Effects of Dietary Supplementation with Chitosan on the Muscle Composition, Digestion, Lipid Metabolism, and Stress Resistance of Juvenile Tilapia () Exposed to Cadmium-Induced Stress

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 () subjected to cadmium (Cd) 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 Cd 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 (), cytochrome P450 1A (), carnitine palmitoyltransferase-1 (), peroxisome proliferator-activated receptor alpha (), peroxisome proliferator-activated receptor gamma (), hormone-sensitive lipase (), lipoprotein lipase (), malate dehydrogenase (), leptin (), fatty acid synthase (), sterol regulatory element-binding protein 1 (), and stearoyl-CoA desaturase () genes in the liver of juveniles were significantly increased ( < 0.05). In conclusion, dietary chitosan supplementation could alleviate the effects of Cd 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 Cd stress on tilapia.