Effects of restricted feeding, low-energy diet, and implantation of trenbolone acetate plus estradiol on growth, carcass traits, and circulating concentrations of insulin-like growth factor (IGF)-I and IGF-binding protein-3 in finishing barrows.
Effects of restricted feeding (80% ad libitum), feeding a low-energy diet containing 84% DE (2.95 Mcal/kg) of the control diet, and implantation of Revalor H (140 mg trenbolone acetate plus 14 mg estradiol-17beta) on growth, carcass traits, and serum concentrations of insulin-like growth factor (IGF)-I and IGFbinding protein-3 (IGFBP-3) were studied in crossbred finishing barrows beginning from 59 +/- 0.9 kg of body weight. Blood samples were taken every 3 wk and the animals were slaughtered at approximately 105 kg body weight. Restricted feeding caused a decrease (P < 0.01) in ADG; feeding the low-energy diet was effective in reducing backfat thickness but decreased gain:feed; the implantation caused a decrease in ADG, feed intake, and backfat thickness and increased gain:feed. Overall pork quality based on pH, drip loss, and the lightness in color of longissimus muscle was not affected by any of the treatments. Serum IGF-I concentration increased following the implantation but did not change (P > 0.05) due to other treatments. Immunoreactive IGFBP-3 concentration was not changed by any of the treatments. Overall ADG was positively correlated with early-stage (d 21) IGF-I and IGFBP-3 concentrations only in unimplanted barrows, whereas backfat thickness was negatively correlated with d-42 IGF-I concentration in all but unimplanted barrows with ad libitum intake. A strong positive correlation (P < 0.01) between IGF-I and IGFBP-3 concentrations was apparent with increasing age of the animals. Results suggest that growth rate and backfat thickness are decreased by a moderate restriction of feed or energy intake with no accompanying changes in circulating IGF-I and IGFBP-3 concentrations and that the beneficial effect of Revalor H implantation on feed efficiency may be mediated, in part, by IGF-I. Moreover, both IGF-I and IGFBP-3 concentrations may be useful as growth indices in pigs.
Lee
C Y
CY
Department of International Livestock Industry, Chinju National University, South Korea. cylee@cjcc.chinju.ac.kr
Lee
H P
HP
Jeong
J H
JH
Baik
K H
KH
Jin
S K
SK
Lee
J H
JH
Sohnt
S H
SH
D000273:Adipose Tissue / Q000033:anatomy & histology; D000367:Age Factors; D045930:Anabolic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D004338:Drug Combinations; D004343:Drug Implants; D002149:Energy Intake; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology*; D005508:Food Deprivation / Q000502:physiology; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008460:Meat / Q000592:standards*; D011897:Random Allocation; D013552:Swine / Q000097:blood / Q000254:growth & development*; D014204:Trenbolone Acetate / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology*
D045930:Anabolic Agents; D001786:Blood Glucose; D004338:Drug Combinations; D004343:Drug Implants; D018972:Insulin-Like Growth Factor Binding Protein 3; C021828:Revalor; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D014204:Trenbolone Acetate