摘要：The objective of this study was to determine the optimum dose of melastoma M elastoma malabathricum leaf extract that can inhibit the gonad development of Nile tilapia and increase its growth rate. This study used a completely randomized design containing five extract dose treatments (0, 0.5, 1, 2, and 4 g/kg diet doses) and three replications. The undifferentiated Nile tilapia larvae (7 days post hatching) were randomly distributed (n=30) to fifteen aquaria (100×50×50 cm 3 ) and maintained for 112 days using a common recirculation system. The results showed that all dose treatments were not significantly different (P>0.05) in gonadosomatic index values of the D84 and D98 samplings. However, the 1 g/kg diet (D112) was significantly different (P<0.05) in all dose treatments. The final histological results (D112) showed that the 1 g/kg diet obtained the highest inhibition level of the testis and ovary developments, which were still in stage II compared to 0.5 g/kg diet (stage III) and control (stage IV and V). The highest average weight, absolute growth rate, and specific growth rate were obtained in the 1 g/kg diet dose which was significantly different (P<0.05) compared to the control. The percentage of males increased significantly (P<0.05) following the increased dose treatment fed to the fish (4 g/kg diet) with 80.12±4.67%, but the survival rate significantly decreased (P<0.05) compared to the control. The administration of 1 g/kg diet dose obtained the best dose and potential as an inhibiting agent for gonad development in Nile tilapia.
其他摘要：The objective of this study was to determine the optimum dose of melastoma Melastoma malabathricum leaf extract that can inhibit the gonad development of Nile tilapia and increase its growth rate. This study used a completely randomized design containing five extract dose treatments (0, 0.5, 1, 2, and 4 g/kg diet doses) and three replications. The undifferentiated Nile tilapia larvae (7 days post hatching) were randomly distributed (n=30) to fifteen aquaria (100×50×50 cm3) and maintained for 112 days using a common recirculation system. The results showed that all dose treatments were not significantly different (P>0.05) in gonadosomatic index values of the D84 and D98 samplings. However, the 1 g/kg diet (D112) was significantly different (P<0.05) in all dose treatments. The final histological results (D112) showed that the 1 g/kg diet obtained the highest inhibition level of the testis and ovary developments, which were still in stage II compared to 0.5 g/kg diet (stage III) and control (stage IV and V). The highest average weight, absolute growth rate, and specific growth rate were obtained in the 1 g/kg diet dose which was significantly different (P<0.05) compared to the control. The percentage of males increased significantly (P<0.05) following the increased dose treatment fed to the fish (4 g/kg diet) with 80.12±4.67%, but the survival rate significantly decreased (P<0.05) compared to the control. The administration of 1 g/kg diet dose obtained the best dose and potential as an inhibiting agent for gonad development in Nile tilapia.
