Two independent experiments were conducted with broilers to determine the effect of threonine and vitamin A on immune system. In first experiment, dietary treatments contained 0.8%, 0.87%, 0.94 % and 1.01 % total threonine. In second experiment, diets were as follows: basal diet without vitamin A; basal diet plus 1500 IU/Kg vitamin A; basal diet plus 6250 IU/Kg vitamin A; basal diet plus 11000 ...
