Abstract
The current study was carried out to evaluate the effect of eprinomectin (EPM) on fertility parameters, histopathological findings as well as the relative weights of reproductive organs, in comparison with the classical member, ivermectin (IVM) in male albino rats. Thus, forty-eight mature male albino rats were randomly assigned to three equal groups as follows: the control group injected subcutaneously by glycerol (2 ml/kg b.wt., twice at a 4-week interval), the second group was administered ivermectin (0.56 mg/kg b.wt., twice at a 4-week interval subcutaneously), and the third group was administered eprinomectin (0.56 mg/kg b.wt., twice at a 4-week interval subcutaneously). The data obtained demonstrated that eprinomectin administration induced statistically non-significant alterations in sperm motility, count, sperm abnormalities and relative weight of reproductive organs in comparison with the control group. While, ivermectin administration induced a significant decrease (p ≤ 0.05) in sperm motility and count and a significant increase in sperm abnormalities with a significant decrease (p ≤ 0.05) in the relative weight of the testes and accessory sex organs at the 8th week. These findings were further supported by the histopathological examination of the reproductive organs, where ivermectin induced some histopathological alterations in examined reproductive organs (testes, epididymis, prostate & seminal vesicle), including degeneration of spermatogenic and epithelial cells, depletion of spermatozoa, and vacuolar changes. In contrast, eprinomectin-treated rats exhibited normal histological structures of these organs. These findings suggest that eprinomectin could be safely used as a better-choice macrocyclic lactone anthelmintic for use in male animals, especially those intended for breeding purposes.

Key words: Eprinomectin, histopathology, ivermectin, rats, reproduction.