The objective of this study was to compare serum concentrations of the hormones triiodothyronine (T3) and thyroxine (T4) in pigs on commercial line beginning and end of growing-finishing phase, correlating them with productive performance and quality characteristics of carcass and meat. Blood samples were collected from 48 animals at the beginning and end of growing-finishing phase by puncturing the jugular vein, around the same time (08:00 to 10:00a.m.). Measurements of serum thyroid hormones were made by enzyme-immunoassay. It was evaluated the performance and quality of carcass and meat. At the beginning and end of the housing, serum T3 concentrations were 1.85 and 1.32nmol L-1, respectively, and T4 of 100.33 and 86.53nmol L-1, respectively. There was negative correlation between T3 and low-end and average daily weight gain, final weight and backfat thickness. Inicial T4 was moderately and moderately negatively correlated with initial weight. The values of T3 and T4 in pigs early in the growing-finishing phase are larger than in termination. The thyroid hormones are associated with the initial and final weight, backfat thickness at the last lumbar, pH45min and pH24h of growing-finishing pigs.
swine production; weight gain; triiodothyronine; thyroxine