Divakaran Nair, NKalai Selvan, PKAU2020-11-172020-11-172004172283https://krishikosh.egranth.ac.in/handle/1/5810155077MVScThe present study was undertaken to investigate the immunopathologic and toxic effects of endosulfan in chick embryo. The embryos were exposed to endosulfan at various dose levels through different routes. The weight of the embryo, bursa, thymus and spleen, histopathology of the lymphoid organs, liver, kidney and brain and quantification of the preformed maternal IgY level in the egg yolk were the parameters analysed to study the effects. Endosulfan was found to be teratogenic at the grven dose levels. The abnormalities observed were agenesis of beak, crossed beak, short lower beak, eventration of viscera and curled toe. Endosulfan did not cause any significant gross changes in the developing embryos except mild haemorrhages. Endosulfan treatment did not produce any significant reduction in the weight of the embryos as well as the weight of the lymphoid organs. On histopathological examinations endosulfan was found to be nephrotoxic and hepatotoxic to the embryos. Varying degrees of degeneration and necrosis was evident in kidney and liver. Effect on the bursa, thymus and spleen were mild to moderate where in the degenerative changes predominated. Dose dependent increase in the involution process of the thymus as evidenced by increase in the Hassal's zone was observed. The lesions in the developing lymphoid organs reflected that endosulfan is toxic to the system and going to affect the immunocompetency by way of immunosuppression and thereby rendering the chicks susceptible to various diseases. The study indicated that the endosulfan treatment did not have any effect on the preformed maternal immunoglobulin level in the egg yolk.EnglishThesis