Eicosapentaenoic Acid Content Research Articles

Complete replacement of fishmeal with unconventional animal protein sources: A comparative study of the effects of use of mealworm, earthworm and zooplankton on growth parameters, fatty acid composition and sensory profile rainbow trout

The global trend in aquaculture is to replace fishmeal with an alternative and sustainable source of protein for fish farming. As a result, some species of invertebrates have found a place in aquaculture as a rich source of protein and a promising substitute for fishmeal. This study aimed to investigate the effects of alternative protein sources on the growth parameters of rainbow trout (Oncorhynchus mykiss) as well as the fatty acid profile and the sensory quality of the fish fillets. The gas chromatography technique with a flame ionization detector was used to determine the fatty acid composition of the rainbow trout fillets, while different equations were used to determine the growth parameters and the hepatosomatic index. The sensory evaluation of the rainbow trout fillet was determined by a descriptive sensory analysis, a quality assessment and a consumer acceptance test. The replacement of fishmeal by mealworms (MWD) and earthworms (EWD) resulted in a positive effect on growth parameters, feed conversion, and hepatosomatic index (HSI) values. The mortallity of the rainbow trout fed with the experimental diets was less than 28 %. The eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content of the trout fillets decreased with the inclusion of MWD (1.34 and 5.20 %, respectively) and EWD (1.74 and 6.41 %, respectively) in the trout diet. Feeding rainbow trout with MWD and EWD caused a decrease in the n-3/n-6 ratio compared to FMD (0.32 and 0.34, respectively vs. 0.56), whereas the addition of ZOD resulted in the increase of the n-3/n-6 ratio (0.67). The samples of fillets of trout fed with MWD and EWD belonged to the "very good" level of average sensory quality, while the fillets of trout fed with zooplankton were in the "good" quality range. Regarding acceptability by consumers all rainbow trout fillets shown good consumer acceptance.

Cultivation of Aurantiochytrium sp. Using Pickle Seasoning Liquid Waste and Application of the Raw Biomass for Fish Aquaculture

AbstractAurantiochytrium sp. strain L3W is a heterotrophic microorganism that produces docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), which are essential for the growth of marine fish. In this study, pickle seasoning liquid waste was used for culturing strain L3W and the raw biomass of strain L3W was then fed to red sea bream fingerlings (Pagus major) to confirm its usability as a source of DHA and EPA. The strain L3W was cultured on the three pickle seasoning liquid waste samples, Akimurasaki, Hiroshimana, Shisohijiki, diluted with sand-filtered seawater at initial pH values of 4 and 7 under unsterile conditions. The growth of strain L3W was highest at 3.71 g/L on Hiroshimana at an initial pH of 7 with DHA and EPA production at 71.4 and 6.8 mg/g-biomass, respectively. Preparing the raw biomass of strain L3W by the 200 L-scale cultivation using the American Type Culture Collection 790By+ medium because of the DHA and EPA contents close to that produced in the Hiroshimana medium with an initial pH of 7, the raw biomass was spiked to the diet at 3%, 5%, and 10%. The final DHA and EPA contents in the whole body were increased by 4.26 and 3.03 times, respectively, by adding the strain L3W biomass at 10%. These results confirmed the feasibility of a carbon cycling scenario in which the strain L3W is cultivated using liquid food waste with the resultant biomass is utilized as a source of DHA and EPA for fish aquaculture. Graphical Abstract

FADS1 Genetic Variant and Omega-3 Supplementation Are Associated with Changes in Fatty Acid Composition in Red Blood Cells of Subjects with Obesity.

Obesity is characterized by low-grade chronic inflammation, which can be modulated by lipid mediators derived from omega-3 (n-3) polyunsaturated fatty acids (PUFA). Obesity is a multifactorial disease, where genetic and environmental factors strongly interact to increase its development. In this context, the FADS1 gene encodes the delta-5 desaturase protein, which catalyzes the desaturation of PUFA. The rs174547 genetic variant of FADS1 has been associated with alterations in lipid metabolism, particularly with decreases in eicosapentaenoic acid (EPA) and arachidonic acid (AA) concentrations. To analyze the effect of an n-3-supplemented diet on the fatty acid profile and composition in red blood cells (RBCs) of obese subjects carrying the rs174547 variant of the FADS1 gene. Seventy-six subjects with obesity were divided into two groups: omega-3 (1.5 g of n-3/day) and placebo (1.5 g of sunflower oil/day). The dietary intervention consisted of a four-month follow-up. Anthropometric, biochemical, and dietary variables were evaluated monthly. The total fatty acid profile in RBC was determined using gas chromatography. The rs174547 variant was analyzed through allelic discrimination. The n-3 index (O3I) increased at the end of the intervention in both groups. Subjects carrying the CC genotype showed significant differences (minor increase) in n-6, n-3, total PUFA, EPA, DHA, and the O3I in RBCs compared to TT genotype carriers in the n-3 group. The diet supplemented with EPA and DHA is ideal for providing the direct products that bypass the synthesis step affected by the FADS1 rs174547 variant in subjects carrying the CC genotype. The O3I confirmed an increase in n-3 fatty acids in RBCs at the end of the intervention.

The influence of storage conditions on hygiene condition and eicosapentaenoic acid oxidation in Nannochloropsis algae for sustainable food supply.

Nannochloropsis algae contain approximately 20% polyunsaturated fatty acids (PUFA) and hold significant potential for high-quality eicosapentaenoic acid (EPA) food industrialization. However, EPA in Nannochloropsis sp. is prone to oxidation, and microbial growth is a critical factor affecting the shelf life of fresh food. Storage composition and temperature are primary factors influencing microbial growth, yet these aspects are not fully understood. This study investigates the effects of temperature and encapsulation on EPA content in nano-products over time. Nano-powder and nanobeads derived from Nannochloropsis sp. served as raw materials. Additionally, changes in aerobic plate counts and coliform groups were monitored. The results indicated that nanobeads, due to their more complex processing and less mature packaging, were more susceptible to coliform contamination compared to nano-powder. In terms of EPA stability, nanobeads exhibited a longer storage life than nano-powder. The oxidation rate of both nano-powder and nanobeads was faster at 37 °C than at 25 °C. These findings can inform general shelf life estimation, rapid detection of total lipid content in nano-products and macro extraction of nano-oil. Moreover, they have significant implications for delaying EPA oxidation in nano-products and improving hygienic quality control for microbial detection. © 2024 Society of Chemical Industry.

Differences in quality between canned and pouched tuna packed with various media

Canned and pouched tuna products may be present in different liquid media such as brine, different types of oil and sauces in the markets. Limited reported information about the pouched tuna products and the differences between them in different liquid media available in Turkish markets. pH values of CW and PW were lower than the others. TBA values of all groups were found to be below the limits for development of an objectionable odor/taste. Omega 6/omega3 ratio was determined very high in CS and PS. On the other hand, higher content of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were found in CW and PW when compared with others (CO, CS, PO, PS). Heavy metal contents of tuna products, they were found to be safe according to limits for arsenic, mercury, lead and cadmium levels. L* values of all canned tunas (CO, CS, CW) were significantly higher than the pouched tunas (PO, PS, PW). b* values of both CW and PW were lower than the other groups. CW got the significantly lowest overall quality, color and taste scores when compared with the others. As a matter of fact, pouched tuna products especially PW were recommended for health purposes.

Modeling enzyme competition in eicosanoid metabolism in macrophage cells using a cybernetic framework

Cellular metabolism is a complex process involving the consumption and production of metabolites, as well as the regulation of enzyme synthesis and activity. Modeling of metabolic processes is important to understand the underlying mechanisms, with a wide range of applications in metabolic engineering and health sciences. Cybernetic modeling is a powerful technique that accounts for unknown intricate regulatory mechanisms in complex cellular processes. It models regulation as goal-oriented, where the levels and activities of enzymes are modulated by the cybernetic control variables to achieve the cybernetic objective. This study used cybernetic model to study the enzyme competition between arachidonic acid (AA) and eicosapentaenoic acid (EPA) metabolism in murine macrophages. AA and EPA compete for the shared enzyme cyclooxygenase. Upon external stimuli, AA produces proinflammatory 2-series prostaglandins and EPA metabolizes to antiinflammatory 3-series prostaglandins, where proinflammatory and antiinflammatory responses are necessary for homeostasis. The cybernetic model adequately captured the experimental data for control and EPA-supplemented conditions. The model is validated by performing an F-test, conducting leave-one-out-metabolite cross-validation, and predicting an unseen experimental condition. The cybernetic variables provide insights into the competition between AA and EPA for the cyclooxygenase enzyme. Predictions from our model suggest that the system undergoes a switch from a predominantly proinflammatory state in the control to an antiinflammatory state with EPA-supplementation. The model can also be used to analytically determine the AA and EPA concentrations required for the switch to occur. The quantitative outcomes enhance understanding of proinflammatory and antiinflammatory metabolism in RAW 264.7 macrophages.

Dietary astaxanthin alleviates black soldier fly oil-induced negative changes of fatty acids content and muscle quality on Oncorhynchus mykiss via mammalian target of rapamycin and AMP-activated protein kinase pathway

This study evaluated the effect of black soldier fly (Hermetia illucens) larvae oil (BO) produced by a novel technique, subcritical butane extraction, on the flesh quality, lipid nutrients and muscle growth of rainbow trout (Oncorhynchus mykiss) fillet, and investigated the alleviating mechanisms of dietary astaxanthin (AST) supplementation. Two hundred and forty fish (215.16 ± 2.30 g) were distributed to three groups with four replicates. Fish were fed three experimental diets for 8 weeks: the control diet (CD diet), total fish oil of the CD diet was replaced with BO to formulate the BO100 diet, and then 1 g/kg AST was supplemented with the BO100 diet to formulate the AST diet. Results showed that the final body weight and the sarcomere length of fillet were significantly increased and the protein phosphorylation levels of mammalian target of rapamycin (mTOR) and p70 S6 kinase were enhanced in the BO100 group compared to the CD group (P < 0.05). However, there was a reduction in the hardness, springiness and chewiness of fillets, with a decrease in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels in the fish of the BO100 group (P < 0.05). Supplementation of AST in the BO100 diet mitigated the impairment of springiness and chewiness and further promoted the sarcomere length of fillet (P < 0.05). Furthermore, dietary AST partially restored the EPA and DHA content of fillet by increasing the phosphorylation levels of serine/threonine kinase (AKT) and AMP-activated protein kinase α (AMPKα) (P < 0.05) and activating the gene expression of unsaturated fatty acid synthesis. To conclude, BO produced by subcritical butane extraction can be a readily available oil source for rainbow trout feed that can be used to promote muscle growth in rainbow trout. Further dietary AST supplementation can alleviate BO-induced lipid accumulation, restore DHA levels and improve the flesh quality of rainbow trout fillet.

PSIX-6 Algal oil as an alternative source of docosahexaenoic acid in feline diets

Abstract The global demand for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation by humans and their necessity in companion animal foods has raised questions related to environmental sustainability and nutrient content of fish oil. The combination of reported diminishing EPA and DHA content in fish oil and the forecasting of a significant decline in global fish stocks over the next decade make it critical to consider alternative sources of omega-3 fatty acids to reduce dependence on fish harvests. Cultured algal oil has been identified as a promising and viable alternative to fish-based oils. As such, the purpose of this study was to determine the inclusion level of algal oil in cat foods necessary to deliver the same serum concentrations of DHA provided from fish oil. Cats (n = 26) were first fed a control food formulated to avoid ingredients that contain long chain omega-3 fatty acids [ɑ-linolenic (ALA), EPA, and DHA] for 5 wk, to establish a baseline serum concentrations of these fatty acids. Cats were then randomized into two groups, and fed test foods containing either fish oil or algal oil in sequential increasing levels of DHA (0.2%, 0.4%, and 0.6%) for 5-wk periods each. Blood was analyzed for serum DHA and EPA concentrations after each of these feeding periods. A regression analysis was used to calculate a bioequivalence factor between fish oil and algal oil inclusion levels. There was no difference (P &amp;gt; 0.05) in intake or body weight between cats consuming diets containing algal oil or fish oil. Analysis of serum fatty acid concentrations showed that increasing fish and algal oil had no effect (P &amp;gt; 0.05) on serum linolenic acid, ALA, or arachidonic acid; however, increasing fish and algal oil did have an effect on DHA such that serum DHA was increased at similar rates as fish oil (P = 0.050) and algal oil (P = 0.026) levels were increased in the diet. Although increasing levels of fish and algal oil both increased serum EPA concentrations (P &amp;lt; 0.001), fish oil increased serum EPA to a greater extent than algal oil when fed at all levels. Overall, these data indicate that inclusion of algal oil is a good alternative dietary source of DHA, but less of EPA, and that algal oil will need to be added to the diet in higher concentrations to achieve similar serum EPA concentrations as fish oil.

Growth performance, fatty acid profile, antioxidant capacity, liver and gut histopathology in Asian seabass (Lates calcarifer) fed various levels of oxidized fish oil and vitamin E

A 60-day research was carried out to investigate interactive effects of dietary oxidized fish oil (OXFO) and vitamin E (Vit E) interaction effects on the growth, body composition and health indices in Asian seabass juveniles (Lates calcarifer, 21.9 ± 0.1 g). Fresh fish oil (FFO) and two levels of OXFO (50 and 100 % dietary inclusion level) along with three levels of Vit E (125, 250 and 500 mg) were used to design a 3 × 3 factorial research trial. Accordingly, nine experimental diets were formulated, including FFO+125 (FFO + 125 mg Vit E), FFO+250 (FFO + 250 mg Vit E), FFO+500 (FFO + 500 mg Vit E), 50 %OXFO+125 (blends (1:1) of FFO + OXFO +125 mg Vit E), 50 %OXFO+250 (blends (1:1) of FFO + OXFO +250 mg Vit E), 50 %OXFO+500 (blends (1:1) of FFO + OXFO +500 mg Vit E), 100 %OXFO+125 (OXFO +125 mg Vit E), 100 %OXFO+250 (OXFO +250 mg Vit E) and 100 %OXFO+500 (OXFO +500 mg Vit E). Four hundred five L. calcarifer juveniles were stocked into twenty-seven 300-L circular tanks (15 fish/tank), in a flow through system. The greatest and least final weights were recorded in fish fed 50 %OXFO+250 and 100 %OXFO+125 diets (129.4 vs. 114.8 g final weight) diets, respectively. Whole body lipid content in fish fed FFO+125 increased compared to the other treatments. Fish oil oxidation significantly reduced Vit E concentration in the liver, meanwhile supplementing diet with 500 mg Vit E enhanced Vit E contents of the liver and muscle (P < 0.05). Eicosapentaenoic acid and long chain polyunsaturated fatty acids (LC-PUFA) contents of fillet increased with increasing dietary OXFO content to 50 %, and supplementing diet with 250 mg Vit E enhanced LC-PUFA content of fillet. Hepatic catalase, superoxide dismutase and glutathione peroxidase activities reduced by supplementing diets with Vit E. Sever pathological alterations occurred in liver and gut of L. calcarifer by dietary inclusion of OXFO or high Vit E concentration (500 mg). In summary, supplementing OXFO containing diets with moderate levels of Vit E (250 mg) could improve growth performance and feed utilization by ameliorating oxidative stress indices, improving antioxidant capacity, and increasing body LC-PUFA content in L. calcarifer.

Enrichment of EPA and DHA in glycerides by selective enzymatic ethanolysis

It has been reported that eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in glycerides have various biological functions. This study presents an effective method for enriching glycerides rich in EPA and DHA through lipase-catalyzed alcoholysis. The results showed that Eversa® Transform 2.0 had the strongest discrimination against DHA and EPA in alcoholysis, which was verified by molecular docking. Additionally, selectivity of the lipase and ratio of DHA and EPA in glyceride products were significantly affected by alcohol type. Under the optimal conditions, the contents of EPA and DHA in glycerides after ethanolysis reached 12.91 % and 55.40 %, respectively, with a DHA yield of 79.22 %. In this study, an interesting finding was that Eversa® Transform 2.0 could effectively differentiate EPA and DHA during alcoholysis to allow us to prepare DHA-enriched glycerides and EPA-enriched ethyl esters after removing saturated and monounsaturated ethyl esters.

Production of eicosapentaenoic acid by Vacuoliviride crystalliferum under 20% CO2 conditions

Utilizing flue gas CO2 to co-produce eicosapentaenoic acid (EPA) with microalgae is considered an ideal approach for combating climate change and reducing cultivation costs. However, microalgal species that can efficiently produce EPA under high-CO2 conditions are scarce. This study identified that the eustigmatophycean strain Vacuoliviride crystalliferum demonstrates rapid growth under 20 % CO2 conditions (0.22 vvm), achieving a biomass concentration and productivity of 3.90 g/L and 229.26 mg/L/d, respectively. The EPA content and EPA productivity were found to be 4.28 % (w/w) and 9.80 mg/L/d, respectively. Additionally, an improved biomass concentration of 3.39 g/L and EPA content and productivity of 4.32 % (w/w) and 11.28 mg/L/d were obtained in a 30 L up-scaled cultivation system. Taken together, these findings suggest that V. crystalliferum is a promising candidate for integrating flue gas sequestration with EPA production.

Testing combined effects of environmental trace metals/arsenic and marine trophic status on the bioaccumulation in Pacific oysters: Insights from 22-site field samplings

Pacific oysters were sampled from 22 human-impacted sites in northeastern Japan to measure Cr, Cu, Zn, Pb, Cd, and As. The hazard quotient was slightly >1 for Cu and/or As at two sites, but <1 for all metal species and As at the other sites, indicating low human health risks. Oysters' Cu, Zn, and Pb contents were positively related to their concentrations in the sediment, while Cr and As were not. Oysters' Cu and Zn were negatively related to the inorganic nitrogen in seawater, while oysters' Pb and As showed positive relationships with the particulate organic carbon. These findings suggest that marine trophic status affects oysters' metal uptake differently among the metal species. Furthermore, oysters' Cr, Cu, Zn, and Pb contents were negatively related to their eicosapentaenoic acid content and condition index. Therefore, the nutritional conditions of oysters may influence their elimination or accumulation of these metals.

Effects of Bergamot (Citrus bergamia Risso) By-Product on Growth Performance and Meat Quality of Growing Rabbits.

This study aimed to investigate the effects of feeding dried bergamot pulp to rabbits on animal performance and meat quality. Thirty rabbits were assigned to two groups (balanced for body weight, 804.4 ± 2.35 g) and fed individually for 60 days a basal diet (control) or the basal diet in which part of the cereals was replaced with 10% of dried bergamot pulp (DBP). There were no effects of DBP on growth performance, carcass yield, or the crude protein and ether extract composition of meat. The concentrations of α-linolenic acid (C18:3 n-3) and eicosapentaenoic acid (C20:5 n-3) increased in the longissimus thoracis et lumborum muscle (p < 0.01 and p = 0.021, respectively) after integrating dried bergamot pulp into the diet, leading to higher levels of total of ω-3 fatty acids (p < 0.01) compared to the control treatment. The inclusion of dried bergamot pulp improved the oxidative stability in meat (p < 0.001), where TBARS values were lower after 4 and 7 days of refrigerated storage (p < 0.001) in the DBP group than in the control group. Finally, feeding dried bergamot pulp to rabbits improves meat quality without negatively influencing growth performance.

Preparation of trilayer film with slow-release, antioxidant, and antibacterial activities and its effects on scallop preservation

Scallops are renowned for their delicious taste and rich nutritional profile, including high contents of eicosapentaenoic acid and docosahexaenoic acid. However, they are highly susceptible to spoilage caused by lipid oxidation and microorganism proliferation. Therefore, in this study, trilayer films based on gelatin/gelatin-dextran/gelatin with different concentrations (0%, 0.3%, 0.6%, 0.9%, and 1.2%, w/w) of active fillers (citronellal and α-tocopherol) were developed to preserve scallop adductor muscle during cold storage. Scanning electron microscopy images showed that each layer was well-bonded with no gaps, indicating the successful preparation of the trilayer films. The addition of citronellal and α-tocopherol resulted in a porous cross-section with a slightly rough surface and increased hydrophobicity of the trilayer films. With increase in concentrations of citronellal and α-tocopherol, the thickness, opacity, antioxidant capability, and antibacterial activity of the trilayer films increased, while water vapor permeability and mechanical properties decreased. Both citronellal and α-tocopherol showed controlled release properties in four food simulants, with the longest release times in 95% (v/v) ethanol solution. Furthermore, the incorporation of 1.2% (w/w) of active fillers into the trilayer film significantly enhanced the chemical and microbiological stabilities of the scallop adductor muscles, thereby prolonging their shelf life by six days during cold storage. The developed trilayer films showed excellent controlled release, antibacterial properties, and antioxidant capabilities, indicating their potential for effective preservation of aquatic food products.

A Comparative Study on the Muscle and Gut Microbiota of Opsariichthys bidens from Rice Field and Pond Culture Breeding Modes.

To investigate difference in the quality of the different parts (back, tail muscles, and fish skin) of Opsariichthys bidens from pond and rice field cultures, a comparative study was conducted in terms of nutritional composition, volatile flavor profiles and gut microbiota. In detail, the texture, free amino acids, fatty acids were further assessed. The results suggested that the moisture content, crude protein and crude fat content in the skin of O. bidens are higher than those in the back and tail muscles, regardless of breeding modes. The fish cultured in the rice field had a higher protein content than those from the pond culture, while the fat content of the rice field-cultured fish was significantly low compared to the fish from the pond culture, especially in the back and tail parts. A total of 43 volatile components were detected by Gas Chromatography-Mass Spectrometry (GC-MS), with a maximum of 18 types of aldehydes and the highest concentration being nonanal. Compared to pond cultures, the fish from the rice field cultures showed more abundant flavor composition and odor-active compounds. The total content of DHA (Docosahexaenoic Acid) and EPA (Eicosapentaenoic Acid) in the rice field-cultured fish was higher than that of the pond group, while no significant disparity in amino acid composition was observed (p > 0.05). Comparative and clustering analyses of gut microbiota revealed notable discrepancies in the gut microbiota of O. bidens from two aquaculture systems. However, an inherent correlation between the gut microbiome and meat quality would be further emphasized in further studies. This study can offer a theoretical reference for the development of high-quality aquatic products by selecting the appropriate aquaculture models.

Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA) Ameliorate Heart Failure through Reductions in Oxidative Stress: A Systematic Review and Meta-Analysis.

The objectives of this study were to explore the role that eicosapentaenoic acid (EPA) and/or docosahexaenoic acid (DHA) plays in heart failure (HF), highlighting the potential connection to oxidative stress pathways. Following PRISMA guidelines, we conducted electronic searches of the literature in MEDLINE and EMBASE focusing on serum EPA and/or DHA and EPA and/or DHA supplementation in adult patients with heart failure or who had heart failure as an outcome of this study. We screened 254 studies, encompassing RCTs, observational studies, and cohort studies that examined HF outcomes in relation to either serum concentrations or dietary supplementation of EPA and/or DHA. The exclusion criteria were pediatric patients, non-HF studies, abstracts, editorials, case reports, and reviews. Eleven studies met our criteria. In meta-analyses, high serum concentrations of DHA were associated with a lower rate of heart failure with a hazard ratio of 0.74 (CI = 0.59-0.94). High serum concentrations of EPA also were associated with an overall reduction in major adverse cardiovascular events with a hazard ratio of 0.60 (CI = 0.46-0.77). EPA and DHA, or n3-PUFA administration, were associated with an increased LVEF with a mean difference of 1.55 (CI = 0.07-3.03)%. A potential explanation for these findings is the ability of EPA and DHA to inhibit pathways by which oxidative stress damages the heart or impairs cardiac systolic or diastolic function producing heart failure. Specifically, EPA may lower oxidative stress within the heart by reducing the concentration of reactive oxygen species (ROS) within cardiac tissue by (i) upregulating nuclear factor erythroid 2-related factor 2 (Nrf2), which increases the expression of antioxidant enzyme activity, including heme oxygenase-1, thioredoxin reductase 1, ferritin light chain, ferritin heavy chain, and manganese superoxide dismutase (SOD), (ii) increasing the expression of copper-zinc superoxide dismutase (MnSOD) and glutathione peroxidase, (iii) targeting Free Fatty Acid Receptor 4 (Ffar4), (iv) upregulating expression of heme-oxygenase-1, (v) lowering arachidonic acid levels, and (vi) inhibiting the RhoA/ROCK signaling pathway. DHA may lower oxidative stress within the heart by (i) reducing levels of mitochondrial-fission-related protein DRP-1(ser-63), (ii) promoting the incorporation of cardiolipin within the mitochondrial membrane, (iii) reducing myocardial fibrosis, which leads to diastolic heart failure, (iv) reducing the expression of genes such as Appa, Myh7, and Agtr1α, and (v) reducing inflammatory cytokines such as IL-6, TNF-α. In conclusion, EPA and/or DHA have the potential to improve heart failure, perhaps mediated by their ability to modulate oxidative stress.

Immobilized Burkholderia cepacia lipase and its application in selective enrichment of EPA by hydrolysis of fish oil

Eicosapentaenoic acid (EPA), an orally active Omega-3 long-chain polyunsaturated fatty acid, has attracted much attention for its medical and healthcare value. Due to a large amount of polyunsaturated fatty acids (PUFA) including docosahexanoic acid (DHA) in fish oil, the highly specific enrichment of EPA from fish oil is difficult to achieve. In our study, we conducted immobilization studies on Burkholderia cepacia lipase (BCL) and its application in the selective enrichment of EPA in fish oil. BCL was immobilized on resin LX201A by covalent crosslinking, and immobilization conditions including glutaraldehyde concentration, pH, time were optimized. The optimal immobilization conditions were 0.5% glutaraldehyde, 4 h, and pH 8.0. The loading rate of BCL reached to 93.5%, and its activity was up to 68263 U/g under the optimal immobilization conditions. After hydrolysis reaction of fish oil for 15h catalyzed by immobilized BCL, EPA content showed a more increase by 33.2%, while a slight increase by 0.78% in DHA content. Moreover, after recycling use for 10 times, the catalytic efficiency of immobilized BCL remained at 93.0%. These indicated that immobilized BCL possessed good selectivity, reusability and stability, providing great application potential in EPA selective enrichment in fish oil industry.

AMPK activation by dietary acadesine improves fillet texture in large yellow croaker (Larimichthys crocea) fed a linseed oil-based diet

The impacts of AMP-activated protein kinase (AMPK) activation by dietary acadesine (AICAR) on growth performance and muscle quality of large yellow croaker (Larimichthys crocea) fed a linseed oil-based diet (LO) were investigated by a 56-day feeding trial in this study. Fish (initial weight: 92.24 ± 0.30 g) were fed fish oil-based diet (FO), LO or LA (LO diet supplemented with 150 mg kg−1 AICAR) with three replicates of each treatment. Results indicated that weight gain rate and specific growth rate (SGR) were significantly decreased in the LO and LA groups than those of the fish fed FO, while the opposite was true for the feed conversion ratio. Moreover, the SGR of fish fed LA was significantly lower than that of the LO group. Dietary linseed oil and AICAR significantly lowered muscle eicosapentaenoic acid and docosahexaenoic acid contents. Furthermore, the LO group showed significantly lower fillet hardness, chewiness and pH, while higher lipid loss than those of the FO group. However, the FO and LA groups had similar fillet hardness, lipid loss and pH. Compared with the fish fed FO and LA, the LO group possessed significantly lower p-AMPK protein level and p-AMPK/AMPK ratio in muscle. The phosphorylation of TOR protein and the ratios of p-TOR/TOR and p-S6/S6 were significantly decreased in muscle of the LA group than those of the fish fed FO and LO. Meanwhile, totally replacing fish oil with linseed oil inhibited the AMPK/SIRT1/PGC-1α pathway, changed myofibre characteristics (e.g., density, diameter and type of myofibre) and raised the expression of genes or activity of enzyme related to anaerobic metabolism in fish muscle. Dietary AICAR activated AMPK/SIRT1/PGC-1α pathway, restored myofibre characteristics and promoted aerobic metabolism-related genes expression in muscle to some extent. In conclusion, total substitution of dietary fish oil with linseed oil reduced growth, feed utilization and nutritive value of large yellow croaker. And high level of dietary linseed oil induced softer texture and poorer liquid holding capacity (LHC) of muscle, which may be ascribed to the myofibre characteristics changed by linseed oil through depressing muscle AMPK/SIRT1/PGC-1α pathway. Inclusion of AICAR in a linseed oil-based diet improved fish muscle hardness and LHC, which may be relevant to the activated muscle AMPK/SIRT1/PGC-1α pathway and restored myofibre characteristics by AICAR. Notably, dietary AICAR could inhibit TOR pathway by activating AMPK in muscle, which may be responsible for the further decreased SGR of fish fed a linseed oil-based diet.

Efficient expression of OUC-Sb-lip2 in Yarrowia lipolytica and its comprehensive utilization in the enrichment of DHA and EPA from fish oil

Lipases are widely used in the modification of functional lipids, particularly in the enrichment of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). In this study, a lipase named OUC-Sb-lip2 was expressed in Yarrowia lipolytica, achieving a promising enzyme activity of 472.6 U/mL by optimizing the culture medium, notably through olive oil supplementation. A significant proportion (58.8%) of the lipase activity was located in the cells, whereas 41.2% was secreted into the supernatant. Both whole-cell and immobilized OUC-Sb-lip2 were used to enrich DHA and EPA from fish oil. The whole-cell approach increased the DHA and EPA contents to 2.59 and 2.55 times that of the original oil, respectively. Similarly, the immobilized OUC-Sb-lip2 resulted in a 2.00-fold increase in DHA and an 1.99-fold increase in EPA after a 6-h hydrolysis period. Whole cell and the immobilized OUC-Sb-lip2 retained 48.7% and 52.7% of their activity after six cycles of reuse, respectively.

Automated preparation of plasma lipids, metabolites, and proteins for LC/MS-based analysis of a high-fat diet in mice

Blood plasma is one of the most commonly analyzed and easily accessible biological samples. Here, we describe an automated liquid-liquid extraction platform that generates accurate, precise, and reproducible samples for metabolomic, lipidomic, and proteomic analyses from a single aliquot of plasma while minimizing hands-on time and avoiding contamination from plasticware. We applied mass spectrometry to examine the metabolome, lipidome, and proteome of 90 plasma samples to determine the effects of age, time of day, and a high-fat diet in mice. From 25 μl of mouse plasma, we identified 907 lipid species from 16 different lipid classes and subclasses, 233 polar metabolites, and 344 proteins. We found that the high-fat diet induced only mild changes in the polar metabolome, upregulated apolipoproteins, and induced substantial shifts in the lipidome, including a significant increase in arachidonic acid and a decrease in eicosapentaenoic acid content across all lipid classes.