Effect of estrogen hormone, 17β-estradiol on feminization of banana shrimp, Penaeus merguiensis (de Man, 1888) postlarvae and the identification of the age of external sex differentiation

Abstract

In the majority of species in which monosex culture is practised, the female is more economically attractive than the male because of its faster growth rate (Beardmore et al., 2001). Due to the profitability surrounding commercial shrimp farming, a study was conducted to determine the effect of estrogen hormone, 17ß-estradiol (E2) on the feminization and also to identify the age of external sex differentiation of banana shrimp, Penaeus merguiensis postlarvae (PL), starting from the first day of PL. From the results of feminization via a lower E2 hormone (0–1000 mg/kg) application revealed that, a concentration of 800 mg/kg was able to produce 79.3% females, while a 1000 mg/kg concentration would produce 85.3% PL shrimps with a 19.16% to 45.6% survival rate. By applying a higher E2 hormone concentration (1000–1800 mg/kg) of 1200 mg/kg to the shrimps’ feeding, 99% females were produced, while an application of between 1400 and 1800 mg/kg concentration was identified to produce 100% female PL shrimps with a 45.6% to 60.17% survival rate. The optimum concentration for application was identified at a higher dosage, which was at 1600 mg/kg, with a 100% feminization results followed by good weight and length growth rate compared to the results from other dosage applications. From the sex identification, the shrimp’s sex organ appeared at 50 days of culture (PL50) for both male and female shrimps. For the male shrimp PL, an Appendix Masculine was identified at its second pleopod; Male Gonophores at the fifth pereiopods and an Early Male Petasma was identified at the first pleopod. For the female, a Sharp Ridge Thelycum was identified at the fifth pereiopod of the shrimp. As a conclusion, even though the concentration to produce 100% females could be identified, further studies should be carried out to improve the survival rate of the PL shrimps, possibly by the use of hormone treatments in the future.