Effect of melatonin supplementation on the ontogeny of immunity in the Large White turkey poult.

An experiment was performed to determine the effect of melatonin supplementation on the ontogeny of immunity in the Large White turkey poult. Melatonin (50 microg/mL) or diluent only (control) was administered via the drinking water from hatch to 28 d of age. The cutaneous basophil hypersensitivity (CBH) reaction to phytohemagglutinin (PHA-P) and primary antibody responses to Chukar red blood cells (CRBC) were determined at five intervals; 0, 1, 7, 14, and 21 d posthatch. At each of these times, including 28 d posthatch, 10 poults were killed and lymphoid organ and body weights were determined. Melatonin administration accelerated (P < or = 0.05) the development of cell-mediated (PHA-P-induced CBH reaction) and humoral (CRBC-induced antibody titer) immune responses, and these responses were elevated above controls through 21 d posthatch. The bursal weight, but not thymus or spleen, was elevated in melatonin treated poults as compared to controls. Body weights were increased in melatonin treated poults as compared to controls. These data suggest that posthatch melatonin supplementation is beneficial to neonatal immune parameters and growth responses of Large White turkey poults.