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An eight-week feeding trail was carried out to investigate the impacts of different dietary arachidonic acid (ARA) supplementations on growth performance, antioxidant capacity, tissue fatty acid profiles, and lipid metabolism of mud crab (Scylla paramamosain) juvenile. Six isonitrogenous (480 g kg-1 crude protein) and isolipidic (80 g kg-1 crude lipid) diets were formulated to contain 0.40, 2.50, 4.60, 8.90, 12.50, and 15.70 g ARA kg-1 (dry matter), respectively. Each experimental treatment included 24 mud crab juveniles (initial weight 11.29 ± 0.09 g) and was assigned to triplicate groups (n = 3). Crabs fed diets with 2.50, 4.60, and 8.90 g kg-1 ARA presented significantly higher percent weight gain (PWG) and specific growth rate (SGR) than those fed the other diets. Based on two-slope broken-line and quadratic curve regression analysis of PWG against dietary ARA levels, optimal dietary ARA levels were determined to be 5.20 g kg-1 and 6.20 g kg-1, respectively. Crabs fed with 4.60 g kg-1 ARA diet showed the lowest activities of alanine aminotransferase (ALT) as well as aspartate aminotransferase (AST) in hemolymph among all treatments. In hemolymph and hepatopancreas, total antioxidant capacity (T-AOC), the activities of total superoxide dismutase (T-SOD), and glutathione peroxidase (GSH-Px) as well as the contents of reduced glutathione (GSH) rose first and then dropped with the increase of dietary ARA levels, while the concentration of malondialdehyde (MDA) showed an opposite trend. Tissue fatty acid profiles reflected diets fatty acid compositions. The ARA contents in hepatopancreas and muscle significantly increased with the increase of dietary ARA levels. Furthermore, the areas of blasenzellen (B) cells and restzellen (R) cells were significantly downregulated with the increase of dietary ARA levels. Crabs fed with 0.40 g kg-1 ARA diet showed significantly higher gene expression levels of fatty acid synthase (fas) as well as acetyl-CoA carboxylase (acc) among all treatments. Relative gene expression levels of 6-phosphogluconate dehydrogenase (6pgd) as well as glucose-6-phosphate dehydrogenase (g6pd) have been significantly upregulated in 0.40 and 2.50 g kg-1 ARA groups. Relative gene expression level of fatty acid binding protein 1 (fabp1) significantly increased in 4.60, 8.90, 12.50, and 15.70 g kg-1 ARA groups. However, the gene expression levels of fatty acid binding protein 4 (fabp4) as well as scavenger receptor class 2 (srb2) have not been influenced by dietary ARA levels. What is more, crabs fed diets with 4.60, 8.90, 12.50, and 15.70 g kg-1 ARA had a significantly higher expression level of carnitine palmitoyltransferase 1 (cpt1) than those fed diets with 0.40 and 2.50 g kg-1 ARA. In summary, optimum dietary ARA can promote growth, enhance antioxidant capacity, and improve health of mud crab juveniles. It also demonstrated that lipogenesis has been restrained with the increasing dietary ARA levels. These findings could provide theoretical guidance and reference for the lipid nutrition research as well as the development of the commercial diet in mud crab. [ABSTRACT FROM AUTHOR]

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]

The objective of the present study was to evaluate the effects of dietary choline levels on growth performance, antioxidant capacity, innate immunity and hemocyte apoptosis of Litopenaeus vannamei. Six isonitrogenous and isolipidic diets were formulated to contain different choline levels: 2.91 (basal diet), 3.85, 4.67, 6.55, 10.70 and 18.90 g kg−1choline, respectively. The results indicated that shrimp fed diet with 4.67 g kg−1 choline had the highest final body weight (FBW), percent weight gain (PWG), specific growth rate (SGR), feed efficiency (FE), and activities of alkaline phosphatase (AKP) and phenoloxidase (PO) in hemolymph among all treatments. Shrimp fed diet with 18.90 g kg−1 choline exhibited significantly lower crude lipid in hepatopancreas than those fed diets with 2.91, 3.85, 4.67 and 6.55 g kg−1 choline (P < 0.05). The concentration of reactive oxygen species (ROS) and apoptosis rate in hemocytes significantly decreased with the increase of dietary choline levels (P < 0.05). Shrimp fed diets with 6.55, 10.70 and 18.90 g kg−1 choline had significantly higher scavenging ability of hydroxyl radical (SAHR) and total antioxidant capacity (T-AOC) in hemolymph than those fed diet with 2.91 g kg−1 choline (P < 0.05). Dietary choline supplementation down-regulated the expression of genes related to apoptosis such as caspase-1 , caspase-3 , caspase-8 , p53 , and p38MAPK in hemocytes (P < 0.05), while up-regulated the expression of anti-apoptosis gene bcl2 in hemocytes (P < 0.05). Overall, the results of the present study demonstrated that appropriate dietary choline could improve growth performance and feed utilization, enhance antioxidant capacity and innate immunity, and mitigate apoptosis in Litopenaeus vannamei. Moreover, the inhibition of hemocyte apoptosis by dietary choline may be regulated by the p38MAPK-p53 signaling pathway. A plausible mechanism for how choline affects growth performance, antioxidant capacity, and innate immunity, and inhibits hemocyte apoptosis in Litopenaeus vannamei. Solid red arrows indicate promotion and black lines indicate suppression. [Display omitted] • The optimal choline requirement was estimated to be 3.27 g kg−1 for juvenile Litopenaeus vannamei. • Dietary choline could enhance antioxidant effects by a series of enzymatic reactions. • Dietary excessive choline could significantly reduce ROS concentration and apoptotic rate in hemocytes. • Inhibitory effect of dietary choline on hemocyte apoptosis may be regulated by p38MAPK-p53 signaling pathway. [ABSTRACT FROM AUTHOR]

An 8-week feeding trial was conducted to investigate the effects of different dietary dosage forms of zinc on growth performance, meat quality, antioxidant and immune capacity of juvenile Pacific white shrimp, Litopenaeus vannamei. Four isonitrogenous and isolipidic diets were formulated to contain different dosage forms of zinc, the control diet (no-supplemented zinc), I-Zn diet (120 mg kg−1 zinc from zinc sulfate), M-Zn diet (60/60 mg kg−1, zinc sulfate/zinc amino acid complex = 1:1) and Availa-Zn diet (60 mg kg−1 zinc from zinc amino acid complex), respectively. A total of 480 shrimp juveniles with initial weight 1.84 ± 0.02 g were randomly divided into four diets with four replications, each replication consisted of 30 shrimp. The results revealed that shrimp fed the M-Zn diet had significantly higher percent weight gain (PWG), specific growth rate (SGR), feed efficiency (FE), protein efficiency ratio (PER) and protein retention efficiency (PRE) than those fed the other diets. The significantly higher concentration of glucose (GLU) in hemolymph was observed in shrimp fed the M-Zn diet. Shrimp fed the diets supplemented with zinc amino acid complex had significantly lower values of drip and thawing losses of whole shrimp or muscle compared to those fed the control and I-Zn diets, which indicated that shrimp fed the diets supplemented with zinc amino acid complex had a better water-holding capacity. Moreover, shrimp fed the Availa-Zn diet had significantly higher the activities of alkaline phosphatase (AKP), acid phosphatase (ACP) and lysozyme (LZM) in hepatopancreas than those fed the control and I-Zn diets. Meanwhile, shrimp fed the M-Zn and Availa-Zn diets showed an up-regulation of expression levels of Cu-Zn sod , akp , acp and lzm in hepatopancreas. Principal component analysis (PCA) and multivariate correlation analysis demonstrated that shrimp fed the experimental diets exhibited significant variations and shrimp fed the M-Zn diet showed better growth response and meat quality. These findings could contribute to provide scientific evidences into the business application of zinc amino acid complex. • Zinc amino acid complex had higher bioavailability compared to zinc sulfate. • Zinc amino acid complex could improve growth performance and feed utilization. • Zinc amino acid complex enhanced water-holding capacity of muscle and whole shrimp. • Shrimp fed zinc amino acid complex showed higher antioxidant ability and immunity. [ABSTRACT FROM AUTHOR]

• Faba bean changed fatty acids composition in white muscle of carps. • Faba bean changed oxidation state in white muscle and hepatopancreas of carps. • Faba bean caused myofiber atrophy and collagen turnover interruption in carps. In order to further explain the fillet texture improvement of Yellow River carp (Cyprinus carpio) fed with faba bean (Vicia faba L.), a three-month rearing trial was conducted to investigate fatty acid composition, antioxidant capacity, myofiber development, collagen deposition and transcriptome in white muscle of two farmed carp groups (One was fed only faba bean, the other was fed commercial diet). As a strong oxidant, faba bean changed fatty acids composition in white muscle, especially DHA and EPA, up-regulated the levels of reactive oxygen species (ROS) and down-regulated major antioxidant enzyme activities in the hepatopancreas and white muscle. Through the analysis of transcriptome and subsequent verification analysis, we speculated that the increase of ROS led to the decrease of myofiber diameter and collagen metabolism. This study provides a theoretical basis for further understanding the regulation of faba bean on fillet texture characteristic of Yellow River carp. [ABSTRACT FROM AUTHOR]