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. Di-n-butyl phthalate (DBP) is widely used as a plasticizer in personal care and medical products and is known to induce toxicity in the male reproductive organs in both mammals and birds. In this study, there was investigation of the effects of DBP on the epithelium of the rete testis, proximal, and distal efferent ductules and epididymal duct of adult Japanese quail (Coturnix japonica) following treatment with varying doses during the pre-pubertal and peri-pubertal periods. Pre-pubertal quail (n = 25) 4 weeks post-hatching were dosed orally with 10, 50, 200 and 400 mg DBP/kg/d, for 30 days and control birds were administered corn-oil only (n = 5 per group). Histo-metrically, there was lesser (P