Dietary pyridoxine requirement of juvenile Jian carp (Cyprinus carpio var. Jian)

In a 80-day feeding trial, a total of 1050 juvenile Jian carp (Cyprinus carpio var. Jian) with in average initial weight of 10.71 +/- 0.05 g were fed semi-purified diets containing seven graded levels of pyridoxine (0.20, 1.71, 3.23 4.96, 6.31, 8.58 and 12.39 mg pyridoxine kg(-1) diet). Results indicated that with increasing dietary pyridoxine levels Lip to 4.96 mg kg(-1) diet, percent weight gain (PWG) and specific growth rate (SGR) were improved, and no differences were found with further increase of pyridoxine levels. Feed intake also followed the similar pattern to that observed with PWG and SGR when dietary pyridoxine levels were <= 6.32 mg kg(-1) diet. But feed efficiency and protein efficiency ratio were not affected by pyridoxine levels. Crude protein of carcass, productive protein value and plasma ammonia concentration were improved with increasing dietary pyridoxine levels Lip to 4.96 mg kg(-1) diet. Amylase activities in the intestine were improved with increasing dietary pyridoxine levels Lip to 4.96 mg kg(-1) diet, but protease and lipase activities in the intestine were not affected by pyridoxine levels. Na+, K+-ATPase and Gamma-glutamyl transpeptidase activities in proximal intestine, mid intestine (M1) and distal intestine (DI) were lowest when fed the diet containing 1.71 mg pyridoxine kg(-1) diet. The alkaline phosphatase activities in MI and DI followed the same pattern. The dietary pyridoxine requirement of juvenile Jian carp based on PWG estimated by broken line model was 6.07 mg pyridoxine kg(-1) diet.