Diagonal 643, 08028, Barcelona, Spain
| | - Arjan P Palstra
- Wageningen Marine Research, Wageningen University & Research, Korringaweg 5, 4401, NT, Yerseke, The Netherlands. .,Wageningen Livestock Research, Wageningen University & Research Animal Breeding and Genomics, PO Box 338, 6700, AH, Wageningen, The Netherlands.
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16
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Jansen HJ, Liem M, Jong-Raadsen SA, Dufour S, Weltzien FA, Swinkels W, Koelewijn A, Palstra AP, Pelster B, Spaink HP, Thillart GEVD, Dirks RP, Henkel CV. Rapid de novo assembly of the European eel genome from nanopore sequencing reads. Sci Rep 2017; 7:7213. [PMID: 28775309 PMCID: PMC5543108 DOI: 10.1038/s41598-017-07650-6] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 06/28/2017] [Indexed: 02/07/2023] Open
Abstract
We have sequenced the genome of the endangered European eel using the MinION by Oxford Nanopore, and assembled these data using a novel algorithm specifically designed for large eukaryotic genomes. For this 860 Mbp genome, the entire computational process takes two days on a single CPU. The resulting genome assembly significantly improves on a previous draft based on short reads only, both in terms of contiguity (N50 1.2 Mbp) and structural quality. This combination of affordable nanopore sequencing and light weight assembly promises to make high-quality genomic resources accessible for many non-model plants and animals.
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Affiliation(s)
| | - Michael Liem
- Institute of Biology, Leiden University, Leiden, The Netherlands
| | | | - Sylvie Dufour
- Muséum National d'Histoire Naturelle, Sorbonne Universités, Research Unit BOREA, Biology of Aquatic Organisms and Ecosystems, CNRS, IRD, UCN, UA, Paris, France
| | - Finn-Arne Weltzien
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Department of Basic Science and Aquatic Medicine, Oslo, Norway
| | | | | | - Arjan P Palstra
- Animal Breeding and Genomics Centre, Wageningen Livestock Research, Wageningen University & Research, Wageningen, The Netherlands
| | - Bernd Pelster
- Institute of Zoology and Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Herman P Spaink
- Institute of Biology, Leiden University, Leiden, The Netherlands
| | | | | | - Christiaan V Henkel
- Institute of Biology, Leiden University, Leiden, The Netherlands.
- University of Applied Sciences Leiden, Leiden, The Netherlands.
- Generade Centre of Expertise in Genomics, Leiden, The Netherlands.
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Jéhannet P, Heinsbroek LTN, Palstra AP. Ultrasonography to assist with timing of spawning in European eel. Theriogenology 2017; 101:73-80. [PMID: 28708518 DOI: 10.1016/j.theriogenology.2017.06.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 06/09/2017] [Accepted: 06/10/2017] [Indexed: 10/19/2022]
Abstract
Ovulation in the European eel can be induced by injection of DHP (17α,20β-dihydroxy-4-pregnen-3-one). The timing of injection is based on the developmental stage of the oocytes. The oocyte stage is determined by invasive biopsy or through external indicators of the oocyte hydration response: body weight index (BWI) and body girth index (BGI). However, in European eel, BWI and BGI are inaccurate indicators because the individual hydration response is highly variable. The aim of this study was to identify indicators of oocyte maturation non-invasively by applying ultrasonography. Ultrasound parameters that were determined were the body wall thickness; diameter of the cloaca opening; grey scale median (GSM) of the ovary, and diameters (vertical and horizontal) and surface area of ovary, liver and swim bladder. Data of farmed and wild eels were combined for correlation analyses and principal component analyses (PCA). Ovary and liver parameters were not correlated with the average oocyte stage. Body wall thickness was negatively correlated to the average oocyte stage but variability was high. The swim bladder vertical diameter (Sbv) was negatively correlated with the average oocyte stage and with the oocyte diameter. Swim bladder area (Sba) was also negatively correlated to the average oocyte stage but less accurate. Results showed that during the final stages of oocyte maturation, the swim bladder becomes smaller. This is most probably due to the pressure that is caused by the increasing ovaries as a result of the oocyte hydration response. Females with an average oocyte stage between 4.5 and 7.0 and an average oocyte diameter higher than 800 μm, had Sbv values decreasing from 4.3 to 2.4 mm and Sba values from 52 down to 11 mm2. The correlation between Sbv and oocyte stage is more strict than for BWI or BGI which makes Sbv not only a parameter that can be determined non-invasively but also one that is more accurate in indicating the oocyte developmental stage. Therefore, ultrasonography, and in particular the ultrasound imaging of the swim bladder, represents a useful tool to assist with the timing of spawning as induced by injection of DHP.
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Affiliation(s)
- Pauline Jéhannet
- Wageningen University & Research Animal Breeding and Genomics, Wageningen Livestock Research, PO Box 338, 6700 AH Wageningen, The Netherlands
| | - Leon T N Heinsbroek
- Aquaculture and Fisheries Group, Wageningen University & Research, PO Box 338, 6700 AH Wageningen, The Netherlands
| | - Arjan P Palstra
- Wageningen University & Research Animal Breeding and Genomics, Wageningen Livestock Research, PO Box 338, 6700 AH Wageningen, The Netherlands.
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18
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Affiliation(s)
- Josep V Planas
- Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona Barcelona, Spain
| | - Arjan P Palstra
- Animal Breeding and Genomics Centre, Wageningen Livestock Research, Wageningen University and Research Wageningen, Netherlands
| | - Leonardo J Magnoni
- Centro Interdisciplinar de Investigacoes Marinhas e Medioambientales Porto, Portugal
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Palstra AP, Fukaya K, Chiba H, Dirks RP, Planas JV, Ueda H. The Olfactory Transcriptome and Progression of Sexual Maturation in Homing Chum Salmon Oncorhynchus keta. PLoS One 2015; 10:e0137404. [PMID: 26397372 PMCID: PMC4580453 DOI: 10.1371/journal.pone.0137404] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 08/17/2015] [Indexed: 11/19/2022] Open
Abstract
Reproductive homing migration of salmonids requires accurate interaction between the reception of external olfactory cues for navigation to the spawning grounds and the regulation of sexual maturation processes. This study aimed at providing insights into the hypothesized functional link between olfactory sensing of the spawning ground and final sexual maturation. We have therefore assessed the presence and expression levels of olfactory genes by RNA sequencing (RNAseq) of the olfactory rosettes in homing chum salmon Oncorhynchus keta Walbaum from the coastal sea to 75 km upstream the rivers at the pre-spawning ground. The progression of sexual maturation along the brain-pituitary-gonadal axis was assessed through determination of plasma steroid levels by time-resolved fluoroimmunoassays (TR-FIA), pituitary gonadotropin subunit expression and salmon gonadotropin-releasing hormone (sgnrh) expression in the brain by quantitative real-time PCR. RNAseq revealed the expression of 75 known and 27 unknown salmonid olfactory genes of which 13 genes were differentially expressed between fish from the pre-spawning area and from the coastal area, suggesting an important role of these genes in homing. A clear progression towards final maturation was characterised by higher plasma 17α,20β-dihydroxy-4-pregnen-3-one (DHP) levels, increased pituitary luteinizing hormone β subunit (lhβ) expression and sgnrh expression in the post brain, and lower plasma testosterone (T) and 17β-estradiol (E2) levels. Olfactomedins and ependymin are candidates among the differentially expressed genes that may connect olfactory reception to the expression of sgnrh to regulate final maturation.
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Affiliation(s)
- Arjan P. Palstra
- Institute for Marine Resources and Ecosystem Studies (IMARES), Wageningen University and Research Centre, Korringaweg 5, 4401 NT Yerseke, The Netherlands
- Animal Breeding and Genomics Centre, Wageningen UR Livestock Research, PO Box 338, 6700 AH Wageningen, The Netherlands
- * E-mail:
| | - Kosuke Fukaya
- Laboratory of Aquatic Bioresources and Ecosystem, Section of Ecosystem Conservation, Field Science Center for Northern Biosphere, Hokkaido University, Sapporo, 060-0809 Hokkaido, Japan
| | - Hiroaki Chiba
- School of Marine Biosciences, Kitasato University, Kitasato 1-15-1, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan
| | - Ron P. Dirks
- ZF-screens BV, J.H. Oortweg 19, 2333 CH Leiden, The Netherlands
| | - Josep V. Planas
- Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona and Institut de Biomedicina de la Universitat de Barcelona (IBUB), Barcelona, Spain
| | - Hiroshi Ueda
- Laboratory of Aquatic Bioresources and Ecosystem, Section of Ecosystem Conservation, Field Science Center for Northern Biosphere, Hokkaido University, Sapporo, 060-0809 Hokkaido, Japan
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20
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Palstra AP, Blok MC, Kals J, Blom E, Tuinhof-Koelma N, Dirks RP, Forlenza M, Blonk RJW. In- and outdoor reproduction of first generation common sole Solea solea under a natural photothermal regime: Temporal progression of sexual maturation assessed by monitoring plasma steroids and gonadotropin mRNA expression. Gen Comp Endocrinol 2015; 221:183-92. [PMID: 25583580 DOI: 10.1016/j.ygcen.2014.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 12/01/2014] [Accepted: 12/12/2014] [Indexed: 11/22/2022]
Abstract
Reproduction of many temperate fishes is seasonal and maturation and spawning of gametes are under photothermal control. Reproductive success of first generation (G1) common sole Solea solea in captivity has been low. In this study, the sexual maturation status has been assessed during the prespawning months in G1 sole that were housed (a) outdoor under the natural photoperiod and temperature, or (b) indoor under artificial photothermal induction. Maturation was assessed in male and female G1 broodstock in November as controls, after which the remaining population was divided over two outdoor flow-through tanks placed in a pond and two indoor recirculating aquaculture system (RAS) tanks. Subsequently, maturation status (gonadosomatic index GSI and plasma levels of testosterone T and 17β-estradiol E2) was assessed in one tank for each condition in January, February and during spawning in early April, while fish in the other tank were not disturbed in achieving reproductive success. Quantitative real-time PCR was performed to determine species-specific gonadotropin mRNA expression in females. Successful G1 spawning and egg fertilisation occurred in all experimental tanks. Gonadal development was similar under both conditions. Higher E2 and T levels were found in indoor housed females. Gonadotropin expression revealed similar profiles between outdoor and indoor housed females. G1 sole could be reproduced in the outdoor tanks under the natural photoperiod and in the indoor tanks under artificial simulation of this regime that includes a potentially crucial chilling period of 2-3 months at 5-7 °C.
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Affiliation(s)
- A P Palstra
- Institute for Marine Resources and Ecosystem Studies (IMARES), Wageningen Aquaculture, Wageningen University and Research Centre, Korringaweg 5, 4401 NT Yerseke, The Netherlands(1).
| | - M C Blok
- Institute for Marine Resources and Ecosystem Studies (IMARES), Wageningen Aquaculture, Wageningen University and Research Centre, Korringaweg 5, 4401 NT Yerseke, The Netherlands(1)
| | - J Kals
- Institute for Marine Resources and Ecosystem Studies (IMARES), Wageningen Aquaculture, Wageningen University and Research Centre, Korringaweg 5, 4401 NT Yerseke, The Netherlands(1)
| | - E Blom
- Institute for Marine Resources and Ecosystem Studies (IMARES), Wageningen Aquaculture, Wageningen University and Research Centre, Korringaweg 5, 4401 NT Yerseke, The Netherlands(1)
| | | | - R P Dirks
- NewCatch BV, J.H. Oortweg 19, 2333 CH Leiden, The Netherlands
| | - M Forlenza
- Cell Biology and Immunology Group, Wageningen University, De Elst 1, 6708 WD Wageningen, The Netherlands
| | - R J W Blonk
- Institute for Marine Resources and Ecosystem Studies (IMARES), Wageningen Aquaculture, Wageningen University and Research Centre, Korringaweg 5, 4401 NT Yerseke, The Netherlands(1)
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Rurangwa E, Sipkema D, Kals J, Ter Veld M, Forlenza M, Bacanu GM, Smidt H, Palstra AP. Impact of a novel protein meal on the gastrointestinal microbiota and the host transcriptome of larval zebrafish Danio rerio. Front Physiol 2015; 6:133. [PMID: 25983694 PMCID: PMC4415425 DOI: 10.3389/fphys.2015.00133] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 04/14/2015] [Indexed: 01/06/2023] Open
Abstract
Larval zebrafish was subjected to a methodological exploration of the gastrointestinal microbiota and transcriptome. Assessed was the impact of two dietary inclusion levels of a novel protein meal (NPM) of animal origin (ragworm Nereis virens) on the gastrointestinal tract (GIT). Microbial development was assessed over the first 21 days post egg fertilization (dpf) through 16S rRNA gene-based microbial composition profiling by pyrosequencing. Differentially expressed genes in the GIT were demonstrated at 21 dpf by whole transcriptome sequencing (mRNAseq). Larval zebrafish showed rapid temporal changes in microbial colonization but domination occurred by one to three bacterial species generally belonging to Proteobacteria and Firmicutes. The high iron content of NPM may have led to an increased relative abundance of bacteria that were related to potential pathogens and bacteria with an increased iron metabolism. Functional classification of the 328 differentially expressed genes indicated that the GIT of larvae fed at higher NPM level was more active in transmembrane ion transport and protein synthesis. mRNAseq analysis did not reveal a major activation of genes involved in the immune response or indicating differences in iron uptake and homeostasis in zebrafish fed at the high inclusion level of NPM.
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Affiliation(s)
- Eugene Rurangwa
- Institute for Marine Resources and Ecosystem Studies, Wageningen University and Research Centre Yerseke, Netherlands
| | - Detmer Sipkema
- Laboratory of Microbiology, Wageningen University Wageningen, Netherlands
| | - Jeroen Kals
- Institute for Marine Resources and Ecosystem Studies, Wageningen University and Research Centre Yerseke, Netherlands
| | - Menno Ter Veld
- Aquaculture and Fisheries Group, Wageningen University Wageningen, Netherlands
| | - Maria Forlenza
- Cell Biology and Immunology Group, Wageningen University Wageningen, Netherlands
| | - Gianina M Bacanu
- Laboratory of Microbiology, Wageningen University Wageningen, Netherlands
| | - Hauke Smidt
- Laboratory of Microbiology, Wageningen University Wageningen, Netherlands
| | - Arjan P Palstra
- Institute for Marine Resources and Ecosystem Studies, Wageningen University and Research Centre Yerseke, Netherlands
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22
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Palstra AP, Mes D, Kusters K, Roques JAC, Flik G, Kloet K, Blonk RJW. Forced sustained swimming exercise at optimal speed enhances growth of juvenile yellowtail kingfish (Seriola lalandi). Front Physiol 2015; 5:506. [PMID: 25620933 PMCID: PMC4287099 DOI: 10.3389/fphys.2014.00506] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 12/04/2014] [Indexed: 01/28/2023] Open
Abstract
Swimming exercise at optimal speed may optimize growth performance of yellowtail kingfish in a recirculating aquaculture system. Therefore, optimal swimming speeds (Uopt in m s−1 or body lengths s−1, BL s−1) were assessed and then applied to determine the effects of long-term forced and sustained swimming at Uopt on growth performance of juvenile yellowtail kingfish. Uopt was quantified in Blazka-type swim-tunnels for 145, 206, and 311 mm juveniles resulting in values of: (1) 0.70 m s−1 or 4.83 BL s−1, (2) 0.82 m s−1 or 3.25 BL s−1, and (3) 0.85 m s−1 or 2.73 BL s−1. Combined with literature data from larger fish, a relation of Uopt (BL s−1) = 234.07(BL)−0.779 (R2 = 0.9909) was established for this species. Yellowtail kingfish, either forced to perform sustained swimming exercise at an optimal speed of 2.46 BL s−1 (“swimmers”) or allowed to perform spontaneous activity at low water flow (“resters”) in a newly designed 3600 L oval flume (with flow created by an impeller driven by an electric motor), were then compared. At the start of the experiment, ten fish were sampled representing the initial condition. After 18 days, swimmers (n = 23) showed a 92% greater increase in BL and 46% greater increase in BW as compared to resters (n = 23). As both groups were fed equal rations, feed conversion ratio (FCR) for swimmers was 1.21 vs. 1.74 for resters. Doppler ultrasound imaging showed a statistically significant higher blood flow (31%) in the ventral aorta of swimmers vs. resters (44 ± 3 vs. 34 ± 3 mL min−1, respectively, under anesthesia). Thus, growth performance can be rapidly improved by optimal swimming, without larger feed investments.
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Affiliation(s)
- Arjan P Palstra
- Institute for Marine Resources and Ecosystem Studies, Wageningen Aquaculture†, Wageningen University and Research Centre Yerseke, Netherlands
| | - Daan Mes
- Institute for Marine Resources and Ecosystem Studies, Wageningen Aquaculture†, Wageningen University and Research Centre Yerseke, Netherlands
| | - Kasper Kusters
- Institute for Marine Resources and Ecosystem Studies, Wageningen Aquaculture†, Wageningen University and Research Centre Yerseke, Netherlands
| | - Jonathan A C Roques
- Department of Animal physiology, Institute for Water and Wetland Research, Radboud University Nijmegen Nijmegen, Netherlands
| | - Gert Flik
- Department of Animal physiology, Institute for Water and Wetland Research, Radboud University Nijmegen Nijmegen, Netherlands
| | | | - Robbert J W Blonk
- Institute for Marine Resources and Ecosystem Studies, Wageningen Aquaculture†, Wageningen University and Research Centre Yerseke, Netherlands
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Palstra AP, Rovira M, Rizo-Roca D, Torrella JR, Spaink HP, Planas JV. Swimming-induced exercise promotes hypertrophy and vascularization of fast skeletal muscle fibres and activation of myogenic and angiogenic transcriptional programs in adult zebrafish. BMC Genomics 2014; 15:1136. [PMID: 25518849 PMCID: PMC4378002 DOI: 10.1186/1471-2164-15-1136] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 12/11/2014] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND The adult skeletal muscle is a plastic tissue with a remarkable ability to adapt to different levels of activity by altering its excitability, its contractile and metabolic phenotype and its mass. We previously reported on the potential of adult zebrafish as a tractable experimental model for exercise physiology, established its optimal swimming speed and showed that swimming-induced contractile activity potentiated somatic growth. Given that the underlying exercise-induced transcriptional mechanisms regulating muscle mass in vertebrates are not fully understood, here we investigated the cellular and molecular adaptive mechanisms taking place in fast skeletal muscle of adult zebrafish in response to swimming. RESULTS Fish were trained at low swimming speed (0.1 m/s; non-exercised) or at their optimal swimming speed (0.4 m/s; exercised). A significant increase in fibre cross-sectional area (1.290±88 vs. 1.665±106 μm2) and vascularization (298±23 vs. 458±38 capillaries/mm2) was found in exercised over non-exercised fish. Gene expression profiling by microarray analysis evidenced the activation of a series of complex transcriptional networks of extracellular and intracellular signaling molecules and pathways involved in the regulation of muscle mass (e.g. IGF-1/PI3K/mTOR, BMP, MSTN), myogenesis and satellite cell activation (e.g. PAX3, FGF, Notch, Wnt, MEF2, Hh, EphrinB2) and angiogenesis (e.g. VEGF, HIF, Notch, EphrinB2, KLF2), some of which had not been previously associated with exercise-induced contractile activity. CONCLUSIONS The results from the present study show that exercise-induced contractile activity in adult zebrafish promotes a coordinated adaptive response in fast muscle that leads to increased muscle mass by hypertrophy and increased vascularization by angiogenesis. We propose that these phenotypic adaptations are the result of extensive transcriptional changes induced by exercise. Analysis of the transcriptional networks that are activated in response to exercise in the adult zebrafish fast muscle resulted in the identification of key signaling pathways and factors for the regulation of skeletal muscle mass, myogenesis and angiogenesis that have been remarkably conserved during evolution from fish to mammals. These results further support the validity of the adult zebrafish as an exercise model to decipher the complex molecular and cellular mechanisms governing skeletal muscle mass and function in vertebrates.
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Affiliation(s)
| | | | | | | | | | - Josep V Planas
- Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain.
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Magnoni LJ, Palstra AP, Planas JV. Fueling the engine: induction of AMP-activated protein kinase in trout skeletal muscle by swimming. ACTA ACUST UNITED AC 2014; 217:1649-52. [PMID: 24526729 DOI: 10.1242/jeb.099192] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AMP-activated protein kinase (AMPK) is well known to be induced by exercise and to mediate important metabolic changes in the skeletal muscle of mammals. Despite the physiological importance of exercise as a modulator of energy use by locomotory muscle, the regulation of this enzyme by swimming has not been investigated in fish. We found that sustained swimming (40 days at 0.75 body lengths s(-1)) increased AMPK activity in red and white trout skeletal muscle (3.9- and 2.2-fold, respectively) as well as the expression of AMPK target genes involved in energy use: lipoprotein lipase and citrate synthase in red and white muscle and CPT1β1b and PGC-1α in red muscle. Furthermore, electrical pulse stimulation of cultured trout myotubes increased AMPK activity and glucose uptake (1.9- and 1.2-fold, respectively) in an AMPK-dependent manner. These results suggest that AMPK may play an important mediatory role in the metabolic adaptation to swimming in fish skeletal muscle.
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Affiliation(s)
- Leonardo J Magnoni
- Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Institut de Biomedicina de la Universitat de Barcelona (IBUB), 08028 Barcelona, Spain
| | - Arjan P Palstra
- Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Institut de Biomedicina de la Universitat de Barcelona (IBUB), 08028 Barcelona, Spain
| | - Josep V Planas
- Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Institut de Biomedicina de la Universitat de Barcelona (IBUB), 08028 Barcelona, Spain
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25
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Palstra AP, Beltran S, Burgerhout E, Brittijn SA, Magnoni LJ, Henkel CV, Jansen HJ, van den Thillart GEEJM, Spaink HP, Planas JV. Deep RNA sequencing of the skeletal muscle transcriptome in swimming fish. PLoS One 2013; 8:e53171. [PMID: 23308156 PMCID: PMC3540090 DOI: 10.1371/journal.pone.0053171] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 11/26/2012] [Indexed: 11/20/2022] Open
Abstract
Deep RNA sequencing (RNA-seq) was performed to provide an in-depth view of the transcriptome of red and white skeletal muscle of exercised and non-exercised rainbow trout (Oncorhynchus mykiss) with the specific objective to identify expressed genes and quantify the transcriptomic effects of swimming-induced exercise. Pubertal autumn-spawning seawater-raised female rainbow trout were rested (n = 10) or swum (n = 10) for 1176 km at 0.75 body-lengths per second in a 6,000-L swim-flume under reproductive conditions for 40 days. Red and white muscle RNA of exercised and non-exercised fish (4 lanes) was sequenced and resulted in 15–17 million reads per lane that, after de novo assembly, yielded 149,159 red and 118,572 white muscle contigs. Most contigs were annotated using an iterative homology search strategy against salmonid ESTs, the zebrafish Danio rerio genome and general Metazoan genes. When selecting for large contigs (>500 nucleotides), a number of novel rainbow trout gene sequences were identified in this study: 1,085 and 1,228 novel gene sequences for red and white muscle, respectively, which included a number of important molecules for skeletal muscle function. Transcriptomic analysis revealed that sustained swimming increased transcriptional activity in skeletal muscle and specifically an up-regulation of genes involved in muscle growth and developmental processes in white muscle. The unique collection of transcripts will contribute to our understanding of red and white muscle physiology, specifically during the long-term reproductive migration of salmonids.
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Affiliation(s)
- Arjan P Palstra
- Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona and Institut de Biomedicina de la Universitat de Barcelona (IBUB), Barcelona, Spain.
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26
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Anteneh W, Getahun A, Dejen E, Sibbing FA, Nagelkerke LAJ, De Graaf M, Wudneh T, Vijverberg J, Palstra AP. Spawning migrations of the endemic Labeobarbus (Cyprinidae, Teleostei) species of Lake Tana, Ethiopia: status and threats. J Fish Biol 2012; 81:750-765. [PMID: 22803734 DOI: 10.1111/j.1095-8649.2012.03362.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The reproductive biology of the only known intact species flock of large cyprinids, the 16 Labeobarbus species of Lake Tana (Ethiopia), has been extensively studied for the past two decades. Seven species of Labeobarbus are known to migrate >50 km upstream into tributary rivers for spawning during the rainy season (July to October), whereas eight other species are absent from these rivers and probably developed a new strategy of lacustrine spawning (macro-spatial segregation). One species (L. intermedius) probably spawns in the lake as well as in the rivers. Between the early 1990s and 2000s, the riverine spawners showed a decline of 75% in both biomass and number in both fishery independent surveys and in commercial catches. Reproductive migration makes fishes vulnerable to fisheries and other threats like habitat modifications. Lacustrine spawners are probably more resilient as they are not known to form spawning aggregations that can easily be exploited by fishermen. In addition, upstream rivers and catchments around Lake Tana are highly degraded by erosion and recently subjected to intensive habitat modification for irrigation and hydroelectric power generation. This article reviews results of field studies on the Labeobarbus spawning migration from Lake Tana to spawning rivers, giving emphasis on segregation and homing. It also summarizes existing and emerging threats which form potential causes for the decline of the migratory Labeobarbus species. Knowledge gaps on the reproductive biology are identified for further investigation.
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Affiliation(s)
- W Anteneh
- Bahir Dar University, College of Science, Department of Biology, Bahir Dar, Ethiopia
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27
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Magnoni LJ, Vraskou Y, Palstra AP, Planas JV. AMP-activated protein kinase plays an important evolutionary conserved role in the regulation of glucose metabolism in fish skeletal muscle cells. PLoS One 2012; 7:e31219. [PMID: 22359576 PMCID: PMC3281052 DOI: 10.1371/journal.pone.0031219] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Accepted: 01/04/2012] [Indexed: 12/16/2022] Open
Abstract
AMPK, a master metabolic switch, mediates the observed increase of glucose uptake in locomotory muscle of mammals during exercise. AMPK is activated by changes in the intracellular AMP:ATP ratio when ATP consumption is stimulated by contractile activity but also by AICAR and metformin, compounds that increase glucose transport in mammalian muscle cells. However, the possible role of AMPK in the regulation of glucose metabolism in skeletal muscle has not been investigated in other vertebrates, including fish. In this study, we investigated the effects of AMPK activators on glucose uptake, AMPK activity, cell surface levels of trout GLUT4 and expression of GLUT1 and GLUT4 as well as the expression of enzymes regulating glucose disposal and PGC1α in trout myotubes derived from a primary muscle cell culture. We show that AICAR and metformin significantly stimulated glucose uptake (1.6 and 1.3 fold, respectively) and that Compound C completely abrogated the stimulatory effects of the AMPK activators on glucose uptake. The combination of insulin and AMPK activators did not result in additive nor synergistic effects on glucose uptake. Moreover, exposure of trout myotubes to AICAR and metformin resulted in an increase in AMPK activity (3.8 and 3 fold, respectively). We also provide evidence suggesting that stimulation of glucose uptake by AMPK activators in trout myotubes may take place, at least in part, by increasing the cell surface and mRNA levels of trout GLUT4. Finally, AICAR increased the mRNA levels of genes involved in glucose disposal (hexokinase, 6-phosphofructokinase, pyruvate kinase and citrate synthase) and mitochondrial biogenesis (PGC-1α) and did not affect glycogen content or glycogen synthase mRNA levels in trout myotubes. Therefore, we provide evidence, for the first time in non-mammalian vertebrates, suggesting a potentially important role of AMPK in stimulating glucose uptake and utilization in the skeletal muscle of fish.
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Affiliation(s)
- Leonardo J. Magnoni
- Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona I Institut de Biomedicina de la Universitat de Barcelona (IBUB), Barcelona, Spain
| | - Yoryia Vraskou
- Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona I Institut de Biomedicina de la Universitat de Barcelona (IBUB), Barcelona, Spain
| | - Arjan P. Palstra
- Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona I Institut de Biomedicina de la Universitat de Barcelona (IBUB), Barcelona, Spain
| | - Josep V. Planas
- Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona I Institut de Biomedicina de la Universitat de Barcelona (IBUB), Barcelona, Spain
- * E-mail:
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28
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Pérez L, Peñaranda DS, Dufour S, Baloche S, Palstra AP, Van Den Thillart GEEJM, Asturiano JF. Influence of temperature regime on endocrine parameters and vitellogenesis during experimental maturation of European eel (Anguilla anguilla) females. Gen Comp Endocrinol 2011; 174:51-9. [PMID: 21871894 DOI: 10.1016/j.ygcen.2011.08.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2011] [Revised: 08/06/2011] [Accepted: 08/10/2011] [Indexed: 01/03/2023]
Abstract
We examined the effect of temperature in European silver eels during their maturation induced by injections of carp pituitary extract on endocrine parameters: pituitary fshβ and lhβ expression, plasma 17β-estradiol (E2) and vitellogenin, estrogen receptor 1 (esr1), and vitellogenin 2 (vtg2) expression in liver. A variable thermal regime (T10) that increased from 10° to 14° and 17°C was compared with a constant 20°C regime (T20) during 12 weeks. T10 caused a faster development until week 8, higher fshβ, lhβ, esr1 expression, and higher E2 levels. The results strongly suggest that T10 is inducing a higher endogenous FSH level which increases the E2 circulating level during vitellogenesis. A variable thermal regime induced an fshβ expression and E2 profile in vitellogenic hormonally matured eel females that were more similar to the profile observed in other naturally maturing fish.
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Affiliation(s)
- L Pérez
- Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain.
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29
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Palstra AP, Guerrero MA, de Laak G, Klein Breteler JPG, van den Thillart GEEJM. Temporal progression in migratory status and sexual maturation in European silver eels during downstream migration. Fish Physiol Biochem 2011; 37:285-96. [PMID: 21556699 PMCID: PMC3107437 DOI: 10.1007/s10695-011-9496-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 02/14/2011] [Indexed: 05/25/2023]
Abstract
The onset of downstream migration of European eels is accompanied by a cessation of feeding and the start of sexual maturation which stresses the link between metabolism and sexual maturation, also suggesting an important role for exercise. Exercise has been tested with eels in swim tunnels and was found to stimulate the onset of sexual maturation. In this study, we have investigated the interplay between migration and maturation in the field during the downstream migration of female silver eels. Temporal changes in migratory status and sexual maturation among silver eels of the upstream Rhine River system over 3 months of the migration season (August, September and October) were determined in biometrical parameters, plasma 17β-estradiol and calcium levels, oocyte histology and gonadal fat levels. Furthermore, the ecological relevant parameters age as determined by otolithometry and health aspects indicated by haematocrit, haemoglobin and swim-bladder parasite load were measured. Silver eels were estimated to be 14 years old. A strong temporal progression in migratory stage was shown over the months of downstream migration. Catches probably represented a mix of reproductive migrants and feeding migrants of which the ratio increased over time. Furthermore, this study confirmed our hypothesis linking the migratory stage to early maturation as indicated by enlargement of the eyes, oocyte growth and fat deposition in the oocytes, exactly the same changes as found induced by exercise but not ruling out environmental influences. Migrants show extensive fat uptake by the oocytes, probably stimulated by the swimming exercise. In addition, at least 83% of the silver eels in this spawning run may have suffered from negative effects of swim-bladder parasites on their swimming performance.
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Affiliation(s)
- Arjan P Palstra
- Molecular Cell Biology, Institute of Biology, Leiden University (IBL), Sylvius Laboratory, Leiden, The Netherlands.
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Abstract
Improved knowledge on the swimming physiology of fish and its application to fisheries science and aquaculture (i.e., farming a fitter fish) is currently needed in the face of global environmental changes, high fishing pressures, increased aquaculture production as well as increased concern on fish well-being. Here, we review existing data on teleost fish that indicate that sustained exercise at optimal speeds enhances muscle growth and has consequences for flesh quality. Potential added benefits of sustained exercise may be delay of ovarian development and stimulation of immune status. Exercise could represent a natural, noninvasive, and economical approach to improve growth, flesh quality as well as welfare of aquacultured fish: a FitFish for a healthy consumer. All these issues are important for setting directions for policy decisions and future studies in this area. For this purpose, the FitFish workshop on the Swimming Physiology of Fish ( http://www.ub.edu/fitfish2010 ) was organized to bring together a multidisciplinary group of scientists using exercise models, industrial partners, and policy makers. Sixteen international experts from Europe, North America, and Japan were invited to present their work and view on migration of fishes in their natural environment, beneficial effects of exercise, and applications for sustainable aquaculture. Eighty-eight participants from 19 different countries contributed through a poster session and round table discussion. Eight papers from invited speakers at the workshop have been contributed to this special issue on The Swimming Physiology of Fish.
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Affiliation(s)
- Arjan P. Palstra
- Departament de Fisiologia, Facultat de Biologia, Universitat de Barcelona and Institut de Biomedicina de la Universitat de Barcelona (IBUB), Av. Diagonal 645, 08028 Barcelona, Spain
- Present Address: Institute for Marine Resources and Ecosystem Studies (IMARES) of the Wageningen University, P.O. Box 77, 4400 AB Yerseke, The Netherlands
| | - Josep V. Planas
- Departament de Fisiologia, Facultat de Biologia, Universitat de Barcelona and Institut de Biomedicina de la Universitat de Barcelona (IBUB), Av. Diagonal 645, 08028 Barcelona, Spain
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31
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Burgerhout E, Brittijn SA, Kurwie T, Decker P, Dirks RP, Palstra AP, Spaink HP, Van den Thillart GEEJM. First artificial hybrid of the eel species Anguilla australis and Anguilla anguilla. BMC Dev Biol 2011; 11:16. [PMID: 21396126 PMCID: PMC3063818 DOI: 10.1186/1471-213x-11-16] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 03/13/2011] [Indexed: 11/10/2022]
Abstract
Background Studies on artificial hybridization of different Anguilla species were conducted recently, i.e. female A. australis with male A. dieffenbachii, and female A. japonica with male A. anguilla. The existence of these artificial hybrids was however not demonstrated by independent genetic methods. Two species - A. anguilla and A. australis - that are phylogenetically close but have different sexual maturation times (12-25 weeks and 6-8 weeks, respectively), were expected to produce favourable hybrids for reproduction studies. Results A modification of the protocol for the reproduction of Anguilla japonica was used to produce eight-day Anguilla australis larvae, with a success rate of 71.4%. Thus ten out of 14 females produced eggs that could be fertilized, and three batches resulted in mass hatching. Hybrid larvae from female A. australis x male A. Anguilla survived for up to seven days post fertilization (dpf). The early development of the hybrid showed typical characteristics of A. anguilla tail pigmentation at 50 hours post fertilization (hpf), indicating expression of genes derived from the father. Conclusions In this paper we describe the first production of hybrid larvae from male A. anguilla and female A. australis and their survival for up to 7 dpf. A species-specific nucleotide difference in the 18 S rDNA gene confirmed that genes from both A. australis and A. anguilla were present in the hybrids. The developmental stages of the hybrid eel embryos and larvae are described using high resolution images. Video footage also indicated a heart beat in 5-dpf larva.
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Affiliation(s)
- Erik Burgerhout
- ZF-screens BV, Niels Bohrweg 11, 2333 CA Leiden, The Netherlands
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Lefebvre F, Fazio G, Palstra AP, Székely C, Crivelli AJ. An evaluation of indices of gross pathology associated with the nematode Anguillicoloides crassus in eels. J Fish Dis 2011; 34:31-45. [PMID: 21118268 DOI: 10.1111/j.1365-2761.2010.01207.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This study compares two alternative indices for quantifying the gross pathology of the swimbladder of eels, Anguilla anguilla (L.), infected with the nematode Anguillicoloides crassus. Two observers recorded twice the scores obtained by the two indices on the same set of 71 wild caught eels (from elver to silver eels, French Mediterranean lagoons). The Length Ratio Index (LRI), performed better than the Swimbladder Degenerative Index (SDI), in three of four predefined criteria of decision. First, the LRI better correlated with an estimate of the swimbladder volume reduction, a functional consequence of the infection (representativeness). Also, the LRI was less prone to subjectivity (inter-observer variability) and more precise (intra-observer variability), although less easy to generate (time needed for measurement/assessment). Using a sub-sample of 32 unaffected eels (showing minor if any swimbladder damage and no living worms at autopsy), we ascertained a linear relationship between the swimbladder length and the total body length, a prerequisite of isometric growth, to definitively accept the new ratio index as a valid alternative to the SDI. Also, because the LRI can be recorded on live specimens with radio-imagery (non-invasive method), we recommend its use, and provide a graph of correspondence between the SDI scores, the LRI scores and the estimated proportion of gas loss in the swimbladder.
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Palstra AP, Tudorache C, Rovira M, Brittijn SA, Burgerhout E, van den Thillart GEEJM, Spaink HP, Planas JV. Establishing zebrafish as a novel exercise model: swimming economy, swimming-enhanced growth and muscle growth marker gene expression. PLoS One 2010; 5:e14483. [PMID: 21217817 PMCID: PMC3013094 DOI: 10.1371/journal.pone.0014483] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 12/13/2010] [Indexed: 12/05/2022] Open
Abstract
Background Zebrafish has been largely accepted as a vertebrate multidisciplinary model but its usefulness as a model for exercise physiology has been hampered by the scarce knowledge on its swimming economy, optimal swimming speeds and cost of transport. Therefore, we have performed individual and group-wise swimming experiments to quantify swimming economy and to demonstrate the exercise effects on growth in adult zebrafish. Methodology/Principal Findings Individual zebrafish (n = 10) were able to swim at a critical swimming speed (Ucrit) of 0.548±0.007 m s−1 or 18.0 standard body lengths (BL) s−1. The optimal swimming speed (Uopt) at which energetic efficiency is highest was 0.396±0.019 m s−1 (13.0 BL s−1) corresponding to 72.26±0.29% of Ucrit. The cost of transport at optimal swimming speed (COTopt) was 25.23±4.03 µmol g−1 m−1. A group-wise experiment was conducted with zebrafish (n = 83) swimming at Uopt for 6 h day−1 for 5 days week−1 for 4 weeks vs. zebrafish (n = 84) that rested during this period. Swimming zebrafish increased their total body length by 5.6% and body weight by 41.1% as compared to resting fish. For the first time, a highly significant exercise-induced growth is demonstrated in adult zebrafish. Expression analysis of a set of muscle growth marker genes revealed clear regulatory roles in relation to swimming-enhanced growth for genes such as growth hormone receptor b (ghrb), insulin-like growth factor 1 receptor a (igf1ra), troponin C (stnnc), slow myosin heavy chain 1 (smyhc1), troponin I2 (tnni2), myosin heavy polypeptide 2 (myhz2) and myostatin (mstnb). Conclusions/Significance From the results of our study we can conclude that zebrafish can be used as an exercise model for enhanced growth, with implications in basic, biomedical and applied sciences, such as aquaculture.
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Affiliation(s)
- Arjan P Palstra
- Departament de Fisiologia, Facultat de Biologia, Institut de Biomedicina de la Universitat de Barcelona, Universitat de Barcelona, Barcelona, Spain.
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Crespo D, Palstra AP, Planas JV. Tumor Necrosis Factor alpha Mediates Luteinizing Hormone Stimulation of Prostaglandin Synthesis in Trout Preovulatory Follicles. Biol Reprod 2010. [DOI: 10.1093/biolreprod/83.s1.354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Palstra AP, van den Thillart GEEJM. Swimming physiology of European silver eels (Anguilla anguilla L.): energetic costs and effects on sexual maturation and reproduction. Fish Physiol Biochem 2010; 36:297-322. [PMID: 20390348 PMCID: PMC2923712 DOI: 10.1007/s10695-010-9397-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Accepted: 01/28/2010] [Indexed: 05/02/2023]
Abstract
The European eel migrates 5,000-6,000 km to the Sargasso Sea to reproduce. Because they venture into the ocean in a pre-pubertal state and reproduce after swimming for months, a strong interaction between swimming and sexual maturation is expected. Many swimming trials have been performed in 22 swim tunnels to elucidate their performance and the impact on maturation. European eels are able to swim long distances at a cost of 10-12 mg fat/km which is 4-6 times more efficient than salmonids. The total energy costs of reproduction correspond to 67% of the fat stores. During long distance swimming, the body composition stays the same showing that energy consumption calculations cannot be based on fat alone but need to be compensated for protein oxidation. The optimal swimming speed is 0.61-0.67 m s(-1), which is approximately 60% higher than the generally assumed cruise speed of 0.4 m s(-1) and implies that female eels may reach the Sargasso Sea within 3.5 months instead of the assumed 6 months. Swimming trials showed lipid deposition and oocyte growth, which are the first steps of sexual maturation. To investigate effects of oceanic migration on maturation, we simulated group-wise migration in a large swim-gutter with seawater. These trials showed suppressed gonadotropin expression and vitellogenesis in females, while in contrast continued sexual maturation was observed in silver males. The induction of lipid deposition in the oocytes and the inhibition of vitellogenesis by swimming in females suggest a natural sequence of events quite different from artificial maturation protocols.
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Affiliation(s)
- Arjan P Palstra
- Molecular Cell Biology, Institute of Biology, Leiden University (IBL), Leiden, 2333 CC, The Netherlands.
- Departament de Fisiologia, Facultat de Biologia, Universitat de Barcelona, 08028, Barcelona, Spain.
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Palstra AP, Crespo D, van den Thillart GEEJM, Planas JV. Saving energy to fuel exercise: swimming suppresses oocyte development and downregulates ovarian transcriptomic response of rainbow trout Oncorhynchus mykiss. Am J Physiol Regul Integr Comp Physiol 2010; 299:R486-99. [PMID: 20445157 DOI: 10.1152/ajpregu.00109.2010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Metabolic processes and sexual maturation closely interact during the long-distance reproductive migration of many fish species to their spawning grounds. In the present study, we have used exercise experimentally to investigate the effects on sexual maturation in rainbow trout. Pubertal autumn-spawning seawater-raised female rainbow trout Oncorhynchus mykiss (n = 26; 50 cm, 1.5 kg) were rested or swum at a near optimal speed of 0.75 body lengths per second in a 6,000-liter swim flume under natural reproductive conditions (16 degrees C fresh-water, starvation, 8:16-h light-dark photoperiod). Fish were sampled after arrival and subsequently after 10 days (resting or swimming 307 km) and 20 days (resting or swimming 636 km). Ovarian development was significantly reduced in the swimmers. Analysis of the expression of key factors in the reproductive axis included pituitary kiss1-receptor, lh, and fsh and ovarian lh-receptor, fsh-receptor, aromatase, and vitellogenin-receptor (vtgr). Swimmers had lower pituitary lh and ovarian vtgr expression than resters. Furthermore, the number of late vitellogenic oocytes was lower in swimmers than in resters, probably resulting from the lower vtgr expression, and vitellogenin plasma levels were higher. Therefore, swimming exercise suppresses oocyte development possibly by inhibiting vitellogenin uptake. Transcriptomic changes that occurred in the ovary of exercised fish were investigated using a salmonid cDNA microarray platform. Protein biosynthesis and energy provision were among the 16 functional categories that were all downregulated in the ovary. Downregulation of the transcriptomic response in the ovary illustrates the priority of energy reallocation and will save energy to fuel exercise. A swimming-induced ovarian developmental suppression at the start of vitellogenesis during long-term reproductive migration may be a strategy to avoid precocious muscle atrophy.
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Affiliation(s)
- Arjan P Palstra
- Dept. de Fisiologia, Facultat de Biologia, Universitat de Barcelona and Institut de Biomedicina de la Universitat de Barcelona, Barcelona 08028, Spain.
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Palstra AP, Schnabel D, Nieveen MC, Spaink HP, van den Thillart G. Swimming suppresses hepatic vitellogenesis in European female silver eels as shown by expression of the estrogen receptor 1, vitellogenin1 and vitellogenin2 in the liver. Reprod Biol Endocrinol 2010; 8:27. [PMID: 20302623 PMCID: PMC2847565 DOI: 10.1186/1477-7827-8-27] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Accepted: 03/19/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND When European silver eels (Anguilla anguilla) venture into the Atlantic Ocean for their 6,000 km semelparous spawning run to the Sargasso Sea, they are still in a prepubertal stage. Further sexual development appears to be blocked by dopaminergic inhibition of hypothalamus and pituitary activity. Recently, we found that swimming for several weeks in freshwater stimulated the incorporation of fat droplets in the oocytes. So, it was hypothesized that long term swimming in seawater would release the inhibition further and would also stimulate the production of vitellogenin by the liver. METHODS For this study a swim-flume was constructed to allow simulated migration of migratory female silver eels for 3 months (1,420 km) in natural seawater at 20 degrees C. Primers were designed for polymerase chain reactions to measure the mRNA expression of estrogen receptor 1 (esr1), vitellogenin1 (vtg1) and vitellogenin2 (vtg2) genes in the liver of European female silver eels. RESULTS In comparison to resting eels, swimming eels showed a diminished expression of esr1, vtg1 and vtg2 in the liver. They also had lower plasma calcium (Ca; indicative of vitellogenin) levels in their blood. This showed that vitellogenesis is more strongly suppressed in swimming than in resting eels. However, when eels were subsequently stimulated by 3 weekly carp pituitary extract injections, the expression of the same genes and plasma levels of Ca strongly increased in both groups to similar levels, thus equalizing the initial differences between resting and swimming. CONCLUSIONS It is concluded that vitellogenesis remains suppressed during resting and even more during swimming. The fact that swimming stimulates fat deposition in the oocytes but suppresses vitellogenesis indicates that these events are separated in nature and occur sequentially. Swimming-suppressed vitellogenesis may imply that in nature eels undergo vitellogenesis and final maturation near or at the spawning grounds.
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Affiliation(s)
- Arjan P Palstra
- Molecular Cell Biology, Institute of Biology, Leiden University (IBL), Einsteinweg 55, 2333 CC Leiden, The Netherlands
- Departament de Fisiologia, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain
| | - Denhi Schnabel
- Molecular Cell Biology, Institute of Biology, Leiden University (IBL), Einsteinweg 55, 2333 CC Leiden, The Netherlands
- Departamento Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología/UNAM, Av. Universidad #2001, Col. Chamilpa C.P. 62210, Cuernavaca, Morelos, Mexico
| | - Maaike C Nieveen
- Molecular Cell Biology, Institute of Biology, Leiden University (IBL), Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Herman P Spaink
- Molecular Cell Biology, Institute of Biology, Leiden University (IBL), Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Guido van den Thillart
- Molecular Cell Biology, Institute of Biology, Leiden University (IBL), Einsteinweg 55, 2333 CC Leiden, The Netherlands
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Palstra AP, Schnabel D, Nieveen MC, Spaink HP, van den Thillart GEEJM. Temporal expression of hepatic estrogen receptor 1, vitellogenin1 and vitellogenin2 in European silver eels. Gen Comp Endocrinol 2010; 166:1-11. [PMID: 19766647 DOI: 10.1016/j.ygcen.2009.09.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Revised: 07/17/2009] [Accepted: 09/09/2009] [Indexed: 10/20/2022]
Abstract
Because European silver eels have never been caught during or after their 6000-km reproductive migration to the Sargasso Sea, all existing knowledge on their sexual maturation comes from hormonal stimulation. Silver eels that start their oceanic migration are still immature with pre-vitellogenic oocytes. Hence we assumed that vitellogenesis should start with the expression of the estrogen receptor in the liver before the circulating 17beta-estradiol (E2) can have any effect. In this study we followed the hepatic vitellogenesis upon 4 weekly injections with carp pituitary extracts (CPE). New molecular primers for the expression of the estrogen receptor 1 (esr1), vitellogenin1 (vtg1) and vitellogenin2 (vtg2) in the liver were developed. Sequences of vtg2 and esr1 were not previously described in Anguilla anguilla. All eels showed weekly increase of the eye size and pectoral fin length, which are signs of early maturation. The same occurred with the gonadosomatic index, the oocyte stage and diameter, and number of deposited fat droplets. Early vitellogenesis appeared as a 3-step process (1) E2-levels and esr1 expression were significantly increased already after one injection, (2) vtg1 and vtg2 expression were significantly increased after one and two injections, respectively, and (3) vtg1 and vtg2 expression increased further after three and four injections. Then also plasma calcium (corresponds with plasma vitellogenin) increased and yolk globuli appeared in the oocytes. These results show that esr1 is the first of the three genes examined that is expressed during the onset of hepatic vitellogenesis. Furthermore, ovarian vitellogenesis (appearance of yolk globuli in oocytes) occurs 1-2 weeks later than the onset of hepatic vitellogenesis.
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Affiliation(s)
- Arjan P Palstra
- Molecular Cell Biology, Institute of Biology, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands.
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Palstra AP, Schnabel D, Nieveen MC, Spaink HP, van den Thillart GE. Male silver eels mature by swimming. BMC Physiol 2008; 8:14. [PMID: 18616800 PMCID: PMC2474648 DOI: 10.1186/1472-6793-8-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Accepted: 07/10/2008] [Indexed: 11/28/2022]
Abstract
Background If European silver eels are prevented from reproductive migration, they remain in a prepubertal stage by dopaminergic inhibition of pituitary activity. Because this inhibition is likely a requirement for an extended female growth stage, we tested if it is sex-specific by subjecting both sexes to stimulation by GnRHa (Gonadotropin-Releasing Hormone agonist) – injection or 3-months swimming in seawater. Results In contrast to females, males showed a two- to three-fold higher LHβ (luteinising hormone β subunit) – expression, a three- to five-fold higher GSI (Gonadosomatic index) and induced spermatogenesis when compared with the untreated control group. Conclusion Dopaminergic inhibition is thus not effective in males and swimming results in natural maturation, probably via GnRH-release.
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Affiliation(s)
- Arjan P Palstra
- Integrative Zoology, Institute of Biology, Leiden University (IBL), van der Klaauw Laboratory, Kaiserstraat 63, 2311 GP Leiden, The Netherlands.
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Palstra AP, van Ginneken VJT, Murk AJ, van den Thillart GEEJM. Are dioxin-like contaminants responsible for the eel (Anguilla anguilla) drama? Naturwissenschaften 2006; 93:145-8. [PMID: 16508793 DOI: 10.1007/s00114-005-0080-z] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Accepted: 12/18/2005] [Indexed: 10/25/2022]
Abstract
Eel populations worldwide are dangerously close to collapsing. Our study is the first to show that current levels of dioxin-like contaminants are strong candidates because of their devastating effects on development and survival of eel embryos. Female and male silver eels were artificially stimulated to maturation and reproduction by treatment with carp pituitary extracts and hCG, respectively. During maturation of female European silver eels, about 60 g fat per kg eel is incorporated in the oocytes. Together with the fat, however, persistent organic pollutants such as dioxin-like polychlorinated biphenyls (PCBs) are incorporated too. The total dioxin-like toxic potency of the individual gonad batches was determined as 2,3,7,8-tetrachlorodibenzo-p-dioxine equivalents (TEQs), using an in vitro reporter gene assay. The observed differences in development and survival showed a significant negative correlation with the TEQ levels in the gonads, already at levels far below the maximal allowable level for fish consumption, i.e., 4 ng TEQ/kg fish. The clear inverse relationship between the TEQ level and the survival period of the fertilised eggs strongly suggests that the current levels of dioxin-like compounds seriously impair the reproduction of the European eel. The peak of the environmental levels of dioxin-like PCBs and the decline of eel coincide worldwide, further suggesting that, in addition to other threats, these contaminants contributed significantly to the current collapse in eel populations.
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Affiliation(s)
- A P Palstra
- Integrative Zoology, Institute of Biology Leiden, Leiden University, P.O. Box 9511, Kaiserstraat 63, 2300 RA Leiden, The Netherlands.
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Tanck MW, Palstra AP, van der Weerd M, Leffering CP, van der Poel JJ, Bovenhuis H, Komen J. Segregation of microsatellite alleles and residual heterozygosity at single loci in homozygous androgenetic common carp (Cyprinus carpio L.). Genome 2001; 44:743-51. [PMID: 11681597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Thirty-three androgenetic progeny groups of common carp were analysed using 11 microsatellite markers to (i) verify the homozygous status of the 566 androgenetic individuals, (ii) analyse the microsatellite allele segregation, and (iii) study the possible association of microsatellite alleles with phenotypic traits. In total, 92% of the androgenetic individuals proved to be homozygous at all 11 loci. Forty-three of the 47 heterozygous individuals were heterozygous at a single locus only. This heterozygosity was probably due to DNA fragments caused by UV irradiation of the eggs. although the maternal origin of the fragments could not be proved beyond doubt. Screening with 11 microsatellites also revealed two linkage groups, a segregation distortion at two microsatellite loci, and the possible association of some microsatellites with mass, length, stress-related plasma cortisol levels, and basal plasma glucose levels. The success of the linkage and association study could be explained by a low recombination frequency due to high chiasma interference. This would imply a relatively short genetic map for common carp.
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Affiliation(s)
- M W Tanck
- Institute of Animal Sciences, Wageningen University, The Netherlands
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Tanck MWT, Palstra AP, Weerd MVD, Leffering CP, Poel JJVD, Bovenhuis H, Komen J. Segregation of microsatellite alleles and residual heterozygosity at single loci in homozygous androgenetic common carp (Cyprinus carpio L.). Genome 2001. [DOI: 10.1139/g01-072] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Thirty-three androgenetic progeny groups of common carp were analysed using 11 microsatellite markers to (i) verify the homozygous status of the 566 androgenetic individuals, (ii) analyse the microsatellite allele segregation, and (iii) study the possible association of microsatellite alleles with phenotypic traits. In total, 92% of the androgenetic individuals proved to be homozygous at all 11 loci. Forty-three of the 47 heterozygous individuals were heterozygous at a single locus only. This heterozygosity was probably due to DNA fragments caused by UV irradiation of the eggs, although the maternal origin of the fragments could not be proved beyond doubt. Screening with 11 microsatellites also revealed two linkage groups, a segregation distortion at two microsatellite loci, and the possible association of some microsatellites with mass, length, stress-related plasma cortisol levels, and basal plasma glucose levels. The success of the linkage and association study could be explained by a low recombination frequency due to high chiasma interference. This would imply a relatively short genetic map for common carp.Key words: doubled haploids, residual heterozygosity, microsatellite allele segregation, linkage analysis, common carp.
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