Lysine is one of the most important essential amino acid in fish feeds needed for optimum growth of fish. The combination of different feedstuff with suitable components of lysine can help to boost lysine content in fish feeds. Sources of lysine for fish feeds includes soybean waste, leucaena leucocephala leaves, fish meal and earthworm powder. The goal of this investigation is to enhance lysine content in fish feeds by incorporating different ratio of each chosen feed constituents. The investigation was conducted using central composite design (CCD) as statistical tool. The optimal lysine content was obtained at 25.00 %, 20.88 %, 10.00 % and 20.00 % of earthworm powder, soybean waste, leucaena leucocephala leaves and fish meal, respectively. The lysine content in formulated fish feeds was significantly affected by the composition of earthworm powder and fish meal in fish feed formulation. Earthworm powder and fish meal have contributed the largest portion of lysine in fish feed due to high lysine content which were 4.48 % w/w and 3.60 % w/w, respectively. The optimized fish feed shows high lysine content of 23.39 % w/w which doubles the lysine content in commercial fish feed (11.21 % w/w). The composition of fish feed obtained from this study can be used as guidelines for formulation of high lysine fish feeds for African catfish fingerlings.
Keywords: lysine; optimization; fish feed; African catfish