Effects of gradation in protein-calorie restriction on the hypothalo-pituitary-gonadal axis in young domestic fowl.
The effect of protein-calorie restriction on the circulating concentration of luteinizing hormone (LH) was investigated in the young domestic fowl. Two-week-old broiler chicks were fed isocaloric synthetic diets with varying levels of soy protein for a period of 14 days. Growth rate, as indicated by body weight, was decreased as the level of protein in the diet was reduced. Body weights of birds on a 3% protein diet were only 29.7% that of birds on a 24% protein diet. Severe protein-calorie restriction was also associated with depressed plasma LH levels in birds of both sexes, with male birds appearing to be more sensitive to this deficiency. A reduction of protein in the diet from 24% to 3% was associated with a 69% decrease in LH in males and a 43% decrease in females. In addition to lower circulating concentrations of LH, protein-calorie restriction was associated with a reduction in gonadal weight. Testes weights in birds on a 3% protein diet were only 16% of those on a 24% protein diet. Studies with synthetic luteinizing hormone releasing hormone (LHRH) indicated that protein-calorie restriction alters luteinizing hormone secretion via a hypothalamic effect.
D000818:Animals; D001835:Body Weight; D002645:Chickens / Q000254:growth & development / Q000502:physiology*; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage*; D002149:Energy Intake; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D006066:Gonads / Q000502:physiology*; D007031:Hypothalamus / Q000502:physiology*; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D009929:Organ Size; D010902:Pituitary Gland / Q000502:physiology*; D013737:Testis / Q000033:anatomy & histology
D004044:Dietary Proteins; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone