Insulin-like growth factor (IGF)-I but not IGF-II promotes lean growth and feed efficiency in broiler chickens

被引:68
作者
Tomas, FM
Pym, RA
McMurtry, JP
Francis, GL
机构
[1] CSIRO, Div Human Nutr, Cooperat Res Ctr Tissue Growth & Repair, Adelaide, SA 5000, Australia
[2] Univ Queensland, Dept Farm Anim Med & Prod, Brisbane, Qld 4072, Australia
[3] USDA ARS, Inst Livestock & Poultry Sci, Growth Biol Lab, Beltsville, MD 20705 USA
关键词
IGF-I; IGF-II; growth; protein turnover; chickens;
D O I
10.1006/gcen.1998.7072
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
The efficacy of exogenous IGFs to stimulate growth and modulate protein and fat deposition was examined in a number of broiler chicken lines. From around 600 g body weight the chickens received a continuous infusion of vehicle (0.1 M acetic acid), human recombinant IGF-I or [Gly(1)]IGF-II at 300 mu g/kg body weight per day, or a combined infusion of 150 mu g/kg/day of each IGF for 2 weeks. Experiment 1 used commercial broiler female chickens and included measurements of nitrogen balance, N-tau-methylhistidine excretion and muscle protein synthesis rates. In Experiment 2 the same treatments were applied to three experimental lines of chickens selected for high food consumption (relatively fat), high food utilisation efficiency (relatively lean), or at random (control). IGF-I, but not IGF-II, significantly increased growth rate and food utilisation efficiency by around 10-15% in each experiment, an effect which was consistent across all genotypes. Nitrogen balance was significantly increased by IGF-I in Experiment 1 as was carcass nitrogen content in Experiment 2, indicating that the increased growth was in lean tissue. Carcass fat was consistently reduced in chickens receiving IGF-I and was related to the levels of circulating IGF-I (r(2) = 0.30, P less-than 0.01) but not triiodothyronine. Protein synthesis rates were unaffected by treatment and could not account for increased growth rate. However, there was a significant reduction in N-tau-methylhistidine excretion indicating a reduced rate of muscle protein breakdown in IGF-I-treated chickens (1.56%/day vs 2.05%/day for IGF-I-treated vs controls, P less-than 0.05). The efficiency of feed utilisation was inversely related to the rate of protein breakdown (r(2) = 0.25, P less-than 0.01). In conclusion, these experiments are the first to report an enhancement of growth and food utilisation efficiency by broiler chickens receiving exogenous IGF-I. Our results show that IGF-I may be important in controlling the growth and efficiency of food utilisation of young chickens at least in part by modulating the rates of protein breakdown. (C) 1998 Academic Press.
引用
收藏
页码:262 / 275
页数:14
相关论文
共 55 条
[51]   THE ENERGETIC EFFICIENCY OF METABOLISM [J].
WEBSTER, AJF .
PROCEEDINGS OF THE NUTRITION SOCIETY, 1981, 40 (01) :121-128
[52]   EFFECTS OF INSULIN-LIKE GROWTH-FACTORS ON CHICK-EMBRYO HEPATOCYTES [J].
WIDMER, U ;
SCHMID, C ;
ZAPF, J ;
FROESCH, ER .
ACTA ENDOCRINOLOGICA, 1985, 108 (02) :237-244
[53]   PHYSIOLOGICAL-ROLE OF THE INSULIN-LIKE GROWTH-FACTOR BINDING-PROTEINS [J].
ZAPF, J .
EUROPEAN JOURNAL OF ENDOCRINOLOGY, 1995, 132 (06) :645-654
[54]  
ZAPF J, 1994, INT CONGR SER, V1056, P381
[55]   INSULIN-LIKE GROWTH FACTOR-I IMPROVES GLUCOSE AND LIPID-METABOLISM IN TYPE-2 DIABETES-MELLITUS [J].
ZENOBI, PD ;
JAEGGIGROISMAN, SE ;
RIESEN, WF ;
RODER, ME ;
RUDOLFFROESCH, E .
JOURNAL OF CLINICAL INVESTIGATION, 1992, 90 (06) :2234-2241