Epoxiconazole causes changes in testicular histology and sperm production in the Japanese quail (coturnix coturnix japonica)

The fungicide epoxiconazole (Epox), a triazole, belongs to the group of azole compounds which are extensively used as fungicides in various fruit crops. The frequent use of agricultural lands for wintering by migrating birds can be the source of their increased dietary intake of agricultural pesticides. We investigated whether exposure to epoxiconazole causes effects on avian fertility and reproduction, using the Japanese quail (Coturnix coturnix japonica) as a model species for the assessment of reproductive effects of pesticides in wild birds. Epoxiconazole was administered to adult Japanese quail for three weeks at dietary levels of 10, 50 and 500 ppm and possible effects on reproduction were investigated. Epoxiconazole administration resulted in a significantly decreased number of spermatids in the 50 and 500 ppm dose groups. Histopathology showed a reduced number of testicular canaliculi with visible germ cells and a reduction in spermatid number. However, testis weight was not affected up to the highest dose level. There was no impact on hormone levels, fertility and reproductive outcome as laying rate and percentage of fertile eggs were not altered. Likewise treatment had no influence on the egg or chick parameters evaluated. A time and dose related transfer of Epox into the eggs was determined in all treatment groups. We conclude, that dietary treatment of Japanese quail with 50 and 500 ppm of the triazole fungicide Epox resulted in a clear impact on the testis. The evaluation of the additional endpoints spermatid count and testicular histology have proven useful and are recommended for future studies on avian reproduction