Growth Indices and Muscle Development in Broiler-chickens Fed Equi-protein Replacement of Soyabean Meal with Discarded Cashew Nut Meal

Abstract

The goal of this study was to evaluate the influence of diets containing soyabean meal (SBM) protein replaced with discarded cashew nut meal (DCNM) protein on the growth indices and, breast and hind limb muscles of broilers. Three hundred and sixty growing broilers aged 5 weeks were used for the investigation. The control diet had 25.0g 100g-1 SBM and this was replaced on equi-protein basis at 10, 20, 30, 40 and 50% levels by DCNM. The experimental diets were fed for 21 days (5th-8th weeks of age). Thereafter, the chickens were slaughtered and the carcass, organs and the breast and hind limb muscles dissected out and measured. The final weight (FW), average weight gains (AWG) and the fat retention (FR) tends to be significantly influenced by the dietary treatment. The FW and AWG of birds on DCNM-based diets were higher than those fed the control diet with about 4.2-9.6% and 3.1-14.9%, respectively. Of the carcass characteristics measured only the drumsticks, wing, head and belly fat tend to be significantly (P<0.05) influenced by the dietary treatments. The relative weight of the heart of the birds increased from 4.6±0.6g kg-1 body weight in those fed the control diet to 5.6±0.5g kg-1 body weight in birds fed 50% SBM+50% DCNM-based diet while the relative weight of the spleen (1.6±0.2g kg-1) of birds fed the control diet tend to be significantly (P<0.05) higher than those fed the DCNM-based diets (1.0±0.1-1.3±0.3g kg-1 body weight). The weights, lengths and breadths of the Musculus supra coracoideus, Pectoralis thoracicus and Gastrocnemeus did not varied widely among the treatments as indicated by the low coefficient of variation values (1.9-7.0%). Giving the relative abundance of the DCNM in Nigeria, it was suggested that DCNM could be used to replace expensive SBM in broiler diets.