The effect of diet on liver glycogen and body composition in the chick

Experiments were conducted to study the effects of diet on liver glycogen and body composition in the three-week-old chick. When percent protein and percent lysine were varied, liver glycogen concentration declined significantly as protein and lysine increased, 32.6 vs. 19.4 mg/g for the 14 and 35% protein diets, respectively. Carcass fat decreased and carcass moisture increased in a pattern similar to glycogen as protein and lysine increased in the diets. When seven levels of lysine were fed in isocaloric, isonitrogenous diets, glycogen content was not significantly different in any of the treatments. Liver glycogen was highest at the lowest energy level when dietary energy was increased and protein held constant. Carcass fat varied with the energy level but was also influenced by the amino acid balance. The data suggest that percent carbohydrate to percent fat ratio in the diet (both calculated) is an important factor affecting glycogen, but more research is needed to determine the mechanisms controlling the glycogen content of the liver.