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Aaskov ML, Nelson D, Lauridsen H, Huong DTT, Ishimatsu A, Crossley DA, Malte H, Bayley M. Do air-breathing fish suffer branchial oxygen loss in hypoxic water? Proc Biol Sci 2023; 290:20231353. [PMID: 37700647 PMCID: PMC10498054 DOI: 10.1098/rspb.2023.1353] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 08/18/2023] [Indexed: 09/14/2023] Open
Abstract
In hypoxia, air-breathing fish obtain O2 from the air but continue to excrete CO2 into the water. Consequently, it is believed that some O2 obtained by air-breathing is lost at the gills in hypoxic water. Pangasionodon hypophthalmus is an air-breathing catfish with very large gills from the Mekong River basin where it is cultured in hypoxic ponds. To understand how P. hypophthalmus can maintain high growth in hypoxia with the presumed O2 loss, we quantified respiratory gas exchange in air and water. In severe hypoxia (PO2: ≈ 1.5 mmHg), it lost a mere 4.9% of its aerial O2 uptake, while maintaining aquatic CO2 excretion at 91% of the total. Further, even small elevations in water PO2 rapidly reduced this minor loss. Charting the cardiovascular bauplan across the branchial basket showed four ventral aortas leaving the bulbus arteriosus, with the first and second gill arches draining into the dorsal aorta while the third and fourth gill arches drain into the coeliacomesenteric artery supplying the gut and the highly trabeculated respiratory swim-bladder. Substantial flow changes across these two arterial systems from normoxic to hypoxic water were not found. We conclude that the proposed branchial oxygen loss in air-breathing fish is likely only a minor inefficiency.
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Affiliation(s)
- Magnus L. Aaskov
- Division of Zoophysiology, Department of Biology, Aarhus University, 8000C Aarhus, Denmark
| | - Derek Nelson
- Department of Biological Sciences, University of North Texas, 1155 Union Circle, Denton, TX 76203, USA
| | - Henrik Lauridsen
- Comparative Medicine Lab, Department of Clinical Medicine, Aarhus, Denmark
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | - Atsushi Ishimatsu
- Institute for East China Sea Research, Nagasaki University, Nagasaki, Japan
| | - Dane A. Crossley
- Department of Biological Sciences, University of North Texas, 1155 Union Circle, Denton, TX 76203, USA
| | - Hans Malte
- Division of Zoophysiology, Department of Biology, Aarhus University, 8000C Aarhus, Denmark
| | - Mark Bayley
- Division of Zoophysiology, Department of Biology, Aarhus University, 8000C Aarhus, Denmark
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Hai DM, Yen DT, Liem PT, Tam BM, Huong DTT, Hang BTB, Hieu DQ, Garigliany MM, Coppieters W, Kestemont P, Phuong NT, Farnir F. A High-Quality Genome Assembly of Striped Catfish (Pangasianodon hypophthalmus) Based on Highly Accurate Long-Read HiFi Sequencing Data. Genes (Basel) 2022; 13:genes13050923. [PMID: 35627308 PMCID: PMC9141817 DOI: 10.3390/genes13050923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 04/19/2022] [Revised: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 11/26/2022] Open
Abstract
The HiFi sequencing technology yields highly accurate long-read data with accuracies greater than 99.9% that can be used to improve results for complex applications such as genome assembly. Our study presents a high-quality chromosome-scale genome assembly of striped catfish (Pangasianodon hypophthalmus), a commercially important species cultured mainly in Vietnam, integrating HiFi reads and Hi-C data. A 788.4 Mb genome containing 381 scaffolds with an N50 length of 21.8 Mb has been obtained from HiFi reads. These scaffolds have been further ordered and clustered into 30 chromosome groups, ranging from 1.4 to 57.6 Mb, based on Hi-C data. The present updated assembly has a contig N50 of 14.7 Mb, representing a 245-fold and 4.2-fold improvement over the previous Illumina and Illumina-Nanopore-Hi-C based version, respectively. In addition, the proportion of repeat elements and BUSCO genes identified in our genome is remarkably higher than in the two previously released striped catfish genomes. These results highlight the power of using HiFi reads to assemble the highly repetitive regions and to improve the quality of genome assembly. The updated, high-quality genome assembled in this work will provide a valuable genomic resource for future population genetics, conservation biology and selective breeding studies of striped catfish.
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Affiliation(s)
- Dao Minh Hai
- FARAH/Sustainable Animal Production, Faculty of Veterinary Medicine, University of Liege (B43), 4000 Liege, Belgium;
- College of Aquaculture and Fisheries, Can Tho University, Can Tho 900000, Vietnam; (D.T.Y.); (P.T.L.); (B.M.T.); (D.T.T.H.); (B.T.B.H.); (D.Q.H.); (N.T.P.)
| | - Duong Thuy Yen
- College of Aquaculture and Fisheries, Can Tho University, Can Tho 900000, Vietnam; (D.T.Y.); (P.T.L.); (B.M.T.); (D.T.T.H.); (B.T.B.H.); (D.Q.H.); (N.T.P.)
| | - Pham Thanh Liem
- College of Aquaculture and Fisheries, Can Tho University, Can Tho 900000, Vietnam; (D.T.Y.); (P.T.L.); (B.M.T.); (D.T.T.H.); (B.T.B.H.); (D.Q.H.); (N.T.P.)
| | - Bui Minh Tam
- College of Aquaculture and Fisheries, Can Tho University, Can Tho 900000, Vietnam; (D.T.Y.); (P.T.L.); (B.M.T.); (D.T.T.H.); (B.T.B.H.); (D.Q.H.); (N.T.P.)
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho 900000, Vietnam; (D.T.Y.); (P.T.L.); (B.M.T.); (D.T.T.H.); (B.T.B.H.); (D.Q.H.); (N.T.P.)
| | - Bui Thi Bich Hang
- College of Aquaculture and Fisheries, Can Tho University, Can Tho 900000, Vietnam; (D.T.Y.); (P.T.L.); (B.M.T.); (D.T.T.H.); (B.T.B.H.); (D.Q.H.); (N.T.P.)
| | - Dang Quang Hieu
- College of Aquaculture and Fisheries, Can Tho University, Can Tho 900000, Vietnam; (D.T.Y.); (P.T.L.); (B.M.T.); (D.T.T.H.); (B.T.B.H.); (D.Q.H.); (N.T.P.)
| | - Mutien-Marie Garigliany
- FARAH/Veterinary Public Health, Faculty of Veterinary Medicine, University of Liege (B43), 4000 Liege, Belgium;
| | | | - Patrick Kestemont
- Research Unit in Environmental and Evolutionary Biology, Institute of Life, Earth & Environnment, University of Namur, rue de Bruxelles 61, 5000 Namur, Belgium;
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho 900000, Vietnam; (D.T.Y.); (P.T.L.); (B.M.T.); (D.T.T.H.); (B.T.B.H.); (D.Q.H.); (N.T.P.)
| | - Frédéric Farnir
- FARAH/Sustainable Animal Production, Faculty of Veterinary Medicine, University of Liege (B43), 4000 Liege, Belgium;
- Correspondence:
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Hieu DQ, Hang BTB, Lokesh J, Garigliany MM, Huong DTT, Yen DT, Liem PT, Tam BM, Hai DM, Son VN, Phuong NT, Farnir F, Kestemont P. Salinity significantly affects intestinal microbiota and gene expression in striped catfish juveniles. Appl Microbiol Biotechnol 2022; 106:3245-3264. [PMID: 35366085 DOI: 10.1007/s00253-022-11895-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [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: 01/21/2022] [Revised: 03/08/2022] [Accepted: 03/19/2022] [Indexed: 12/17/2022]
Abstract
In the present study, juvenile striped catfish (Pangasianodon hypophthalmus), a freshwater fish species, have been chronically exposed to a salinity gradient from freshwater to 20 psu (practical salinity unit) and were sampled at the beginning (D20) and the end (D34) of exposure. The results revealed that the intestinal microbial profile of striped catfish reared in freshwater conditions were dominated by the phyla Bacteroidetes, Firmicutes, Proteobacteria, and Verrucomicrobia. Alpha diversity measures (observed OTUs (operational taxonomic units), Shannon and Faith's PD (phylogenetic diversity)) showed a decreasing pattern as the salinities increased, except for the phylogenetic diversity at D34, which was showing an opposite trend. Furthermore, the beta diversity between groups was significantly different. Vibrio and Akkermansia genera were affected differentially with increasing salinity, the former being increased while the latter was decreased. The genus Sulfurospirillium was found predominantly in fish submitted to salinity treatments. Regarding the host response, the fish intestine likely contributed to osmoregulation by modifying the expression of osmoregulatory genes such as nka1a, nka1b, slc12a1, slc12a2, cftr, and aqp1, especially in fish exposed to 15 and 20 psu. The expression of heat shock proteins (hsp) hsp60, hsp70, and hsp90 was significantly increased in fish reared in 15 and 20 psu. On the other hand, the expression of pattern recognition receptors (PRRs) were inhibited in fish exposed to 20 psu at D20. In conclusion, the fish intestinal microbiota was significantly disrupted in salinities higher than 10 psu and these effects were proportional to the exposure time. In addition, the modifications of intestinal gene expression related to ion exchange and stressful responses may help the fish to adapt hyperosmotic environment. KEY POINTS: • It is the first study to provide detailed information on the gut microbiota of fish using the amplicon sequencing method. • Salinity environment significantly modified the intestinal microbiota of striped catfish. • Intestinal responses may help the fish adapt to hyperosmotic environment.
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Affiliation(s)
- Dang Quang Hieu
- Research Unit in Environmental and Evolutionary Biology, Institute of Life Earth & Environment (ILEE), University of Namur, Namur, Belgium.
| | - Bui Thi Bich Hang
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Jep Lokesh
- Université de Pau Et Des Pays de L'Adour, Saint-Pee-sur-Nivelle, E2S UPPA, INRAE, NuMéA, France
| | - Mutien-Marie Garigliany
- Department of Pathology, Faculty of Veterinary Medicine, University of Liège, Liege, Belgium
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Duong Thuy Yen
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Pham Thanh Liem
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Bui Minh Tam
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Dao Minh Hai
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam.,Department of Animal Production, Faculty of Veterinary Medicine, University of Liège, Liege, Belgium
| | - Vo Nam Son
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Frédéric Farnir
- Department of Animal Production, Faculty of Veterinary Medicine, University of Liège, Liege, Belgium
| | - Patrick Kestemont
- Research Unit in Environmental and Evolutionary Biology, Institute of Life Earth & Environment (ILEE), University of Namur, Namur, Belgium.
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Hieu DQ, Hang BTB, Huong DTT, Kertaoui NE, Farnir F, Phuong NT, Kestemont P. Salinity affects growth performance, physiology, immune responses and temperature resistance in striped catfish (Pangasianodon hypophthalmus) during its early life stages. Fish Physiol Biochem 2021; 47:1995-2013. [PMID: 34708321 DOI: 10.1007/s10695-021-01021-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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: 10/14/2020] [Accepted: 10/05/2021] [Indexed: 06/13/2023]
Abstract
In this study, striped catfish larvae were gradually exposed to the increase of different salinities, and then they reached the levels of 0, 5, 10, 15, and 20 psu after 10 days, followed by heat shock at 39 °C to determine stress tolerance. After the 10-day experiment, the survival rate of fish exposed to the 20 psu treatment was only 28.6 ± 4%, significantly lower than that of the other treatments. The results showed that the osmolality of the whole-body (WB) homogenate was gradually and significantly increased with salinity elevation, except in fish exposed to freshwater and 5 psu treatments, while there were no significant changes in WB Na+/K+-ATPase activity. Digestive enzymatic activities, i.e., pepsin, α-amylase, alkaline phosphatase, and leucine alanine peptidase (leu-ala) generally increased with salinity, but not aminopeptidase and trypsin. Lysozyme and peroxidase activities increased in fish larvae exposed to 15 and 20 psu. These increases proportionally improved growth performance, with the lowest and the highest final weights observed in fish reared at 0 psu (0.08 ± 0.03 g/larvae) and 20 psu (0.11 ± 0.02 g/larvae), respectively, although the average growth recorded at 20 psu could be biased by the high mortality in this group. Occurrence of skeleton deformities, such as in caudal vertebrae and branchiostegal rays, was significantly higher in fish exposed to the higher osmotic conditions (15.0 ± 1.2% and 10.3 ± 2.1% respectively at 0 psu vs. 31.0 ± 2.9% and 49.0 ± 5.6%, respectively at 15 psu). After the 12.5-h heat shock, survival rates significantly differed between treatments with the highest survival observed in fish submitted to 5 psu (68.9%), followed by those exposed to 0 (27%) and 10 (20%) while all fish died at 15 psu. These findings suggest that the striped catfish larvae could be reared in salinity up to 5 to 10 psu with a higher survival and tolerance to thermal stress when compared to fish maintained in freshwater.
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Affiliation(s)
- Dang Quang Hieu
- Research Unit in Environmental and Evolutionary Biology, Institute of Life, Earth & Environment (ILEE), University of Namur (UNamur), Rue de Bruxelles 61, B-5000, Namur, Belgium
| | - Bui Thi Bich Hang
- College of Aquaculture and Fisheries, Cantho University, Campus II, Cantho City, Viet Nam
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Cantho University, Campus II, Cantho City, Viet Nam
| | - Najlae El Kertaoui
- Research Unit in Environmental and Evolutionary Biology, Institute of Life, Earth & Environment (ILEE), University of Namur (UNamur), Rue de Bruxelles 61, B-5000, Namur, Belgium
| | - Frédéric Farnir
- Department of Animal Production, Faculty of Veterinary Medicine, University of Liege, 4000, Liege, Belgium
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Cantho University, Campus II, Cantho City, Viet Nam
| | - Patrick Kestemont
- Research Unit in Environmental and Evolutionary Biology, Institute of Life, Earth & Environment (ILEE), University of Namur (UNamur), Rue de Bruxelles 61, B-5000, Namur, Belgium.
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Le Anh Dao N, Phu TM, Douny C, Quetin-Leclercq J, Hue BTB, Bach LT, Quynh Nhu T, Thi Bich Hang B, Thi Thanh Huong D, Thanh Phuong N, Kestemont P, Scippo ML. Effects of Phyllanthus amarus and Euphorbia hirta Dip Treatments on the Protection of Striped Catfish (Pangasianodon hypophthalmus) Fillets against Spoilage during Ice Storage. Journal of Aquatic Food Product Technology 2021. [DOI: 10.1080/10498850.2021.1987606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Nguyen Le Anh Dao
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
- FARAH – Veterinary Public Health, Laboratory of Food Analysis, University of Liège, Liege, Belgium
| | - Tran Minh Phu
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Caroline Douny
- FARAH – Veterinary Public Health, Laboratory of Food Analysis, University of Liège, Liege, Belgium
| | - Joëlle Quetin-Leclercq
- Louvain Drug Research Institute, Pharmacognosy Research Group, Université Catholique de Louvain, Brussels, Belgium
| | - Bui Thi Buu Hue
- College of Natural Sciences, Can Tho University, Can Tho City, Vietnam
| | - Le Thi Bach
- College of Natural Sciences, Can Tho University, Can Tho City, Vietnam
| | - Truong Quynh Nhu
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Bui Thi Bich Hang
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Patrick Kestemont
- Research Unit in Environmental and Evolutionary Biology, Research Institute of Life, Earth & Environment (ILEE), University of Namur, Namur, Belgium
| | - Marie-Louise Scippo
- FARAH – Veterinary Public Health, Laboratory of Food Analysis, University of Liège, Liege, Belgium
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Morgan R, Tunnah L, Tuong DD, Hjelmstedt P, Nhu PN, Stiller KT, Phuong NT, Huong DTT, Bayley M, Wang T, Milsom WK. Striped catfish (Pangasianodon hypophthalmus) use air-breathing and aquatic surface respiration when exposed to severe aquatic hypercarbia. J Exp Zool A Ecol Integr Physiol 2021; 335:820-830. [PMID: 33773086 DOI: 10.1002/jez.2453] [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] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 01/26/2021] [Indexed: 11/06/2022]
Abstract
We investigated the extent to which the facultative air-breathing fish, the striped catfish (Pangasianodon hypophthalmus), uses air-breathing to cope with aquatic hypercarbia, and how air-breathing is influenced by the experimental exposure protocol and level of hypercarbia. We exposed individuals to severe aquatic hypercarbia (up to Pw CO2 = 81 mmHg) using step-wise and progressive exposure protocols while measuring gill ventilation rate, heart rate, mean arterial blood pressure, and air-breathing frequency, as well as arterial blood pH and PCO2 . We confirm that P. hypophthalmus is tolerant of hypercarbia. Under both protocols gill ventilation rate, heart rate, and mean arterial blood pressure were maintained near control levels even at very high CO2 levels. We observed a marked amount of individual variation in the PwCO2 at which air-breathing was elicited, with some individuals not responding at all. The experimental protocol also influenced the onset of air-breathing. Air-breathing began at lower Pw CO2 in the step-wise protocol (23 ± 4.1 mmHg) compared with the progressive protocol (46 ± 7.8 mmHg). Air-breathing was often followed by aquatic surface respiration, at higher PCO2 (71 ± 5.2 mmHg) levels. On average, the blood PCO2 was approximately 43% lower (46 ± 2.5 mmHg) than water Pw CO2 (~81 mmHg) at our highest tested CO2 level. While this suggests that aerial CO2 elimination is an effective, and perhaps critical, respiratory strategy used by P. hypophthalmus to cope with severe hypercarbia, this observation may also be explained by a long lag time required for equilibration.
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Affiliation(s)
- Rachael Morgan
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Louise Tunnah
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Dang D Tuong
- Department of Aquatic Nutrition and Products Processing, College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | - Per Hjelmstedt
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, Skara, Sweden
| | - Pham N Nhu
- Department of Aquatic Nutrition and Products Processing, College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | - Kevin T Stiller
- Production Biology - The Norwegian Institute of Food, Fisheries and Aquaculture Research, Nofima AS, Sjølseng, Sunndalsøra, Norway
| | - Nguyen Thanh Phuong
- Department of Aquatic Nutrition and Products Processing, College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | - Do Thi Thanh Huong
- Department of Aquatic Nutrition and Products Processing, College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | - Mark Bayley
- Department of Bioscience, Zoophysiology, Aarhus, Denmark
| | - Tobias Wang
- Department of Bioscience, Zoophysiology, Aarhus, Denmark
| | - William K Milsom
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
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Nhu TQ, Dam NP, Bich Hang BT, Bach LT, Thanh Huong DT, Buu Hue BT, Scippo ML, Phuong NT, Quetin-Leclercq J, Kestemont P. Immunomodulatory potential of extracts, fractions and pure compounds from Phyllanthus amarus and Psidium guajava on striped catfish (Pangasianodon hypophthalmus) head kidney leukocytes. Fish Shellfish Immunol 2020; 104:289-303. [PMID: 32544554 DOI: 10.1016/j.fsi.2020.05.051] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [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: 02/22/2020] [Revised: 05/14/2020] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
This study aimed to identify major phytochemical constituents, as well as compare the immunomodulatory effects of Psidium guajava L. and Phyllanthus amarus Schun and Thonn crude ethanol extracts and their fractions on striped catfish (Pangasianodon hypophthalmus) head kidney leukocytes (HKLs). Moreover, pure constituents were also investigated for their effects on those cells: hypophyllanthin, identified as a major constituent of P. amarus crude extracts and its hexane fraction; corosolic acid, ursolic acid, and oleanolic acid, identified in P. guajava crude extract, ethyl acetate and dichloromethane fractions; with other terpenic derivatives, as well as guajaverin and avicularin, identified with other flavonoids by LC-UV-MS in the crude P. guajava extract and its ethyl acetate fraction. Cell viability, respiratory burst assay (RBA), nitric oxide synthase (NOS) and lysozyme activity in HKLs were analyzed after 24 h stimulation with each extract (10, 20 and 40 μg/mL) or pure compound (7.5, 15 and 30 μM). Our results show that the hexane fraction of both plant extracts inhibited the viability of HKLs, while several other fractions enhanced the cell viability. All P. guajava fractions at all or some concentration considerably enhanced the RBA production in HKLs. Similarly, NOS production was also significantly increased by some or all concentrations of P. guajava dichloromethane and ethyl acetate fractions. However, the NOS production was dose-dependently inhibited in HKLs treated with Pa ethyl acetate and both plants aqueous fractions at 10 or 10 and 40 μg/mL respectively. The lysozyme activity in cells treated with P. guajava crude extracts and all its organic solvent fractions were stronger than those in P. amarus treatments. Pure compounds including corosolic acid, guajaverin, ursolic acid, hypophyllanthin inhibited the HKLs viability according to concentration and type of compound. All pure compounds except avicularin significantly stimulated, at certain or all concentrations, the RBA production and/or the lysozyme activity in HKLs. The NOS production was significantly reduced in HKLs treated with oleanolic acid (30 μM) and hypophyllanthin (7.5 μM) while its level was increased by hypophyllanthin at 30 μM. These results highlighted that the crude ethanol extracts of P. guajava and P. amarus, their fractions and some of their pure components at certain concentrations can potentially act as immunomodulators, and could be considered as valuable candidates in fishery sciences.
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Affiliation(s)
- Truong Quynh Nhu
- Research Unit in Environmental and Evolutionary Biology (URBE), Institute of Life, Earth and Environment (ILEE), University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium; College of Aquaculture and Fisheries, Cantho University, Campus II, Cantho City, Viet Nam.
| | - Nguyen Phuc Dam
- Department of Chemistry Education, School of Education, Can Tho University, Can Tho City, Viet Nam; Louvain Drug Research Institute (LDRI) Pharmacognosy Research Group, Université Catholique de Louvain, B-1200, Brussels, Belgium.
| | - Bui Thi Bich Hang
- College of Aquaculture and Fisheries, Cantho University, Campus II, Cantho City, Viet Nam.
| | - Le Thi Bach
- Department of Chemistry, College of Natural Sciences, Can Tho University, Can Tho City, Viet Nam.
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Cantho University, Campus II, Cantho City, Viet Nam.
| | - Bui Thi Buu Hue
- Department of Chemistry, College of Natural Sciences, Can Tho University, Can Tho City, Viet Nam.
| | - Marie-Louise Scippo
- Department of Food Sciences, Laboratory of Food Analysis, Faculty of Veterinary Medicine, Fundamental and Applied Research for Animals & Health (FARAH), Veterinary Public Health, University of Liège, Bât. B43bis, 10 Avenue de Cureghem, Sart-Tilman, Liège, Belgium.
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Cantho University, Campus II, Cantho City, Viet Nam.
| | - Joëlle Quetin-Leclercq
- Louvain Drug Research Institute (LDRI) Pharmacognosy Research Group, Université Catholique de Louvain, B-1200, Brussels, Belgium.
| | - Patrick Kestemont
- Research Unit in Environmental and Evolutionary Biology (URBE), Institute of Life, Earth and Environment (ILEE), University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium.
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Nhu TQ, Bich Hang BT, Cornet V, Oger M, Bach LT, Anh Dao NL, Thanh Huong DT, Quetin-Leclercq J, Scippo ML, Phuong NT, Kestemont P. Single or Combined Dietary Supply of Psidium guajava and Phyllanthus amarus Extracts Differentially Modulate Immune Responses and Liver Proteome in Striped Catfish ( Pangasianodon hyphophthalmus). Front Immunol 2020; 11:797. [PMID: 32431710 PMCID: PMC7214933 DOI: 10.3389/fimmu.2020.00797] [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: 11/19/2019] [Accepted: 04/07/2020] [Indexed: 01/16/2023] Open
Abstract
Guava Psidium guajava L (Pg) and bhumi amla Phyllanthus amarus Schum. et Thonn (Pa) are well-known plants in traditional medicine. However, the capacity of these plants for improving the immune system of aquatic species has received less attention so far. This study aimed to investigate the effects of single supply or mixture of Pg and Pa extracts on immune responses, disease resistance and liver proteome profiles in striped catfish Pangasianodon hypophthalmus. Fish were fed diets including basal diet 0% or one of three doses of each plant extract, either alone or in mixture, 0.08, 0.2, or 0.5% Pg, Pa or mixture (Pg:Pa, v/v) for 6 weeks. The immune parameters (respiratory burst activity (RBA); nitric oxide synthase (NOS), total immunoglobulin, lysozyme, and complement activities) were examined at W3, W6 post-feeding, and after challenge test. The growth parameters and the challenge test with Edwardsiella ictaluri were done at W6. The liver proteome profiles were analyzed in W6 at 0.08 and 0.5% of each extract. The results showed that extract-based diets significantly improved growth parameters in the Pg0.2 group compared to control. The cellular immune responses in spleen and the humoral immune responses in plasma were significantly improved in a dose and time-dependent manner. Diets supplemented with single Pg and Pa extracts, and to lesser extent to combined extracts, could significantly decrease the mortality of striped catfish following bacterial infection compared to control. The proteomic results indicated that some pathways related to immune responses, antioxidant and lipid metabolism were enriched in liver at W6. Several proteins (i.e., CD8B, HSP90AA1, HSP90AB1, PDIA3, CASP8, TUBA1C, CCKAR, GNAS, GRIN2D, PLCG1, PRKCA, SLC25A5, VDAC2, ACTN4, GNAI2, LCK, CARD9, NLRP12, and NLRP3) were synergistically upregulated in mixture of Pg and Pa-based diets compared to control and single dietary treatments. Taken together, the results revealed that single Pg and Pa extracts at 0.2 and 0.5% and their mixture at 0.08 and 0.5% have the potential to modulate the immune mechanisms and disease resistance of striped catfish. Moreover, the combination of Pg and Pa in diets suggested positive synergistic effects liver proteome profile related to immune system processes.
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Affiliation(s)
- Truong Quynh Nhu
- Research Unit in Environmental and Evolutionary Biology (URBE), Institute of Life, Earth and Environment, University of Namur, Namur, Belgium.,College of Aquaculture and Fisheries, Cantho University, Cantho City, Vietnam
| | - Bui Thi Bich Hang
- College of Aquaculture and Fisheries, Cantho University, Cantho City, Vietnam
| | - Valérie Cornet
- Research Unit in Environmental and Evolutionary Biology (URBE), Institute of Life, Earth and Environment, University of Namur, Namur, Belgium
| | - Mathilde Oger
- Research Unit in Environmental and Evolutionary Biology (URBE), Institute of Life, Earth and Environment, University of Namur, Namur, Belgium
| | - Le Thi Bach
- College of Natural Sciences, Cantho University, Cantho City, Vietnam
| | - Nguyen Le Anh Dao
- College of Aquaculture and Fisheries, Cantho University, Cantho City, Vietnam
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Cantho University, Cantho City, Vietnam
| | - Joëlle Quetin-Leclercq
- Pharmacognosy Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Marie-Louise Scippo
- Laboratory of Food Analysis, Department of Food Sciences, Faculty of Veterinary Medicine, Fundamental and Applied Research for Animals & Health, Veterinary Public Health, University of Liège, Liège, Belgium
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Cantho University, Cantho City, Vietnam
| | - Patrick Kestemont
- Research Unit in Environmental and Evolutionary Biology (URBE), Institute of Life, Earth and Environment, University of Namur, Namur, Belgium
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9
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Le Anh Dao N, Phu TM, Douny C, Quetin-Leclercq J, Hue BTB, Bach LT, Quynh Nhu T, Thi Bich Hang B, Thi Thanh Huong D, Thanh Phuong N, Kestemont P, Scippo ML. Screening and comparative study of in vitro antioxidant and antimicrobial activities of ethanolic extracts of selected Vietnamese plants. International Journal of Food Properties 2020. [DOI: 10.1080/10942912.2020.1737541] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Nguyen Le Anh Dao
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
- FARAH – Veterinary Public Health, Laboratory of Food Analysis, University of Liège, Liege, Belgium
| | - Tran Minh Phu
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Caroline Douny
- FARAH – Veterinary Public Health, Laboratory of Food Analysis, University of Liège, Liege, Belgium
| | - Joëlle Quetin-Leclercq
- Louvain Drug Research Institute, Pharmacognosy Research Group, Université Catholique De Louvain, Brussels, Belgium
| | - Bui Thi Buu Hue
- College of Natural Sciences, Can Tho University, Can Tho City, Vietnam
| | - Le Thi Bach
- College of Natural Sciences, Can Tho University, Can Tho City, Vietnam
| | - Truong Quynh Nhu
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Bui Thi Bich Hang
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Patrick Kestemont
- Research Unit in Environmental and Evolutionary Biology, Research Institute of Life, Earth & Environment (ILEE), University of Namur, Namur, Belgium
| | - Marie-Louise Scippo
- FARAH – Veterinary Public Health, Laboratory of Food Analysis, University of Liège, Liege, Belgium
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10
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Gam LTH, Thanh Huong DT, Tuong DD, Phuong NT, Jensen FB, Wang T, Bayley M. Effects of temperature on acid-base regulation, gill ventilation and air breathing in the clown knifefish, Chitala ornata. J Exp Biol 2020; 223:jeb216481. [PMID: 32001546 DOI: 10.1242/jeb.216481] [Citation(s) in RCA: 3] [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] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 01/23/2020] [Indexed: 11/20/2022]
Abstract
Chitala ornata is a facultative air-breathing fish, which at low temperatures shows an arterial PCO2 (PaCO2 ) level only slightly elevated above that of water breathers. By holding fish with in-dwelling catheters at temperatures from 25 to 36°C and measuring blood gasses, we show that this animal follows the ubiquitous poikilotherm pattern of reducing arterial pH with increasing temperature. Surprisingly, the temperature increase caused an elevation of PaCO2 from 5 to 12 mmHg while the plasma bicarbonate concentration remained constant at around 8 mmol l-1 The temperature increase also gave rise to a larger fractional increase in air breathing than in gill ventilation frequency. These findings suggest that air breathing, and hence the partitioning of gas exchange, is to some extent regulated by acid-base status in air-breathing fish and that these bimodal breathers will be increasingly likely to adopt respiratory pH control as temperature rises, providing an interesting avenue for future research.
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Affiliation(s)
- Le Thi Hong Gam
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Dang Diem Tuong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Frank Bo Jensen
- Department of Biology, University of Southern Denmark, 5230 Odense, Denmark
| | - Tobias Wang
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
- Aarhus Institute of Advanced Studies, 8000 Aarhus C, Denmark
| | - Mark Bayley
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
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11
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Nhu TQ, Bich Hang BT, Vinikas A, Bach LT, Buu Hue BT, Thanh Huong DT, Quetin-Leclercq J, Scippo ML, Phuong NT, Kestemont P. Screening of immuno-modulatory potential of different herbal plant extracts using striped catfish (Pangasianodon hypophthalmus) leukocyte-based in vitro tests. Fish Shellfish Immunol 2019; 93:296-307. [PMID: 31352112 DOI: 10.1016/j.fsi.2019.07.064] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [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: 03/02/2019] [Revised: 07/16/2019] [Accepted: 07/24/2019] [Indexed: 06/10/2023]
Abstract
Many medicinal plants have been shown to possess biological effects, including immuno-modulatory activities on human and other mammals. However, studies about the potential mechanisms of plant extracts on the humoral and tissular immunities in fish have received less attention. This study aimed to screen the immunestimulating properties of 20 ethanol plant extracts on striped catfish Pangasianodon hypophthalmus leukocytes. The peripheral blood mononuclear cells (PBMCs) and head kidney leukocytes (HKLs) of striped catfish (50 ± 5 g per fish) were stimulated at 10 and 100 μg of each plant extract per mL of cell culture medium. Several humoral immune parameters (lysozyme, complement and total immunoglobulin) were examined at 24-h post stimulation (hps). Furthermore, the responses of four cytokine genes, namely il1β, ifrγ 2a and b, and mhc class II were assessed by quantitative real-time PCR at 6, 12, 24, and 48 hps. The results showed that lysozyme, complement as well as total immunoglobulin levels in both PBMCs and HKLs were regulated by some of the plant extracts tested in a concentration-dependent manner; some plant extracts induced the highest immune responses at the low dose (10 μg mL-1) while others were more efficient at high dose (100 μg mL-1). Among the extracts, five extracts including garlic Allium sativum L. (As), neem Azadirachta indica A. Juss (Ai), asthma-plant Euphorbia hirta L. (Eh), bhumi amla Phyllanthus amarus Schum. et Thonn (Pa), and ginger Zingiber officinale Rosc (Zo) induced significant changes in the expression of pro-inflammatory cytokine (il1β), antiviral cytokines (ifrγ 2a and b) and adaptive immune cytokine (mhc class II) in striped catfish cells. Pa always modulated the strongest expression of the four cytokines in PBMCs and HKLs over the whole experimental period (p < 0.05), whereas Zo did not stimulate the mhc class II expression in striped catfish leukocytes throughout experimental periods. These in vitro results demonstrated that some plant extracts could differently modulate great potential immune response in fish, supporting their applications in further in vivo experiments.
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Affiliation(s)
- Truong Quynh Nhu
- Research Unit in Environmental and Evolutionary Biology (URBE), Institute of Life, Earth and Environment (ILEE), University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium; College of Aquaculture and Fisheries, Cantho University, Campus II, Cantho City, Viet Nam.
| | - Bui Thi Bich Hang
- College of Aquaculture and Fisheries, Cantho University, Campus II, Cantho City, Viet Nam.
| | - Anais Vinikas
- Pharmacognosy Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Avenue E. Mounier, 72 bte B1. 72.03, Brussels, Belgium.
| | - Le Thi Bach
- College of Natural Sciences, Cantho University, Campus II, Cantho City, Viet Nam.
| | - Bui Thi Buu Hue
- College of Natural Sciences, Cantho University, Campus II, Cantho City, Viet Nam.
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Cantho University, Campus II, Cantho City, Viet Nam.
| | - Joëlle Quetin-Leclercq
- Pharmacognosy Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Avenue E. Mounier, 72 bte B1. 72.03, Brussels, Belgium.
| | - Marie-Louise Scippo
- Department of Food Sciences, Laboratory of Food Analysis, Faculty of Veterinary Medicine, Fundamental and Applied Research for Animals & Health (FARAH), Veterinary Public Health, University of Liège, bât. B43bis, 10 Avenue de Cureghem, Sart-Tilman, Liège, Belgium.
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Cantho University, Campus II, Cantho City, Viet Nam.
| | - Patrick Kestemont
- Research Unit in Environmental and Evolutionary Biology (URBE), Institute of Life, Earth and Environment (ILEE), University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium.
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12
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Tuong DD, Huong DTT, Phuong NT, Bayley M, Milsom WK. Ventilatory responses of the clown knifefish, Chitala ornata, to arterial hypercapnia remain after gill denervation. J Comp Physiol B 2019; 189:673-683. [PMID: 31552490 DOI: 10.1007/s00360-019-01236-6] [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] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 08/22/2019] [Accepted: 09/12/2019] [Indexed: 01/20/2023]
Abstract
The aim of this study was to corroborate the presence of CO2/H+-sensitive arterial chemoreceptors involved in producing air-breathing responses to aquatic hypercarbia in the facultative air-breathing clown knifefish (Chitala ornata) and to explore their possible location. Progressively increasing levels of CO2 mixed with air were injected into the air-breathing organ (ABO) of one group of intact fish to elevate internal PCO2 and decrease blood pH. Another group of fish in which the gills were totally denervated was exposed to aquatic hypercarbia (pH ~ 6) or arterial hypercapnia in aquatic normocarbia (by injection of acetazolamide to increase arterial PCO2 and decrease blood pH). Air-breathing frequency, gill ventilation frequency, heart rate and arterial PCO2 and pH were recorded during all treatments. The CO2 injections into the ABO induced progressive increases in air-breathing frequency, but did not alter gill ventilation or heart rate. Exposure to both hypercarbia and acetazolamide post-denervation of the gills also produced significant air-breathing responses, but no changes in gill ventilation. While all treatments produced increases in arterial PCO2 and decreases in blood pH, the modest changes in arterial PCO2/pH in the acetazolamide treatment produced the greatest increases in air-breathing frequency. These results strengthen the evidence that internal CO2/H+ sensing is involved in the stimulation of air breathing in clown knifefish and suggest that it involves extra-branchial chemoreceptors possibly situated either centrally or in the air-breathing organ.
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Affiliation(s)
- Dang Diem Tuong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam.
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | | | - Mark Bayley
- Department of Bioscience Zoophysiology, Aarhus University, Aarhus, Denmark
| | - William K Milsom
- Department of Zoology, University of British Columbia, Vancouver, Canada
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13
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Ha NTK, Huong DTT, Phuong NT, Bayley M, Jensen FB. Impact and tissue metabolism of nitrite at two acclimation temperatures in striped catfish (Pangasianodon hypophthalmus). Aquat Toxicol 2019; 212:154-161. [PMID: 31128416 DOI: 10.1016/j.aquatox.2019.05.008] [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] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 05/06/2019] [Accepted: 05/14/2019] [Indexed: 06/09/2023]
Abstract
Elevated concentrations of nitrite develop occasionally in various aquatic habitats and aquaculture facilities, providing a potential danger for freshwater fish that take up nitrite via the gill chloride uptake mechanism. We studied the uptake, effects and metabolism of nitrite in blood, heart and skeletal muscle at two temperatures in striped catfish Pangasianodon hypophthalmus, a facultative air-breathing fish that is heavily cultivated in Southeast Asia. Exposure to 0.8 mM ambient nitrite increased blood [nitrite] and [methaemoglobin] (metHb) to high values at day 1, but values subsequently decreased towards controls at day 7. Blood [nitrite] and metHb content were unexpectedly higher at 27 °C (∼1.2 mM; 69% at day 1) than at 33 °C (∼0.9 mM; 55%), reflecting a lower nitrite uptake at the highest temperature, possibly via an increased reliance on air-breathing relative to water-breathing with temperature increase. A large fraction of the nitrite taken up was effectively eliminated by being detoxified to nitrate. Further, erythrocyte metHb reductase activity was increased during nitrite exposure, efficiently reducing metHb to functional haemoglobin. The uptake of nitrite into white skeletal musculature (main part of the fish) was much lower than into heart tissue. While heart [nitrite] was close to blood plasma levels, muscle [nitrite] peaked at ∼0.2 mM at day 1 and subsequently declined to ∼0.05 mM at day 7, which is below levels reported in various commercial cured meat products. Nitrite was partly metabolized to iron-nitrosyl, S-nitroso and N-nitroso compounds. The increase in nitros(yl)ated compounds was marginal in skeletal muscle and more pronounced in heart tissue.
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Affiliation(s)
- Nguyen Thi Kim Ha
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Viet Nam; Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark; Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Viet Nam
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Viet Nam
| | - Mark Bayley
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Frank Bo Jensen
- Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
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14
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Thinh PV, Thanh Huong DT, Gam LTH, Damsgaard C, Phuong NT, Bayley M, Wang T. Renal acid excretion contributes to acid-base regulation during hypercapnia in air-exposed swamp eel ( Monopterus albus). ACTA ACUST UNITED AC 2019; 222:jeb.198259. [PMID: 30975740 DOI: 10.1242/jeb.198259] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [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: 12/13/2018] [Accepted: 04/07/2019] [Indexed: 02/02/2023]
Abstract
The swamp eel (Monopterus albus) uses its buccal cavity to air breathe, while the gills are strongly reduced. It burrows into mud during the dry season, is highly tolerant of air exposure, and experiences severe hypoxia both in its natural habitat and in aquaculture. To study the ability of M. albus to compensate for respiratory acidosis, we implanted catheters to sample both arterial blood and urine during hypercapnia (4% CO2) in either water or air, or during whole-animal air exposure. These hypercapnic challenges caused an immediate reduction in arterial pH, followed by progressive compensation through a marked elevation of plasma HCO3 - over the course of 72 h. There was no appreciable rise in urinary acid excretion in fish exposed to hypercapnia in water, although urine pH was reduced and ammonia excretion did increase. In the air-exposed fish, however, hypercapnia was attended by a large elevation of ammonia in the urine and a large rise in titratable acid excretion. The time course of the increased renal acid excretion overlapped with the time period required to elevate plasma HCO3 -, and we estimate that the renal compensation contributed significantly to whole-body acid-base compensation.
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Affiliation(s)
- Phan Vinh Thinh
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam.,Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Le Thi Hong Gam
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Christian Damsgaard
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Mark Bayley
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| | - Tobias Wang
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark .,Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus C, Denmark
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15
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Sackville MA, Shartau RB, Damsgaard C, Hvas M, Phuong LM, Wang T, Bayley M, Thanh Huong DT, Phuong NT, Brauner CJ. Water pH limits extracellular but not intracellular pH compensation in the CO 2-tolerant freshwater fish Pangasianodon hypophthalmus. ACTA ACUST UNITED AC 2018; 221:jeb.190413. [PMID: 30352827 DOI: 10.1242/jeb.190413] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [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: 08/07/2018] [Accepted: 10/17/2018] [Indexed: 11/20/2022]
Abstract
Preferentially regulating intracellular pH (pHi) confers exceptional CO2 tolerance on fish, but is often associated with reductions in extracellular pH (pHe) compensation. It is unknown whether these reductions are due to intrinsically lower capacities for pHe compensation, hypercarbia-induced reductions in water pH or other factors. To test how water pH affects capacities and strategies for pH compensation, we exposed the CO2-tolerant fish Pangasianodon hypophthalmus to 3 kPa P CO2 for 20 h at an ecologically relevant water pH of 4.5 or 5.8. Brain, heart and liver pHi was preferentially regulated in both treatments. However, blood pHe compensation was severely reduced at water pH 4.5 but not 5.8. This suggests that low water pH limits acute pHe but not pHi compensation in fishes preferentially regulating pHi Hypercarbia-induced reductions in water pH might therefore underlie the unexplained reductions to pHe compensation in fishes preferentially regulating pHi, and may increase selection for preferential pHi regulation.
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Affiliation(s)
- Michael A Sackville
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Ryan B Shartau
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | | | - Malthe Hvas
- Department of Bioscience, Aarhus University, 8000 Aarhus-C, Denmark
| | - Le My Phuong
- College of Aquaculture and Fisheries, Can Tho University, 92000 Can Tho City, Vietnam
| | - Tobias Wang
- Department of Bioscience, Aarhus University, 8000 Aarhus-C, Denmark
| | - Mark Bayley
- Department of Bioscience, Aarhus University, 8000 Aarhus-C, Denmark
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, 92000 Can Tho City, Vietnam
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Can Tho University, 92000 Can Tho City, Vietnam
| | - Colin J Brauner
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
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16
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Gam LTH, Jensen FB, Huong DTT, Phuong NT, Bayley M. The effects of elevated environmental CO 2 on nitrite uptake in the air-breathing clown knifefish, Chitala ornata. Aquat Toxicol 2018; 196:124-131. [PMID: 29367072 DOI: 10.1016/j.aquatox.2018.01.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [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: 10/30/2017] [Revised: 01/09/2018] [Accepted: 01/13/2018] [Indexed: 06/07/2023]
Abstract
Nitrite and carbon dioxide are common environmental contaminants in the intensive aquaculture ponds used to farm clown knifefish (Chitala ornata) in the Mekong delta, Vietnam. Here we tested the hypothesis that hypercapnia reduces nitrite uptake across the gills, because pH regulation will reduce chloride uptake and hence nitrite uptake as the two ions compete for the same transport route via the branchial HCO3-/Cl- exchanger. Fish fitted with arterial catheters were exposed to normocapnic/normoxic water (control), nitrite (1 mM), hypercapnia (21 mmHg CO2), or combined hypercapnia (acclimated hypercapnia) and nitrite for 96 h. Blood was sampled to measure acid-base status, haemoglobin derivatives and plasma ions. Plasma nitrite increased for 48 h, but levels stayed below the exposure concentration, and subsequently decreased as a result of nitrite detoxification to nitrate. The total uptake of nitrite (evaluated as [NO2-] + [NO3-]) was significantly decreased in hypercapnia, in accordance with the hypothesis. Methemoglobin and nitrosylhemoglobin levels were similarly lower during hypercapnic compared to normocapnic nitrite exposure. The respiratory acidosis induced by hypercapnia was half-compensated by bicarbonate accumulation in 96 h, which was mainly chloride-mediated (i.e. reduced Cl- influx via the branchial HCO3-/Cl- exchanger). Plasma osmolality and main ions (Na+, Cl-) were significantly decreased by hypercapnia and by nitrite exposure, consistent with inhibition of active transport. We conclude that hypercapnia induces a long-lasting, and mainly chloride-mediated acid-base regulation that reduces the uptake of nitrite across the gills.
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Affiliation(s)
- Le Thi Hong Gam
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Viet Nam
| | - Frank Bo Jensen
- Department of Biology, University of Southern Denmark, Odense, Denmark
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Viet Nam
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Viet Nam
| | - Mark Bayley
- Zoophysiology, Department of Bioscience, Aarhus University, Building 1131 C.F. Møllers Allé 3, DK-8000 Aarhus C., Denmark.
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17
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Phuong LM, Huong DTT, Malte H, Nyengaard JR, Bayley M. Ontogeny and morphometrics of the gills and swim bladder of air-breathing striped catfish Pangasianodon hypophthalmus. ACTA ACUST UNITED AC 2018; 221:jeb.168658. [PMID: 29191864 DOI: 10.1242/jeb.168658] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [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: 08/21/2017] [Accepted: 11/27/2017] [Indexed: 11/20/2022]
Abstract
The air-breathing fish Pangasianodon hypophthalmus has been shown to have highly plastic branchial surfaces whose area (SA) increases with temperature and aquatic hypoxia. This modulation occurs through development of inter-lamellar cell mass (ILCM). Paradoxically, in conditions where this fish has been shown capable of covering its entire aerobic scope from the water phase, it has been shown to have a very small branchial SA. To address this paradox, we measured the SA, harmonic mean diffusion distance (τh) and calculated the anatomic diffusion factor (ADF) of the branchial and swim bladder surfaces in fish ranging from 3 to 1900 g at 27°C in normoxia. Since the lamellae were distinguishable from the ILCM, we measured the actual SA as well as the potential SA if ILCM were lost. As a result of low τh, P. hypophthalmus has a high capacity for branchial oxygen uptake with or without ILCM. Actual and potential gill ADF were 361 and 1002 cm2 µm-1 kg-1, respectively, for a 100 g fish and the ADF of the swim bladder was found to be 308 cm2 µm-1 kg-1 By swimming fish to exhaustion at different temperatures, we show that modulation of this SA is rapid, indicating that the apparent paradox between previous studies is eliminated. Regression analysis of log-log plots of respiratory SA in relation to body mass shows that the gill scales with mass similarly to the SA in active water-breathing fish, whereas the swim bladder scales with mass more like the mammalian lung does. This fish presents a combination of respiratory surfaces not previously seen in air-breathing fish.
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Affiliation(s)
- Le My Phuong
- Zoophysiology Section, Department of Bioscience, Aarhus University, Denmark.,Department of Aquatic Nutrition and Products Processing, College of Aquaculture and Fisheries, Can Tho University, 900000 Can Tho City, Vietnam
| | - Do Thi Thanh Huong
- Department of Aquatic Nutrition and Products Processing, College of Aquaculture and Fisheries, Can Tho University, 900000 Can Tho City, Vietnam
| | - Hans Malte
- Zoophysiology Section, Department of Bioscience, Aarhus University, Denmark
| | - Jens Randel Nyengaard
- Core Center for Molecular Morphology, Section for Stereology and Microscopy, Department of Clinical Medicine, Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, 8000 Aarhus C, Denmark
| | - Mark Bayley
- Zoophysiology Section, Department of Bioscience, Aarhus University, Denmark
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18
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Thinh NQ, Phu TM, Douny C, Phuong NT, Huong DTT, Kestemont P, Scippo ML. Bioconcentration and half-life of quinalphos pesticide in rice-fish integration system in the Mekong Delta, Vietnam. J Environ Sci Health B 2018; 53:35-41. [PMID: 29035631 DOI: 10.1080/03601234.2017.1371551] [Citation(s) in RCA: 2] [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] [Indexed: 06/07/2023]
Abstract
In order to determine the distribution and enable the elimination of quinalphos, a popular active pesticide compound used in the Mekong Delta, an experiment was set up in a rice-fish integration system in Can Tho City, Vietnam. Fish was stocked into the field when the rice was two-months old. Quinalphos was applied twice in doses of 42.5 g per 1000 m2. Water, fish and sediment samples were collected at time intervals and analyzed by a Gas Chromatography Electron Capture Detector system. The results show that quinalphos residues in fish muscles were much higher than those of the water and the bioconcentration factor (logBCF) was above 2 for the fish. The half-life of first and second quinalphos applications were 12.2 and 11.1 days for sediment, 2.5 and 1.1 days for silver barb, 1.9 and 1.3 days for common carp, and 1.1 and 1.0 days for water, respectively.
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Affiliation(s)
- Nguyen Quoc Thinh
- a Department of Fish Nutrition and Aquatic Food Processing , College of Aquaculture and Fisheries, Can Tho University , Can Tho City , Vietnam
- b Department of Food Sciences, Laboratory of Food Analysis , FARAH - Veterinary Public Health, University of Liège , Liège , Belgium
| | - Tran Minh Phu
- a Department of Fish Nutrition and Aquatic Food Processing , College of Aquaculture and Fisheries, Can Tho University , Can Tho City , Vietnam
| | - Caroline Douny
- b Department of Food Sciences, Laboratory of Food Analysis , FARAH - Veterinary Public Health, University of Liège , Liège , Belgium
| | - Nguyen Thanh Phuong
- a Department of Fish Nutrition and Aquatic Food Processing , College of Aquaculture and Fisheries, Can Tho University , Can Tho City , Vietnam
| | - Do Thi Thanh Huong
- a Department of Fish Nutrition and Aquatic Food Processing , College of Aquaculture and Fisheries, Can Tho University , Can Tho City , Vietnam
| | - Patrick Kestemont
- c Research Unit in Environmental and Evolutionary Biology, University of Namur , Namur , Belgium
| | - Marie-Louise Scippo
- b Department of Food Sciences, Laboratory of Food Analysis , FARAH - Veterinary Public Health, University of Liège , Liège , Belgium
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Thinh PV, Phuong NT, Brauner CJ, Huong DTT, Wood AT, Kwan GT, Conner JL, Bayley M, Wang T. Acid-base regulation in the air-breathing swamp eel (Monopterus albus) at different temperatures. J Exp Biol 2018; 221:jeb.172551. [DOI: 10.1242/jeb.172551] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 02/12/2018] [Indexed: 11/20/2022]
Abstract
Vertebrates reduce arterial blood pH (pHa) when body temperature increases. In water-breathers this response occurs primarily by reducing plasma HCO3− levels with small changes in the partial pressure of CO2 (PCO2). In contrast, air-breathers mediate the decrease in pHa by increasing arterial PCO2 (PaCO2) at constant plasma HCO3− by reducing lung ventilation relative to metabolic CO2 production. Much less is known in bimodal breathers that utilize both water and air. Here, we characterize the influence of temperature on arterial acid-base balance and intracellular pH (pHi) in the bimodal breathing swamp eel, Monopterus albus. This teleost uses the buccopharyngeal cavity for gas exchange and has very reduced gills. When exposed to ecologically relevant temperatures (20, 25, 30 and 35°C) for 24 and 48h, pHa decreased by -0.025 pH units/°C (U/°C) in association with an increased PaCO2, but without changes in plasma [HCO3−]. Intracellular pH (pHi) was also reduced with increased temperature. The slope of pHi of liver and muscle was -0.014 and -0.019 U/°C, while the heart muscle showed a smaller reduction (-0.008U/°C). When exposed to hypercapnia (7 or 14 mmHg) at either 25 or 35°C, Monopterus albus elevated plasma [HCO3−] and therefore seemed to defend the new pHa set-point, demonstrating an adjusted control of acid-base balance with temperature. Overall, the effects of temperature on acid-base balance in Monopterus albus resemble air-breathing amniotes, and we discuss the possibility that this pattern of acid-base balance results from a progressive transition in CO2 excretion from water to air as temperature rises.
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Affiliation(s)
- Phan Vinh Thinh
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Colin J. Brauner
- Department of Zoology, University of British Columbia, 6270 University Blvd.,Vancouver, BC, V6T 1Z4, Canada
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | | | - Garfield T. Kwan
- Scripps Institution of Oceanography, University of California San Diego, USA
| | | | - Mark Bayley
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Tobias Wang
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
- Aarhus Institute of Advanced Studies, 8000 Aarhus C, Denmark
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20
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Gam LTH, Jensen FB, Damsgaard C, Huong DTT, Phuong NT, Bayley M. Extreme nitrite tolerance in the clown knifefish Chitala ornata is linked to up-regulation of methaemoglobin reductase activity. Aquat Toxicol 2017; 187:9-17. [PMID: 28351760 DOI: 10.1016/j.aquatox.2017.03.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [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: 01/24/2017] [Revised: 03/09/2017] [Accepted: 03/15/2017] [Indexed: 06/06/2023]
Abstract
The clown knifefish is a facultative air breather, which is widely farmed in freshwater ponds in Vietnam. Here we report a very high nitrite tolerance (96h LC50 of 7.82mM) in this species and examine the effects of 1mM (LC5) and 2.5mM (LC10) ambient nitrite on haemoglobin (Hb) derivatives, electrolyte levels, acid-base status, and total body water content during 7days of exposure. Furthermore, we tested the hypothesis that erythrocyte methaemoglobin (metHb) reductase activity is upregulated by nitrite exposure. Plasma nitrite levels increased for 2-3days but stayed below environmental levels and fell towards control values during the last half of the exposure period. Plasma nitrate, in contrast, rose continuously, reflecting detoxification of nitrite to nitrate. MetHb generated from the reaction between nitrite and erythrocyte Hb reached 38% at day 2, but then decreased to 17% by the end of experiment. The first order rate constant for metHb reduction by erythrocyte metHb reductase increased from 0.01 in controls to 0.046min-1 after 6days of nitrite exposure, showing up-regulation of this enzyme. While such upregulation has been suggested in nitrite-exposed fish species, this study provides the first experimental evidence.
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Affiliation(s)
- Le Thi Hong Gam
- College of Aquaculture and Fisheries, Can Tho Uiniversity, Can Tho City, Viet Nam
| | - Frank Bo Jensen
- Department of Biology, University of Southern Denmark, Odense, Denmark
| | | | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho Uiniversity, Can Tho City, Viet Nam
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Can Tho Uiniversity, Can Tho City, Viet Nam
| | - Mark Bayley
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark.
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21
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Hvas M, Damsgaard C, Gam LTH, Huong DTT, Jensen FB, Bayley M. The effect of environmental hypercapnia and size on nitrite toxicity in the striped catfish (Pangasianodon hypophthalmus). Aquat Toxicol 2016; 176:151-160. [PMID: 27135703 DOI: 10.1016/j.aquatox.2016.04.020] [Citation(s) in RCA: 6] [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] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 04/07/2016] [Accepted: 04/21/2016] [Indexed: 06/05/2023]
Abstract
Striped catfish (Pangasianodon hypophthalmus) are farmed intensively at high stocking densities in Vietnam where they are likely to encounter environmental hypercapnia as well as occasional high levels of aquatic nitrite. Nitrite competes with Cl(-) for uptake at the branchial HCO3(-)/Cl(-) exchanger, causing a drastic reduction in the blood oxygen carrying capacity through the formation of methaemoglobin and nitrosylhaemoglobin. Environmental hypercapnia induces a respiratory acidosis where the branchial HCO3(-)/Cl(-) exchange activity is reduced in order to retain HCO3(-) for pH recovery, which should lead to a reduced nitrite uptake. To assess the effect of hypercapnia on nitrite uptake, fish were cannulated in the dorsal aorta, allowing repeated blood sampling for measurements of haemoglobin derivatives, plasma ions and acid-base status during exposure to 0.9mM nitrite alone and in combination with acute and 48h acclimated hypercapnia over a period of 72h. Nitrite uptake was initially reduced during the hypercapnia-induced acidosis, but after pH recovery the situation was reversed, resulting in higher plasma nitrite concentrations and lower functional haemoglobin levels that eventually caused mortality. This suggests that branchial HCO3(-)/Cl(-) exchange activity is reduced only during the initial acid-base compensation, but subsequently increases with the greater availability of internal HCO3(-) counter-ions as pH is compensated. The data further suggest that branchial Na(+)/H(+) exchange plays a significant role in the initial phase of acid-base compensation. Overall, longer term environmental hypercapnia does not protect against nitrite uptake in P. hypophthalmus, but instead enhances it. In addition, we observed a significant size effect in nitrite accumulation, where large fish attained plasma [nitrite] above the ambient concentration, while small fish did not. Small P. hypophthalmus instead had significantly higher plasma [nitrate], and haemoglobin concentrations, revealing greater capacity for detoxifying nitrite by oxidising it to nitrate.
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Affiliation(s)
- Malthe Hvas
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | | | - Le Thi Hong Gam
- College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | - Frank B Jensen
- Department of Biology, University of Southern Denmark, Denmark
| | - Mark Bayley
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark.
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22
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Lefevre S, Findorf I, Bayley M, Huong DTT, Wang T. Increased temperature tolerance of the air-breathing Asian swamp eel Monopterus albus after high-temperature acclimation is not explained by improved cardiorespiratory performance. J Fish Biol 2016; 88:418-432. [PMID: 26563596 DOI: 10.1111/jfb.12696] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [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: 05/26/2014] [Accepted: 03/13/2015] [Indexed: 06/05/2023]
Abstract
This study investigated the hypothesis that in the Asian swamp eel Monopterus albus, an air-breathing fish from south-east Asia that uses the buccopharyngeal cavity for oxygen uptake, the upper critical temperature (TU) is increased by acclimation to higher temperature, and that the increased TU is associated with improved cardiovascular and respiratory function. Monopterus albus were therefore acclimated to 27° C (current average) and 32° C (current maximum temperature as well as projected average within 100-200 years), and both the effect of acclimation and acute temperature increments on cardiovascular and respiratory functions were investigated. Two weeks of heat acclimation increased upper tolerated temperature (TU ) by 2° C from 36·9 ± 0·1° C to 38·9 ± 0·1° C (mean ± s.e.). Oxygen uptake (M˙O2) increased with acclimation temperature, accommodated by increases in both aerial and aquatic respiration. Overall, M˙O2 from air (M˙O2a ) was predominant, representing 85% in 27° C acclimated fish and 80% in 32° C acclimated fish. M˙O2 increased with acute increments in temperature and this increase was entirely accommodated by an increase in air-breathing frequency and M˙O2a . Monopterus albus failed to upregulate stroke volume; rather, cardiac output was maintained through increased heart rate with rising temperature. Overall, acclimation of M. albus to 32° C did not improve its cardiovascular and respiratory performance at higher temperatures, and cardiovascular adaptations, therefore, do not appear to contribute to the observed increase in TU.
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Affiliation(s)
- S Lefevre
- Zoophysiology, Aarhus University, Department of Bioscience, C. F. Møllers Allé 3, 8000 Aarhus C, Denmark
- College of Aquaculture and Fisheries, Can Tho University, Campus II, 3/2 Street, Nink Kieu District, Can Tho City, Vietnam
| | - I Findorf
- Zoophysiology, Aarhus University, Department of Bioscience, C. F. Møllers Allé 3, 8000 Aarhus C, Denmark
- College of Aquaculture and Fisheries, Can Tho University, Campus II, 3/2 Street, Nink Kieu District, Can Tho City, Vietnam
| | - M Bayley
- Zoophysiology, Aarhus University, Department of Bioscience, C. F. Møllers Allé 3, 8000 Aarhus C, Denmark
| | - D T T Huong
- College of Aquaculture and Fisheries, Can Tho University, Campus II, 3/2 Street, Nink Kieu District, Can Tho City, Vietnam
| | - T Wang
- Zoophysiology, Aarhus University, Department of Bioscience, C. F. Møllers Allé 3, 8000 Aarhus C, Denmark
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23
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Regan MD, Turko AJ, Heras J, Andersen MK, Lefevre S, Wang T, Bayley M, Brauner CJ, Huong DTT, Phuong NT, Nilsson GE. Ambient CO2, fish behaviour and altered GABAergic neurotransmission: exploring the mechanism of CO2-altered behaviour by taking a hypercapnia dweller down to low CO2 levels. J Exp Biol 2016; 219:109-18. [DOI: 10.1242/jeb.131375] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
ABSTRACT
Recent studies suggest that projected rises of aquatic CO2 levels cause acid–base regulatory responses in fishes that lead to altered GABAergic neurotransmission and disrupted behaviour, threatening fitness and population survival. It is thought that changes in Cl− and HCO3− gradients across neural membranes interfere with the function of GABA-gated anion channels (GABAA receptors). So far, such alterations have been revealed experimentally by exposing species living in low-CO2 environments, like many oceanic habitats, to high levels of CO2 (hypercapnia). To examine the generality of this phenomenon, we set out to study the opposite situation, hypothesizing that fishes living in typically hypercapnic environments also display behavioural alterations if exposed to low CO2 levels. This would indicate that ion regulation in the fish brain is fine-tuned to the prevailing CO2 conditions. We quantified pH regulatory variables and behavioural responses of Pangasianodon hypophthalmus, a fish native to the hypercapnic Mekong River, acclimated to high-CO2 (3.1 kPa) or low-CO2 (0.04 kPa) water. We found that brain and blood pH was actively regulated and that the low-CO2 fish displayed significantly higher activity levels, which were reduced after treatment with gabazine, a GABAA receptor blocker. This indicates an involvement of the GABAA receptor and altered Cl− and HCO3− ion gradients. Indeed, Goldman calculations suggest that low levels of environmental CO2 may cause significant changes in neural ion gradients in P. hypophthalmus. Taken together, the results suggest that brain ion regulation in fishes is fine-tuned to the prevailing ambient CO2 conditions and is prone to disruption if these conditions change.
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Affiliation(s)
- Matthew D. Regan
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Andy J. Turko
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Joseph Heras
- Department of Ecology and Evolutionary Biology, University of California at Irvine, Irvine, CA 92697-2525, USA
| | | | - Sjannie Lefevre
- Department of Biosciences, University of Oslo, Oslo NO-0316, Norway
| | - Tobias Wang
- Department of Bioscience, Aarhus University, 8000 Aarhus-C, Denmark
| | - Mark Bayley
- Department of Bioscience, Aarhus University, 8000 Aarhus-C, Denmark
| | - Colin J. Brauner
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | | | - Göran E. Nilsson
- Department of Biosciences, University of Oslo, Oslo NO-0316, Norway
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Bayley M, Phuong M, Damsgaard C, Huong DTT, Wang T. Atypical respiratory Physiology of a recent air‐breathing fish: Pangasius. FASEB J 2015. [DOI: 10.1096/fasebj.29.1_supplement.1033.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Mark Bayley
- Department of BioscienceZoophysiology Aarhus UniversityAarhusJutlandDenmark
| | - My Phuong
- Department of BioscienceZoophysiology Aarhus UniversityAarhusJutlandDenmark
| | | | | | - Tobias Wang
- Department of BioscienceZoophysiology Aarhus UniversityAarhusJutlandDenmark
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25
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Damsgaard C, Phuong LM, Huong DTT, Jensen FB, Wang T, Bayley M. High affinity and temperature sensitivity of blood oxygen binding in Pangasianodon hypophthalmus due to lack of chloride-hemoglobin allosteric interaction. Am J Physiol Regul Integr Comp Physiol 2015; 308:R907-15. [PMID: 25810388 DOI: 10.1152/ajpregu.00470.2014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 03/23/2015] [Indexed: 01/19/2023]
Abstract
Air-breathing fishes represent interesting organisms in terms of understanding the physiological changes associated with the terrestrialization of vertebrates, and, further, are of great socio-economic importance for aquaculture in Southeast Asia. To understand how environmental factors, such as high temperature, affect O2 transport in air-breathing fishes, this study assessed the effects of temperature on O2 binding of blood and Hb in the economically important air-breathing fish Pangasianodon hypophthalmus. To determine blood O2 binding properties, blood was drawn from resting cannulated fishes and O2 binding curves made at 25°C and 35°C. To determine the allosteric regulation and thermodynamics of Hb O2 binding, Hb was purified, and O2 equilibria were recorded at five temperatures in the absence and presence of ATP and Cl(-). Whole blood had a high O2 affinity (O2 tension at half saturation P50 = 4.6 mmHg at extracellular pH 7.6 and 25°C), a high temperature sensitivity of O2 binding (apparent heat of oxygenation ΔH(app) = -28.3 kcal/mol), and lacked a Root effect. Further, the data on Hb revealed weak ATP binding and a complete lack of Cl(-) binding to Hb, which, in part, explains the high O2 affinity and high temperature sensitivity of blood O2 binding. This study demonstrates how a potent mechanism for increasing O2 affinity is linked to increased temperature sensitivity of O2 transport and provides a basic framework for a better understanding of how hypoxia-adapted species will react to increasing temperatures.
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Affiliation(s)
- Christian Damsgaard
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark;
| | - Le My Phuong
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark; College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Frank B Jensen
- Department of Biology, University of Southern Denmark, Odense, Denmark; and
| | - Tobias Wang
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Mark Bayley
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
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Damsgaard C, Gam LTH, Dang DT, Van Thinh P, Huong DTT, Wang T, Bayley M. High capacity for extracellular acid-base regulation in the air-breathing fish Pangasianodon hypophthalmus. J Exp Biol 2015; 218:1290-4. [DOI: 10.1242/jeb.117671] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 03/09/2015] [Indexed: 02/03/2023]
Abstract
The evolution of accessory air-breathing structures is typically associated with reduction of the gills, although branchial ion transport remains pivotal for acid-base and ion-regulation. Therefore, air-breathing fishes are believed to have a low capacity for extracellular pH regulation during a respiratory acidosis. In the present study, we investigated acid-base regulation during hypercapnia in the air-breathing fish Pangasianodon hypophthalmus in normoxic and hypoxic water at 28-30°C. Contrary to previous studies, we show that this air-breathing fish has a pronounced ability to regulate pHe during hypercapnia, with complete metabolic compensation of extracellular pH within 72 h of exposure to hypoxic hypercapnia with CO2 levels above 34 mmHg. The high capacity for pHe regulation relies on a pronounced ability to increase [HCO3−]plasma. Our study illustrates the diversity in the physiology of air-breathing fishes, such that generalizations across phylogenies may be difficult.
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Affiliation(s)
| | - Le Thi Hong Gam
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Diem Tuong Dang
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Phan Van Thinh
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Tobias Wang
- Zoophysiology, Institute for Bioscience, Aarhus University, Aarhus, Denmark
| | - Mark Bayley
- Zoophysiology, Institute for Bioscience, Aarhus University, Aarhus, Denmark
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Andrieu M, Rico A, Phu TM, Huong DTT, Phuong NT, Van den Brink PJ. Ecological risk assessment of the antibiotic enrofloxacin applied to Pangasius catfish farms in the Mekong Delta, Vietnam. Chemosphere 2015; 119:407-414. [PMID: 25063964 DOI: 10.1016/j.chemosphere.2014.06.062] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [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: 11/08/2013] [Revised: 06/19/2014] [Accepted: 06/22/2014] [Indexed: 05/02/2023]
Abstract
Antibiotics applied in aquaculture production may be released into the environment and contribute to the deterioration of surrounding aquatic ecosystems. In the present study, we assessed the ecological risks posed by the use of the antibiotic enrofloxacin (ENR), and its main metabolite ciprofloxacin (CIP), in a Pangasius catfish farm in the Mekong Delta region, Vietnam. Water and sediment samples were collected in a stream receiving effluents from a Pangasius catfish farm that had applied ENR. The toxicity of ENR and CIP was assessed on three tropical aquatic species: the green-algae Chlorella sp. (72 h - growth inhibition test), the micro-invertebrate Moina macrocopa (48 h - immobilization test), and the Nile tilapia (Oreochromis niloticus). The toxic effects on O. niloticus were evaluated by measuring the cholinesterase (ChE) and catalase (CAT) activities in the fish brain and muscles, respectively, and by considering feed exposure and water exposure separately. Ecological risks were assessed by comparing maximum exposure concentrations with predicted no effect concentrations for cyanobacteria, green algae, invertebrates and fish derived with available toxicity data. The results of this study showed that maximum antibiotic concentrations in Pangasius catfish farm effluents were 0.68 μg L(-1) for ENR and 0.25 μg L(-1) for CIP (dissolved water concentrations). Antibiotics accumulated in sediments down-stream the effluent discharge point at concentrations up to 2590 μg kg(-1) d.w. and 592 μg kg(-1) d.w. for ENR and CIP, respectively. The calculated EC50 values for ENR and CIP were 111000 and 23000 μg L(-1) for Chlorella sp., and 69000 and 71000 μg L(-1) for M. macrocopa, respectively. Significant effects on the ChE and CAT enzymatic activities of O. niloticus were observed at 5 g kg(-1) feed and 400-50000 μg L(-1), for both antibiotics. The results of the ecological risk assessment performed in this study indicated only minor risks for cyanobacteria communities, suggesting that residual concentrations of ENR and CIP after medication are not likely to result in severe toxic effects on exposed aquatic ecosystems. However, more studies should be performed by considering other antibiotic treatments used in Pangasius catfish production and the potential ecotoxicological effects of relevant antibiotic mixtures on sediment communities.
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Affiliation(s)
- Margot Andrieu
- Department of Aquatic Ecology and Water Quality Management, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen, The Netherlands
| | - Andreu Rico
- Department of Aquatic Ecology and Water Quality Management, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen, The Netherlands; Alterra, Centre for Water and Climate, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen, The Netherlands.
| | - Tran Minh Phu
- College of Aquaculture and Fisheries, Can Tho University, 3/2 Street, Campus II, Can Tho, Viet Nam
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, 3/2 Street, Campus II, Can Tho, Viet Nam
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Can Tho University, 3/2 Street, Campus II, Can Tho, Viet Nam
| | - Paul J Van den Brink
- Department of Aquatic Ecology and Water Quality Management, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen, The Netherlands; Alterra, Centre for Water and Climate, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen, The Netherlands
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Ern R, Huong DTT, Cong NV, Bayley M, Wang T. Effect of salinity on oxygen consumption in fishes: a review. J Fish Biol 2014; 84:1210-20. [PMID: 24665828 DOI: 10.1111/jfb.12330] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [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: 11/26/2012] [Accepted: 12/22/2013] [Indexed: 05/20/2023]
Abstract
The effect of salinity on resting oxygen uptake was measured in the perch Perca fluviatilis and available information on oxygen uptake in teleost species at a variety of salinities was reviewed. Trans-epithelial ion transport against a concentration gradient requires energy and exposure to salinities osmotically different from the body fluids therefore imposes an energetic demand that is expected to be lowest in brackish water compared to fresh and sea water. Across species, there is no clear trend between oxygen uptake and salinity, and estimates of cost of osmotic and ionic regulation vary from a few per cent to >30% of standard metabolism.
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Affiliation(s)
- R Ern
- Zoophysiology, Department of Biological Sciences, Aarhus University, Aarhus, Denmark
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Lefevre S, Wang T, Jensen A, Cong NV, Huong DTT, Phuong NT, Bayley M. Air-breathing fishes in aquaculture. What can we learn from physiology? J Fish Biol 2014; 84:705-731. [PMID: 24498927 DOI: 10.1111/jfb.12302] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
During the past decade, the culture of air-breathing fish species has increased dramatically and is now a significant global source of protein for human consumption. This development has generated a need for specific information on how to maximize growth and minimize the environmental effect of culture systems. Here, the existing data on metabolism in air-breathing fishes are reviewed, with the aim of shedding new light on the oxygen requirements of air-breathing fishes in aquaculture, reaching the conclusion that aquatic oxygenation is much more important than previously assumed. In addition, the possible effects on growth of the recurrent exposure to deep hypoxia and associated elevated concentrations of carbon dioxide, ammonia and nitrite, that occurs in the culture ponds used for air-breathing fishes, are discussed. Where data on air-breathing fishes are simply lacking, data for a few water-breathing species will be reviewed, to put the physiological effects into a growth perspective. It is argued that an understanding of air-breathing fishes' respiratory physiology, including metabolic rate, partitioning of oxygen uptake from air and water in facultative air breathers, the critical oxygen tension, can provide important input for the optimization of culture practices. Given the growing importance of air breathers in aquaculture production, there is an urgent need for further data on these issues.
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Affiliation(s)
- S Lefevre
- Zoophysiology section, Department of Bioscience, C. F. Møllers Allé 3, 8000 Aarhus C, Denmark
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Ern R, Huong DTT, Phuong NT, Wang T, Bayley M. Oxygen delivery does not limit thermal tolerance in a tropical eurythermal crustacean. ACTA ACUST UNITED AC 2013; 217:809-14. [PMID: 24198257 DOI: 10.1242/jeb.094169] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [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: 11/20/2022]
Abstract
In aquatic environments, rising water temperatures reduce water oxygen content while increasing oxygen demand, leading several authors to propose cardiorespiratory oxygen transport capacity as the main determinant of aquatic animal fitness. It has also been argued that tropical species, compared with temperate species, live very close to their upper thermal limit and hence are vulnerable to even small elevations in temperature. Little, however, is known about physiological responses to high temperatures in tropical species. Here we report that the tropical giant freshwater shrimp (Macrobrachium rosenbergii) maintains normal growth when challenged by a temperature rise of 6°C above the present day average (from 27°C to 33°C). Further, by measuring heart rate, gill ventilation rate, resting and maximum oxygen uptake, and hemolymph lactate, we show that oxygen transport capacity is maintained up to the critical maximum temperature around 41°C. In M. rosenbergii heart rate and gill ventilation rate increases exponentially until immediately below critical temperatures and at 38°C animals still retained more than 76% of aerobic scope measured at 30°C, and there was no indication of anaerobic metabolism at the high temperatures. Our study shows that the oxygen transport capacity is maintained at high temperatures, and that other mechanisms, such as protein dysfunction, are responsible for the loss of ecological performance at elevated temperatures.
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Affiliation(s)
- Rasmus Ern
- Department of Bioscience, Aarhus University, Aarhus, Denmark
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Iversen NK, Lauridsen H, Huong DTT, Van Cong N, Gesser H, Buchanan R, Bayley M, Pedersen M, Wang T. Cardiovascular anatomy and cardiac function in the air-breathing swamp eel (Monopterus albus). Comp Biochem Physiol A Mol Integr Physiol 2013; 164:171-80. [DOI: 10.1016/j.cbpa.2012.08.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 08/21/2012] [Accepted: 08/22/2012] [Indexed: 11/29/2022]
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Lefevre S, Wang T, Huong DTT, Phuong NT, Bayley M. Partitioning of oxygen uptake and cost of surfacing during swimming in the air-breathing catfish Pangasianodon hypophthalmus. J Comp Physiol B 2012; 183:215-21. [DOI: 10.1007/s00360-012-0701-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 07/24/2012] [Accepted: 07/27/2012] [Indexed: 11/25/2022]
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Iversen NK, Huong DTT, Bayley M, Wang T. Autonomic control of the heart in the Asian swamp eel (Monopterus albus). Comp Biochem Physiol A Mol Integr Physiol 2011; 158:485-9. [DOI: 10.1016/j.cbpa.2010.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 12/03/2010] [Accepted: 12/05/2010] [Indexed: 11/17/2022]
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Lefevre S, Huong DTT, Wang T, Phuong NT, Bayley M. Hypoxia tolerance and partitioning of bimodal respiration in the striped catfish (Pangasianodon hypophthalmus). Comp Biochem Physiol A Mol Integr Physiol 2011; 158:207-14. [DOI: 10.1016/j.cbpa.2010.10.029] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 10/26/2010] [Accepted: 10/27/2010] [Indexed: 11/29/2022]
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Findorf I, Bayley M, Huong DTT, Wang T. Effects of high temperature on cardiovascular and respiratory functions in the air-breathing fish Monopterus albus. Comp Biochem Physiol A Mol Integr Physiol 2009. [DOI: 10.1016/j.cbpa.2009.04.269] [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: 10/20/2022]
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Huong DTT, Tuan NA, Ha NK, Wang T, Bayley M, Phuong NT. Induced spawning in the swamp eel (Monopterus albus) using human chorionic gonadotropine and artificial rain stimulation. Comp Biochem Physiol A Mol Integr Physiol 2009. [DOI: 10.1016/j.cbpa.2009.04.270] [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: 10/20/2022]
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Huong DTT, Hai TN, Phuong NT, Bayley M, Wang T. Growth rate of mudskipper (Pseudapocryptes lanceolatus, Bloch 1801) exposed to different salinities. Comp Biochem Physiol A Mol Integr Physiol 2009. [DOI: 10.1016/j.cbpa.2009.04.271] [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: 10/20/2022]
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Okuno A, Yang WJ, Jayasankar V, Saido-Sakanaka H, Huong DTT, Jasmani S, Atmomarsono M, Subramoniam T, Tsutsui N, Ohira T, Kawazoe I, Aida K, Wilder MN. Deduced primary structure of vitellogenin in the giant freshwater prawn, Macrobrachium rosenbergii, and yolk processing during ovarian maturation. J Exp Zool 2002; 292:417-29. [PMID: 11857476 DOI: 10.1002/jez.10083] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A cDNA encoding vitellogenin (Vg) in the giant freshwater prawn, Macrobrachium rosenbergii, was cloned based on the cDNA sequence of vitellin (Vn) fragments A-N and B-42 determined previously, and its amino acid sequence deduced. The open reading frame (ORF) encoded 2,537 amino acid residues and its deduced amino acid sequence possessed three consensus cleavage sites, R-X-R-R, similar to those reported in Vgs of insects. The deduced primary structure of Vg in M. rosenbergii was seen to be similar to that of Penaeus japonicus, especially in the N-terminal region. It is therefore likely that Vgs in crustacean species including prawns and other related decapods exhibit a similar structural pattern. Based on the deduced primary structure of Vg and analysis of the various Vg and Vn subunits found in the hemolymph and ovary during ovarian maturation, we demonstrated the post-translational processing of Vg in M. rosenbergii. This is the first time that Vg processing has been clearly demonstrated in a crustacean species. Vg, after being synthesized in the hepatopancreas, is considered to be cleaved by a subtilisin-like endoprotease to form two subunits, A and proB, which are then released into the hemolymph. In the hemolymph, proB is possibly cleaved by a processing enzyme of unknown identity to give rise to subunits B and C/D. The three processed subunits A, B, and C/D are sequestered by the ovary to give rise to three yolk proteins, Macr-VnA, VnB, and VnC/D.
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Affiliation(s)
- Atsuro Okuno
- Japan International Research Center for Agricultural Sciences, Tsukuba, Ibaraki 305-8686, Japan
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