Histological Study on Seminal Plasma Absorption and Spermiophagy in the Epididymal Region of Domestic Fowl

Abstract

Absorption of seminal plasma and spermiophagy in the fowl epididymal region were studied ultrastructurally and histochemically. Epithelial cells of the rete testis had sparse coated vesicles and rarely showed spermiophagy. Many macrophages in the lumen of the rete testis actively phagocytosed spermatozoa. Nonciliated cells in the proximal efferent ductules had well-developed microvilli, coated vesicles, numerous tubular structures, and lysosomes in their apical cytoplasm. They rarely contained fragments of spermatozoa. Intense alkaline phosphatase activity was observed at the luminal borders of these cells. Ciliated cells had no features indicating active absorption of seminal plasma. Epithelial cells of the connecting ductules and epididymal duct had numerous microvilli, a few vesicles, and small lysosomes. They did not contain spermatozoa. Intense acid phosphatase activity was observed on the luminal and lateral surfaces of the epithelial cells of the connecting ductules and epididymal duct. After injection of horseradish peroxidase into the excurrent ducts, a large amount of reaction product was detected in the vesicles and tubular structures of the nonciliated cells of the proximal efferent ductules. These results suggest that the absorption of seminal plasma occurred mainly in the efferent ductules, and that spermiophagy by macrophages occurred in the rete testis in the fowl epididymal region.