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.

Abstract

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.

• Authors: C Y Lee, H P Lee, J H Jeong, K H Baik, S K Jin, J H Lee, S H Sohnt
• Journal: Journal of animal science (J Anim Sci) Vol. 80 Issue 1 Pg. 84-93 (Jan 2002) ISSN: 0021-8812 [Print] United States
• PMID: 11831532 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anabolic Agents
• Blood Glucose
• Drug Combinations
• Drug Implants
• Insulin-Like Growth Factor Binding Protein 3
• Revalor
• Estradiol
• Insulin-Like Growth Factor I
• Trenbolone Acetate

Topics

• Adipose Tissue (anatomy & histology)
• Age Factors
• Anabolic Agents (administration & dosage, pharmacology)
• Animals
• Blood Glucose (analysis)
• Drug Combinations
• Drug Implants
• Energy Intake
• Estradiol (administration & dosage, pharmacology)
• Food Deprivation (physiology)
• Insulin-Like Growth Factor Binding Protein 3 (blood)
• Insulin-Like Growth Factor I (metabolism)
• Male
• Meat (standards)
• Random Allocation
• Swine (blood, growth & development)
• Trenbolone Acetate (administration & dosage, analogs & derivatives, pharmacology)