A. K. Yadav, P. P. Srivastava, P. Shrivastava, W. S. Lakra, R. Dayal and Shipra Chowdhary
The present study was conducted to evaluate the interactions between different fats in the diets and the gill tissues of threatened Asian catfish, Clarias batrachus (average weight 55.83 + 3.14 g). The catfish was fed with six diets (FISOL, F1; BETAL, F2; SOYAL, F3; LINOL, F4; MIXOL, F5; SATOL, F6) and a control (NATFO, F7) with natural food. FISOL BETAL, SOYAL, LINOL and SATOL diets contains 10.0% fish oil, beef tallow, soybean oil, linseed oil and saturated oil in F1, F2, F3, F4 and F6 diets, respectively. The MIXOL, F5, contains 2.5% each of fish oil, tallow, soybean oil, linseed oil. Histological changes following dietary interventions were assessed by light microscope after feeding the diets for 12-weeks. C. batrachus fed with Natural feed (NATFO, F7) showing normal primary gill lamellae (PGL), secondary gill lamellae (SGL). Fishes fed with fish oil (FISOL, F1) showing swelling in PGL whereas, fishes fed with tallow (BETAL, F2) showing fusion of PGL and SGL. Fishes fed fishes with soybean (SOYAL, F3) showing knob like swelling and cartilaginous cells, enlarged cartilaginous cells and linseed oil (LINOL, F4) fed fishes showing fusion of PGL, SGL and enlarged cartilaginous cells. Gill of C. batrachus fed with mixed oil (MIXOL, F5) showing prominent cartilaginous cells, damaged PGL while fishes fed with saturated oil (SATOL, F6) showing fusion of epithelial cells of PGL and SGL and damaged cartilaginous cells. It was deduced that addition of various fats in the diet has impact in the gill tissues; however, cheaper fat source could be used for normal growth and also to reduce the feed cost for aquaculture of this premium commodity. The results suggest that addition of variety of fats has direct relation with the histological changes in the fish gills.
