Combined estrogen and elevated temperature treatments induce feminization in Nile tilapia, Oreochromis niloticus

Nile tilapia has proven to be sensitive to change phenotypic sex upon exposure to steroid hormone and high temperature during the critical period of gonad differentiation. It is more difficult to feminize XY males than to masculinize XX females. High temperature feminization has also been observed in very few cases in Nile tilapia. Therefore, this study was designed to increase the feminization rates using combined treatments of estrogen hormone (either diethylstilbestrol, DES, or 17α-ethynylestradiol, EE2) and high temperature (36 oC) during the sensitive period of gonad differentiation in Nile tilapia. The parents genotype of the crosses was XX♀ × XY♂; XX♀ × YY♂ and XX♀ × XX♂. Progenies from each cross were exposed to one of six types of treatments:…