RESUMO
In 60-day feeding trials, broilers were fed commercial diets in which different amounts of methanol-grown yeast LI-70 replaced fish and soybean meal. In the first trial, all-mash diets containing up to 15% yeast produced growth rates and efficiencies of feed conversion almost equal to those of the soybean meal control and slightly below those of the fish meal control. In the second trial, pelleted diets containing up to 25% yeast were used. For yeast levels up to 15%, growth rates were faster than for the soybean meal control and slightly slower than for the fish meal control. Diets with more than 15% yeast lacked selenium. Diets containing 25% yeast as the sole source of protein but supplemented with .3 ppm selenium produced growth rates and efficiencies of feed conversion equal to those of the controls.