Ductus epididymidis compartments and morphology of epididymal spermatozoa in llamas

In this work, an attempt was made to asses possible regional specializations in the llama ductus epididymidis. According to histological and histochemical criteria, six segments (I-VI) were identified. Segment I was a short region where ductuli efferentes joined the ductus epididymidis. Segments II and III showed maximal epithelial height and mitotic activity, respectively, and weak LDH activity. Epithelial cells in segment IV contained PAS-positive, amylase and neuraminidase-resistant secretory granules. Segment V showed strong acid phosphatase and lactate dehydrogenase activities. Segment VI was characterized by moderate acid phosphatase and high lactate dehydrogenase activities, respectively, and by maximal spermatozoa packaging. Scanning electron microscopy of epididymal spermatozoa revealed that cytoplasmic droplet translocation was accomplished at the distal part of the corpus epididymidis. Bent middle pieces characterized spermatozoa during droplet translocation.