Micro-stereological study of the avian epididymal region.

Morphometric studies of the epididymal region of three avian species (Gallus domesticus, Coturnix coturnix japonica, Japanese quail, and Numida meleagris, guinea-fowl) were performed using a stereological compensating eyepiece graticule. The proportions of the volume of the region made up of rete testis lacunae, proximal and distal efferent ductules, connecting ducts, ductus epididymidis, blood vessels and connective tissue were determined. The efferent ductules constituted the largest proportion of the tubular components of the organs in the three birds (35.3% for the chicken, 56% for the quail and 61.9% for the guinea-fowl), while the ductus epididymidis formed only 7.6%, 2.4% and 1.8% of the total epididymal volume in the domestic fowl, quail and guinea-fowl respectively. The connective tissue component made up 38.7%, 27.3% and 22.6% respectively. The significance of these results is discussed in relation to the likely functions of the various components of the epididymal region.