Effects of two kinds of polysaccharides on growth, serum antioxidant indices and tissue cadmium accumulation of Schizothorax prenanti

The present study aimed to determine the effects of dietary 0.40% chondroitin sulfate (CS) and 0.40% acidolysis oxidated konjac glucomannan (AOKGM) added to feed for 8 weeks on growth, antioxidant indices and tissues (liver, kidney and gill) cadmium accumulation of Schizothorax prenanti. A total of 450 healthy S. prenanti individuals with similar body weight (98.00±8.54) g were randomly assigned to three groups with three replicates per group and 50 fish per replicate. After 8 weeks, the growth and the serum antioxidant indices of S. prenanti were determined. In addition, the cadmium stress test was carried out for 15 days (0, 0.10, 0.25, 1.00 mg/L), and the serum antioxidant indices and tissues cadmium accumulation of fish under cadmium stress were determined. The results were as follows: compared with the control group, specific growth rate (SGR), spleen index (SI) and head kidney index (HKI) were increased when the diets were supplemented with CS and AOKGM. Additionally, the crude lipid, crude protein and ash content of muscles were significantly increased when both polysaccharides were added. Compared with the control group, the serum superoxide dismutase (SOD) activity, total protein (TP) and nitric oxide (NO) content of the fish were significantly increased, and glucose (GLU) content of fish was significantly decreased when diets were supplemented with both polysaccharides. The glutathione peroxidase (GSH-Px) activity and cholesterol (TC) content of fish were significantly increased, and malondialdehyde (MDA) content of fish was significantly decreased when CS was added to the diet. Compared with 0 mg/L cadmium, MDA content was the highest and SOD activity was the lowest at 1.00 mg/L cadmium, GSH-Px activity was significantly decreased and NO content was significantly increased at 0.25 and 1.00 mg/L cadmium. Compared with 0 mg/L cadmium, the SOD activity significantly increased, and MDA content significantly decreased, while NO content significantly decreased at 0.10-1.00 mg/L cadmium when diets were supplemented with both polysaccharides. CS significantly increased GSH-Px activity at 0.10 and 0.25 mg/L cadmium. AOKGM significantly increased GSH-Px activity at 0.25 and 1.00 mg/L cadmium. Compared with 0 mg/L cadmium, the cadmium accumulation in liver, kidney and gill of fish significantly increased at different cadmium concentrations, while CS and AOKGM decreased the cadmium content of tissues. Taken together, the results showed that 0.40% CS and AOKGM had certain effects on the growth and antioxidant capacity of S. prenanti, and it reduced the cadmium accumulation in tissues. This study provides a new theoretical basis for the development of nutritional feed for S. prenanti.