Cell death in the infundibulum and magnum regions of the oviduct in the domestic fowl (Gallus domesticus) during natural moulting

Abstract

The infundibular region of the oviduct has several functions including: engulfing the ovulated oocyte; providing a site for fertilization and forming the chalaziferous components of the developing egg. At approximately 18 months of age, laying hens enter the moulting phase of the reproductive cycle, during which egg production decreases or ceases due to oviductal regression. Although extensive research has been conducted on the effects of moulting on the physiological condition of hens, relatively little is known about the histomorphological changes which occur in the oviduct during this process. The present study was undertaken to compare the histomorphology of the infundibular epithelium in laying and moulting commercial hens. A total of 10 laying (32 weeks old) and 10 moulting (75 weeks old) commercial hens were used in the present study. Tissue samples from the infundibulum were fixed in buffered neutral formalin for 5 days. The samples were later processed routinely for light microscopy and stained with haematoxylin and eosin, as well as Periodic acid Schiff-Alcian blue (PAS-AB). The infundibulum was sub-divided into proximal funnel and distal tubular regions. In laying hens the funnel region was lined by a ciliated simple columnar epithelium. In moulting hens this region displayed localized areas of swollen, nonciliated cells with pale-staining cytoplasm and nuclei. The tubular infundibular region in laying hens was lined by a pseudostratified columnar epithelium composed of ciliated and non-ciliated cells. The latter cells stained positive for PAS indicating the presence of neutral mucins. The epithelium in the tubular region of moulting birds contained cells at different stages of degeneration. Alcian blue, as well as PAS- AB cells were observed, indicating the presence of acidic and mixed mucins. The results of the study indicate that the infundibular epithelium differs histologically and physiologically during the laying and moulting phases of the reproductive cycle.