Abstract

This study investigated the effects of substituting varying levels of a plant protein mixture (PPM) with freshwater shrimp meal (FSM) on growth, digestibility, and economic returns of Nile tilapia. Monosex male Oreochromis niloticus fingerlings (initial body weight, 28 ±0.01 g) were cultured in cages installed in an earthen pond and tanks for 180 and 60 days, respectively. The PPM comprised 50% soybean meal, 25% sunflower cake and 25% cotton seed cake. Replacement of FSM was done at 25, 50, 75 and 100% and diets labelled D1, D2, D3 and D4, respectively. Test diets were compared with a control diet (D0, 0% PPM). After 6 months, fish fed diets D0 and D1 did not differ (p>0.05) in growth performance. There was significant decrease (p<0.05) in fish weight gain as PPM levels increased. Crude protein digestibility decreased significantly (p<0.05) with increasing inclusion levels of PPM. Diet D0 had the highest digestibility followed by D1 and D2 although D0, D1 and D2 were not significantly different (p>0.05). Diet D0 and D1 were not significantly different (p>0.05) hence cost benefit analysis showed that D1 was economically viable than D0. Therefore, PPM could partially replace FSM up to 25% without adverse effects on growth performance. 

Key words: Caridina nilotica, digestibility, economic returns, Nile tilapia, plant protein mixture.