Effect of short-term intermittent exposure to waterborne estradiol on the reproductive physiology of the round goby (Neogobius melanostomus)

Tatiana Guellard,Hanna Kalamarz-Kubiak,Bartłomiej Arciszewski

doi:10.1007/s11356-020-09702-3

Abstract

The objective of this study was to determine how the short-term exposure to a supraphysiological concentration of waterborne 17β-estradiol (E2) influences on melatonin (Mel) and thyroxine (T4) concentrations in plasma and E2 and 11-ketotestosterone (11-KT) concentrations in plasma and gonads in both sexes of round goby (Neogobius melanostomus) during the pre-spawning, spawning, late spawning and non-spawning phases. The experimental protocol was based on short-term, repeated exposures of fish to a supraphysiological dose of waterborne E2. Mel level was unchanged on exposure to E2 during the investigated phases, and its role in determining a time frame for spawning in both sexes of round goby seems to be stable in those conditions. T4 and sex steroids (E2 and 11-KT) were sensitive to the exposure of E2, and those changes influence gonads by accelerating oocyte development, ovulation and regression and inhibiting spermatogenesis in this species. The results demonstrate that the physiological responses of fish in all investigated phases were altered over a short window of exposure, indicating that short-term exposure to a supraphysiological dose of E2 may impact fish in the wild. Furthermore, round goby can be recommended as a very suitable model for studying endocrine disruptors, which is sensitive to even short exposure to E2.

Highlights

There are several compounds entering an aquatic environment with municipal, pharmaceutical, agricultural and industrial sewage that can disturb the functioning of the endocrine system in fishes
Determination of 17β-estradiol concentrations in water In N. melanostomus females and males, there were no statistically significant differences in concentrations of plasma T4 in pre-spawning phase, while in other phases, plasma T4 concentrations were significantly increased in response to E2 exposure (p < 0.05) (Fig. 3a and b)
No changes in hepatosomatic index (HSI) after exposure to E2 have been reported in both sexes of Japanese medaka (Oryzias latipes) by Kang et al (2002). This is the first study to determine the influence of short-term, intermittent exposure to a supraphysiological concentration of waterborne E2 on Mel and T4 concentrations in plasma and E2 and 11-KT concentrations in plasma and gonads, supported by histological analysis of gonads, in both sexes of N. melanostomus during the reproductive cycle

Summary

Introduction

There are several compounds entering an aquatic environment with municipal, pharmaceutical, agricultural and industrial sewage that can disturb the functioning of the endocrine system in fishes. These types of compounds belong to pollutants called endocrine disrupting compounds (EDCs). The highest and supraphysiological concentrations of E2 have been detected in coastal zones exposed to discharges from large urban agglomerations and runoff from animal agricultural wastes (Elnwishy et al 2012; Zhang et al 2014; Afifi et al 2016)

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