Abstract
The study was conducted to evaluate the effects of chromium picolinate (CrP) on growth, carcass characteristics and serum metabolites in growing-finishing pigs. A total of 96 Landrace$\times$Yorkshire$\times$Duroc hybrid pigs, initial live weight about $38.12{\pm}00kg$, were randomly assigned to 2 groups (16 pigs per pen, 3 pens per group), each group had 48 pigs with an equal number of barrows and gilts. The pigs were fed the diet with or without $200{\mu}g/kg$ Cr from CrP. The results indicated that the addition of $200{\mu}g/kg$ CrP increased ADG by 3.58% and decreased feed conversion rate (FCR) by 3.00% compared to the control group. Pigs fed CrP had 7.58% (p<0.05) higher carcass lean percentage, 15.55% (p<0.05) larger longissimus muscle area (LMA) and 10.90% (p<0.05) lower back fat thickness, 15.17% (p<0.05) lower carcass fat percentage. In addition, the IGF-I level in serum was elevated by 79.20% (p<0.05), the Insulin and cortisol level decreased by 27.35% (p<0.05) and 34.58% (p<0.05) respectively with supplementation of CrP. Analysis of subcutaneous fat (10th rib) showed that the activity of hormone sensitive lipase (HSL) increased by 79.58% (p<0.05) and the activities of isocitrate dehydrogenase (ISD) and malate dehydrogenase (MDH) decreased significantly by 15.06% (p<0.05) and 54.53% (p<0.05) respectively in the $200{\mu}g/kg$ CrP group. The concentration of RNA, RNA/DNA in LMA increased by 31.89% (p<0.05) and 5.41% (p<0.05) respectively with the addition of CrP. These results suggest that CrP reduced fat deposits by decreasing lipogenic enzyme activities and increasing HSL activity and may have promoted muscle anabolic metabolism through elevated IGF-I levels.