The effect of methionine deficiency on body weight, food and energy utilization in the chick.

The effect of dietary methionine deficiency was studied in broiler chicks. Graded levels of methionine: 0.25, 0.32, 0.39 and 0.46% in semipurified, soybean meal-corn starch diets were used as treatments. Food intake, body weights and body components were determined. Results show that a moderate methionine deficiency (0.32 and 0.39%) had no effect on growth and energy metabolism expressed as metabolizable energy, productive energy, heat production and tissue gains. Increased food intake in these two groups was reflected not as increased weight gain, but as greater quantities of tissue fat. The experimental group with severe methionine deficiency (0.25%) showed depressed body weight gain, food intake and efficiency of food utilization, with some increase in heat production. Therefore, in general, two types of nutritional responses occurred in broilers, based upon the severity of the methionine deficiency.