Plasma growth hormone, insulin-like growth factor I, and insulin-like growth factor binding proteins in pigs with divergent genetic merit for postweaning average daily gain.
Characteristics of growth hormone (GH), IGF-I, and IGF-binding proteins (IGFBP) were studied in gilts sampled from lines of pigs selected for either fast (line F, n = 14) or slow (line S, n = 14) postweaning ADG. Repeated blood samples were obtained from gilts (approximately 55 kg BW) during a period of feed deprivation and again during refeeding. Averaged across time, the difference in mean plasma GH concentrations of F and S gilts was not significant (7.7 vs 6.4 ng/mL; P > .20) during feed deprivation, and frequently, height, and amplitude of GH pulses did not differ (P > .25) for F and S pigs. Overall, F gilts had greater concentrations of plasma IGF-I than S gilts during feed deprivation (217.3 vs 145.1 ng/mL; P < .03). Across line, plasma IGF-I decreased (P < .01) during feed deprivation. Average GH did not differ (P > .40) for F and S gilts during the refeeding period. Average plasma IGF-I tended (P = .05) to be greater in F gilts than in S gilts during refeeding. Consistent with changes over time during feed deprivation, plasma IGF-I averaged across line increased (P < .01) in response to refeeding. Averaged across time (0 and 48 h refeeding), activity of IGFBP-2 (singlet band at 34 kDa) did not differ significantly (P = .17) in F and S gilts. However, there was a tendency (P = .13) for a line x time interaction.(ABSTRACT TRUNCATED AT 250 WORDS)
Clutter
A C
AC
Department of Animal Science, Oklahoma State University, Stillwater 74078, USA.
Spicer
L J
LJ
Woltmann
M D
MD
Grimes
R W
RW
Hammond
J M
JM
Buchanan
D S
DS
D000818:Animals; D001947:Breeding; D002352:Carrier Proteins / Q000097:blood*; D005260:Female; D013006:Growth Hormone / Q000097:blood*; D018971:Insulin-Like Growth Factor Binding Protein 2; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008297:Male; D013552:Swine / Q000097:blood / Q000235:genetics / Q000254:growth & development*; D014886:Weaning; D015430:Weight Gain / Q000235:genetics* / Q000502:physiology
D002352:Carrier Proteins; D018971:Insulin-Like Growth Factor Binding Protein 2; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone