AbstractA study was conducted with fry ofCatla catla(Hamilton) to investigate the effects of dietary lipid supplements on growth, feed conversion, tissue fatty acid composition and the intestinal lipase activity. Four treatment diets were prepared using purified ingredients incorporating sunflower oil (n‐6 fatty acids), cod liver oil (n‐3 fatty acid source) and a mixture (1:1) of sunflower and cod liver oil in three diets. The fourth diet was lipid‐free and served as the control. The best growth and survival was recorded for fish given the diet having a mixture of n‐3 and n‐6 fatty acids (weight gain was 380 and survival was 93), followed by the n‐6 diet (320 and 88), the n‐3 diet (290 and 84) and the lipid‐free diet (239.9 and 82). Feed conversion ratio (FCR) and per cent protein deposited (PPD) followed a similar trend. The intestinal lipase activity (expressed as μg α‐naphthol liberated mg_1protein hr‐1) was 83.3, 74.2, 80.1 and 53.7 for n‐3 and n‐6, n‐6, n‐3 and lipid‐free diet treatments respectively. The fatty acid profile of the whole body was shown to be influenced by dietary fatty acid composition. The results of this laboratory study indicated that a combination of n‐3 and n‐6 fatty acids is important for growth and survival of this species. The extent to which such observations will be relevant in field conditions can be stated only after results of fe
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