Groundnut and Cottonseed Meals in Tilapia Juvenile Diets: Effects on Apparent Nutrient Digestibility, Short-Term Growth Performance, Feed Utilization and Carcass Composition

Abstract

Oilseed by-products constitute a potential ingredient in fish feeds owing to their low cost, availability, and high protein contents. However, plant proteins tend to be deficient in essential amino acids limiting their utilization and incorporation in fish diets. This study evaluated the apparent nutrient digestibility, growth performance, feed utilization and whole-body composition of Nile tilapia fed diets containing 30% of cottonseed meal (CSM) or groundnut meal (GNM). The plant proteins corresponded to approximately 12% of dietary protein and replaced 42% to 46% of fish meal protein, respectively. The test diets; groundnut meal (GND30) and cottonseed meal (CSD30) were formulated to contain 32% crude protein and 14% crude lipid, with a gross energy density of 20 MJ/kg. A fish meal based diet served as a control (CD). Overall, the results showed that, with the exception of mean final body weight, weight gain (%), SGR and FCR did not differ among the diets but was highest in CD followed by GND30 and CSD30. The CSD30 resulted in significant reductions in protein and lipid digestibility, whereas nitrogen free extract digestibility was not affected in all diets. In general, 30% inclusion level of CSM and GNM are suitable replacements for fish meal in diets for Nile tilapia.