Abstract
Newly hatched White Leghorn male chicks were used in this study. Different doses of T3 (O.1 or 1 ppm) or TRH (1 or 5 ppm) were administered in the feed for an 8-week period. Chicken growth hormone (cGH) (10 μg/kg BW) was injected (i.v.) into a different group of chicks twice daily for 1 week starting at 7 weeks of age. A different group received both T3 (0.1 and 1 ppm) and cGH. Serum concentrations of T4, T3 and GH, antibody production against sheep red blood cells (SRBC) and Brucella Abortus (BA), and in vitro proliferative response of both T- and B-lymphocytes to mitogenic stimulation were measured. Supplementation of T3 (1 ppm) significantly lowered T4 and increased T3 concentrations. No effect of any hormone treatment on antibody production was observed. T3 supplementation and cGH injection alone or with T3 (0.1 ppm) significantly increased blastogenic response of lymphocytes to either Con-A or LPS mitogenic stimulation. It was concluded that T3 and GH are involved in lymphocyte activity of chickens.