~ 279 ~ International Journal of Fisheries and Aquatic Studies 2019; 7(2): 279-281 . E-ISSN: 2347-5129 P-ISSN: 2394-0506 (ICV-Poland) Impact Value: 5.62 (GIF) Impact Factor: 0.549 IJFAS 2019; 7(2): 279-281 © 2019 IJFAS www.fisheriesjournal.com Received: 14-01-2019 Accepted: 18-02-2019 Swati Jadhav Department of Zoology, R. P. College, Osmanabad Maharashtra, India Atul Humbe Department of Zoology, SGRG. Shinde College, Paranda. Dist Osmanabad, Maharashtra, India Nitin Padwal Department of Zoology, S.P. College, Bhoom Dist Osmanabad, Maharashtra, India Correspondence Swati Jadhav Department of Zoology, R. P. College, Osmanabad, Maharashtra, India Histopathological changes of the intestine of the freshwater fish, Channa gachua (Hamilton, 1822) due to infection of metacercaria of trematode parasites Swati Jadhav, Atul Humbe and Nitin Padwal Abstract Channa gachua (HAMILTON, 1822) (Family: Channaidae) are considered to be the most delicious fish, is one of the fish that are naturally available and abundant in nature. The metacercariae of Azygia anguisticauda (Stafford, 1904) Bhalerao, 1942 are found infesting the intestine of these fishes tremendous. During present studies, the four layers of the intestine namely; serosa, muscualris layer, submucosa and mucosa were found severely affected. In T.S. of intestine of Channa gachua (HAMILTON, 1822), it has been observed that the Azygia anguisticauda (Stafford, 1904) Bhalerao, 1942 slowly damage to the intestinal villi, serosa layers, vacuolization in tunica muscularis and lamina propria which indicate that trematodes highly destruct to the host intestine. Keywords: histopathology, Channa gachua (HAMILTON, 1822), intestine Introduction Pisces represent a major group of organisms which serve as hosts for many parasites including metacercariae [7] . Parasites are one of the chief causes of mass mortality in fish populations [15, 16] . Parasites when make contact with a host at cellular level, the host reacts bringing into cellular and serological reaction, which is an inflammatory reaction. It is thought that the host is able to distinguish between self and non-self-material, it is not clear as to how these recognition is carried out at genetic level. With the increasing interests in aquatic parasitic infections are becoming threats for fish health management and aquatic crop production throughout the world. Adult fluke invades different organs such as gills, digestive tract, liver and kidney. Earlier studies have been made on the trematode parasite found in the fish [1-6, 14, 15, 19, 22] . It is therefore a vital area for proper pay attention to be given by the scientists for sustainable aquaculture production. Freshwater Channa gachua of the family Channaidae inhabit a good number of metazoan parasites. Metacercarial infections particularly of Azygia anguisticauda (Stafford, 1904) Bhalerao, 1942 are heavy in these fishes since they act as intermediate hosts for these digenetic trematodes. If a human accidentally consumes the raw or semi cooked fish, the fluke attaches to human esophagus and causes injury. Parasites effects major pathogenic effects on fish result from hemorrhaging and thickening of the swim bladder wall. They may cause tissue damage and impaired respiration and signs of stress [8] , this way cause economic loss. Helminth parasites (Cestodes, trematode, nematode) developed the organs of attachment and antienzyme mechanism for their survival in the body of host. They live in a very hazardous environment, as there is continuous movement of the gut lining, the food present in gut, peristaltic movement and the food material is propelled further down in gut and they are exposed to the gastric and other digestive secretions ingest nutrition by digesting the intestinal content and partially by damaging the intestinal wall with the help of their proteolytic enzymes with their protease inhibitors [11, 12] supposed that proteolytic enzymes or other lytic secretion played a role in pronounced tissue reaction. The physiological conditions in a gut of particular host (fishes) with regard to pH or other physiological Characters may provide favourable or unfavourable site for metabolism of particular species. The nature of diet of the host have profound effect on the growth of helminth parasites, may be lacking in nutritional factor, essential for the development of parasite. This work is an attempt to bring out the different aspect of pathology of infection of fresh water fish Channa gachua (Hamilton, 1822), by trematode, Azygia anguisticauda (Stafford, 1904) Bhalerao, 1942.