Effect of supplementation of soyabean diet with L-and D,L-methionine on the growth of mudfish Clarias anguillaris (L) fingerlings

Abstract

Two experiments were carried out to study the effect of dietary supplements of methionine on the growth and food utilization of mudlish Clarias anguillaris. In bot11 studies C. anguillaris fingcrlings {17.20g and 1.02g. initial mean weight respectively) were fed full fat soybean diets supplemented with :raded levels of L-and D. L-methionine and the growth was monitored for 12 and 14 weeks respectively. Growili rate and food utilization were significantly higher (P<0.05) when they were fed soybean diets supplemented with 0.2% L-and D, L-methionine than 0.4, 0.6 and 0.8%. An increase in the level of Land D, L-metllionine beyond 0.2% resulted in a significam reduction in the growth rate of the fish. Growth and food utilizatinn were better in fish fed the casein and fish meal positive control diets tllan me 0.2% supplemented soybean diets. The unsupplernented soybean diets were poorly utilized by the mudfish fingerlings. The size disparity of fingerlings had no effect on the  dietary requirement for the L-and D, L-rnemionine. Since the less expensive D. L-methionine can substitute L-methionine in the diet, the use of D, L-mcthionine in dietary supplemenlS is more cost effective than the use of L-metbioninc.