LAUSR

Abstract The purpose of this work was to research the impact of N2- fixing cyanobacterium Anabaena sp. supplementation in the diet or as a culture in the fishpond of Nile tilapia. The growth performance and chemical analysis of fish body were investigated before challenging with Aeromonas hydrophila (.A. hydrophila). While biochemistry of the serum, immunity, and health status of Nile tilapia were investigated before and after the challenge test. Oreochromis niloticus (monosex males) were randomly allotted into three groups, according to Anabaena supplementation in the fish diet or pond. Groups including, a control group was provided with the experimental diet without supplement, the AM (Anabaena meal) group was provided with the experimental diet enclosure Anabaena (15 g/100 g rations), and the A (Anabaena cultivated in the pond) group was provided with the experimental diet but Anabaena was cultivated in the pond. The results showed that both ways of Anabaena supplementation significantly (P ≤ 0.05) improved growth performance parameters and increased protein in body composition before A. hydrophila challenge compared with the control. On the other hand, the serum biochemical parameters and immunity status of Nile tilapia significantly (P ≤ 0.05) improved before and after experimental challenge.