Effects of herbal extract supplementation on growthperformance and insulin-like growth factor (IGF)-Isystem in finishing pigs

Abstract

The study's main objective was to investigate the effects of a specifi c blend of herbal extracts (HEs) on growth performance, antioxidant status, and components of the insulin-like growth factor (IGF) system in fi nishing pigs. A total of 16 PIC (Pig Improvement Company) pigs (60.1 1.2 kg; eight gilts and eight barrows) were randomly assigned to one of the two dietary groups, with four pens/group (per pen: one gilt, one barrow). The pigs were fed with a basal diet containing 0 (control) or 250 mg HEs /kg diet for 47 days. The results indicated that herbal extract supplementation led to an increase (P<0.05) on the average daily gain and serum IGF-I level, and a decrease (P<0.05) on serum malondialdehyde and feed conversion ratio. However, feed intake was not affected (P>0.05). IGF-I, insulin receptor mRNA levels (liver, stomach, duodenum, muscle) and IGF-I receptor (IGF-IR) mRNA (stomach, duodenum, muscle) were high (P<0.05), while the level of IGF-IR mRNA was low (P<0.05) in the liver tissue compared with the control pigs. The results suggest that herbal extract supplementation has an antioxidant capacity, enhance the growth performance and exhibits tissue-specifi c regulation of IGF-IR mRNA level. In addition, the results also suggest the possible physiological role of the IGF system in controlling the HEs-supported growth of fi nishing pigs.