Physiological Effects of Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA)—A Review

A large multisite lipidomic investigation of parity and aging in dairy cows

Efforts to optimize the longevity of dairy cows are hindered by the increased risk of adverse health events, culling, or dying on farm with increased parity. Lipidomics provides a platform to help identify important biomarkers and biological pathways associated with increased parity and associated aging. A large multisite (15 pasture-based, 15 TMR farms) cross-sectional study collected plasma samples from nonlactating, late pregnant, dry cows (n = 696, ∼27 d prepartum) and peak milk cows (n = 796, ∼58 DIM) in a disproportionate stratified random sampling frame (parity: 0, 1, 2, >2 for dry cows; 1, 2, 3, >3 for peak milk cows). A total of 185 lipid species, comprising the lipids classes of phospholipids, sphingomyelins (SM) and triacylglycerols, were quantified in a targeted, liquid chromatography-MS approach. Dry and peak milk cohorts were analyzed separately throughout. Variation in lipid profiles were mostly attributed to farm of origin (36%-41% of variation), with feeding system explaining 13% to 21% and parity explaining 6% to 9%, according to ANOVA simultaneous component analysis modeling. Multiple linear regression and orthogonal partial least squares (O-PLS) investigated the association of the lipid profile with age (d), whereas discriminant analysis compared first parity with >3 parity cows in O-PLS discriminant analysis, random forest, and support vector machine models. Rankings of the most important lipid species for each model type were compared. Phospholipids with 40 carbon atoms and 6 double bond equivalents (40:6) were consistently decreased with increasing parity and age across both dry and peak milk cohorts. These lipids most likely contained stearate (18:0) and docosahexaenoic acid (DHA, C22:6n-3), an n-3 fatty acid. Additionally, phospholipids with 40:5 and 38:6, lysophosphatidylcholine (17:0), SM(35:1), and SM(35:2) were commonly identified lipids that decreased in concentration with parity and age. Docosahexaenoic acid has been associated with improved cattle health, reproduction, and milk production and quality. This study raises the hypothesis that reduced DHA levels in older cows may be an important factor increasing susceptibility to adverse health events, reduced reproductive performance, and herd removal. Studies that supplement DHA or its precursors can test this hypothesis and may be important in optimizing longevity of cows.

Transcriptomic Signature of Lipid Production in Australian Aurantiochytrium sp. TC20

Aurantiochytrium not only excels in producing long-chain polyunsaturated fatty acids such as docosahexaenoic acid for humans, but it is also a source of essential fatty acids with minimal impacts on wild fisheries and is vital in the transfer of atmospheric carbon to oceanic carbon sinks and cycles. This study aims to unveil the systems biology of lipid production in the Australian Aurantiochytrium sp. TC20 by comparing the transcriptomic profiles under optimal growth conditions with increased fatty acid production from the early (Day 1) to late exponential growth phase (Day 3). Particular attention was paid to 227 manually annotated genes involved in lipid metabolism, such as FAS (fatty acid synthetase) and subunits of polyunsaturated fatty acids (PUFA) synthase. PCA analysis showed that differentially expressed genes, related to lipid metabolism, efficiently discriminated Day 3 samples from Day 1, highlighting the key robustness of the developed lipid-biosynthesis signature. Highly significant (pFDR < 0.01) upregulation of polyunsaturated fatty acid synthase subunit B (PFAB) involved in fatty acid synthesis, lipid droplet protein (TLDP) involved in TAG-synthesis, and phosphoglycerate mutase (PGAM-2) involved in glycolysis and gluconeogenesis were observed. KEGG enrichment analysis highlighted significant enrichment of the biosynthesis of unsaturated fatty acids (pFDR < 0.01) and carbon metabolism pathways (pFDR < 0.01). This study provides a comprehensive overview of the transcriptional landscape of Australian Aurantiochytrium sp. TC20 in the process of fatty acid production.

Targeted metabolomics identified novel metabolites, predominantly phosphatidylcholines and docosahexaenoic acid-containing lipids, predictive of incident chronic kidney disease in middle-to-elderly-aged Chinese adults

BACKGROUND

Evidence is limited regarding the association of circulating metabolites with decline of kidney function, letting alone their value in prediction of development of chronic kidney disease (CKD).

METHODS

This study included 3802 participants aged 64.1 ± 7.4 years from the Dongfeng-Tongji cohort, among whom 3327 were CKD-free at baseline (estimated glomerular filtration rate [eGFR] > 60 ml/min per 1.73 m2). We measured baseline levels of 211 metabolites with liquid chromatography coupled with mass spectrometry, including 25 amino acids, 12 acyl-carnitines, 161 lipids, and 13 other metabolites.

RESULTS

The mean (SD) absolute annual change in eGFR was -0.14 ± 4.11 ml/min per 1.73 m2 per year, and a total of 472 participants who were free of CKD at baseline developed incident CKD during follow-up of 4.6 ± 0.2 years (14.2 %). We identified a total of 22 metabolites associated with annual eGFR change and survived Bonferroni correction for multiple testing, including seven metabolites associated with eGFR increase (six being docosahexaenoic acid [DHA]-containing lipids) and 15 associated with eGFR decline (nine being phosphatidylcholines [PCs]). Among them, eight metabolites obtained non-zero coefficients in least absolute shrinkage and selection operator (LASSO) regression on incident CKD, indicating predictive potential, including one amino acid (arginine), one acyl-carnitine (C2), one lysophosphatidylcholine (LPC 22:6), two PCs (32:1 and 34:3), one triacylglycerol (TAG 56:8 [22:6]) and two other metabolites (inosine, niacinamide), and the composite score of these eight metabolites showed an odds ratio (OR) of 8.79 (95 % confidence interval [CI]: 7.49, 10.32; P < 0.001) per SD increase in association with incident CKD. The addition of the metabolite score increased the c-statistic of the reference model of traditional risk factors (including baseline eGFR) by 0.065 (95 % CI: 0.046 to 0.084; P = 3.39 × 10-11) to 0.765 (0.742 to 0.788) in 1000 repetitions of 10-fold cross-validation, while the application of two advanced machine learning algorithms, random forest (RF), and extreme gradient boosting (XGBoost) models produced similar c-statistics, to 0.753 (0.729 to 0.777) and 0.778 (0.733 to 0.824) with increases of 0.074 (0.055 to 0.093; P = 4.11 × 10-14) and 0.073 (0.032 to 0.114; P = 4.00 × 10-4), respectively.

CONCLUSIONS

In this study, we identified 22 metabolites associated with longitudinal eGFR change, nine of which were PCs and six were DHA-containing lipids. We screened out a panel of eight metabolites which improved prediction for the development of CKD by 9 % beyond traditional risk factors including baseline eGFR. Our findings highlighted involvement of lipid metabolism in kidney function impairment, and provided novel predictors for CKD risk.

Effects of Diet Supplemented With Hydrolyzable Tannin on the Growth Performance, Antioxidant Capacity, and Muscle Nutritional Quality of Juvenile Mastacembelus armatus

In this study, four groups of diet were prepared, with eel commercial diet without hydrolyzable tannin (HT) as the control group (H0), and the other three groups were fed with diet containing 0.05% (H1), 0.1% (H2), and 0.2% (H3) doses of HT to juvenile Mastacembelus armatus with an initial body weight of (0.40 ± 0.005) g. Juvenile fish in all groups were fed continuously for 60 days. Growth indices, hepatopancreatic antioxidant enzymes, biochemical indices (including total superoxide dismutase [T-SOD], catalase [CAT], malondialdehyde [MDA], total antioxidant capacity [T-AOC], alanine aminotransferase [ALT], aspartate aminotransferase [AST], alkaline phosphatase [AKP], and triglyceride [TG]), the content of muscle amino acids and fatty acids, stomach and intestine enzyme activities (pepsin, amylase, lipase), and genes expressions were evaluated. The results showed that 0.1% HT significantly improved the growth performance, hepatopancreatic antioxidant capacity, as well as muscle quality and lipase activity of juvenile M. armatus. In summary, the optimal addition level of HT in the diet of juvenile M. armatus is 0.1%, which helps to improve aquaculture efficiency and improve the muscle quality of M. armatus. However, the long-term effects of feeding HT on M. armatus and its physiological reaction mechanism need to be further explored.

Effects of Dietary Lipid Levels on the Growth, Muscle Fatty Acid and Amino Acid Composition, Antioxidant Capacity, and Lipid Deposition in Mirror Carp (Cyprinus carpio)

In fish, increasing the crude lipid level of feed can save protein and improve feed utilization. Mirror carp (Cyprinus carpio) is one of the most widely farmed fish species in the world. In this study, mirror carp larvae were fed isonitrogenous diets with different lipid levels (3%, 5%, 7%, 9%, 11%, and 13%). The rearing trial lasted for eight weeks. The results revealed that when the fat content was 9%, the AWGR, WGR, and FCR were highest, whereas FCR was lowest. The AWGR was correlated with the dietary lipid level, and the regression equation was y = -2.312x2 + 45.01x + 214.49. Compared with those in the control group, the T-CHO and TG contents were significantly greater in the 13% lipid content groups and significantly lower in the 9% lipid content groups (p < 0.05). In terms of muscle quality, the contents of MUFAs, PUFAs, and DHA + EPA were significantly greater than those in the other experimental groups (p < 0.05). Oil red O staining revealed a lipid content of 13% with severe fat deposition. In addition, the results of the analysis of antioxidant enzyme activity revealed that the activities of GSH, CAT and T-AOC were significantly greater at the 9% lipid content, and that the MDA content was significantly greater at the 13% lipid content (p < 0.05). Similarly, the mRNA levels of GH, IGF-I, FAS, and LPL were significantly highest at a lipid level of 9% (p < 0.05). The above results revealed that the optimal dietary lipid requirement for the fast growth of mirror carp (6.86 ± 0.95 g) was 9.74% on the basis of nonlinear regression analysis of the AWGR. The dietary lipid level (9%) improved the growth, stress resistance, and lipid utilization of mirror carp to a certain extent.

EPA and DHA promote cell proliferation and enhance activity of the Akt-TOR-S6K anabolic signaling pathway in primary muscle cells of turbot (Scophthalmus maximus L.)

Fish growth and health are predominantly governed by dietary nutrient supply. Although the beneficial effects of omega-3 polyunsaturated fatty acids supplementation have been shown in a number of fish species, the underlying mechanisms are still mostly unknown. In this study, we conducted an investigation into the effects of EPA and DHA on cell proliferation, nutrient sensing signaling, and branched-chain amino acids (BCAA) transporting in primary turbot muscle cells. The findings revealed that EPA and DHA could stimulate cell proliferation, promote protein synthesis and inhibit protein degradation through activation of target of rapamycin (TOR) signaling pathway, a pivotal nutrient-sensing signaling cascade. While downregulating the expression of myogenin and myostatin, EPA and DHA increased the level of myogenic regulatory factors, such as myoD and follistatin. Furthermore, we observed a significant increase in the concentrations of intracellular BCAAs following treatment with EPA or DHA, accompanied by an upregulation of the associated amino acid transporters. Our study providing valuable insights into the mechanisms underlying the growth-promoting effects of omega-3 fatty acids in fish.

Salicornia ramosissima Biomass as a Partial Replacement of Wheat Meal in Diets for Juvenile European Seabass (Dicentrarchus labrax)

The green tips of Salicornia ramosissima are used for human consumption, while, in a production scenario, the rest of the plant is considered a residue. This study evaluated the potential of incorporating salicornia by-products in diets for juvenile European seabass, partially replacing wheat meal, aspiring to contribute to their valorization. A standard diet and three experimental diets including salicornia in 2.5%, 5% and 10% inclusion levels were tested in triplicate. After 62 days of feeding, no significant differences between treatments were observed in fish growth performances, feeding efficiency and economic conversation ratio. Nutrient digestibility of the experimental diets was unaffected by the inclusion of salicornia when compared to a standard diet. Additionally, salicornia had significant modulatory effects on the fish muscle biochemical profiles, namely by significantly decreasing lactic acid and increasing succinic acid levels, which can potentially signal health-promoting effects for the fish. Increases in DHA levels in fish fed a diet containing 10% salicornia were also shown. Therefore, the results suggest that salicornia by-products are a viable alternative to partially replace wheat meal in diets for juvenile European seabass, contributing to the valorization of a residue and the implementation of a circular economy paradigm in halophyte farming and aquaculture.

Effect of milk fat globules on growth and metabolism in rats fed an unbalanced diet

We assessed the effects of supplementing milk fat globules (MFG) on the growth and development of the skeleton in rats fed a Western unbalanced diet (UBD). The UBD is high in sugar and fat, low in protein, fiber, and micronutrients, and negatively impacts health. The MFG-a complex lipid-protein assembly secreted into milk-has a unique structure and composition, which differs significantly from isolated and processed dietary ingredients. Rats consuming the UBD exhibited growth retardation and disrupted bone structural and mechanical parameters; these were improved by supplementation with small MFG. The addition of small MFG increased the efficiency of protein utilization for growth, and improved trabecular and cortical bone parameters. Furthermore, consumption of UBD led to a decreased concentration of saturated fatty acids and increased levels of polyunsaturated fatty acids (PUFA), particularly omega-6 PUFA, in the serum, liver, and adipose tissue. The addition of small MFG restored PUFA concentration and the ratio of omega-6 to omega-3 PUFA in bone marrow and adipose tissue. Finally, large but not small MFG supplementation affected the cecal microbiome in rats. Overall, our results suggest that natural structure MFG supplementation can improve metabolism and bone development in rats fed an UBD, with the effects depending on MFG size. Moreover, the benefits of small MFG to bone development and metabolism were not mediated by the microbiome, as the detrimental effects of an UBD on the microbiome were not mitigated by MFG supplementation.

Synbiotic-Glyconutrient Additive Reveals a Conducive Effect on Growth Performance, Fatty Acid Profile, Sensory Characteristics, and Texture Profile Analysis in Finishing Pig

This study aims to investigate the effect of synbiotic-glyconutrients (SB-GLN) additive on growth performance, fatty acid profile, sensory characteristics, and texture profile analysis in finishing pig. Landrace × Yorkshire ♀ × (Duroc ♂) (n = 60) pigs with average body weight of 54.88 ± 1 kg were allocated into one of three dietary treatment groups in a complete randomized block design with four replicates of five pigs (two barrows and three gilts) per pen. The test treatments (TRT) were CON-corn-soybean meal basal diet; TRT 1-CON+ 0.25% SB-GLN; and TRT 2-CON + 0.5% SB-GLN. SB-GLN contains 1 × 107 CFU/g each of: L. plantarum, B. subtilis, and S. Cerevisiae, and 5% yeast cell wall β-Glucans (from S. Cerevisiae), and 14% of glyconutrients (N-acetylglucosamine, D-xylose, and Fucose). Pigs fed SB-GLN supplement showed linearly increased (p < 0.05) body weight, daily gain, and daily feed at the end of week 5, 10, and the overall experimental period. In addition, G:F showed a tendency to decrease (p < 0.1) at the end of week 10 and the overall experimental period. In addition, pigs that received a graded level of SB-GLN showed a tendency to increase (p < 0.1) their longiness muscle area and decreased (p < 0.05) cooking loss. The sensory results of pork belly (tenderness and juiciness) and loin (flavor) meat, and the texture profile analysis parameters of hardness 1, cohesiveness, and gumminess (belly), and hardness 2, chewiness, and springiness (loin) meat were linearly higher (p < 0.05) in the SB-GLN group. The values of fatty acid like butyric acid, caproic acid, undecylic acid, tridecylic acid, myristic acid, pentadecyclic acid, palmitic acid, margaric acid, stearic acid, eicosapentaenoic acid, and lignoceric acid were higher in pork belly fat of the SB-GLN-treated group compared to CON. Moreover, pigs that received SB-GLN exhibited higher crude fat and lauric acid, myristic acid, pentacyclic acid, palmitic acid, margaric acid, Octadecanoic acid, Oleic acid, linoleic acid, and eicosapentaenoic acid FA profiles in belly-lean meat. Also, the FA profile of the SB-GLN-treated group loin-lean meat showed increased lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, oleic acid, linoleic acid, alpha-linoleic acid, and eicosapentaenoic acid. The SB-GLN-treated group pork belly fat, belly lean meat, and loin-lean meat showed linearly increased docosahexaenoic acid, nervonic acid, omega 3, omega 6, ω-6: ω-3, Σ saturated FA, Σ un-SFA, Σ mono-USFA, Σ poly-USFA, MUFA/SFA, and PUFA/SFA. Therefore, we infer that the inclusion of 0.5% SB-GLN additive to finishing pig diet would be more beneficial to enhance their performance, and to increase the essential FA profile of pork meat for human consumption.

Soy Protein Isolate-Chitosan Nanoparticle-Stabilized Pickering Emulsions: Stability and In Vitro Digestion for DHA

The purpose of the study was to investigate the stability and oral delivery of DHA-encapsulated Pickering emulsions stabilized by soy protein isolate-chitosan (SPI-CS) nanoparticles (SPI-CS Pickering emulsions) under various conditions and in the simulated gastrointestinal (GIT) model. The stability of DHA was characterized by the retention rate under storage, ionic strength, and thermal conditions. The oral delivery efficiency was characterized by the retention and release rate of DHA in the GIT model and cell viability and uptake in the Caco-2 model. The results showed that the content of DHA was above 90% in various conditions. The retention rate of DHA in Pickering emulsions containing various nanoparticle concentrations (1.5 and 3.5%) decreased to 80%, while passing through the mouth to the stomach, and DHA was released 26% in 1.5% Pickering emulsions, which was faster than that of 3.5% in the small intestine. After digestion, DHA Pickering emulsions proved to be nontoxic and effectively absorbed by cells. These findings helped to develop a novel delivery system for DHA.

The Histone Deacetylase Inhibitory Potential of Chicken Egg Yolk Fat and Their Fatty Acid Composition

Histone deacetylation is a key biochemical event associated with transcriptional regulation. Histone deacetylases (HDACs) mediate the deacetylation of histones. Fatty acids have been reported to function as histone deacetylase inhibitors (HDACi). The present instigation reports the HDAC inhibitory activity of egg yolks and egg yolk-derived fat of country and farm chicken for the first time. Egg yolks and fatty acids derived from both country (CCEF) and farm chicken (FCEF) demonstrated significant HDAC enzyme activity inhibition. Furthermore, egg yolks, CCEF, and FCEF exhibited DPPH free radical scavenging effects. The analysis of fatty acid profiles revealed varying degrees of saturated, mono-, and polyunsaturated fatty acids in the egg yolks. Palmitic acid (C16 : 0) was found to be the most abundant saturated fatty acid in both CCEF and FCEF. Among the monounsaturated fatty acids, oleic acid (C18 : 1) was the most abundant in both CCEF and FCEF. In terms of polyunsaturated fatty acids, a significant difference was observed in the content of linoleic acid (C18 : 2), an omega-6 fatty acid, and docosahexaenoic acid (C22 : 6), an omega-3 fatty acid, between CCEF and FCEF. These findings present exciting prospects for the development of histone deacetylase inhibitors based on egg yolk fat.

Influence of light conditions on the production of chrysolaminarin using Phaeodactylum tricornutum in artificially illuminated photobioreactors

The light conditions are of utmost importance in any microalgae production process especially involving artificial illumination. This also applies to a chrysolaminarin (soluble 1,3-β-glucan) production process using the diatom Phaeodactylum tricornutum. Here we examine the influence of the amount of light per gram biomass (specific light availability) and the influence of two different biomass densities (at the same amount of light per gram biomass) on the accumulation of the storage product chrysolaminarin during nitrogen depletion in artificially illuminated flat-panel airlift photobioreactors. Besides chrysolaminarin, other compounds (fucoxanthin, fatty acids used for energy storage [C16 fatty acids], and eicosapentaenoic acid) are regarded as well. Our results show that the time course of C-allocation between chrysolaminarin and fatty acids, serving as storage compounds, is influenced by specific light availability and cell concentration. Furthermore, our findings demonstrate that with increasing specific light availability, the maximal chrysolaminarin content increases. However, this effect is limited. Beyond a certain specific light availability (here: 5 µmolphotons  gDW -1  s-1 ) the maximal chrysolaminarin content no longer increases, but the rate of increase becomes faster. Furthermore, the conversion of light to chrysolaminarin is best at the beginning of nitrogen depletion. Additionally, our results show that a high biomass concentration has a negative effect on the maximal chrysolaminarin content, most likely due to the occurring self-shading effects.

Seasonal variation in the metabolome expression of Jania rubens (Rhodophyta) reveals eicosapentaenoic acid as a potential anticancer metabolite

Seaweeds of the intertidal zone are subjected to diverse stresses due to environmental changes in radiation, salinity, water quality, herbivore communities, etc. Thus, marine seaweeds developed various unique compounds to deal with environmental fluctuations. Therefore, they are a good source of unique novel compounds. Here, we explored the seasonal metabolomic changes in Jania rubens and found notable changes between extracts of different seasons in the metabolomic profile and in their anticancer activity. The most bioactive extract was from samples collected during the Fall season, which demonstrated an LC50 of 178.39 (± 10.02 SD) µg/ml toward Non Small Cell Lung Cancer (NSCLC) followed by the Winter season extract. The Fall and Winter extracts also displayed more resemblance in their metabolic profile relative to Spring and Summer extracts. The Fall extract was fractionated and tested for cytotoxic activity toward an array of cancer cell lines. Eventually, using a bio-guided assay and multiple fractionation steps, we isolated and identified the essential fatty acid, eicosapentaenoic acid, as the active anticancer agent, showing an LC50 of 5.23 (± 0.07 SD) µg/ml toward NSCLC. Our results emphasize the potential use of J. rubens as a source of beneficial fatty acids and stress the importance of environmental effects on metabolic constitutes.

Functional roles and novel tools for improving-oxidative stability of polyunsaturated fatty acids: A comprehensive review

Polyunsaturated fatty acids may be derived from a variety of sources and could be incorporated into a balanced diet. They protect against a wide range of illnesses, including cancer osteoarthritis and autoimmune problems. The PUFAs, ω-6, and ω-3 fatty acids, which are found in both the marine and terrestrial environments, are given special attention. The primary goal is to evaluate the significant research papers in relation to the human health risks and benefits of ω-6 and ω-3 fatty acid dietary resources. This review article highlights the types of fatty acids, factors affecting the stability of polyunsaturated fatty acids, methods used for the mitigation of oxidative stability, health benefits of polyunsaturated fatty acids, and future perspectives in detail.

Unravelling the Lipids Content and the Fatty Acid Profiles of Eight Recently Described Halophytophthora Species and H. avicennae from the South Coast of Portugal

In this study, mycelia of eight recently described species of Halophytophthora and H. avicennae collected in Southern Portugal were analysed for lipids and fatty acids (FA) content to evaluate their possible use as alternative sources of FAs and understand how each species FAs profile relates to their phylogenetic position. All species had a low lipid percentage (0.06% in H. avicennae to 0.28% in H. frigida). Subclade 6b species contained more lipids. All species produced monounsaturated (MUFA), polyunsaturated (PUFA) and saturated (SFA) FAs, the latter being most abundant in all species. H. avicennae had the highest FA variety and was the only producer of γ-linolenic acid, while H. brevisporangia produced the lowest number of FAs. The best producer of arachidonic acid (ARA) and eicosapentaenoic acid (EPA) was H. thermoambigua with 3.89% and 9.09% of total FAs, respectively. In all species, palmitic acid (SFA) was most abundant and among the MUFAs produced oleic acid had the highest relative percentage. Principal component analysis (PCA) showed partial segregation of species by phylogenetic clade and subclade based on their FA profile. H. avicennae (Clade 4) differed from all other Clade 6 species due to the production of γ-linolenic and lauric acids. Our results disclosed interesting FA profiles in the tested species, adequate for energy (biodiesel), pharmaceutical and food industries (bioactive FAs). Despite the low amounts of lipids produced, this can be boosted by manipulating culture growth conditions. The observed interspecific variations in FA production provide preliminary insights into an evolutionary background of its production.

Dietary Effect of Palm Kernel Oil Inclusion in Feeding Finishing Lambs on Meat Quality

This study evaluated the effects of palm kernel oil (PKO) in the diet of lambs on carcass characteristics, quality, and fatty acid profile of the meat. Forty uncastrated male Santa Inês lambs were used and divided among the treatments: PKOzero without inclusion; PKO1.3—added 1.3%; PKO2.6—added 2.6%; PKO3.9—added 3.9%; PKO5.2—added 5.2%. The carcass characteristics, the variables related to meat color, and the chemical composition of the Longissimus lumborum of lambs were not affected by the PKO inclusion. The weight of the carcasses at slaughter, hot and cold, half carcass, loin-eye area, and commercial cuts decreased linearly when PKO was added to the lamb diet (p < 0.01). CCY decreased linearly to the inclusion level of 2.66% PKO (RMSE 2.204). Total conjugated linoleic acid CLA and C18:3 n-3 GA concentrations remained stable until the inclusion levels of 3.44% PKO (RMSE 0.0956) and 2.17% (RMSE 0.0637), decreasing its concentrations as the increased level of PKO. The presence of PKO in the lambs’ diet up to the level of 5.2% did not change the meat quality characteristics; thus, from the point of view of lamb meat production and fatty acid profile, the inclusion of PKO is not beneficial.

Age-related alterations in the nutritional quality of Arctic grayling (Thymallus arcticus)

The biochemical composition of the muscle in Arctic graylings at three age stages was evaluated and compared. For conventional biochemical composition, there was no significant difference in the crude protein content among the three age stages, but the crude fat content in the 1 year old was significantly lower than that of the others (P < 0.05). For amino acids composition, there was no significant difference in the content of essential amino acids and delicious amino acids among the three age stages, but the essential amino acid index of the 2 year old was the highest (72.205), indicating that its essential amino acid composition was more suitable for human needs. For fatty acids composition, the content of monounsaturated fatty acids (2.759 mg/g) and polyunsaturated fatty acids (3.422 mg/g) of the 3 year old was significantly higher than that of the others (P < 0.05), and it also had relatively lowest atherogenicity index (0.419) and thrombogenicity index (0.179) and the highest hypocholesterolemic/hypercholesterolemic fatty acid ratio (2.404), indicating that its fatty acid composition was healthier and more beneficial to the prevention of human cardiovascular and cerebrovascular diseases. For minerals composition, the contents of iron, zinc, and copper increased with age, while the contents of selenium and manganese decreased with age, with the highest selenium content in the 1 year old (1.522 mg/kg). The chromium, arsenic, lead, and cadmium contents were all lower than the Chinese national standard. In conclusion, the nutritional composition of Arctic graylings variated with age and consumers could select suitable Arctic graylings based on their nutritional needs. PRACTICAL APPLICATION: This work analyzed the nutritional components in the muscle of Arctic graylings at different ages, which can provide an effective reference for consumers when purchasing Arctic graylings.

The comparison of largemouth bass (Micropterus salmoides) fed trash fish and formula feeds: Growth, flesh quality and metabolomics

This study compared the growth, flesh quality and metabolomics of largemouth bass (Micropterus salmoides) fed trash fish and formula feeds. Trash fish (TF), self-made feed (SF) and commercial feed (CF) were prepared with crude protein levels of 172.2 g/kg, 503.5 g/kg and 504.1 g/kg (666.2 g/kg, 547.3 g/kg and 535.1 g/kg based on dry matter), respectively. Then, the three diets were fed to largemouth bass with an initial body weight of 75.0 ± 0.1 g for 12 weeks. SF and CF groups presented significantly lower feed intake (FI), feed conversion ratio (FCR) and higher protein efficiency ratio (PER) than TF group based on dry matter basis without affecting the weight gain (P &lt; 0.05). The yellowness (b*) in dorsal muscle, flesh heat-insoluble collagen and free flavor amino acids contents in SF group were significantly higher (P &lt; 0.05), while drip loss were significantly lower (P &lt; 0.05) than those of TF group. Compared to TF group, SF and CF groups showed significantly higher flesh polyunsaturated fatty acids (PUFAs), n-3 PUFAs and n-6 PUFAs contents, flesh hardness, shear force and muscle fiber density (P &lt; 0.05), and lower flesh total free amino acids, essential amino acids, muscle fiber diameter, intestine villus height and muscular thickness (P &lt; 0.05). The serum total protein, triglyceride and cholesterol levels in SF group were significantly lower than those in TF and CF groups (P &lt; 0.05). In the muscle metabolomics, 177 differential metabolites were detected between SF and TF groups, which mainly enriched in pathways as biosynthesis of amino acid, histidine metabolism, glycine, serine and threonine metabolism, etc. Conclusively, feeding largemouth bass with formula feeds improved flesh fatty acid profile and flesh texture without negative effects on the growth, but the flesh free amino acids contents were lower than the fish fed trash fish.

An Evaluation of Replacing Fishmeal with Chlorella Sorokiniana in the Diet of Pacific White Shrimp (Litopenaeus Vannamei): Growth, Body Color, and Flesh Quality

This study was conducted to investigate the effects of replacing fishmeal (FM) with Chlorella sorokiniana on growth and flesh quality of Pacific white shrimp, Litopenaeus vannamei. A control diet was formulated to contain 560 g/kg FM, and then chlorella meal was used to replace 0% (C-0), 20% (C-20), 40% (C-40), 60% (C-60), 80% (C-80), and 100% (C-100) of dietary FM, respectively. The six isoproteic and isolipidic diets were fed to shrimp (1.37 ± 0.02 g) for 8 weeks. The results showed that weight gain (WG) and protein retention (PR) of C-20 group were significantly higher than those of C-0 group (P < 0.05), while no significant differences were observed in WG and PR between C-0 and C-40 groups (P > 0.05). When the replaced level of FM by chlorella meal reached 60%, the WG of shrimp decreased and feed conversion ratio (FCR) increased significantly (P < 0.05). The quadratic regression analysis indicated that substituted fishmeal levels with chlorella meal were 20.50% and 28.25%, respectively, to obtain the highest WG and lowest FCR. In C-40 and C-60 groups, the body surface presented higher redness than the control (P < 0.05). No significant differences in the whole body and muscle composition, SOD, T-AOC, GSH-PX activities, MDA contents, total collagen content, steaming loss, texture property, free delicious amino acids contents, PUFAs, and n-3/n-6 PUFAs in flesh were observed among the three groups of C-0, C-20, and C-40 (P > 0.05). Compared to the control group, C-60, C-80, and C-100 groups showed lower flesh hardness, chewiness, shear force, and higher steaming loss and resilience (P < 0.05). There were no significant differences in serum TP, TG, GLU, and ALB contents, boiling loss, freezing loss, total free amino acids, SAFs and MUFAs among all the groups (P >0.05). Conclusively, in a diet containing 560 g/kg FM, chlorella meal could replace 40% dietary FM without negative effects on the growth and flesh quality, while increase the body redness of white shrimp.

Influence of exogenous phytohormone supplementation on the pigment and fatty acid content of three marine diatoms

Diatoms are ubiquitous photosynthetic microorganisms with great potential for biotechnological applications. However, their commercialisation is hampered by production costs, requiring hence optimisation of cultivation methods. Phytohormones are plant growth regulators which may be used to influence physiological processes in microalgae, including diatoms. In this study, the model species Phaeodactylum tricornutum (Phaeodactylaceae) and two Irish isolates of Stauroneis sp. (Stauroneidaceae) and Nitzschia sp. (Bacillariaceae) were grown with varying amounts of the phytohormones indoleacetic acid (IAA), gibberellic acid (GA3), methyl jasmonate (MJ), abscisic acid (ABA) or salicylic acid (SA), and their influence on pigment and fatty acid profiles was monitored. The application of GA3 (200 mg/l) stimulated the growth of P. tricornutum which accumulated 52% more dry biomass compared to the control and concomitantly returned the highest eicosapentaenoic acid (EPA) yield (0.6 mg/l). The highest fucoxanthin yield (0.18 mg/l) was obtained for P. tricornutum cultivated with GA3 (2 mg/l) supplementation. In Stauroneis sp., SA (1 mg/l) had the most positive effect on EPA, the content of which was enhanced up to 45.7 μg/mg (4.6% of total dry weight). The SA (1 mg/l) treatment also boosted carotenogenesis in Nitzschia sp., leading to 1.7- and 14-fold increases in fucoxanthin and β-carotene compared to the control, respectively. Of note, MJ (0.5 mg/l) increased the EPA content of all diatom species compared to their controls. These results indicate that phytohormone-based treatments can be used to alter the pigment and lipid content of microalgae, which tend to respond in dose- and species-specific manners to individual compounds.Key points• Response to phytohormones was investigated in diatoms from distinct families.• MJ (0.5 mg/l) caused an increase in EPA cellular content in all three diatoms.• Phytohormones mostly caused dose-dependent and species-specific responses.

Risk and benefit assessment of seafood consumption harvested from the Pertuis Charentais region of France

Seafood is well recognized as a major source of Long Chain n-3 Polyunsaturated Fatty Acids (LC n-3 PUFA, especially ecosapentaenoic acid, i.e. EPA and docosaheaxaenoic acid, i.e. DHA) and essential trace elements (As, Cu, Fe, Mn, Se, and Zn). It is also a source of non-essential trace elements (Ag, Cd, Hg, Pb) that can be deleterious for health even at low concentrations. Edible parts of sixteen species (fish, cephalopods, crustaceans and bivalves) of great importance in the Pertuis Charentais region, one of the main shellfish farming and fishing areas along the french coastline, were sampled in winter and analyzed to determine their fatty acid (FA) composition and trace element concentrations. Based on these analyses, a suite of indices was calculated to estimate risk and benefit of seafood consumption: the n-6/n-3 ratio, the atherogenic index, the thrombogenic index, the EPA + DHA daily recommended portion, as well as the maximum safe consumption. The results showed that fish contributed the most to LC n-3 PUFA supply, while bivalves and crustaceans were more beneficial in essential trace elements. Whatever the species, the concentrations of non-essential elements were not limiting for seafood consumption, as important amounts of the analyzed species can be eaten daily or weekly before becoming hazardous to consumers. Yet, concentrations of Hg in dogfish and seabass can become a concern for frequent seafood consumers (>three meals a week), confirming that varying seafood items is a key point for consumers to optimize the benefits of diverse seafood resources. Considering FA composition, whiting and pilchard are the most beneficial fish species for human diet, while surmullet was the least beneficial one. However, using an index integrating the relative risk due to Hg content, the surmullet appears as one of the most beneficial. This study provides a temporal shot of the quality of marine resources consumed in winter period in the studied area and highlights the complexity of a quantitative risk and benefit assessment with respect to the biochemical attributes of selected seafood.

Bioactive Lipids of Seaweeds from the Portuguese North Coast: Health Benefits versus Potential Contamination

The total lipid content and lipidic profile of seaweeds harvested in the North Coast and purchased in Portugal were determined in this paper. The amount of total lipids in the different species of seaweeds varied between 0.7 ± 0.1% (Chondrus crispus) and 3.8 ± 0.6% (Ulva spp.). Regarding the fatty acid content, polyunsaturated fatty acids (PUFA) ranged between 0–35%, with Ulva spp. presenting the highest amount; monounsaturated fatty acids (MUFA) varied between 19 and 67%; and saturated fatty acids (SFA) were predominant in C. crispus (45–78%) and Gracilaria spp. (36–79%). Concerning the nutritional indices, the atherogenicity index (AI) was between 0.4–3.2, the thrombogenicity index (TI) ranged from 0.04 to 1.95, except for Gracilaria spp., which had a TI of 7.6, and the hypocholesterolemic/hypercholesterolemic ratio (HH) values ranged between 0.88–4.21, except for Gracilaria spp., which exhibited values between 0.22–9.26. The n6/n3 ratio was below 1 for most of the species evaluated, except for Ascophyllum nodosum, which presented a higher value, although below 2. Considering the PUFA/SFA ratio, seaweeds presented values between 0.11–1.02. The polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons (AHCs) contamination of seaweeds under study was also quantified, the values found being much lower than the maximum levels recommended for foodstuff.

Inositol hexaphosphate modulates the behavior of macrophages through alteration of gene expression involved in pathways of pro- and anti-inflammatory responses, and resolution of inflammation pathways

Inositol hexaphosphate (IP6) is a dietary compound commonly obtained from corn, rice, etc. Although we may consume significant amount of IP6 daily, it is unclear whether this diet will impact macrophages' fate and function. Therefore, we characterized the underlying relationship between IP6 and macrophage polarization in this study. We specifically examined the signature gene expression profiles associated with pro- and anti-inflammatory responses, and resolution of inflammation pathways in macrophages under the influence of IP6. Interestingly, our data suggested that IP6 polarizes bone marrow-derived macrophages (BMDM) into an M2a-like subtype. Our results also demonstrated that IP6 reduces lipopolysaccharide-induced apoptosis and pro-inflammatory responses in macrophages. In contrast, the expression levels of genes related to anti-inflammatory responses and resolution of inflammation pathways are upregulated. Our findings collectively demonstrated that IP6 has profound modulation effects on macrophages, which warrant further research on the therapeutic benefits of IP6 for inflammatory diseases.

Biosafety evaluation of Nannochloropsis oculata and Schizochytrium sp. oils as novel human milk fat substitutes

The biosafety assessment of novel human milk fat substitutes (HMFs) from microalgae oils of Nannochloropsis oculata and Schizochytrium sp. was evaluated by testing the cytotoxic activity using IEC-6 cells, and by conducting a sub-chronic 28-day dietary study using Sprague-Dawley (SD) suckling rats in this study. The results of the cytotoxic activity of IEC-6 cells treated with HMFs showed no apparent effect on cell viability at the tested concentrations (0-1000 μg mL^-1). For the 28-day sub-chronic study, five rat dietary feeds with 7.5% fat were designed to have the DHA content in the range from 0 to 2.0% using corn oil as a basal oil. After the 28-day treatment, SD rats fed HMFs did not show toxicity signs and adverse effects, based on the results of clinical observation, body weight, food consumption, behavior, hematology, clinical chemistry, and necropsy findings. These results could lead to the conclusion that the inclusion of the new synthesized HMFs into the pre-weaning SD rat diet was acceptable for SD rats and did not exhibit toxic characteristics and adverse features, indicating that the HMFs from microalgal oils were safe and had the potential to be used as a promising feedstock in infant formula.

Colloidal Particles in Tuna Head Soup: Chemical Localization, Structural Change, and Antioxidant Property

In this work, chemical localization, structural changes, and antioxidant properties of tuna colloidal particles (TCPs) in boiling tuna head soup were examined. The results demonstrated that TCPs might be core–shell colloidal spherical structures. The hydrophobic core consisted of triglycerides and chloride ions. The hydrophilic shell layer consisted of chloride ions, sodium ions, phospholipids, protein, and glycosyl molecules. Coalescence of TCPs occurred during the boiling process, and water may enter the hydrophobic core of TCPs after the boiling time of 60 min. TCPs had excellent antioxidant properties against H₂O₂-induced human umbilical vein endothelial cell injury. It might be resulted from that TCPs could decrease cell apoptosis proportion and downregulate mRNA levels of endoplasmic reticulum-bounded chaperone protein glucose-related protein (GRP78), C/EBP homologous protein (CHOP), and activating transcription factor-4 (ATF4). This work can provide useful basic information to understand the colloidal system in foods, especially in soup. In addition, it may also promote the potential high-value-added utilization of aquatic by-products.

Recent Discoveries in the Field of Lipid Bio-Based Ingredients for Meat Processing

Current culture and pace of lifestyle, together with consumer demand for ready-to-eat foods, has influenced the food industry, particularly the meat sector. However, due to the important role that diet plays in human health, consumers demand safe and healthy food products. As a consequence, even foods that meet expectations for convenience and organoleptic properties must also meet expectations from a nutritional standpoint. One of the main nutritionally negative aspects of meat products is the content and composition of fat. In this sense, the meat industry has spent decades researching the best strategies for the reformulation of traditional products, without having a negative impact in technological processes or in the sensory acceptance of the final product. However, the enormous variety of meat products as well as industrial and culinary processes means that a single strategy cannot be established, despite the large volume of work carried out in this regard. Therefore, taking all the components of this complex situation into account and utilizing the large amount of scientific information that is available, this review aims to comprehensively analyze recent advances in the use of lipid bio-based materials to reformulate meat products, as well as their nutritional, technological, and sensorial implications.

Temperature Differentially Affects Gene Expression in Antarctic Thraustochytrid Oblongichytrium sp. RT2316-13

Oblongichytrium RT2316-13 synthesizes lipids rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The content of these fatty acids in the total lipids depended on growth temperature. Sequencing technology was used in this work to examine the thraustochytrid's response to a decrease in growth temperature from 15 °C to 5 °C. Around 4% (2944) of the genes were differentially expressed (DE) and only a few of the DE genes (533 upregulated; 206 downregulated) had significant matches to those in the SwissProt database. Most of the annotated DE genes were related to cell membrane composition (fatty acids, sterols, phosphatidylinositol), the membrane enzymes linked to cell energetics, and membrane structure (cytoskeletal proteins and enzymes). In RT2316-13, the synthesis of long-chain polyunsaturated fatty acids occurred through ω3- and ω6-pathways. Enzymes of the alternative pathways (Δ8-desaturase and Δ9-elongase) were also expressed. The upregulation of the genes coding for a Δ5-desaturase and a Δ5-elongase involved in the synthesis of EPA and DHA, explained the enrichment of total lipid with these two long-chain fatty acids at the low temperature. This molecular response has the potential to be used for producing microbial lipids with a fatty acids profile similar to that of fish oils.

The Role of Omega-3 Polyunsaturated Fatty Acids from Different Sources in Bone Development

N-3 polyunsaturated fatty acids (PUFAs) are essential nutrients that must be obtained from the diet. We have previously showed that endogenous n-3 PUFAs contribute to skeletal development and bone quality in fat-1 mice. Unlike other mammals, these transgenic mice, carry the n-3 desaturase gene and thus can convert n-6 to n-3 PUFAs endogenously. Since this model does not mimic dietary exposure to n-3 PUFAs, diets rich in fish and flaxseed oils were used to further elucidate the role of n-3 PUFAs in bone development. Our investigation reveals that dietary n-3 PUFAs decrease fat accumulation in the liver, lower serum fat levels, and alter fatty acid (FA) content in liver and serum. Bone analyses show that n-3 PUFAs improve mechanical properties, which were measured using a three-point bending test, but exert complex effects on bone structure that vary according to its source. In a micro-CT analysis, we found that the flaxseed oil diet improves trabecular bone micro-architecture, whereas the fish oil diet promotes higher bone mineral density (BMD) with no effect on trabecular bone. The transcriptome characterization of bone by RNA-seq identified regulatory mechanisms of n-3 PUFAs via modulation of the cell cycle and peripheral circadian rhythm genes. These results extend our knowledge and provide insights into the molecular mechanisms of bone remodeling regulation induced by different sources of dietary n-3 PUFAs.

Alternative extraction techniques to obtain, isolate and purify proteins and bioactive from aquaculture and by-products

Oceans cover more than 70% of the earth's surface and provide a great ecosystem for habitat of a large divers of marine species. The marine species are rich sources of bioactive compound that can be applied in medicine, pharmacology and food industry. Besides the marine species, fish processing industry also produces substantial volumes of by-products that can be used for a variety of purposes. Thus, it is important to find approaches to access to these valuable compounds. Nowadays, more factors have been considered in selecting an appropriate method for extraction of bioactive compounds such as consume less time and solvent, to be fast and ecofriendly. Concerns regarding entering the pollutions to the environment resulted to invest on the methods practicable with less chemical solvents and even green ones, however, implementation of stricter regulations and policies is required to encourage researchers to set up the procedures with reduced toxic agents to guarantee the environmental safety. In the current chapter the most common marine derived compounds and innovative methods for their extraction will be discussed.

Combination of Lactobacillus plantarum and Saccharomyces cerevisiae DV10 as Starter Culture to Produce Mango Slurry: Microbiological, Chemical Parameters and Antioxidant Activity

The aim of this study was to develop a nondairy fermented product based on mango slurry. Lactobacillus plantarum and Saccharomyces cerevisiae DV10 were used as starter cultures in single and co-cultivations. The microbial populations and metabolites produced during mango slurry fermentation were investigated. At the end of all fermentations, the bacterial populations were higher than 6.0 log CFU/mL. Lactic acid was the main organic acid produced, achieving up to 6.12 g/L after 24 h in co-culture with L. plantarum and S. cerevisiae DV10. Volatile compounds were determined after 24 h of fermentation, the co-cultures of L. plantarum and S. cerevisiae DV10 could decrease terpenes and produce alcohols and esters. The co-cultivations obtained the most total phenolics as well as showed the strongest 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radical scavenging activity, ferric-reducing antioxidant power (FRAP) and low-density lipoprotein (LDL) oxidation inhibition. Hence, a high-bioactivity probiotic product was successfully obtained via mango slurry fermentation inoculated with a co-culture of L. plantarum and S. cerevisiae DV10.

Gelatin molecular structures affect behaviors of fish oil-loaded traditional and Pickering emulsions

As the differences of traditional and Pickering emulsions might have resulted from stabilizer structures, this study analyzes the effects of gelatin molecular structures (uncrosslinked molecules vs. crosslinked molecules) on the preparation, long-term storage, and dilution of fish oil-loaded traditional and Pickering emulsions. Both traditional and Pickering emulsions have three types of droplets with different sizes, and all the droplet sizes were exponentially decreased with the increase of stabilizer concentration. Pickering emulsions have slightly lower droplet sizes compared with traditional emulsions. Traditional emulsions have three different emulsion forms (liquid, redispersible emulsion gel, and unredispersible emulsion gel), whereas Pickering emulsions only have the liquid form. Emulsion creaming stability was dependent on stabilizer molecular structures and stabilizer concentrations. The two emulsions have similar and good dilution stability. This work demonstrates that gelatin molecular structures affect droplet size, emulsion forms, and creaming stability, but not droplet size types and emulsion dilution stability.

Fatty acid and lipophilic vitamin composition of seaweeds from Antalya and Çanakkale (Turkey)

The lipophilic vitamin and fatty acid profiles were determined in five edible seaweeds: Corallina elongata J. Ellis & Solander, 1786; Cystoseira barbata (Stackhouse) C. Agardh, 1820; Jania rubens (Linnaeus) J.V. Lamouroux, 1816; Laurencia obtusa (Hudson) J.V. Lamouroux, 1813 and Sargassum vulgare C. Agardh, 1820. Saturated fatty acids (SFAs) were the major fatty acid group, and16:0 formed the highest SFA content (34–40%). 16:0 was higher in the brown seaweeds (C. barbata, 40.55%; S. vulgare, 37.11%) than in the red seaweeds (C. elongata, 36.5%; L. obtusa, 34.57%; J. rubens, 34.22%). The other major fatty acids in the seaweeds were 18:1n-9 and 16:1n-7 from MUFA in the analyzed species. In addition, EPA was found in significant levels in the red seaweeds, whereas DHA was not detected in the analyzed species. The findings showed that difference among species were not statistically significant (p = 0.09–0.11), yet differences between two families (Sargassaceae and Corallinaceae) were significant (p = 0.006) in the fatty acid profile (p < 0.01). Also, differences between the Corallinaceae and Rhomomelaceae families were partially significant (p = 0.011–0.013) (p < 0.01). K1 and K2 vitamins as well as δ-tocopherol, α-tocopherol and retinol acetate were determined to be present in the seaweed extracts. Finally, ergosterol, stigmasterol and ß-sitosterol were found in all samples in differing ratios per species.

Protective effect of hydroxytyrosol and rosemary extract in a comparative study of the oxidative stability of Echium oil

The oxidative stability of Echium oil has been studied by two accelerated oxidation methodologies namely Rancimat and differential scanning calorimetry at selected temperatures in the range 50-110 °C. Kinetic analyses have provided Arrhenius parameters, oxidative stability indexes (OSI), temperature coefficients (t_coef), Q₁₀ and OSI at 20 °C (OSI₂₀) for both methodologies focussing on secondary and tertiary oxidation products. Peroxide, p-anisidine and polar compounds values have been measured to characterize from primary to tertiary oxidation products. In general, susceptibility of this oil to oxidation has been found to be larger than for other vegetable oils, according to the OSI₂₀ values estimated by Rancimat and differential scanning calorimetry. However, the values of t_coeff and Q₁₀ are found to be similar to those described for vegetable oils. In addition, a study of the influence of two antioxidants, namely hydroxytyrosol and rosemary extract on the oxidative stability of Echium oil has been carried out using both methodologies. Protective effects over oxidation by up to a threefold increase of OSI₂₀ values have been found for both antioxidants at the highest dose utilized.

Changes in the liver transcriptome of farmed Atlantic salmon (Salmo salar) fed experimental diets based on terrestrial alternatives to fish meal and fish oil

Background

Dependence on marine natural resources threatens the sustainability of Atlantic salmon aquaculture. In the present study, Atlantic salmon fed for 14 weeks with an experimental diet based on animal by-products and vegetable oil (ABP) exhibited reduced growth performance compared with others fed a fish meal/fish oil based experimental diet (MAR) and a plant protein/vegetable oil-based experimental diet (VEG). To characterize the molecular changes underlying the differences in growth performance, we conducted a 44 K microarray study of the liver transcriptome of the three dietary groups.

Results

The microarray experiment identified 122 differentially expressed features (Rank Products, PFP < 10%). Based on their associated Gene Ontology terms, 46 probes were classified as metabolic and growth-relevant genes, 25 as immune-related, and 12 as related to oxidation-reduction processes. The microarray results were validated by qPCR analysis of 29 microarray-identified transcripts. Diets significantly modulated the transcription of genes involved in carbohydrate metabolism (gck and pfkfb4), cell growth and proliferation (sgk2 and htra1), apoptosis (gadd45b), lipid metabolism (fabp3, idi1, sqs), and immunity (igd, mx, ifit5, and mhcI). Hierarchical clustering and linear correlation analyses were performed to find gene expression patterns among the qPCR-analyzed transcripts, and connections between them and muscle and liver lipid composition. Overall, our results indicate that changes in the liver transcriptome and tissue lipid composition were driven by cholesterol synthesis up-regulation by ABP and VEG diets, and the lower carbohydrate intake in the ABP group. Two of the microarray-identified genes (sgk2 and htra1) might be key to explaining glucose metabolism regulation and the dietary-modulation of the immune system in fish. To evaluate the potential of these genes as predictive biomarkers, we subjected the qPCR data to a stepwise discriminant analysis. Three sets of no more than four genes were found to be able to predict, with high accuracy (67–94%), salmon growth and fatty acid composition.

Conclusions

This study provides new findings on the impact of terrestrial animal and plant products on the nutrition and health of farmed Atlantic salmon, and a new method based on gene biomarkers for potentially predicting desired phenotypes, which could help formulate superior feeds for the Atlantic salmon aquaculture industry.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-5188-6) contains supplementary material, which is available to authorized users.

Defatted Microalgae-Mediated Enrichment of n-3 Polyunsaturated Fatty Acids in Chicken Muscle Is Not Affected by Dietary Selenium, Vitamin E, or Corn Oil

Background

We previously showed enrichments of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) in broiler chicks fed defatted microalgae.

Objectives

The aims of this study were to determine 1) if the enrichments affected meat texture and were enhanced by manipulating dietary corn oil, selenium, and vitamin E concentrations and 2) how the enrichments corroborated with hepatic gene expression involved in biosynthesis and oxidation of EPA and DHA.

Methods

Day-old hatching Cornish Giant cockerels (n = 216) were divided into 6 groups (6 cages/group and 6 chicks/cage). Chicks were fed 1 of the 6 diets: a control diet containing 4% corn oil, 25 IU vitamin E/kg, and 0.2 mg Se/kg (4CO), 4CO + 10% microalgae (defatted Nannochloropsis oceanica; 4CO+ MA), 4CO+ MA - 2% corn oil (2CO+MA), 2CO+MA + 75 IU vitamin E/kg (2CO+MA+E), 2CO+MA + 0.3 mg Se/kg (2CO+MA+Se), and 2CO+MA+E + 0.3 mg Se/kg (2CO+MA+E+Se). After 6 wk, fatty acid profiles, DHA and EPA biosynthesis and oxidation, gene expression, lipid peroxidation, antioxidant status, and meat texture were measured in liver, muscles, or both.

Results

Compared with the control diet, defatted microalgae (4CO+MA) enriched (P < 0.05) DHA and EPA by ≤116 and 24 mg/100 g tissue in the liver and muscles, respectively, and downregulated (41-76%, P < 0.01) hepatic mRNA abundance of 4 cytochrome P450 (CYP) enzymes (CYP2C23b, CYP2D6, CYP3A5, CYP4V2). Supplemental microalgae decreased (50-82%, P < 0.05) lipid peroxidation and improved (16-28%, P < 0.05) antioxidant status in the liver, muscles, or both. However, the microalgae-mediated enrichments in the muscles were not elevated by altering dietary corn oil, vitamin E, or selenium and did not affect meat texture.

Conclusion

The microalgae-mediated enrichments of DHA and EPA in the chicken muscles were associated with decreased hepatic gene expression of their oxidation, but were not further enhanced by altering dietary corn oil, vitamin E, or selenium.

Influence of omega-3 incorporation in sperm preservation medium on physical and kinematic properties of chilled and cryopreserved ram spermatozoa

Two experiments were carried out to investigate the efficiency of supplementing sperm preservation medium with omega-3 polyunsaturated fatty acids on improving liquid-chilled storage and cryopreservation capacity of ram spermatozoa. Ejaculates (n = 100) were collected from five adult rams, Ovis aries, by an artificial vagina twice weekly throughout the period February-April, 2017. After initial evaluation, ejaculates of each collection session from the same males were pooled, diluted (1:10) with Tris-citric acid egg yolk extender, and were further split into five aliquots using a split-sample technique. The first aliquot served as control (omega-free), whereas the other four portions were supplemented with 0.1, 0.2, 0.3 or 0.4 mM omega-3, respectively (T₀ ). Thereafter, the diluted specimens were stored at 4°C for 48 hr, during which sperm physical and morphometric properties were evaluated along with oxidative stress indices (T₂₄ , T₄₈ ). Omega-3 levels that efficiently mitigated the detrimental effects of chilled preservation, and maintained preservation aptitude of spermatozoa were further investigated for sperm cryosurvival against control (untreated). Post-thaw physical and kinematic properties of spermatozoa, in all groups, were objectively evaluated by a computer-assisted sperm analysis (CASA) system. The results showed that, at 48 hr of chilled storage, supplementing preservation medium with 0.4 mM omega-3 was positively correlated (p < 0.01) with each of progressive motility, live sperm, intact acrosome and intact cell membrane (r = 0.83, 0.85, 0.85, 0.89, respectively). Furthermore, a positive correlation (p < 0.01) was observed between inclusion of omega-3 in cryopreservation medium and each of post-thaw total sperm motility, progressive motility, live sperm, normal sperm, intact acrosome, intact cell membrane, VCL, VSL, VAP, ALH and STR (r = 0.76, 0.84, 0.79, 0.90, 0.89, 0.91, 0.61, 0.73, 0.65, 0.78 and 0.60, respectively). These results accentuate efficiency of supplementing the diluent with omega-3 fatty acids on improving chilled and cryopreservation aptitude of ram spermatozoa.

Characterization of Positional Distribution of Fatty Acids and Triacylglycerol Molecular Compositions of Marine Fish Oils Rich in Omega-3 Polyunsaturated Fatty Acids

The regiospecific characteristics of n-3 polyunsaturated fatty acids (PUFAs) in triacylglycerol (TAG) significantly affect the physicochemical and physiological properties of marine fish oils. In this study, the TAG molecular species composition and positional distributions of fatty acids were investigated in three marine fish species rich in omega-3 PUFAs (anchovy, tuna, and salmon). The regiospecific distribution of the fatty acids was measured with the allylmagnesium bromide (AMB) degradation method. The TAG compositions were analyzed with HPLC and the TAG molecular species were identified with APCI/MS. DHA was preferentially distributed at the sn-2 position of TAG, whereas EPA was evenly distributed along the glycerol backbone. The combinations of FAs, DDO, EOP, EPS, DSS, OOS, and PPS were the predominant TAG molecular species, and OOP, DOS, and DPoPo were the characteristic TAG molecules in the anchovy, salmon, and tuna, respectively. These data can be used to distinguish other marine fish species. The TAG composition categorized by TCN and ECN showed well-structured distributions, with double or triple peaks. These findings should greatly extend the use of marine fish oils in food production and may significantly affect the future development of the fish oil industry.