Influence of Dietary Copper on Serum Growth-Related Hormone Levels and Growth Performance of Weanling Pigs

To investigate the effect of dietary copper on serum growth-related hormones levels and growth performance, a total of 60 weanling pigs were randomly assigned to six groups each containing 10 pigs, fed on basal diets supplemented with 0 (control), 100, 150, 200, 250, and 300 mg/kg copper sulfate for 80 days, respectively. The average daily gain (ADG), feed to gain ratio (F/G), feed intake and serum growth hormone (GH), insulin (INS), insulin-like growth factor 1 (IGF-1), and insulin-like growth factor-binding protein 3 (IGFBP-3) levels were detected at interval of 20 days. The results revealed that ADG, and serum GH, INS, IGF-1, and IGFBP-3 concentrations were increased significantly in the pigs fed on diets added with 100, 150, 200, 250, and 300 mg/kg copper sulfate. Meanwhile, in the pigs supplemented with 250 mg/kg copper sulfate, ADG was increased significantly from the 40th to the 60th day of the experiment (P < 0.01), and the levels of GH, INS, IGF-1, and IGFBP-3 in serum were elevated significantly from the 20th to the 40th day of the experiment (P < 0.01). It is concluded that effects of copper supplemented in the diet on the growth of pigs were related to the increasing levels of GH, INS, IGF-1, and IGFBP-3 in serum which were induced by copper. High dietary copper increase the concentrations of growth-related hormones in serum, resulting in improving the growth performance of weanling pigs.