All animal handling and experiments were conducted in accordance with, ‘‘A Guide for Care and Use of Laboratory Animals,’’ approved by the University of the Ryukyus, Okinawa, Japan.
2.2. Experimental design
Two sets of independent experiments were conducted to examine the effects of high temperature on gonadal development in different age groups of Nile tilapia (Fig. 1 ). Firstly, we determined the
optimum temperature to induce permanent sterilization. In addition, using the optimum temperature, we tested the responses of
the fish at different life stages. In order to examine fertility reversal, a number of fish were cultured for additional three to six
months at normal laboratory conditions (25–28 C). Growth parameters, gonadal histology, and blood parameters were determined