Dietary vitamin E requirement for maximizing the growth, conversion efficiency, biochemical composition and haematological status of fingerling Channa punctatus

Abstract

The effect of feeding graded levels of vitamin E (E0, E20, E40, E60, E100, E140, E180, E220, E260) in nine casein–gelatin-based isonitrogenous (450 g kg−1 crude protein) and isoenergetic (17.97 kJ g−1 gross energy) experimental diets was evaluated in fingerling Channa punctatus for 12 weeks. Growth, nutritional and haematological parameters were studied. Hepatic lipid peroxidation as thiobarbituric acid-reactive substances (TBARS) was also assayed. The maximum absolute weight gain (AWG g/fish, 55), best feed conversion ratio (FCR, 1.32), protein retention efficiency (PRE, 40%) and energy retention efficiency (ERE, 76%) were achieved in fish fed on a diet supplemented with 140 mg vitamin E kg−1 diet (E140). A consistent decline in the hepatic TBARS concentration and an improvement in haematocrit (Hct) and haemoglobin (Hb) were displayed in fish fed on diets with increasing concentrations of vitamin E up to 140 mg kg−1 (E0–E140), beyond which (E180–E260) a reverse trend in these parameters was evident. Based on the broken-line regression and exponential analyses of AWG, FCR, PRE, ERE, Hb and Hct data, diets for fingerling C. punctatus should contain vitamin E in the range of 140–169 mg kg−1 to maintain satisfactory fish performance.