The effects of groundnut cake used partially instead of fish meal on development, nutritional profile and some physiological parameters in Nil Tilapias (Oreochromis niloticus, Linnaeus 1758)

In this study, the effects of diets prepared using groundnut cake (GNC) instead of fish meal on growth performance, body composition, amino acid profile, fatty acids, mineral level, digestive enzymes, histology and blood values in tilapia (Oreochromis niloticus) were investigated. In the experiment, where the average water temperature was 27±1°C and lasted for 80 days, 30 tilapia with an average weight of 10 g were stocked in each tank (450L). Experimental groups were planned as control (0% GNC), GNC10 (10% GNC), GNC20 (20% GNC), GNC30 (30% GNC), and GNC40 (40% GNC) with 3 replications. According to the results of the study, the growth performances of tilapia in GNC20 and control group were similar (P<0.05). The ratio of essential amino acids to non-essential amino acids in muscle was highest in the GNC20 group (0.84±0.01) (P<0.05). While no difference was observed in Ʃn3, Ʃn6 and n3/n6 fatty acid values in muscle (P>0.05), liver Ʃn3 and n3/n6 values were found to be higher in the control group. In muscle mineral analysis, it was observed that GNC affected copper, iron, calcium, manganese, potassium and sodium values, while no difference was observed in cobalt, chromium and magnesium. When enzyme activities (protease, lipase, amylase) in the intestine, liver and blood were examined, it was determined that the use of GNC changed digestive enzyme activities in all groups except protease in the liver. While no difference was observed in blood values between the groups, differences were observed in histological measurements. As a result, when the growth performance and economic aspects are evaluated, it is suggested that 20% GNC can be used in tilapia diets. Key Words: Tilapia, Groundnut cake, Nutrition, Aquaculture, Fishmeal