Abstract:

This study was conducted to investigate the effects of dietary fermented chicken manure supplementation on growth performance, muscle nutritional composition and immune function of Procambarus clarkii. Four isonitrogenous and isolipid diets containing 0%, 15%, 30% and 45% fermented chicken manure were formulated and fed to crayfish, which were designated as groups S₀, S₁₅, S₃₀ and S₄₅, respectively. The feeding trial lasted for 56 days. The results showed that in terms of growth performance, the final body weight (23.26 g), relative weight gain rate (286.32%) and specific growth rate (2.40%/d) of crayfish in the S₁₅ group were the highest, and the S₀ group had the highest survival rate (78.9%). There was no significant difference in the above indicators among all groups (P>0.05). In terms of muscle nutritional composition, with the increase of fermented chicken manure inclusion level, the muscle crude protein content increased firstly and then decreased, reaching the maximum value of 17.46% in the S₁₅ group; while the muscle crude fat content showed a gradual downward trend. For intestinal digestive enzymes, no significant difference was observed in intestinal trypsin activity among all groups (P>0.05), with the highest value of 0.27 U/g prot in the S₃₀ group. The activities of amylase and lipase presented a trend of first increasing and then decreasing, both peaked in the S₁₅ group at 30.68 U/g prot and 7.80 U/g prot, respectively. In terms of immune and antioxidant indices, the activities of acid phosphatase and superoxide dismutase increased gradually with the rising addition of fermented chicken manure. Alkaline phosphatase activity increased first and then decreased, with the maximum value of 362.4 U/g prot in the S₃₀ group. Catalase activity and malondialdehyde content decreased firstly and then increased, reaching the lowest levels in the S₃₀ group (3.29 U/mg prot) and S₁₅ group (2.82 nmol/mg prot), respectively. In conclusion, fermented chicken manure can be used as an alternative protein source in the feed of Procambarus clarkii, and the optimal supplemental level is 15%. Under this addition amount, fermented chicken manure has no or slight adverse effects on growth performance, nutritional composition and digestive ability of crayfish, and can effectively enhance their immune performance.

Key words: Procambarus clarkii, fermented chicken manure, growth, nutrition, immunity