Protein and energy relationships in the broiler chicken. Effects of protein quantity and quality on metabolism.
Male broiler chickens growing from 7 to 35 d were fed on a diet containing 150 g crude protein (N x 6.25)/kg diet supplemented with lysine to equal that in diets containing 166, 183 and 200 g crude protein/kg diet (Expt 1). A second group of male broiler chickens growing over the same period were fed on a diet containing 120 g crude protein/kg supplemented with lysine, arginine, tryptophan, threonine and isoleucine equal to that in diets containing 144, 172 and 200 g crude protein/kg diet (Expt 2). Growth was improved by lysine supplementation but not to the level attained by feeding 200 g crude protein/kg (Expt 1). Lysine, arginine, tryptophan, threonine and isoleucine supplementation of a low-protein diet also improved growth, but growth again fell short of that attained by feeding a diet containing 200 g crude protein/kg. Plasma insulin-like growth factor-1 and thyroxine concentrations increased and triiodothyronine decreased as the crude protein level increased from 150 to 200 g/kg diet. Supplemental lysine did not affect plasma levels of these hormones. Although dietary crude protein levels noticeably changed rates of in vitro lipogenesis, changing either the level of a single limiting amino acid or the levels of several limiting amino acids did not change lipogenesis.
Rosebrough
R W
RW
Livestock and Poultry Sciences Institute, United States Department of Agriculture-Agricultural Research Service, Beltsville Agricultural Research Center, MD 20705.
McMurtry
J P
JP
D000596:Amino Acids / Q000008:administration & dosage*; D000818:Animals; D001120:Arginine / Q000008:administration & dosage; D001835:Body Weight; D002645:Chickens / Q000254:growth & development / Q000378:metabolism*; D004044:Dietary Proteins / Q000008:administration & dosage*; D004734:Energy Metabolism / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007532:Isoleucine / Q000008:administration & dosage; D008055:Lipids / Q000096:biosynthesis*; D008239:Lysine / Q000008:administration & dosage; D008297:Male; D013912:Threonine / Q000008:administration & dosage; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D014364:Tryptophan / Q000008:administration & dosage
D000596:Amino Acids; D004044:Dietary Proteins; D008055:Lipids; D007532:Isoleucine; D014284:Triiodothyronine; D013912:Threonine; D007334:Insulin-Like Growth Factor I; D014364:Tryptophan; D001120:Arginine; D008239:Lysine; D013974:Thyroxine