Abstract
AB Aquatic Biology Contact the journal Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AB 28:79-90 (2019) - 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* Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, Hubei 430223, PR China *Corresponding author: xhb@yfi.ac.cn ABSTRACT: Andrias davidianus is one of most farmed amphibians owing to its palatability and nutritional value. In this transitional group between aquatic and terrestrial animals the effects of temperature and sex hormones on sex ratio and growth are not fully understood. Here, we quantified the sex dimorphism of A. davidianus growth with adult males approximately 30% larger than females, and for the first time 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, significantly higher than in the control group (p < 0.05). 17α-estradiol induced larval feminization and produced female bias of 81-100% at concentrations from 25 µg l-1 to 1000 µg l-1. However, sex bias was not observed in larvae exposed to 17α-methyltestosterone at concentrations of 50 µg l-1 and 100 µg l-1. Additionally, growth characteristics at different temperatures showed that 28°C inhibited growth and 24°C promoted growth, reflecting the expression profile of growth-related genes (GH, GHR, and IGF-1). Sex steroids including 17β-estradiol and 17α-methyltestosterone significantly inhibited growth (p < 0.05). The results suggest that water temperature and sex steroids play a vital role in gonad differentiation and growth of A. davidianus. KEY WORDS: Temperature · Sex steroids · Sex ratio · Growth · Andrias davidianus Full text in pdf format PreviousNextCite this article as: Hu Q, Tian H, Xiao H (2019) Effects of temperature and sex steroids on sex ratio, growth, and growth-related gene expression in the Chinese giant salamander Andrias davidianus. Aquat Biol 28:79-90. https://doi.org/10.3354/ab00710 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AB Vol. 28. Online publication date: August 08, 2019 Print ISSN: 1864-7782; Online ISSN: 1864-7790 Copyright © 2019 Inter-Research.
Highlights
Sex is determined in vertebrates either genetically or environmentally, or via a combination of both factors (Nakamura 2009)
The effects of temperature and sex steroid exposure on sex ratio and growth rate have been studied in many species (Chardard et al 1995, Wallace et al 1999, Nakamura 2009, Olmstead et al 2010)
The results showed proliferation of germ cells at approximately 98 dph suggesting the beginning of sex differentiation
Summary
Sex is determined in vertebrates either genetically or environmentally, or via a combination of both factors (Nakamura 2009). In amphibians, when reared at natural temperatures, sex is generally genetically determined; environmental factors, including temperature, have been reported to affect sex (Wallace et al 1999). Rearing at extremes of warm or cold temperatures may disturb sex differentiation and introduce a bias toward male or female. Triturus cristatus larvae reared at temperatures of 14−26°C show a sex ratio of ~50:50. When temperature was increased to 28°C or decreased to 13°C, sex. Sex differentiation in amphibians is affected by temperature and by sex steroids.
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