Morphological and histochemical changes in the dromedary camel epididymis in relation to reproductive activity.

Environmental conditions such as temperature, light and food availability are known to influence the physiological status of animals. The male dromedary camel (Camelus dromedarius) is considered as a seasonal breeder with maximal sexual activity during certain period of the year followed by a decrease in activity during the remaining period. On the other hand, the male camel is also shown as an atypical seasonal breeder because this does not undergo sexual quiescence with complete cessation of spermatogenesis. This animal, however, shows remarkable physiological and behavioral changes during its maximal sexual activity. The annual breeding (rutting) period also influences the epididymis. In this review, an attempt has been made to present the available literature pertaining to gross anatomical, histological, histochemical, immunohistochemical and molecular changes in camel epididymis during breeding and nonbreeding periods, and the changes are believed to be correlated with male sexual behavior and libido. This review may also exhibit the dromedary camel breeding period, which is still unresolved, and thus may prove helpful in determining the exact time of mating, which is important for the success of assisted reproductive outcomes. Further, the review may contribute to a better understanding of the epididymal physiology in camel and may also prove useful in improving reproductive efficiency and population of this animal.

Seasonal morphology and immunoreactivity of cytokeratin and atrial natriuretic peptide in dromedary camel poll glands.

Poll glands are characteristic feature of dromedary camels; although they yield a yellowish offensive secretion, especially during rutting (breeding) season, their function is not yet exactly specified. The present study shows the seasonal morphology and immunoreactivity of cytokeratin (CK) and atrial natriuretic peptide (ANP) in the camel poll gland; the result could clearly specify the role of the gland in camel reproduction. Poll glands are compound tubulo-alveolar in structure. During rutting season, the secretory units showed wide lumina and simple squamous epithelium surrounded by myoepithelial cells; the lumina became narrower and the epithelium changed to simple cuboidal during non-rutting season. Many glandular lobules showed abundant interlobular connective tissue with fewer and smaller secretory units during non-rutting season compared to rutting season. Positive CK and ANP immunoreactivity was detected in the cytoplasm of epithelial cells of secretory units and ducts together with the myoepithelial cells and blood vessels. Although CK immunoreactivity was more intense during rutting season in comparison to non-rutting season, there was no seasonal variation in ANP immunoreactivity. During both seasons, while the glandular capsule, connective tissue septa, interstitium showed negative CK immunoreactions, they reacted moderately to ANP. In conclusion, the poll gland undergoes annual structural and functional changes which are suggested to correlate with the male seasonal sexual behaviour. Further, the biological role of CK and ANP proteins together with their immunohistochemical expression in the camel poll gland suggests a stimulatory effect in the glandular secretory cells, and hence, they might modify camel sexual activity.

Histological and morphometric studies on the dromedary camel epididymis in relation to reproductive activity.

The reproductive efficiency of male dromedary camels under natural conditions is regarded to be low due to a relatively short breeding season and a long prepubertal period. This study was carried out to investigate the histological and morphometric changes in the Sudanese dromedary camel epididymis in relation to the breeding (rutting) and non-breeding (non-rutting) seasons at monthly intervals up to one year. Specimens were collected from different regions of the epididymis of 48 mature and healthy Sudanese male camels slaughtered at Tambul slaughter house in central Sudan. Paraffin sections of the caput, corpus and cauda regions of the epididymis were stained conventionally for general histology and morphometry. The epididymal stereociliated epithelium showed five types of cells: principal, basal, apical, halo and dark cells and the epithelium was surrounded by a thin layer of lamina propria and a circumtubular smooth muscle coat. No significant seasonal histological or morphometric changes were observed in the caput and corpus epididymides. However, a remarkable decrease in epididymal epithelial thickness and length of stereocilia with consequent increase in luminal diameter was observed in the cauda epididymidis during the rutting season; there was also an increase in the smooth muscle coat thickness. Thus, the results suggest that the epididymis of Sudanese dromedary camel is active throughout the year, but the activity remains low during winter and increases to its maximum during summer, especially during the rainy months.