Effect of L-Lysine Supplementation with Different Protein Levels in Diets on Growth, Body Composition and Protein Metabolism in Pearl Spot Etroplus Suratensis (Bloch)

摘要

Experimental diets with 0.5% L-lysine (HCl) having 25, 30, 35 and 40% protein were formulated with purified ingredients except soya meal. At each protein level a diet devoid of L-lysine was used as control. Performance parameters were assessed by conducting feeding trail experiments in pearl spot (Etroplus suratensis) for a period of 41 days. Irrespective of the dietary protein levels, growth of E. suratensis was higher in fish received L-lysine supplemented diets when compared to those reared on control diets. The data on feed conversion ratio (FCR) revealed that the effect of L-lysine supplementation was significantly higher (P < 0.05) at low protein diets (25 and 30%) fed fish than the others. The influence of L-lysine supplementation on Specific Growth Rate (SGR) of E. suratensis was more pronounced at low protein levels than those reared at high protein levels. The protein consumption rate of E. suratensis fed with diets having 25 and 35% protein was higher than that of fish reared on control diet at the same protein level. Similarly the protein production rate was 20.37, 19.74, 3.55 and 3.64 % more than those received diets devoid of L-lysine respectively at 25, 30, 35 and 40% protein levels. The protein utilization efficiency ratio ranged between 73.73 +/- 1.35 to 85.95 +/- 0.72 % and 76.49 +/- 0.99 to 86.21 +/- 0.51 % for the control and the experimental diets fed fishes, respectively. The Protein Production Value (PPV) was greater in the experimental diets fed fish than those fed with control diets and the variation between them was statistically significant (P < 0.05) for those fish reared on low protein diets.