Effects of dietary fermentation products of kitchen waste on growth, apparent digestibility, digestive enzyme activities and serum biochemistry in juvenile allogynogenetic gibel carp (Carassius auratus gibelio) var. CAS III

This study aimed to evaluate the effects of fermentation products of kitchen waste (FPKW) on growth, apparent digestibility, digestive enzyme activities, and serum biochemistry for juvenile allogynogenetic gibel carp "CAS III." A total of 540 fish (7.47 +/- 0.20 g/fish) were distributed among 18 aquariums at a density of 30 fish per tank in a completely randomized design (triplicated) and were fed diets containing 0, 6, 9, 12, 15, and 30% FPKW for 60 days. The results showed the weight gain rate (WGR) of fish varied quadratically with FPKW, and the WGRmax was observed when FPKW supplementation was 11.13%. Compared to the control group, the protease and lipase activities in midgut and hepatopancreas increased significantly when FPKW was 12%. The apparent digestibility of dry matter and crude protein in 30% FPKW group were significantly lower than other groups. The levels of total cholesterol, triglycerides, alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase in serum were significantly higher than other groups when FPKW was 30%. The histological examination of hepatopancreas, midgut, and kidney of fish was consistent with the growth and digestive capacity. In conclusion, there were positive effects on fish when FPKW was less than 12%.