The Effect of Dietary Supplementation of Ulva reticulata Extract on Reproduction of the Male Red Tilapia (Oreochromis sp.)

Plant extract is widely used in aquaculture due to the presence of several secondary metabolites that act as precursors for steroid hormone synthesis in animal reproduction. In this context, Ulva reticulata Forsskal is a marine plant with potential physiological effects on fish reproduction. Therefore, this study aimed to assess the effect of different U. reticulata extract doses on the reproductive capabilities of the male red nile tilapia (Oreochromis sp.). A completely randomized design was used with different doses ofplant extract. These treatments included JK without U. reticulata extract (control), as well as JA, JB, JC, and JD with extractdoses of 0.75, 1.5, 2.25, and 3%, respectively. The parameters evaluated included testis weight, gonad maturation percentage, gonadosomatic index (GSI), hepatosomatic index (HSI), testosterone concentration, sperm motility, and sperm viability. The results showed that the administration of U. reticulata extract at 2.25 to 2.45% proved to be the most effective treatment. This dose caused a threefold increase in gonad maturation, with a weight of 1.38g, a GSI of 2.14%, a 100% GML IV percentage, sperm motility of 82.50%, and sperm viability of 88.97% at weeks 6 and 7 of optimum observation. Furthermore, it reduced IHS value by 0.76% and increased testosterone concentration to 33.23ng/ mL at week 8. Based on the results, feeding U. reticulata extract could improve the reproductive performance of the male red tilapia.