Optimum protein and energy levels for four genotypes of local and exotic grower pullets in the humid tropics

Abstract

Twenty four dietary combinations of metabolisable energy (ME) levels 2,6-3.2 Meal/kg and protein levels 14-22%, were fed to equal numbers of 4 genotypes of local x exotic chickens in 2 experiments, to Identify the optimum diet for growth under tropical conditions. The diet with ME 3.0 Meal/Kg and 18% protein proved the most adequate in promoting maximum biological and economic efficiency for growing pullets 8.20 weeks old. Feed consumption was depressed by ME values above 3.0 Meal/kg (P<0.005) but not by 2.6-3.0 Meal/kg ME values. Body weights at 140 days were significantly correlated with protein levels but negatively with age at first egg. High protein levels accelerated sexual maturity but the correlation was not significant. The local male x exotic female cross exhibited high heterosis and was equal to or better than the exotic, while its reciprocal cross was nearly as poor as the local, in overall performance. Both groups showed slight Indications of dietary specificity but not enough evidence of separate dietary requirements.