Testicular morphology and antispermatogenic effects of 2,4-dichlorophenoxyacetic acid (2,4-D) in male West African Dwarf (WAD) goats

Abstract

This study investigated the testicular morphology as well as the gonadal and extra-gonadal sperm reserves of West African Dwarf (WAD) goats exposed to graded levels of 2,4-dichlorophenoxyacetic acid (2,4-D). Twenty male WAD goats of five goats per group were used for this study. Goats in groups A, B and C received low [75 mg/kg body weight (BW)], medium (100 mg/kg BW) and high (125 mg/kg BW) dose levels of 2,4-D, respectively. The group D goats served as the control. On day 112, goats in the four groups were sacrificed and the testicular and epididymal sperm reserves were determined. Histopathologic changes in the testis of the 2,4-D-exposed and control goats were also assessed. The mean number of spermatozoa in the testes and the various segments of the epididymides decreased significantly (p < 0.05) in all the treatment groups relative to the control. Combined testicular sperm reserve per millilitre for the treatment groups (group A—19.61 ± 2.63 × 108, group B—12.02 ± 1.02 × 108 and group C—9.95 ± 0.97 × 108) reduced significantly (p < 0.05) relative to the mean value (23.52 ± 4.43 × 108) of the control—group D. The total epididymal sperm reserve per millilitre in the treatment groups (group A—24.25 ± 4.19 × 108, group B—17.18 ± 2.57 × 108 and group C—17.88 ± 2.89 × 108) was also found to be significantly (p < 0.05) lower than the mean value (40.85 ± 11.24 × 108) for the control—group D. This reduction in the testicular and epididymal sperm counts of the 2,4-D-exposed WAD goats in this study suggest disruption in spermatogenic activity, which may lead to low productivity. Variable degrees of circulatory disturbances were observed in the testis sections of 2,4-D-exposed goats.