Effects of exposure to 17-alpha-ethynylestradiol on sperm quality of tench (Tinca tinca).

Alterations of sperm quality were studied in tench (Tinca tinca) exposed to sub-lethal doses of 17-alpha-ethynylestradiol-EE2-(50, 100 and 500μg/kg t.w) under semi-static conditions for 30 days. Thus, different biomarkers of sperm quality were assessed: concentration and volume of ejaculate, total number of spermatozoa, percentage of motile spermatozoa, sperm motility and percentage of live and dead spermatozoa. Sperm motility was examined by computer-assisted image analysis and the viability of spermatozoa was assessed through flow cytometry. The most relevant alterations observed were significant reductions in the reproductive parameters such as testicular somatic index, spermatozoa concentration, straight line velocity, curvilinear velocity, average path velocity and wobble in tench exposed to 50μg/kg t.w of EE2. Our study about the effects of EE2 on the sperm quality in tench provides new evidences which strengthen the fact that this synthetic estrogen is included in the list of non-monotonic dose response compounds in animal studies.