The Effects of Fish Feed Supplemented with Azolla Meal on the Growth Performance, Digestive Enzyme Activity, and Health Condition of Genetically-Improved Farmed Tilapia (Oreochromis niloticus)

meal was included in fish feed at different levels (10%, 20%, and 30%) and was fed to genetically-improved farmed tilapia (GIFT) for 90 days. The obtained results demonstrated that the final body weight, weight gain, and specific growth rate decreased significantly in fish fed 30% (P0.05). However, the feed conversion ratio increased significantly in fish fed 30% (P0.05). The body proximate analysis, amylase, lipase, protease, blood phagocytic index, and phagocytic and lysozyme activity were not affected by the inclusion of in tilapia diets and remained similar to those of the control group (P>0.05). The villus length of the foregut was not significantly affected by inclusion in tilapia diets (P>0.05). In the midgut, the villus length significantly (P0.05). The villus length significantly (P0.05). The mucosal length of the tilapia foregut significantly (P0.05). In the foregut and hindgut, the number of goblet cells significantly increased in fish fed at 3% compared to the control, with no differences from those fed at 10% and 20% (P>0.05), while in the midgut, the number of goblet cells significantly (P0.05). Feeding tilapia with resulted in normal hematological and biochemical functions, with insignificant differences for the measured parameters except for the red blood cell count, which significantly (P