Dose-related morphological changes in the epididymal region of sexually active adult male Japanese quail treated with di-n-butyl phthalate (DBP) commencing during the pre-pubertal stage

•Di-n-butyl phthalate (DBP) induces dose-dependent toxicity in quail’s epididymis.•The proximal efferent ductule is more sensitive to the effects of the DBP.•Oligospermia was observed in the lumen of epididymal duct of adult Japanese quails.•Pre-pubertal exposure to DBP could cause infertility in the adult Japanese quails.