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New insights into the mechanism and actions of growth hormone (GH) in poultry.

Authors :
Vasilatos-Younken R
Wang XH
Zhou Y
Day JR
McMurtry JP
Rosebrough RW
Decuypere E
Buys N
Darras V
Beard JL
Tomas F
Source :
Domestic animal endocrinology [Domest Anim Endocrinol] 1999 Oct; Vol. 17 (2-3), pp. 181-90.
Publication Year :
1999

Abstract

Despite well documented anabolic effects of GH in mammals, a clear demonstration of such responses in domestic poultry is lacking. Recently, comprehensive dose-response studies of GH have been conducted in broilers during late post-hatch development (8 to 9 weeks of age). GH reduced feed intake (FI) and body weight gain in a dose-dependent manner, whereas birds pair-fed to the level of voluntary FI of GH-infused birds did not differ from controls. The reduction in voluntary FI may involve centrally mediated mechanisms, as hypothalamic neuropeptide Y protein and mRNA were reduced with GH, coincident with the maximal depression in FI. Growth of breast muscle was also reduced in a dose-dependent manner. Circulating IGF-I was not enhanced by GH, despite evidence that early events in the GH signaling pathway were intact. A GH dose-dependent increase in circulating 3,3',5-triiodothyronine(T3) paralleled decreases in hepatic 5D-III monodeiodinase activity, whereas 5'D-I activity was not altered. This confirms that a marked hyperthyroid response to GH occurs in late posthatch chickens, resulting from a decrease in the degradative pathway of T3 metabolism. This secondary hyperthyroidism would account for the decreased skeletal muscle mass (52) and lack of enhanced IGF-I (53) in GH-treated birds. Based upon these studies, it is now evident that GH does in fact have significant effects in poultry, but metabolic responses may confound the anabolic potential of the hormone.

Details

Language :
English
ISSN :
0739-7240
Volume :
17
Issue :
2-3
Database :
MEDLINE
Journal :
Domestic animal endocrinology
Publication Type :
Academic Journal
Accession number :
10527121
Full Text :
https://doi.org/10.1016/s0739-7240(99)00035-1