Effects of different initial diets on water quality, growth, digestive enzymes and non-specific immune enzymes of Procambarus clarkii

Abstract:

A 42-day study was made comparing the water indexes, growth performance, digestive enzyme and antioxidant enzyme activities of larvae red swamp crayfish (0.017 9±0.000 5) g reared feeding bioflocs, commercial diet and frozen rotifers (Brachionus calyciflorus). The results showed that:During the feeding period, the biofloc group had the lowest concentration of total phosphorus, ammonia nitrogen, nitrite nitrogen and nitrate nitrogen, significantly different from the other two groups. No significant difference was found in final weight, weight gain rate and specific growth rate of larvae crayfish among the three experimental groups while the survival rate of crayfish in the biofloc group was similar with that in the rotifer group and higher than the diet group significantly. Besides, the highest α-amylase and lipase activities were found in the diet group while the biofloc group was the lowest. The trypsin and pepsin activities of crayfish in the biofloc group were significantly higher than those in the diet group. The α-amylase, trypsin and pepsin activities of crayfish in the rotifer group were not different from the other two groups. The total antioxidant capacity (T-AOC) and catalase (CAT) activity of crayfish in the biofloc group was the highest while malondialdehyde (MDA) content was the lowest which were significantly different from the other two experimental groups. Bioflocs has more positive effects on the survival, growth performance, digestive enzymes and antioxidant capacity of larvae crayfish.