Effect of various levels of aflatoxin and ochratoxin A and combinations thereof on protein and energy utilisation in broilers

Studies were conducted to evaluate protein and energy utilisation in broilers fed diets containing various levels of aflatoxin (AF; 0, 0.5, 1 and 2 mg kg^?1) and ochratoxin A (OA; 0, 1, 2 and 4 mg kg^?1) either singly or in different combinations. Total protein efficiency (TPE) was reduced by 50.97, 76.52 and 132.75% at 2 mg kg^?1 AF and 2 and 4 mg kg^?1 OA respectively. Co‐toxicity at two levels, 1 mg kg^?1 AF + 2 mg kg^?1 OA and 2 mg kg^?1 AF + 4 mg kg^?1 OA, resulted in significant reductions of 78.58 and 127.43% respectively in TPE. AF at all three levels and OA at 2 and 4 mg kg^?1 caused significant decreases in net protein utilisation (NPU). Co‐toxicity at all three levels led to significantly lower NPU. The reduction in NPU ranged from 18.68% at 0.5 mg kg^?1 AF to 75.12% at 2 mg kg^?1 AF + 4 mg kg^?1 OA. Significant reductions in metabolisable energy (ME) content were recorded at 1 and 2 mg kg^?1 AF and all three levels of OA. ME content was reduced drastically when both toxins were fed simultaneously. It is suggested that both AF and OA adversely affect energy and protein utilisation in broilers, and this effect is exacerbated when both toxins are fed simultaneously. © 2002 Society of Chemical Industry