Effect of Dietary Sulfur Amino Acids Deficiency on the Energy Metabolism in the Chick

Abstract

The effect of dietary sulfur amino acids (SAA) on energy metabolism was studied in White Leghorn male chicks. The purified diets (ME 13.8kJ/g; nitrogen content 2.512%), using an amino acid mixture as a nitrogen source, containing 100%, 70%, 35% and 0% to the SAA requirement were given ad libitum to chicks during an 8-day experimental period. Energy gain was computed from fat and protein gain using the energy values for both. To estimate heat increment (heat production-basal metabolic rate), the basal metabolic rate was determined with the use of a respiration apparatus system. Results showed that when the SAA level was reduced to 35% and 0%, a significant decrease in body weight gain and in the efficiency of feed utilization was observed. In these groups, in comparison with the 100% group, the proportion of heat production to ingested metabolizable energy tended to increase, while the proportion of energy gain tended to decrease. No great difference was noted in the proportion of heat increment between the 100% group and the other groups. This result indicates that a severely restriction in metabolizable energy ingestion in the 35% and the 0% groups causes an increased proportion of energy for maintenance.