Valine in diets for juvenile Nile tilapia (Oreochromis niloticus): growth performance, chemical composition, blood parameters and skeletal muscle development

Abstract

Valine belongs to the group of branched-chain amino acids, has an important structural role and is primarily deposited as body protein. The present study evaluated the effects of valine in diets of juvenile Nile tilapia. A total of 216 juveniles with weight of 21.40 ± 0.42 g and length of 10.07 ± 1.00 cm were distributed into 18 aquarium in a completely randomized design with six treatments and three replicates. Six diets containing 24.30% digestible protein, 3,100 kcal/kg digestible energy, and increasing valine levels (0.54; 0.63; 0.72; 0.81; 0.90; 0.99%) were prepared. The following factors were evaluated: performance, chemical composition, blood hematological and biochemical, and skeletal muscle development. Differences were observed in productive performance between treatments for weight gain, daily weight gain and apparent feed conversion, where inclusion levels from 0.81% to 0.99% provide better performances. According to the equation of quadratic regression, the inclusion of 0.86% of valine provided greater weight gain. Regarding the hematological and biochemical parameters, there were differences among the treatments for hemoglobin, triglycerides, and cholesterol. Not difference was observed for the chemical composition and muscle fiber growth. It is recommended the inclusion of 0.86% of valine in the diet of juveniles of Nile tilapia because it provides greater weight gain.