author(s)
E Prabu, CBT Rajagopalsamy, B Ahilan, R Santhakumar and A Jemila Thangarani

abstract
A 60-day indoor growth trial was conducted to study the effect of dietary supplementation of biofloc meal with lysine on growth and survival of juvenile Genetically Improved Farmed Tilapia. Five isonitrogenous and isoenergetic experimental diets (32% protein) were prepared at different enrichment levels of crystalline lysine viz., 1.2% (T1), 1.4% (T2), 1.6%(T3), 1.8% (T4) enriched with 20% biofloc meal included diet and control diet (T0) without biofloc meal and lysine. A commercial diet (T5) was used to compare the experimental diets. This feeding trial was conducted in 18 numbers of 40 L plastic troughs in triplicates, utilizing GIFT tilapias weighing an average of 2 g size. During the experimental period, water quality parameters were measured and recorded daily. Among the experimental diets highest mean body weight of GIFT tilapia were recorded in T1 (45.24±4.52 g) followed by T3 (42.90±3.26g), T2 (39.12±0.49g) and T4 (37.27±3.08 g). Hence, the present study was assessed that diet with 20% biofloc meal supplemented with 1.2% lysine can improve the growth of GIFT tilapia without any adverse effect on the fish performance.