DIETARY VITAMIN B_6 REQUIREMENT OF JUVENILE GIBEL CARP,CARASSIUS AURATUS GIBELIO

An 8-week growth trial was conducted to determine the dietary VB6 requirement for gibel carp(Carassius auratas gibelio)(initial body weight of 3.3g).Seven iso-nitrogenous and iso-caloric experimental diets were formulated to contain different levels of VB6(0,1.11,3.29,5.41,12.7,13.3 and 27.3 mg/kg,respectively).The results showed that fish fed the control diet without supplementation of VB6 showed significantly lower specific growth rate,feed conver-sion efficiency,protein efficiency ratio,survival and hepatosomatic index than fish fed diets supplemented with VB6.The feeding rate exhibited no significant differences among the treatments(P 0.05).Fish fed the diet containing 12.70 mg/kg VB6 obtained significantly higher liver GOT activity than the other groups.The liver GPT activity significantly increased in fish fed diets containing ≥5.41 mg VB6/kg.Liver VB6 concentration was highest when fish fed the diet containing 12.7 mg/kg VB6.Based on the broken-line method of the relationships between specific growth rate,GOT and GPT activities and dietary VB6 concentrations,it can be concluded that the dietary VB6 requirement for gibel carp was considered to be 0.95,11.36 or 7.62 mg/kg diet.