[Effects of Entomoxan on various lymphatic organs of the chicken]

The effect of an organochlorine compound (Entomoxan) on the bursa of Fabricius and the thymus was followed in chicks given a ration containing 15 ppm daily for 8 weeks, starting at 3 weeks of age. Birds were killed 2,4,6 or 8 weeks after the start of treatment. Total protein, RNA, DNA, nitrogen, free amino acids and water content were determined in both lymphatic organs. Two weeks of treatment with Entomoxan produced a stress-like effect, with loss of weight of both organs and important biochemical changes. Such changes were still present after 4 weeks, although there was no longer any difference in organ weight in comparison with the controls. After six weeks of treatment the changes in the bursa were slight and there were no changes in the thymus. Some changes were still present at the 8th week, but ther was no indication of a stress effect.