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An 8-week feeding trial was carried out to assess the effect of dietary krill meal on growth performance and expression of genes related to TOR pathway and antioxidation of swimming crab (Portunus trituberculatus). Four experimental diets (45% crude protein and 9% crude lipid) were formulated to obtain different replacements of fish meal (FM) with krill meal (KM); FM was replaced with KM at 0% (KM0), 10% (KM10), 20% (KM20), and 30% (KM30); fluorine concentration in diets were analyzed to be 27.16, 94.06, 153.81, and 265.30 mg kg-1, respectively. Each diet was randomly divided into 3 replicates; ten swimming crabs were stocked in each replicate (initial weight, 5.62 ± 0.19 g). The results indicated that crabs fed with the KM10 diet had the highest final weight, percent weight gain (PWG), and specific growth rate (SGR) among all treatments (P < 0.05). Crabs fed with the KM0 diet had the lowest activities of total antioxidant capacity (T-AOC), total superoxide dismutase (SOD), glutathione (GSH), and hydroxyl radical scavenging activity and had the highest concentration of malondialdehyde (MDA) in the hemolymph and the hepatopancreas (P < 0.05). In the hepatopancreas, the highest content of 20:5n-3 (EPA) and the lowest content of 22:6n-3 (DHA) were shown in crabs fed with the KM30 diet among all treatments (P < 0.05). With the substitution level of FM with KM gradually increasing from 0% to 30%, the color of the hepatopancreas changed from pale white to red. Expression of tor, akt, s6k1, and s6 in the hepatopancreas was significantly upregulated, while 4e-bp1, eif4e1a, eif4e2, and eif4e3 were downregulated with dietary replacement of FM with KM increasing from 0% to 30% (P < 0.05). Crabs fed with the KM20 diet had notably higher expression of cat, gpx, cMnsod, and prx than those fed with the KM0 diet (P < 0.05). Results demonstrated that 10% replacement of FM with KM can promote growth performance and antioxidant capacity and notably upregulate the mRNA levels of genes related to TOR pathway and antioxidant of swimming crab. [ABSTRACT FROM AUTHOR]

Carbohydrate is the cheapest source of energy among the three major nutrient groups, an appropriate amount of carbohydrates can reduce feed cost and improve growth performance, but carnivorous aquatic animals cannot effectively utilize carbohydrates. The objectives of the present study are aimed at exploring the effects of dietary corn starch levels on glucose loading capacity, insulin-mediated glycemic responses, and glucose homeostasis for Portunus trituberculatus. After two weeks of feeding trial, swimming crabs were starved and sampled at 0, 1, 2, 3, 4, 5, 6, 12, and 24 hours, respectively. The results indicated that crabs fed diet with 0% corn starch exhibited lower glucose concentration in hemolymph than those fed with the other diets, and glucose concentration in hemolymph remained low with the extension of sampling time. The glucose concentration in hemolymph of crabs fed with 6% and 12% corn starch diets reached the peak after 2 hours of feeding; however, the glucose concentration in hemolymph of crabs fed with 24% corn starch attained the highest value after 3 hours of feeding, and the hyperglycemia lasted for 3 hours and decreased rapidly after 6 hours of feeding. Enzyme activities in hemolymph related to glucose metabolism such as pyruvate kinase (PK), glucokinase (GK), and phosphoenolpyruvate carboxykinase (PEPCK) were significantly influenced by dietary corn starch levels and sampling time. Glycogen content in hepatopancreas of crabs fed with 6% and 12% corn starch first increased and then decreased; however, the glycogen content in hepatopancreas of crabs fed with 24% corn starch significantly increased with the prolongation of feeding time. In the 24% corn starch diet, insulin-like peptide (ILP) in hemolymph reached a peak after 1 hour of feeding and then significantly decreased, whereas crustacean hyperglycemia hormone (CHH) was not significantly influenced by dietary corn starch levels and sampling time. ATP content in hepatopancreas peaked at 1 h after feeding and then decreased significantly in different corn starch feeding groups, while the opposite trend was observed in NADH. The activities of mitochondrial respiratory chain complexes I, II, III, and V of crabs fed with different corn starch diets significantly increased first and then decreased. In addition, relative expressions of genes related to glycolysis, gluconeogenesis, glucose transport, glycogen synthesis, insulin signaling pathway, and energy metabolism were significantly affected by dietary corn starch levels and sampling time. In conclusion, the results of the present study reveal glucose metabolic responses were regulated by different corn starch levels at different time points and play an important role in clearing glucose through increased activity of insulin, glycolysis, and glycogenesis, along with gluconeogenesis suppression. [ABSTRACT FROM AUTHOR]

This experiment was conducted to evaluate the effects of different carbohydrate levels on the growth performance, glycogen accumulation in tissue, enzyme activities, and expression levels of genes related to hepatopancreatic glucose and lipid metabolism and insulin signaling pathway in swimming crab, Portunus trituberculatus for 8 weeks. The results indicated that crabs fed with the 60.0 g kg-1 carbohydrate diet exhibited the highest final body weight (FBW), percent weight gain (PWG), and specific growth rate (SGR) among all treatments. FBW, PWG, and SGR significantly decreased when dietary carbohydrate levels exceeded 240.0 g kg-1. Light microscopy results showed that dietary excessive carbohydrate levels will lead to vacuole, hepatopancreatic tubule lysis, and lipid droplets in hepatopancreas. Expression levels of genes involved into glucose transport, glucose and lipid metabolism, and insulin-like metabolism in the hepatopancreas were significantly influenced by dietary carbohydrate levels. In general, the results of present study demonstrated that dietary optimal carbohydrate levels could not only improve PWG and SGR but also influence the expression of genes involved in glucose, lipid, and insulin-like metabolism. The optimal actual carbohydrate level was estimated to be 87.8-98.4 g kg-1 based on broken-line and second-order polynomial regression analysis between PWG against dietary carbohydrate levels for juvenile Portunus trituberculatus. [ABSTRACT FROM AUTHOR]

The sterol regulatory element-binding proteins (SREBPs) are a family of transcription factors known to activate the transcription of genes encoding key lipogenic enzymes. The present study reports on the molecular cloning, tissue expression and nutritional regulation of SREBP-1 from the swimming crab Portunus trituberculatus (Miers, 1876). The SREBP-1 full-length cDNA was 3785 bp, encoding a polypeptide of 1039 amino acids. Quantitative PCR analysis revealed that SREBP-1 expression was detected in various tissues, and the significantly higher expression levels were found in eyestalk and hepatopancreas compared with other tested tissues. Additionally, the effects of dietary iron on expression of SREBP-1 were investigated, and the results indicated that SREBP-1 expressions were down-regulated by crabs fed diets containing 218.9 and 373.9 mg/kg iron compared with that fed the basal diet (55.2 mg/kg). Suggesting that the relative expression level of SREBP-1 can be suppressed by dietary iron supplementation. These findings provide further insight into the regulatory capacity of SREBP-1 in the lipid anabolism of P. trituberculatus. Résumé: Les SREBPs (protéines de liaison à l'élément de régulation des stérols) sont une famille de facteurs de transcription connus pour activer la transcription de gènes codant des enzymes lipogéniques. Cette étude présente le clonage moléculaire, l'expression des tissus et la régulation de la nutrition de SREBP-1 du crabe Portunus trituberculatus (Miers, 1876). La longueur totale de l'ADNc de SREBP-1 est de 3785 pb, codant un polypeptide de 1039 acides aminés. Une analyse par PCR quantitative révèle que l'expression de SREBP-1 a été détectée dans différents tissus, et que l'expression significativement la plus élevée a été trouvée dans le pédoncule oculaire et l'hépatopancréas par comparaison aux autres tissus testés. De plus, les effets du fer alimentaire sur l'expression de SREBP-1 a été examiné, et les résultats indiquent que, par comparaison avec un régime de base (55,2 mg kg−1 de fer), les expressions de SREBP-1 ont été régulées à la baisse chez les crabes nourris avec un régime contenant 218,9 et 373,9 mg kg−1 de fer. Ce qui laisse supposer que le niveau d'expression relatif de SREBP-1 peut être réprimé par une supplémentation en fer alimentaire. Ces résultats fournissent plus d'information sur la capacité régulatrice de SREBP-1 dans le metabolisme lipidique de P. trituberculatus. [ABSTRACT FROM AUTHOR]

An 8‐week feeding trial was conducted to evaluate the effects of replacement of fish oil (FO) with blending vegetable oils (VOs) on growth performance, antioxidant enzyme activities and fatty acid composition in tissue of swimming crab Portunustrituberculatus. Five isonitrogenous and isolipidic diets were formulated to contain VOs (colza oil: palm oil: linseed oil = 4:2:1) to replace 0 (the control diet), 250, 500, 750 and 1000 g/kg of FO (defined D0, D25, D50, D75, D100). Three hundred juvenile swimming crabs (initial weight 2.34 ± 0.08 g) were randomly stocked and sorted into 300 individual rectangle plastic baskets in three cement pools. Each treatment has three replicates, one replicate has 20 swimming crabs, and each diet fed 60 crabs distributed in 60 baskets. The results indicated that crabs fed the control diet showed significantly higher survival, final body weight, per cent weight gain (PWG), specific growth rate and moulting frequency, crude protein and crude lipid contents in muscles than those fed the D75 and D100 VO diets (p <.05). Crabs fed the D25 VO diet showed significantly higher concentration of triglyceride, low‐density lipoprotein cholesterol and total protein, activities of superoxide dismutase, catalase and glutathione peroxidase (GSH‐Px) in haemolymph than those fed the control diet (p <.05). Fatty acid composition in hepatopancreas was positively correlated with dietary composition. In summary, based on the PWG, the optimal replacement of FO with VOs was estimated to be 250 g/kg. These findings demonstrated that swimming crabs make better use of FO than VOs. [ABSTRACT FROM AUTHOR]

An 8‐week feeding trial was conducted to evaluate the effects of dietary lipid sources on growth performance, antioxidant enzyme activities and biochemical composition of juvenile swimming crab Portunus trituberculatus of initial weight 2.34 ± 0.08 g. Four different diets were formulated to contain fish oil (FO), soybean oil (SO), linseed oil (LO) or palm oil (PO). The highest final body weight, weight gain, specific growth rate and molting frequency were observed in crabs fed the FO diet. Crabs fed the SO diet showed higher glutathione peroxidase, superoxide dismutase (SOD) and catalase (CAT) activities in both serum and hepatopancreas than those fed the FO diet. The lowest malondialdehyde concentration in hepatopancreas and serum were occurred at crabs fed the SO diet. Crabs fed the LO diet had significantly higher SOD and CAT activities in hepatopancreas compared with those fed the FO diet. Crabs fed the PO diet had the highest activities of fatty acid synthase and carnitine palmitoyltransferase 1 activities in hepatopancreas among all treatments. Fatty acid compositions both in hepatopancreas and muscle reflected those of diets. Overall, these findings demonstrated that physiological–biochemical characteristics and lipid metabolism were significantly regulated by different dietary lipid sources. Moreover, dietary SO and LO supplementation could improve antioxidant ability. [ABSTRACT FROM AUTHOR]

A six-week feeding trial was conducted to evaluate the effects of dietary isoleucine level on growth, myofiber histology, and mRNA levels of genes related to amino acid, glucose and lipid metabolism in swimming crab (Portunus trituberculatus). Six isonitrogenous and isolipidic diets (45% protein and 8% lipid) were formulated to contain graded levels of isoleucine (Ile), with the analyzed levels of isoleucine being 0.69%, 1.06%, 1.32%, 1.78%, 2.03% and 2.38%, respectively. A total of 180 crabs (initial weight 16.30 ± 0.01 g) were housed individually in 180 plastic baskets with 30 crabs assigned to each diet, divided randomly into three replicates of 10 crabs. Each crab was fed twice at 08:00 and 18:00 with a daily feeding ration of 6–8% of crab body weight. Eight crabs from each replicate group were sampled and dissected after the feeding trial to provide hemolymph for biochemical analysis, hepatopancreas for proximate composition, amino acid profile enzyme activity, and gene expression, and muscle for proximate composition, amino acid profile and histology. The results indicated that final weight, percent weight gain and specific growth rate increased significantly as dietary isoleucine level increased from 0.69% to 1.78%, and then decreased with further increased dietary isoleucine. Crabs fed the diets with 1.78%, 2.03% and 2.38% isoleucine showed significantly higher muscle protein contents (17.80%, 17.99% and 17.65% of wet mass) than crabs fed lower levels of isoleucine. The highest concentrations of IGF1R and CHH in hemolymph (187.95 and 529.42 pg ml−1, respectively) and hepatopancreas (24.18 and 38.69 pg ml−1, respectively) were observed in crabs fed the diet with 1.32% isoleucine. Hepatopancreas expression levels of genes related to amino acid metabolism, including s6k1 , bcat , alt and ast , were up-regulated in crabs fed 1.32% isoleucine compared to the other groups, whereas the expression level of tor decreased as dietary isoleucine increased. Expression levels of genes related to glucose intake, such as pi3k , igf1r and glut1 , were significantly higher in crabs fed 1.32% isoleucine compared to crabs fed 0.69% isoleucine. Expression levels of genes related to gluconeogenesis (pepck and g6pase) were significantly higher in crabs fed 0.69% isoleucine than in crabs fed the diets with 1.32% and 1.78% isoleucine. In contrast, expression levels of genes related to glycolysis, including hk , gk and pk , were up-regulated in crabs fed 1.32% isoleucine compared to crabs fed 0.69% isoleucine. Gene expression levels of regulatory factors related to lipid metabolism (foxo , sirt1 and sirt3) were significantly higher in crabs fed 1.32% isoleucine compared to crabs fed the other treatments, while expression levels of genes related to lipolysis (hsl and cpt2) were significantly up-regulated in crabs fed the diets with 1.32% and 1.78% isoleucine. Expression levels of key lipogenesis genes (fas and acc) were down-regulated in crabs fed the diets with 1.32% and 1.78% isoleucine compared to those fed 0.69% isoleucine. Muscle histology indicated that crabs fed the diets with 1.32% and 1.78% isoleucine had significantly lower densities of myofibers (21.67 and 17.33 N/ mm2) compared to crabs fed 0.69% isoleucine. In conclusion, based on percent weight gain, the optimal isoleucine requirement of juvenile swimming crab was calculated to be 1.57% of diet (3.49% dietary protein) by quadratic curve model. Thus, appropriate dietary isoleucine levels (1.32–1.78%) promoted amino acid metabolism and protein synthesis, increased protein deposition, and altered myofiber structure of muscle and, in addition, promoted lipolysis and glycolysis, and reduced lipogenesis and gluconeogenesis in juvenile swimming crab. • Based on PWG, the optimal dietary isoleucine requirement for P. trituberculatus was to be 1.57%. • Increasing dietary isoleucine in the range 1.78%–2.38% promoted protein deposition in body muscle. • Isoleucine at 1.32% of diet up-regulated expression levels of genes related to amino acid metabolism in hepatopancreas. • Isoleucine at 1.32% of diet increased hepatic glycogen content by activating glycolysis and suppressing gluconeogenesis. • 1.32%−1.78% isoleucine of diet increased hepatopancreatic lipid catabolism via activation of the foxo-sirt1/sirt3 pathway. [ABSTRACT FROM AUTHOR]

Cholesterol and phospholipid play an important role in growth, molt and reproduction for crustaceans, although dietary optimum requirement of cholesterol and phospholipids has been determined for Portunus trituberculatus , but it is still unclear whether there was an interaction on each other. Therefore, an eight-week feeding trial was conducted to evaluate the interactive effects of dietary cholesterol and phospholipid levels on growth performance, fatty acid composition in hepatopancreas and the expression of genes related to cholesterol and phospholipid metabolism of Portunus trituberculatus. Six isonitrogenous and isolipid diets were formulated to contain two cholesterol levels (0 % and 0.5 %) and three phospholipid levels (0 %, 2 % and 4 %). The results indicated that specific growth rate (SGR) significantly increased with the increase of dietary phospholipid levels, however, there were no interactive effects between dietary cholesterol and phospholipid on percent weight gain (PWG) and SGR (P > 0.05). The concentration of total-cholesterol (T-CHO) and triacylglycerol (TAG) in hemolymph significantly affected by the interaction between cholesterol and phospholipid (P < 0.05), crabs fed diets with 0.5 % cholesterol supplementation had higher low-density lipoprotein cholesterol (LDL-C) concentration in hemolymph than those fed diets without cholesterol supplementation regardless of phospholipid supplementation (P < 0.05). TAG and LDL-C concentration in hepatopancreas were significantly affected by the interaction between cholesterol and phospholipid (P < 0.05), crabs fed diets with 0.5 % cholesterol supplementation had significantly higher T-CHO and LDL-C concentration in hepatopancreas than those fed diets without cholesterol supplementation (P < 0.05). There was a significant interaction between dietary cholesterol and phospholipid on activity of catalase (CAT) and the concentration of glutathione (GSH) and malondialdehyde (MDA) in hepatopancreas (P < 0.05), and crabs fed diets with cholesterol supplementation had higher superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) in hepatopancreas than those fed diets without cholesterol supplementation (P < 0.05). Moreover, EPA, LC-PUFA, n-3 PUFA, n-3/n-6 PUFA and DHA/E P A in hepatopancreas were significantly affected by the interaction between dietary cholesterol and phospholipid (P < 0.05). The expression of adenosine triphosphate binding cassette transporter G1 (abcg1), C-type 1 class Niemann-Pick protein (npc1), scavenger receptor B (srb) and low-density lipoprotein receptor (ldlr) were up-regulated by dietary cholesterol and phospholipid levels (P < 0.05). In conclusion, the results indicated that dietary appropriate cholesterol and phospholipid levels could significantly improve growth performance and promote cholesterol metabolism. • Interaction between dietary cholesterol and phospholipid did not affect growth performance of swimming crabs. • Interaction between dietary cholesterol and phospholipid could enhance antioxidant capacity of swimming crab. • Dietary cholesterol regulated cholesterol metabolic pathways in hepatopancreas of swimming crab. • Interaction between cholesterol and phospholipid up-regulated the expression of genes related to cholesterol and phospholipid metabolism. • Interaction between cholesterol and phospholipid could promote cholesterol transport and transformation. [ABSTRACT FROM AUTHOR]

An eight-week feeding trial was conducted to evaluate the effect of dietary replacement of fish meal with low-gossypol cottonseed protein concentrate (CPC) on growth performance, body composition, amino acid profiles in tissues, antioxidant capacity and the expression levels of genes related to protein metabolism and inflammation for juvenile swimming crab (Portunus trituberculatus). Six isonitrogenous and isolipidic diets (450 g kg−1 protein and 80 g kg−1 lipid) were formulated to contain graded levels of CPC, and fish meal was replaced with CPC at 0, 10%, 20%, 30%, 40% and 60% levels (CPC00, CPC10, CPC20, CPC30, CPC40 and CPC60), free gossypol concentrations in experimental diets were analyzed to be 0, 32.62, 66.10, 106.71, 133.13, 192.21 mg kg−1 respectively. Arginine, lysine and methionine were added to ensure consistency of these three essential amino acids in all experimental diets. Each diet was randomly assigned to triplicate groups of 30 juvenile swimming crabs (approximately initial weight 7.59 ± 0.06 g) that were stocked in rectangle plastic baskets. Results of present study indicated that crabs fed the CPC60 diet had the lower final weight (FW), percent weight gain (PWG), specific growth rate (SGR) and feed efficiency (FE) than those fed the CPC20 diet, and crabs fed the CPC20 and CPC30 diets had the highest survival among all treatments, and the lowest survival was occurred at crabs fed the CPC60 diet. The hepatopancreas color was blackened with the replacement levels of fish meal with CPC increasing from 0% to 60%. Free gossypol concentration in hepatopancreas significantly increased with increase of dietary replacement levels of fish meal with CPC. Crabs fed the CPC40 and CPC60 diets had lower lipid content in whole body than those fed the other diets. Arginine, lysine, methionine and isoleucine contents in muscle were significantly influenced by dietary replacement levels of fish meal with CPC. ALT, AST, TP, ALB, HDL and ALP in hemolymph, and T-AOC, ALT, AST, SOD, GSH, GSH-ST in hepatopancreas were significantly affected by dietary replacement of fish meal with CPC. Dietary replacement levels of fish meal with CPC could influence the expressions of genes related into protein metabolism such as tor , akt , s6 , s6k1 , 4ebp1 , eif4e1a , eif4e2 , eif4e3 , antioxidant and immune such as gpx, cat, cMnsod and lysozyme , as well as growth such as tlr4 , irak4 , myd88 , traf6 , and inflammation such as relish. In conclusion, based on two slope broken-line and quadratic broken-line regression analysis of PWG against the dietary replacement of fish meal with CPC, the optimal replacement level of fish meal with CPC was estimated to be 19.07% and 22.73% for juvenile swimming crab, respectively. Results demonstrated that CPC could partially replace fish meal, but had no negative effects on growth performance, antioxidant activity and immunity of swimming crab. • The optimal replacement level of FM with CPC was 19.07–22.73% for swimming crab based on PWG. • Hepatopancreas free gossypol concentration significantly increased with increase of dietary CPC. • Replacement of FM with CPC influenced expression of genes related to mTOR pathway and inflammation. [ABSTRACT FROM AUTHOR]

n-3 LC-PUFA is vital to crustaceans for the growth, molting and development, while the precise molecular mechanism underlying the regulation of n-3 LC-PUFA is poorly investigated. Herein, an 8-week nutritional trial and transcriptome analysis were used to investigate the impacts of dietary n-3 PUFA lipid sources including fish oil (FO), krill oil (KO) and linseed oil (LO) on the transcriptome characteristics in hepatopancreas of swimming crab (Portunus trituberculatus). Crabs fed KO diet had significantly higher percent weight gain (PWG) and molting ratio (MR) than those of crabs fed other diets. The transcriptome analysis reveled that a total of 6567 unigenes were annotated in KEGG database, of which the expression of 1126 significantly altered in the KO vs FO group, while the expression of 921 unigenes changed in the LO vs FO group. The differentially expressed genes (DEGs) in KO vs FO comparison group involved in fat digestion and absorption, ABC transporters, adipocytokine signaling pathway, protein digestion and absorption, glycolysis/gluconeogenesis and HIF-1 signaling pathway. While dietary LO significantly altered the expression levels of genes involved in carbohydrate digestion and absorption, mineral absorption, protein processing in endoplasmic reticulum, glycosphingolipid biosynthesis and insect hormone biosynthesis. In addition, dietary KO significantly up-regulated the expression levels of cyp18a1 (participates in the process of ecdysteroids biosynthesis and further controls the molting of crustaceans), tryp (trypsin-like serine proteinases, resists the pathogen invasion), pla2 (phospholipase A2, regulates different inflammatory processes), ABC transporter (ATP-binding cassette transporter, transports amino acids, lipids and proteins into and out of the cell), cpt1 (carnitine palmitoyltransferase I, the major rate-limiting enzyme of mitochondrial fatty acid β-oxidation) and slc2 (solute carrier 2, mediates bidirectional glucose transport). Meanwhile, dietary LO could significantly down-regulated the expression level of cyp315a1 compared to dietary FO. To sum up, swimming crab fed with dietary krill oil could not only enhance the transport of glucose, lipids, fatty acids and other substrates, but also up-regulate the expression levels of genes related to molting, immunity and energy metabolism to promote molting and growth of swimming crab. The present study revealed the molecular responses of crabs to different dietary n-3 PUFA lipid sources, and further provided important clues with respect to elucidating the molecular mechanisms underlying the regulation of EPA and DHA on the molting and growth of swimming crab. • Dietary n-3 PUFA lipid sources affected the transcriptome of hepatopancreas of crab. • Dieatry n-3 PUFA mainly influenced molting, immunity and metabolism of crab. • CYP18A1 and CYP315A1 may play a key role in the molting of swimming crab. • Dietary krill oil may enhance the transport of a variety of substrates. [ABSTRACT FROM AUTHOR]

• Dietary oils affect the composition of lipid molecules in hepatopancreas of crab. • Dietary oils affect stereospecific position of fatty acids in glycerolipids in crab. • Dietary krill oil raises deposition of 20:5n-3 and 22:6n-3 at sn-2 in phospholipids. • Fish oil intake promotes deposition of EPA and DHA at sn-1,2,3 in triglyceride. • LC-PUFA biosynthesis and dietary oils could affect the distribution of fatty acids. While tissue fatty acid compositions reflect that of the dietary lipid source, little information is available on how dietary oils modify lipid class and molecular species profiles in hepatopancreas of crustacean. Herein, an 8-week nutritional trial and untargeted lipidomic analysis were used to investigate the impacts of dietary n-3 PUFA lipid sources including fish oil, krill oil and linseed oil on the lipidomic characteristics of hepatopancreas of swimming crab (Portunus trituberculatus). Dietary krill oil significantly increased distribution of 20:5n-3 and 22:6n-3 at sn-2 in phosphatidylcholine and phosphatidylethanolamine compared to fish oil. Fish oil intake promoted the deposition of 20:5n-3 and 22:6n-3 at sn-1,2,3 in triglyceride compared to linseed oil, which significantly increased the specific accumulation of 18:3n-3 at sn-1,3 in triglyceride and sn-2 in phosphatidylcholine and phosphatidylethanolamine. The study revealed metabolic responses to different dietary n-3 PUFA in swimming crab, which provided novel insight into the lipid nutrition of crustacean. [ABSTRACT FROM AUTHOR]