Lysine requirement and its effect on the body composition of Oreochromis niloticus fingerlings. (Special Issue: The future of fisheries in a changing global climate.)

摘要

In the use of plant based ingredients for production of cost effective feed, lysine being one of the deficient amino acid in such feed must be present in the required quantity for Oreochromis niloticus in order to impact on its production positively. This 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 (9.01-11.09 g) were reared in 35 L plastic troughs. Six diets were formulated, containing 35% crude protein. The diets were formulated with ingredients deficient of lysine (Groundnut cake -3.23 g lysine/100 g diet and guinea corn -1.9 g lysine/100 g diet) for O. niloticus having whole body content of 7.51 g lysine/100 g protein. The diets consist of a basal diet (Diet I, no added lysine), while the test diets (II, III, IV and V) had 4.56, 6.87, 7.30, 7.41 g lysine/100 g 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 (5.37 g lysine/100 g protein). The fish were fed twice daily (09.00 and 18.00 h) 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<0.05). Calculation using regression equations from the relationship between the specific growth rate, weight gain and lysine levels show that lysine requirement for fingerling was 7.12 g/100 g protein, respectively. The requirement of O. niloticus for lysine is 7.12 g lysine/100 g protein.