Maintenance of broiler performance on commercial diets diluted with copra meal and supplemented with feed enzymes

Context. Dilution of commercial feed with moderate levels of copra meal (CM), a byproduct of coconut oil extraction, was shown to maintain broiler performance in older breeds, but reports on its use in modern fast-growing broilers are limited. Aims. We evaluated feed dilution with CM and enzyme supplementation in broiler chickens. We hypothesised that (i) diluting commercial feed with CM will maintain performance of modem fast-growing broilers, and (ii) enzyme supplementation will improve utilisation of the diluted diets. Methods. Experiment 1 studied the performance of growing broilers (10-21 days of age) fed commercial grower diet alone (control), or diluted with one of two levels of CM (50 and 100 g/kg) and with or without enzyme supplementation. Cobb 500 broiler chicks (10 days old), 200 in total, were assigned to five dietary treatments with four replicates, in a completely randomised design. Experiment 2 investigated higher levels of dilution (100 and 200 g CM/kg) and enzyme supplementation of commercial finisher diet in 200 finishing broilers (22-42 days of age) assigned to five treatments with four replicates each. Key results. In Experiment 1, feed intake was reduced (P < 0.05) on the 100 g CM/kg diet without enzyme compared with 50 g CM/kg without enzyme and both of the enzyme-supplemented diets but was not different (P > 0.05) from the control. Bodyweight gain and feed conversion ratio were not affected (P > 0.05) by dietary treatment. In Experiment 2, feed intake was reduced on 200 g CM/kg with enzyme but did not differ (P > 0.05) among the control and other CM-based diets. Bodyweight gain (P < 0.05) was reduced on the 200 g CM/kg diet without enzyme compared with the 100 g CM/kg diet without enzyme. Feed : gain was not affected (P > 0.05) by diet. The relative weight of carcass and cuts, gut segments and annex organs was not affected (P > 0.05) by diet. Conclusions. Diluting commercial grower and finisher diets with 50 and 100 g CM/kg has no adverse effects on performance of modem broilers. At higher levels of dilution (100 and 200 g/kg), enzyme supplementation may be required.