ABSTRACT
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.
Subject(s)
Body Composition , Chickens/metabolism , Diet , Liver Glycogen/metabolism , Animals , Dietary Proteins/administration & dosage , Dietary Proteins/metabolism , Energy Intake , Energy Metabolism , Lysine/administration & dosage , Lysine/metabolism , MaleABSTRACT
The experiments were conducted to determine the available lysine requirement of broiler chicks during the 7-9 week growing period. The chicks were sexed at day old, and the sexes were reared in separate pens in the same facility. Commercial-type broiler rations were fed from day old to 7 weeks of age. At 7 weeks the sexing errors were removed and the pens equalized to 50 birds per pen. The eight dietary treatments were replicated three times per sex. Graded levels of L-lysine-HCL were added to the basal ration to give a stepwise increase of 0.07% lysine per level. The available lysine requirement for female during the 7-9 week period was 0.64% for both growth and feed conversion. When this was expressed as a function of energy, 0.187% available lysine per megacalorie of metabolizable energy (M.E) per kg. of diet was required. The available lysine requirement for males during this period was 0.69 and 0.66% for gain and feed conversion, respectively. Expressed as available lysine per megacalorie of M.E. per kg. of diet, the values would be 0.202 and 0.193%, respectively.
