Determination of gastric evacuation by radiographic method in jewelfish (Hemichromis bimaculatus Gill, 1862)

The aim of this study was to determine the gastric evacuation rates (GER) and duration in jewelfish (Hemichromis bimaculatus). Gastric evacuation rate experiments can be used to estimate the stomach fullness in aquarium fish at a postprandial time so as to avoid the overfeeding of the fish. The influences of fish size L (cm), meal size (g) and temperature T (°C) on gastric evacuation rates of jewelfish fed formulated food (aquarium cichlid fish food) were examined. Fish used in these experiments were ranged in sizes (total length) from cm 6.3 to 9.5 cm that were fed a ranged of meal sizes. The evacuation of food from the stomach of jewelfish was best described by the surface-dependent model independently of meal size. The relationship between gastric evacuation rate and temperatures were described using exponential model while the effects of fish size on gastric evacuation rates was determined by the simple power function of length. The gastric evacuation model of jewelfish fed formulated food could thus be described by (dS_t)/dt=-0.000333 L^0.76 〖 e〗^0.15T S_t^(2/3) (g h-1). At the end of the study, gastric evacuation of jewel fish modeled to avoid overfeeding as well as underfeeding in aquarium culture for different fish size, meal size and temperature (22, 26, 28°C). The optimal feeding management strategies were determined as a resulf of the study in the species of interest.