Body composition and nutrient utilization of chicks fed amino acid diets containing graded amounts of either isoleucine or lysine
Velu, J.G.; Scott, H.M.; Baker, D.H.
Journal of Nutrition 102(6): 741-747
1972
ISSN/ISBN: 0022-3166 PMID: 5028668 Document Number: 50583
Chicks had 5 times as much carcass fat with a diet containing 0.6% isoleucine as with one devoid of isoleucine. Weight gain, feed consumption and gain:feed ratio corresponded to changes in carcass fat. Comparable results were noted when lysine was the variable amino acid except that carcass fat was most at a lower concentration of dietary L-lysine. HCl (0.71%) than was needed for best weight gain and feed consumption (0.95%). Carcass fat of chicks on a N-free diet was about 4 and 2 times that of chicks given the isoleucine- and lysine-free diets. In all instances retention of protein was a linear function of the intake of limiting amino acids. Energy retention and metabolizable energy intake were positively correlated. Carcass fat declined progressively when chicks were equally given diets containing graded amounts (0.4, 0.5, 0.6 and 0.7%) of isoleucine. There was an inverse relation between carcass fat and weight gain.