POOR PERFORMANCE OF BROILERS FED DIETS CONTAINING SOYBEAN-MEAL AS THE SOLE PROTEIN-CONCENTRATE

Broiler chickens fed diets containing soyabean meal as the sole dietary protein concentrate consistently showed poor growth in a number of feeding trials. Soyabean meal processed in Australia gave inferior performance to soyabean meal processed in the U.S.A. Growth was improved at similar dietary energy and protein concentrations by replacing approximately 25% of the soyabean meal with either sunflower meal, cottonseed meal or rapeseed meal but not by supplementing the soyabean meal diet with lysine, methionine and cystine. The responses of broilers to the soyabean meal diet were unaffected by the cereal component of the diet and the beneficial responses observed when sunflower meal replaced part of the soyabean meal were not related to the amino acid composition or digestibility of the diets.