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Effect of dietary triiodothyronine on mixed-lymphocyte responsiveness in young male chickens
1Department of Poultry and Avian Sciences, Cornell University, Ithaca, NY 4853-5601.
The effect of dietary triiodothyronine (T3) supplementation (0, 0.1, 0.1, and 1.0 ppm of T3) on the mixed lymphocyte response (MLR) was examined in MHC-matched young Cornell K and sex-linked dwarf (SLD) strain cockerels at ages 6, 9, and 12 weeks. At all ages, MLR in SLD strain cockerels was significantly lower than in the K strain. Supplementation of 6-week-old cockerels with 0.01 and 0.1 ppm of T3 tended to decrease MLR in both strains, whereas the highest dose of T3 had the opposite effect in the K strain and no effect in the SLD strain compared to the control. No significant effects of T3 on MLR were observed in 9-week-old cockerels. A significant main treatment effect of T3 on MLR was observed in 12-week-old cockerels. At this age dietary T3 decreased MLR in both strains. These results show that allo-aggression, a functional parameter of cell-mediated immunity, can be affected by non-MHC controlled strain differences and by the iodothyronine state of these strains.
The effect of dietary triiodothyronine (T3) supplementation (0, 0.1, 0.1, and 1.0 ppm of T3) on the mixed lymphocyte response (MLR) was examined in MHC-matched young Cornell K and sex-linked dwarf (SLD) strain cockerels at ages 6, 9, and 12 weeks. At all ages, MLR in SLD strain cockerels was significantly lower than in the K strain. Supplementation of 6-week-old cockerels with 0.01 and 0.1 ppm of T3 tended to decrease MLR in both strains, whereas the highest dose of T3 had the opposite effect in the K strain and no effect in the SLD strain compared to the control. No significant effects of T3 on MLR were observed in 9-week-old cockerels. A significant main treatment effect of T3 on MLR was observed in 12-week-old cockerels. At this age dietary T3 decreased MLR in both strains. These results show that allo-aggression, a functional parameter of cell-mediated immunity, can be affected by non-MHC controlled strain differences and by the iodothyronine state of these strains.