The trials of finding non-conventional and alternative aquafeed ingredients are increasing. In this sense, this study evaluated the influence of
coconut oil on the growth, feed utilization, immune, and antioxidative responses of Nile tilapia. Five test diets were formulated by mixing
coconut oil with the other ingredients at 0, 1, 2, 3, and 4% of the total ration and presented for tilapia for 60 successive days. The final weight, SGR,
weight gain (WG), and feed intake were superior in fish delivered 2% of
coconut oil (P < 0.05). Concurrently, fish that received 2%
coconut oil had lower FCR and higher PER than fish of the control and 4% groups (P < 0.05). Higher
lipase activity was observed in fish of 2% and 3% levels than the remaining groups (P < 0.05). Besides, the
amylase and
protease activities of fish in 1%, 2%, and 3% groups were higher than the 0% level (P < 0.05). The total blood
cholesterol, RBCs, and PCV showed higher values in Nile tilapia fed 2% and 3%
coconut oil (P < 0.05). The
lysozyme and phagocytic activities were higher in fish fed 2% and 3% levels than the control (P < 0.05), while the phagocytic index in 2% and 3% levels was higher than 0% and 4% levels. Furthermore, SOD and CAT were higher in fish fed 1%, 2%, and 3% than fish fed 0% and 4% levels while GSH was higher in fish of 1%, 2%, and 3% than fish fed 0% level (P < 0.05). However, the MDA level was markedly lower in fish fed 25, 3%, and 4%
coconut oil than the 0% level (P < 0.05). The intestine's histological structure in all groups appeared normal, forming of intestinal villi projecting from the intestinal wall. Also, the structure of the hepatopancreas had a normal architecture in all groups. To sum up, the inclusion of
coconut oil at 2 to 3% is recommended as a replacer for
fish oil in Nile tilapia diets.