Dietary amino acid l -histidine requirement of fingerling Indian catfish, Heteropneustes fossilis (Bloch), estimated by growth and whole body protein and fat composition

Abstract

An eight-week feeding trial was conducted to determine the dietary histidine requirement of Indian catfish, Heteropneustes fossilis (6.20 ± 1.25 cm, 4.65 ± 0.48 g) in 75-L flow-through circular troughs. Six isonitrogenous (40%) and isoenergetic (17.90 kJ g−1) amino acid test diets with graded levels of l-histidine (0.25–0.75%, dry diet), in gradation of 0.10% histidine were formulated. Fish were randomly stocked in triplicate groups and fed experimental diets at 4% BW per day at 08:00 and 18:00 h. Maximum live weight gain (288%), best FCR (1.40) and PER (1.78) were occurred at 0.55% dietary histidine level. For the live weight gain, FCR, PER and body protein deposition data were examined using quadratic regression analysis, the breakpoints indicating requirements for histidine at 0.58, 0.54, 0.53 and 0.54% of dry diet, respectively. Significantly (P < 0.05) low moisture and higher whole body protein content were obtained in the 0.55% histidine diet, while body fat showed an increasing trend with the increase in dietary concentrations. Ash content remained insignificantly (P > 0.05) low among all dietary groups, except in diet I and diet II. Based on the above results, the recommended diet for young H. fossilis should contain histidine at 0.54% of dry diet, corresponding to 1.35% of dietary protein for optimum growth and efficient feed utilization.