Effects of Partial Replacement of Fishmeal by Locally Available Ingredients on Growth Performance and Feed Utilization Efficiency of Nile Tilapia, Oreochromis niloticus

Abstract

The present study was aimed at evaluating the effects of partial replacement of fishmeal with locally available feed ingredients on growth performance, feed utilization efficiency body composition and apparent digestibility coefficient of protein (ADCp) of Nile tilapia. For this purpose, seven experimental diets were prepared using 0%, 10% and 20% Jatropha, Alfalfa and Brewery waste as partial replacement of fishmeal. Healthy mixed-sex Nile tilapia with an average body weight of 6.5 ± 0.56 g were collected from Ziway Fish and Other Aquatic Life Research Center and stocked in fiberglass plastic tanks in triplicates at a stocking density of 20 fish per tank. The fish were fed three times a day with a control diet for one week and then with experimental diets for a period of four months at a rate of 3-6% body weight of fish. For ADCp studies, fish were reared for 20 days and were fed with control and test diets having an internal marker. Data were collected twice a month. The result showed that the fish fed with control diet,10%Jatropha, 10% Alfalfa and 10% and 20% Brewery waste based diets showed significantly better final body weight (28.7-30.0 g) specific growth rates (1.39-1.47%/day),feed conversion ratio (1.44-1.56) and protein utilization efficiency (0.60-0.66) than the fish fed with 20% Jatropha and Alfalfa based diets (23.8-26.0 g for final body weight, 1.25-1.33%/day for specific growth rate, 1.95-1.97 for food conversion ratio and 0.49-0.54 for protein utilization efficiency). The final survival rates of the experimental fish (73.3-86.6%) did not differ significantly (P>0.05) among feeding treatments. In conclusion, the fish meal can be replaced using the three ingredients up to 10% without negative effects on the growth and feed utilization of Nile tilapia.