The present study investigated optimal lysine levels for local and improved strain of Nile tilapia, Oreochromis niloticus fed with black soldier fly larvae aquafeed supplemented with different levels of lysine. A total of six experimental diets (R-1.12, R-1.30, R-1.53, R-1.75, R-1.91 and R-2.20) were formulated in which 0, 0.2, 0.4, 0.6, 0.8 and 1.2 % of lysine were added at the expense of the glutamic acid, leading to analyzed lysine levels of 1.12, 1.30, 1.53, 1.75, 1.91 and 2.20 % of lysine in the diets, respectively. Partitioned plastic tanks were randomly stocked with fingerlings of both strains (4.15±0.04 g) and were cultured for 84 days.
The results of this study indicated that better growth performance, feed utilization, hematological-biochemical and antioxidant enzyme parameters when with fed with lysine inclusion level of 1.91 % in the diet (R-1.91 %) for local strain and 1.75% in the diet (R-1.75) for improved strain. The estimated optimal level of lysine requirement for both local and improved for weight gain were 1.90 and 1.84% respectively using quadratic regression analysis. Other parameters suggested that optimal levels of lysine ranged between 1.80 to 1.88%. Generally, there was significant effect with dietary lysine when strain, diet and interaction are effects in all analyzed, with excerption of hematocrit and mean corpuscular hemoglobin. These findings suggest that optimal levels lysine is important for reduce cost feeds, production and higher tonnage in aquaculture venture.