The relationship between endogenous insulin-like growth factors and growth in pigs.
Previous studies have reported conflicting data on gender differences in plasma IGF-I in postnatal pigs. There is also debate over the role of IGF-II in regulation of postnatal growth. We have, therefore, determined the concentrations of plasma IGF-I, IGF-II, and IGF-binding protein-3 (IGFBP-3) in boars, barrows, and gilts and related these to postnatal growth characteristics. Plasma concentrations of IGF-I were higher in boars than in gilts or barrows from 13 wk. of age, and plasma IGF-II levels were generally higher in barrows than in boars or gilts. Plasma IGFBP-3 levels were higher in boars than in gilts or barrows at most ages. Between 15 and 23 wk. of age, IGF-I and IGFBP-3, but not IGF-II, were positively associated with growth rate, voluntary feed intake, and gain:feed ratio. Plasma IGF-II, but not IGF-I or IGFBP-3, was positively associated with backfat depth during this period. These results support the hypothesis that circulating IGF-I and IGF-II are regulators of lean and adipose tissue growth, respectively.
Owens
P C
PC
Department of Obstetrics, University of Adelaide, SA, Australia.
Gatford
K L
KL
Walton
P E
PE
Morley
W
W
Campbell
R G
RG
D000375:Aging / Q000378:metabolism; D000821:Animal Feed; D000818:Animals; D001835:Body Weight; D005260:Female; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000378:metabolism; D008297:Male; D012727:Sex Characteristics; D013002:Somatomedins / Q000502:physiology*; D013552:Swine / Q000254:growth & development*
D018972:Insulin-Like Growth Factor Binding Protein 3; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II