Effects of supplementation of amino acids, lysine and methionine on growth performance and feed utilization of Sobaity sea bream juveniles, Sparidentex hasta.

Abstract

This study was conducted to determine the effects of dietary supplementation of lysine and methionine on growth and nutrient utilization of Sobaity sea bream, Sparidentex hasta.A total of 180 juvenile fish with an initial weight of 31.38 ±1.4 g were distributed randomly among eighteen tanks. Fish were fed to satiation three times per day (08:00, 13:00 and 18:00 hours) for 8 weeks with formulated diets containing six different levels of dietary methionine and/or lysine; Diet 1: a control diet without dietary amino acid supplementation; Diet 2: 100% methionine supplementation; Diet 3: 75% methionine and 25% lysine supplementation; Diet 4: 50% methionine and 50% lysine supplementation; Diet 5: 25% methionine and 75% lysine supplementation and Diet 6: 100% lysine supplementation. The results of this study showed that dietary lysine and methionine supplementation significantly affected (P<0.05) growth parameters and feed utilization. The fish fed with high level of methionine supplementation had significantly improved growth performance than the group fed the control diet and treatment 6. Highest feed conversion ratio, protein efficiency ratio and protein retention were observed in diet 3. Though lysine and methionine supplementation showed positive effects on growth and feeding performance, our results suggested that Sobaity juveniles probably required more methionine than lysine.