Effects of varying dietary protein level on the growth, feed efficiency and body composition of lemon fin barb hybrid fingerlings

This study was conducted to determine the optimal dietary protein requirement for lemon fin barb hybrid fingerlings. Triplicate groups of fish (1.00 +/- 0.05 g) were fed twice a day until apparent satiation with five isocaloric (16 kJ/g) diets containing varying protein level ranging from 20 to 40% for 60 days. Survival was not affected by the dietary protein level. The weight gain and specific growth rate were improved with dietary protein level up to 35 %. The best feed conversion ratio (1.61) was achieved at 35% dietary protein level. Protein efficiency ratio was not influenced by the dietary protein level. Using a broken line regression model, the dietary protein requirement of lemon fin barb hybrid was estimated at 34.6 % based on weight gain response but the value was not significantly better than the 30% protein diet. Proximate composition of the fish showed that dietary protein level only affected the protein content of the lemon fin barb hybrid. The study showed the protein retention was increased until 30% and decreased above this level. Lipid retention decreased as the dietary protein increased. It can be concluded that lemon fin barb hybrid required 30-35% protein at gross energy 16 kJ/g for the best growth and feed efficiency.