Effect of adrenocorticotropin and dietary ascorbic acid on the graft-versus-host reaction capacity of chickens.

Two trials using the splenomegaly assay were conducted to assess the effects of adrenocorticotropin (ACTH) and dietary ascorbic acid (AA) on the ability of chickens to mount a graft-vs.-host reaction (GVHR). Broiler chicks served as blood donors. Birds received AA at levels of 0, 150, or 300 mg/kg of feed (ppm). At 6 wk of age, donor birds from each AA group received either three intramuscular injections of ACTH in gelatin at 12-h intervals, comparable injections of the gelatin, or no injections. Thirteen-day-old Single Comb White Leghorn embryos served as recipients. Two recipient embryos per donor were injected in a chorioallantoic vein with either whole blood (Trial 1) or saline-washed and reconstituted blood cells (Trial 1). Eggs were further incubated for 6 days, at which time the embryos were killed and each spleen excised. Relative spleen weights were expressed as milligrams of spleen/100 g embryonic body weight. Significant differences in relative spleen weight or donor plasma corticosterone (CS) levels did not occur in Trial 1. In Trial 2, regardless of AA treatment, relative spleen weights of embryos that received blood cells from donors treated with ACTH were significantly lower than controls. Donor CS was significantly lower in birds that received ACTH. These results indicate that, when washed and reconstituted blood cells are injected into recipients and donor plasma CS is decreased, GVHR capacity is suppressed in ACTH-treated donors.