Effects of Sulfur Supplementation on Thyroid Hormones in Angora Goats Fed With a High-Nitrate Diet

This study was to aimed for determination the effect of high dietary nitrate intake and inorganic sulphur supplementation on thyroids hormones in Angora goats. In this study, eighteen male Angora goats aged 14 months were divided into three groups (n = 6): control group fed with a basal diet, nitrate group fed with a basal diet supplemented with 1500 ppm nitrate, and nitrate + sulfur group fed with a basal diet supplemented with 1500 ppm nitrate and 1.8% sodium sulfate. On days 45, 90, 135, and 180 of the study, the concentrations of the thyroid-stimulating hormone (TSH), total and free triiodothyronine (TT3 and FT3), and tetraiodothyronine (TT4 and FT4) were measured in the serum samples. On day 180, except for TT4, the serum TSH and total and free T3 and free T4 concentrations were higher (P<0.05) in the nitrate + sulfur group than in the control and nitrate groups. This study suggested that Angora goats could tolerate a feed containing 1500 ppm nitrate with respect to the thyroid hormones, and inorganic sulfur might serve as a natural source for alleviating the negative effects of the high-nitrate diet on the thyroid gland in a dose-dependent manner