Effect of dietary riboflavin on growth, feed utilization, body composition and intestinal enzyme activities of juvenile Jian carp (Cyprinus carpio var. Jian)

A total of 1050 Jian carp, Cyprinus carpio var. Jian (23.39 +/- 0.06 g) were randomly divided into seven groups of each three replicates, which were fed respectively with seven semi-purified diets contained 1.25, 2.71, 4.22, 5.78, 7.23, 8.83 and 11.44 mg riboflavin kg-1 diet for 6 weeks. The results showed that riboflavin significantly improved percent weight gain, specific growth rate, feed efficiency and protein efficiency ratio at the level of 4.22 mg kg-1 diet. Gross protein retention efficiency and lipid production value improved with increasing dietary riboflavin levels from 1.25 to 5.78 mg kg-1. Activities of trypsin, lipase, alpha-amylase, Na+,K+-ATPase and alkaline phosphatase in the intestinal tract were significantly improved with increasing riboflavin levels. Weight and protein content of hepatopancreas, intestine protein and intestine length index were also significantly improved.