Histological Changes in the Liver of Nile Tilapia (Oreochromis niloticus) Fed Watermelon (Citrullus lanatus) Seedmeal Diets

The nutritive potential of watermelon (Citrullus lanatus) seedmeal as dietary protein source in the diet of Nile tilapia (Oreochromis niloticus) were evaluated in a 56 day feeding trial using histological changes in the liver as an index of assessment. 150 Oreochromis niloticus fingerlings (6.12±0.05g) were acclimatized for a week, weighed and allotted into five dietary treatments; containing 0, 15, 30, 45 and 60% Citrullus lanatus seedmeal replacement levels for soybean meal respectively. The diets were isonitrogenous and isolipidic. Each treatment was replicated three times with ten fish per replicate. Fish were fed 5% body weight on two equal proportions per day. The result from the study indicated that there was marked vacuolation of hepatocytes of the liver of the fish exposed to different dietary treatments after the experiment which is not dietary treatment related. Keywords: Watermelon, Histopathology, Nile tilapia, Liver