In this study, we evaluated the effects of fermented soybean meal (FSBM) or/and unfermented SBM replacing a portion of fish meal (FM) on the growth performance, antioxidant capacity, immunity, and mechanistic target of rapamycin (mTOR) signaling pathway of juvenile coho salmon (Oncorhynchus kisutch). Four groups of juvenile coho salmon (initial weight 152.23 ± 3.21 g) in triplicate were fed for 12 weeks on four different iso-nitrogen and iso-lipid experimental diets: G0 diet (28% FM protein, control group), G1 diet (18% FM protein and 10% SBM protein), G2 diet (18% FM protein, 5% SBM protein, and 5% FSBM protein), and G3 diet (18% FM protein and 10% FSBM protein). The main results were compared with the G0 diet; the weight gain rate, specific growth rate, and condition factor of juveniles in G3 were increased significantly ( ). The content of muscle crude protein, the total protein, glucose, albumin, total cholesterol in serum, and the total antioxidant capacity in the liver of juveniles in G3 was increased significantly ( ). The activities of pepsin, trypsin, α-amylase, and lipase in the intestine, the superoxide dismutase, catalase, and alkaline phosphatase in the liver of juveniles in G3 were increased significantly ( ). The expression levels of phosphatidylinositide 3-kinases, serine/threonine kinase, mTOR, and ribosomal protein S6 kinase 1 genes in the liver of juveniles in G3 were upregulated significantly ( ). The feed coefficient ratio, viscerosomatic index, the contents of muscle moisture, and malondialdehyde in the liver of juveniles in G3 were decreased significantly ( ). The expression levels of tumor necrosis factor α, interleukin 1β, and interleukin 6 genes in the liver of juveniles in G3 were downregulated significantly ( ). However, there was no significant effect ( ) on the survival rate, food intake, and muscle crude lipid and ash of juveniles among the experimental groups. In conclusion, FSBM to replace a portion FM had a positive effect on the growth performance, protein deposition, antioxidant enzyme activity, digestive enzyme activity, protein synthesis, and immune-related genes of juvenile coho salmon.

This study aims to investigate the effects of partial dietary replacement of fish meal with unfermented and/or fermented soybean meal (fermented by Bacillus cereus) supplemented on the growth performance, whole-body composition, antioxidant and immunity capacity, and their related gene expression of juvenile coho salmon (Oncorhynchus kisutch). Four groups of juveniles (initial weight 159.63 ± 9.54 g) at 6 months of age in triplicate were fed for 12 weeks on four different iso-nitrogen (about 41% dietary protein) and iso-lipid (about 15% dietary lipid) experimental diets. The main results were: Compared with the control diet, the diet with replaced 10% fish meal protein with fermented soybean meal protein supplementation can significantly (p < 0.05) influence the expression of superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, nuclear factor erythroid 2-related factor 2, tumor necrosis factor α and interleukin-6 genes, the growth performance, the serum biochemical indices, and the activity of antioxidant and immunity enzymes. However, there was no significant effect (p > 0.05) on the survival rate (SR) and whole-body composition in the juveniles among the experimental groups. In conclusion, the diet with replaced 10% fish meal protein with fermented soybean meal protein supplementation could significantly increase the growth performance, antioxidant and immunity capacity, and their related gene expression of juveniles.

The objective of this study was to examine the effects of varying levels of dietary chitosan supplementation on mitigating cadmium stress and its influence on growth performance, serum biochemical indices, antioxidant capacity, immune response, inflammatory response, and the expression of related genes in juvenile Genetically Improved Farmed Tilapia (GIFT, Oreochromis niloticus). Five groups of juvenile tilapias (initial body weight 21.21 ± 0.24 g) were fed five diets with different levels (0%, 0.5%, 1.0%, 1.5%, and 2.0%) of chitosan supplementation for 60 days under cadmium stress (0.2 mg/L Cd²⁺). The findings indicated that, compared with the 0% chitosan group, dietary chitosan could significantly increase (p < 0.05) the final weight (Wf), weight gain rate (WGR), specific growth rate (SGR), daily growth index (DGI), and condition factor (CF), while the feed conversion ratio (FCR) expressed the opposite trend in juvenile GIFT. Dietary chitosan could significantly increase (p < 0.05) the activities (contents) of cholinesterase (CHE), albumin (ALB), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), acid phosphatase (ACP), and lysozyme (LZM), while glutamic pyruvic transaminase (GPT), glutamic oxaloacetic transaminase (GOT), and complement 3 (C3) in the serum of juvenile GIFT expressed the opposite trend. Dietary chitosan could significantly increase (p < 0.05) the activities of superoxide dismutase (SOD) and catalase (CAT) and significantly decrease (p < 0.05) the activities (contents) of glutathione S-transferase (GST), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) in the serum of juvenile GIFT. Dietary chitosan could significantly increase (p < 0.05) the activities (contents) of CAT, GST, GSH-Px, and total antioxidant capacity (T-AOC) and significantly decrease (p < 0.05) the contents of MDA in the liver of juvenile GIFT. Dietary chitosan could significantly increase (p < 0.05) the activities (contents) of SOD, GSH-Px, T-AOC, Na⁺-K⁺-ATPase, and Ca²⁺-ATPase and significantly decrease (p < 0.05) the activities (contents) of CAT, GST, and MDA in the gills of juvenile GIFT. Dietary chitosan could significantly up-regulate (p < 0.05) the gene expression of cat, sod, gst, and gsh-px in the liver of juvenile GIFT. Dietary chitosan could significantly up-regulate (p < 0.05) the gene expression of interferon-γ (inf-γ) in the gills and spleen and significantly down-regulate (p < 0.05) the gene expression of inf-γ in the liver and head kidney of juvenile GIFT. Dietary chitosan could significantly down-regulate (p < 0.05) the gene expression of interleukin-6 (il-6), il-8, and tumor necrosis factor-α (tnf-α) in the liver, gills, head kidney, and spleen of juvenile GIFT. Dietary chitosan could significantly up-regulate (p < 0.05) the gene expression of il-10 in the liver, gills, head kidney, and spleen of juvenile GIFT. Dietary chitosan could significantly up-regulate (p < 0.05) the gene expression of transforming growth factor-β (tgf-β) in the liver and significantly down-regulate (p < 0.05) the gene expression of tgf-β in the head kidney and spleen of juvenile GIFT. In conclusion, dietary chitosan could mitigate the impact of cadmium stress on growth performance, serum biochemical indices, antioxidant capacity, immune response, inflammatory response, and related gene expression in juvenile GIFT. According to the analysis of second-order polynomial regression, it was found that the optimal dietary chitosan levels in juvenile GIFT was approximately 1.42% to 1.45%, based on its impact on Wf, WGR, SGR, and DGI.

The objectives of this study were to investigate the effect of different dietary lipid levels on the serum biochemistry, antioxidant responses, initial immunity, and mTOR pathway of juvenile genetic improvement-farmed tilapia (GIFT, Oreochromis niloticus). Six groups of the juveniles (initial body weight 20.66 ± 1.33 g) in triplicate were fed for 90 days using six iso-nitrogen diets with different lipid levels (0.35%, 3.35%, 6.35%, 9.35%, 12.35%, and 15.35%). The main results were as follows: Compared with the control group (0.35%), the diets with different lipid supplementation significantly improved (p < 0.05) the contents of total protein (TP), albumin (ALB), globulin (GLB), glucose (GLU), triglyceride (TG), total cholesterol (T-CHO), high-density lipoprotein (HDL), low-density lipoprotein (LDL), total antioxidant capacity (T-AOC), malondialdehyde (MDA), complement 3 (C3), and immunoglobulin M (IgM), the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), lysozyme (LYZ), and alkaline phosphatase (ALP), the expression level of phosphatidylinositol-3-kinase (PI3K), Akt protein kinase B (Akt), and mammalian target of rapamycin (mTOR) genes in juvenile tilapia. However, diets with different lipid supplementation significantly reduced (p < 0.05) the expression level of tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) genes of juvenile tilapia. In conclusion, the with different lipid supplementation could significantly affect the serum biochemistry, antioxidant responses, initial immunity, and mTOR pathway of juvenile tilapia.

This experiment aims to investigate the effects of partial replacement of fish meal (FM) by soybean meal (SBM) and/or fermented soybean meal (FSBM) on the growth, serum biochemistry, digestion, antioxidation, immunity, and mTOR signaling pathway of juvenile coho salmon (Oncorhynchus kisutch). Four iso-nitrogen and iso-lipid diets were designed and fed to four groups of juvenile coho salmon (152.25 ± 2.96 g) in triplicate for 10 weeks. The four diets were the G0 diet (control group, containing 28% FM protein), the G1 diet (containing 10% SBM protein and 18% FM protein), the G2 diet (containing 5% SBM protein, 5% FSBM protein, and 18% FM protein), and the G3 diet (containing 10% FSBM protein and 18% FM protein). It was found that compared with the G0 diet (control group), the activities of catalase (CAT), superoxide dismutase (SOD), pepsin, trypsin, α-amylase, and lipase, and the expression levels of mammalian target of rapamycin (mtor), protein kinase B (akt), phosphatidylinositol 3-kinase (pi3k), plant ribosome S6K protein kinase (s6ks), and lysozyme (lyz) genes, of juvenile coho salmon fed the G3 diet increased significantly (p < 0.05), and the expression levels of tumor necrosis factor (tnf-α), interleukin-1β (il-1β), and interleukin-6 (il-6) genes of juvenile coho salmon fed the G3 diet decreased significantly (p < 0.05). However, there were no significant differences in growth, muscle composition, and serum biochemistry of juvenile coho salmon fed the G3 diet compared with the G0 diet (p > 0.05). In conclusion, replacing 10% FM protein with FSBM protein could improve the digestion, antioxidation, immunity, and mTOR signaling pathway of juvenile coho salmon.

The aim of this study was to investigate the effects of dietary chitosan supplementation on the muscle composition, digestion, lipid metabolism, and stress resistance, and their related gene expression, of juvenile tilapia (Oreochromis niloticus) subjected to cadmium (Cd²⁺) stress. Juvenile tilapia with an initial body weight of 21.21 ± 0.24 g were fed with a formulated feed containing five different levels (0%, 0.5%, 1.0%, 1.5%, and 2.0%) of chitosan for 60 days, while the water in all experimental groups contained a Cd²⁺ concentration of 0.2 mg/L. The results showed that, compared with the control group (0% chitosan), the contents of crude fat and crude protein in the muscle, the activities of lipase, trypsin, and amylase in the intestine, as well as the relative expression levels of metallothionein (mt), cytochrome P450 1A (cyp1a), carnitine palmitoyltransferase-1 (cpt-1), peroxisome proliferator-activated receptor alpha (pparα), peroxisome proliferator-activated receptor gamma (pparγ), hormone-sensitive lipase (hsl), lipoprotein lipase (lpl), malate dehydrogenase (mdh), leptin (lep), fatty acid synthase (fas), sterol regulatory element-binding protein 1 (srebp1), and stearoyl-CoA desaturase (scd) genes in the liver of juveniles were significantly increased (p < 0.05). In conclusion, dietary chitosan supplementation could alleviate the effects of Cd²⁺ stress on the muscle composition, digestive enzymes, lipid metabolism, and stress resistance, and their related gene expression, of juvenile tilapia, and to some extent reduce the toxic effect of Cd²⁺ stress on tilapia.