Effect of Dietary Selenium Deficiency on the Cell Apoptosis and the Level of Thyroid Hormones in Chicken.

This study assessed the effect of dietary selenium (Se) deficiency on male reproductive function in chicken. A total of 180 Hy-line laying cocks (1 day old; Weiwei) were randomly divided into 2 groups (n = 90) of Se-deficient chickens and control chickens. The control group was fed a basic diet (containing 0.15 mg of Se/kg). The Se-deficient group was fed a Se-deficient corn-soy basal diet (containing 0.033 mg of Se/kg). Fifteen chickens were killed in each group on days 30, 60, and 90, respectively. Then, serum and testes were collected and used in the detection of experimental index. Results indicated that GSH-Px activity and Bcl-2 mRNA level in the testes and thyroidal triiodothyronine (T3) and free triiodothyronine (FT3) levels in serum by dietary Se deficiency were significantly decreased compared to the corresponding control groups. Se deficiency-treated group showed a significant increase in MDA concent, TUNEL-positive cells, and mRNA level of Bax, Caspase3, and p53 in the testes and thyroidal thyroxine (T4), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) levels in serum. Histopathologically, Se deficiency caused impairments in the testes. These results suggested that dietary Se deficiency exerts significant harmful effects on male reproductive organ and that the intrinsic and extrinsic pathways and the upstream regulators such as p53, Bax, and Bcl-2 were all involved in Se deficiency-induced testicular apoptosis.