Authors: Olude O.O, Alegbeleye W.O.A, Obasa S.O,
Journal of Livestock Research for Rural Development 20 (10) 2008
Abstract
A feeding trial was conducted in net hapas (fish enclosures constructed with fine mesh net) suspended in outdoor concrete tank to evaluate the nutritive value of soaked copra meal (a by-product of coconut oil industry) as a dietary protein supplement for soybean meal in practical diets for Nile tilapia (Oreochromis niloticus) fingerlings (mean initial weight, 7.26±0.23g).
Four iso-nitrogenous (30% crude protein) and iso-energetic (16KJ/g) experimental diets were formulated in which soaked copra meal replaced soybean meal at four inclusion levels. The reference/control diet was tagged reference diet, while other diets were tagged TD1, TD2, 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 measurably better than those fed reference diet, but were with values 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. There was however no significant difference (p>0.05) in the apparent protein digestibility and hepatosomatic indices values among the dietary treatments. The results showed that soaked copra meal can be incorporated in the diets of Nile tilapia, Oreochromis niloticus, fingerlings up to 30% without any deleterious effect on growth performance and nutrient utilization.