AB prepress abstract  -  DOI: https://doi.org/10.3354/ab00710

Effects of temperature and sex steroids on sex ratio, growth, and growth-related gene expression in the Chinese giant salamander Andrias davidianus

Qiaomu Hu, Haifeng Tian, Hanbing Xiao*

*Email: xhb@yfi.ac.cn

ABSTRACT: Andrias davidianus is one of most farmed amphibians owing to palatability and nutritional value. As a transitional group from aquatic animals to terrestrial, how temperature and sex hormone effect the sex ratio and growth is unclear. Here, we quantified the growth dimorphism with adult males approximately 30% larger than females, and firstly determined the time of initiation of sex differentiation to be ~98 days post-hatching (dph). Mortality increased significantly with increased temperature, from 9.4% at 20°C to 40.6% at 28 °C. At temperatures ≥30 °C, we observed 100% mortality. The proportion of males was 66.1% at 28 °C which was significantly higher than the control group (P < 0.05). 17β-estradiol induced larval feminization and produced female bias of 81-100% at concentrations from 25 μg/L to 1000 μg/L. However, sex bias was not observed in larvae exposed to 17α-methyltesterone at concentrations of 50 μg/L and 100 μg/L. Additionally, growth characteristics at different temperature showed that 28°C inhibited the growth and 24 °C promoted growth, reflecting the expression profile of growth-related genes (GH, GHR, and IGF-1). Sex steroid hormones including 17β-estradiol and 17α-methyltesterone significantly inhibited growth (P < 0.05). The results suggested that water temperature and sex steroid hormones played a vital role in gonad differentiation and growth of Andrias davidianus