Lysine requirement and its effect on the body composition of Oreochromis niloticus fingerlings

The study was carried out to investigate the lysine requirement and its effect on the body composition of Oreochromis niloticus fingerlings. Two hundred and seventy fingerling O. niloticus (9.01 -11.09g) were reared in 35L plastic troughs. Six diets were formulated, containing 35% crude protein. The diets were formulated with ingredients deficient of lysine (Groundnut cake -3.23g lysine/100g diet and guinea corn -1.9g lysine/100g diet) for O. niloticus having whole body content of 7.51g lysine/100g protein. The diets consist of a basal diet (Diet I, no added lysine), while the test diets (II, III, IV and V) had 4.56g, 6.87g, 7.30g, 7.41g lysine/100g protein respectively. The reference diet was made of Clupeids (mixture of Pellonula afzeliusi and Physalia pellucida), groundnut cake and guinea corn but no added lysine (5.37g lysine/100g protein). The fish were fed twice daily (0900 and 18.00hrs) at 3% body weight for 56 days. There was significant difference in the mean weight gain and food conversion efficiency (P<0.05). The four levels of lysine resulted in quadratic responses (P