Dietary thiamin requirement of fingerling major carp Catla catla (Hamilton).

Abstract

Dietary thiamin requirement of fingerling Catla catla (3.5±0.15g) was evaluated by feeding casein-gelatin-based iso-nitrogenous (350g/kg crude protein) and iso-caloric (16.72kJ/g GE) diets containing six graded levels of thiamin (0, 0.2, 0.4, 0.8, 1.6 and 3.2mg/kg dry diet) for 12weeks. Significantly (p<0.05) higher weight gain (AWG), best feed conversion ratio (FCR), protein retention efficiency (PRE), RNA/DNA ratio and haematological indices were recorded in fish fed diet containing 0.8mg/kg thiamin. Dietary thiamin supplementation improved transketolase activity (TKA) and maximum value was recorded in fish fed 0.8mg/kg thiamin beyond which stagnation in TKA activity was evident. Liver thiamin concentration was found to be maximum in fish fed diet containing 1.6mg/kg thiamin. A significant (p<0.05) consistent reduction in the hepatic thiobarbituric acid reactive substances (TBARS) activity was displayed with incremental concentration of thiamin up to 0.8mg/kg, beyond which a reverse trend was evident. However, a significant (p<0.05) improvement was noted in superoxide dismutase (SOD) and catalase (CAT) activity with the increasing level of dietary thiamin from 0 to 0.8mg/kg. Broken-line regression analysis of AWG, FCR, PRE and TKA estimated the requirement in the range of 0.74-0.79mg/kg dry diet.