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.

OBJECTIVES To understand the mechanism of white fat expansion in the presence of inflammation, we examined the balance of pro- and anti-inflammatory cytokines in epididymal fat during weight gain in DIO mice. METHODS The pro- and anti-inflammatory cytokines were examined in white fat of diet-induced obese mice and lean mice. The mechanism of gene expression was investigated with a focus on intracellular ATP (iATP). ATP activity was tested in cellular and non-cellular systems in activation of serine kinases (IKKβ, JNK and ERK). RESULTS The pro- (TNF-α, IL-1β, IL-6, MCP-1, IFN-γ and OPN) and the anti-inflammatory cytokines (IL-10, IL-1Ra, IL-13, sTNFR2, PEDF and adiponectin) were increased at the same time during the weight gain. The balance was observed even in the absence of tissue expansion upon feeding in lean and obese mice. The iATP levels were positively associated with the cytokine elevation in the adipose tissue. In macrophages, induction of iATP with lauric acid stimulated the expression. Inhibition of iATP with β-oxidation inhibitor (Etomoxir) or mitochondrial uncoupler (2,4-dinitrophenol, DNP) suppressed the expression. ATP exhibited an activity in the activation of inflammatory kinases (IKKβ, JNK and ERK) in the living cells and cell lysate. The kinase activation was blocked in the cells by ATP inhibition. CONCLUSIONS The data suggest that the pro- and anti-inflammatory cytokines are dynamically balanced in the white adipose tissue by iATP.