title: Chronic intravenous infusion of chicken growth hormone increases body fat content of young broiler chickens.
abstract: The purpose of this study was to determine the effects of programmed intravenous infusion of chicken growth hormone (cGH) on growth and metabolism of young broiler chickens (4-7 weeks of age). Four-week-old broiler cockerels, fitted with indwelling jugular catheters, were randomly assigned to three treatment groups (6 birds/group): pulsatile infusion of buffer (phosphate buffer, pH 7.4)[PB-P] at 3 hr intervals, pulsatile infusion of cGH (15 micrograms/kg at 3 hr intervals)[GH-P], or continuous infusion of cGH (120 micrograms/kg-day)[GH-C]. Birds were bled 5 min before (0-min) and 5 min post-infusion (relative to the pulses of PB and cGH) at 5, 6, and 7 weeks of age. Pulsatile infusion of cGH increased (P < 0.05) feed consumption by 24% and reduced (P < 0.05) feed efficiency by 14% without affecting body weight (BW) gain. The relative weights (%BW) of liver, abdominal fat, and bursa of Fabricius were not affected by the pattern of cGH infusion. However, the body fat content of cGH-infused chickens was increased (P < 0.05) by 13% (GH-C) and 17% (GH-P), while body protein and water contents were slightly reduced. Body ash content was not affected by pattern of cGH infusion. When compared with the PB-P controls, the GH-P treatment depressed (P < 0.05) hepatic GH-binding activity by 52% without affecting plasma insulin-like growth factor-I (IGF-I) levels. Continuous infusion of cGH increased (P < 0.05) plasma IGF-I by 16%, thyroxine (T4) by 31%, and glucagon levels by 55%, although plasma GH levels were only 47% higher than those of the PB-P group. However, the GH-P treatment was only half as effective as the GH-C pattern in elevating plasma levels of T4 and glucagon. This study shows that programmed intravenous infusion of cGH increases deposition of body fat in young rapidly-growing broiler chickens.
authors.affiliation: Department of Animal Science and Agricultural Biochemistry, College of Agricultural Sciences, University of Delaware, Newark 19717-1303.
authors.forename: R F
authors.initials: RF
authors.lastname: Moellers
authors.forename: L A
authors.initials: LA
authors.lastname: Cogburn
mesh_terms: D000273:Adipose Tissue / Q000187:drug effects* / Q000254:growth & development; D000821:Animal Feed; D000818:Animals; D001823:Body Composition / Q000187:drug effects; D002645:Chickens / Q000097:blood / Q000254:growth & development* / Q000378:metabolism*; D013006:Growth Hormone / Q000494:pharmacology*; D006728:Hormones / Q000097:blood; D007262:Infusions, Intravenous; D008297:Male; D013997:Time Factors
chemical_list: D006728:Hormones; D013006:Growth Hormone