Olude et al., 2008. Livest. Res. Rural Dev., 20 (10): 169
A feeding trial was conducted in net hapas (fish enclosures constructed with fine mesh net) suspended in an outdoor concrete tank to evaluate the nutritive value of soaked copra meal (a byproduct of the coconut oil industry) as a dietary protein supplement for soyabean meal in practical diets for Nile tilapia (Oreochromis niloticus) fingerlings (mean initial weight 7.260.23 g). Four isonitrogenous (30% crude protein) and isoenergetic (16 KJ/g) experimental diets were formulated in which soaked copra meal replaced soyabean meal at four inclusion levels. The reference/control diet was designated as reference diet, while other diets were tagged as TD1, TD2 and TD3 at replacement levels of 0, 15, 30, and 45% soaked copra meal, respectively. The diets were given at 3% wet body weight to triplicate groups of 10 fish for 70 days. In terms of growth performance and nutrient utilization efficiencies, fish fed TD1 and TD2 performed better than those fed the reference diet, but the values were statistically similar (P>0.05). Apparent protein digestibility coefficients which ranged from 76.1% (reference diet) to 55.2% (TD3) and hepatosomatic indices with a range of 1.33% (reference diet) to 1.21% (TD3) decreased with increasing levels of soaked copra meal. However, there was no significant difference (P>0.05) in the apparent protein digestibility and hepatosomatic indices values among the dietary treatments. These results show that soaked copra meal can be incorporated in the diets of Nile tilapia fingerlings up to 30% without any deleterious effect on growth performance and nutrient utilization.