Age-related changes of serum leptin, insulin, IGF-I and thyroid hormones levels in growing Jinhua and Landrace gilts.

摘要

The present study was aimed to investigate the age-related changes of the serum IGF-I, leptin, insulin, triiodothyronine (T₃) and thyroxine (T₄) levels in pigs of different breeds. Jinhua and Landrace gilts were sampled at 35, 80 and 125 days of age, respectively. Serum hormone levels were measured with RIA. Serum IGF-I, leptin levels increased with age and displayed breed differences. Jinhua gilts showed lower (P<0.05) serum IGF-I and higher (P<0.05) leptin levels compared with Landrace gilts. In contrast, serum T₃, T₄ levels decreased with age, Jinhua gilts had lower serum T₄ levels at 80 days of age. Meanwhile, Jinhua gilts had higher (P<0.01) serum insulin levels. Serum leptin, IGF-I, insulin and T₄ levels correlated with carcass fat content (P<0.05), which suggested that the breed differences of serum hormone levels may contribute to the different phenotypes in adipose tissue deposition.