Seasonal changes effect on Innate immunity and histology of wild catfish Arius arius (Hamilton, 1822) in Parangipettai, south East coast of Tamil Nadu, India.

The study was done to examine the effect of seasonal changes in innate immunity and histology of spleen and head kidney of Arius arius in Parangipettai coast of Tamil Nadu. The catfish was collected from Parangipettai coast in all four seasons. The fish measured and weighed for its total length and weight, blood samples and organs were collected. Lysozyme and NBT activity were measured, along with the total no of different lymphocytes and histology of spleen and Head kidney. The result revealed total leukocytes were maximum in post-monsoon and minimum in summer. If of the innate immune parameters, lysozyme showed maximum 7.5±2.56 μg/ml in monsoon and winter minimum in summer 5.8±1.16 μg/ml, NBT shows maximum of OD at 540nm was 0.5 in August and minimum of 0.25 in April, the histological observation also show differences in the number of MMCs in response to the seasonal affect. The MMCs were monsoon and followed by post monsoon and shows number less than 2 to 5 MMCs in summer.