Effect of supplementary feeding of agro-industrial byproducts on the growth performance of Nile tilapia (<i>Oreochromis niloticus</i> L.) in concrete ponds

Abstract

This study was conducted to evaluate the effect of supplementary feeding of wheat bran, noug cake and brewery waste on the growth of Oreochromis niloticus in concrete ponds. The feeding trial was conducted in eight concrete ponds of about 50 m² each. The control and experimental groups were run in duplicate with stocking density of 2 fish/m². The treatment groups were fed at 5% of their body weight with the respective test feeds and the control group was left to feed on endogenous phytoplankton diet. The results of the experiment showed that fish given supplemental diets grew much faster (ANOVA, P<0.001) than the control group. Although no significant growth differences were observed between the test feeds (ANOVA, p=0.81), fish raised in brewery waste (0.4 g/day) and noug cake (0.37 g/day) showed better growth rate than wheat bran (0.34 g/day). Differences in growth rates between the control and test feeds as well as among the test feeds can be attributed to both direct and indirect effects of supplementary feeds given to the fish. Direct intake of feeds by the fish provides more nutrients resulting in better growth and production. Moreover, addition of supplementary feeds can elevate the level of organic nutrients that favour the growth of flagellate phytoplankton which are good quality food for the fish. We therefore concluded that all supplementary feeds nearly doubled the growth of O. niloticus in ponds. In addition to feed ingredients, information on digestibility, palatability and levels of anti-nutritional substances should be determined under different agro-ecological conditions.

Keywords/phrases: Agro-industrial byproducts, Growth, Oreochromis niloticus, Phytoplankton, Pond experiment, Production, Supplementary feeds

Ethiop. J. Biol. Sci. 11(1): 29-41, 2012