A histomorphometric study on age-related changes in selected lymphoid structures of Chukar partridge (Alectoris chukar)

Background: Chukar partridge (Alectoris chukar) is raised for its highly nutritional and relatively expensive meat. Aims: This study evaluates selected lymphoid organs of juvenile and peripubertal Chukar partridges using a histomorphometric approach. Methods: Thirty one-day-old male and female Chukar partridges were included in the study. Samples were taken from cloacal bursa, thymus, spleen and the caecal tonsil (CT) as well as oesophageal and pyloric tonsils at 80, 100, and 120 days (peripuberty) of age. Ten transverse sections were then taken from each sample of each bird and stained with haematoxylin and eosin (H&E) in order to measure plicae height and follicular width as well as thickness of follicular cortex and medulla in cloacal bursa, villus height and nodular unit (ND) width and height in CT, lobular width as well as lobular cortex and medullar width in thymus, white pulp width in spleen and follicular width in oesophageal and pyloric tonsils, a linear graticule was used, the number of follicles in each plicae in cloacal bursa and the number of follicles in each ND in CT were determined under a light microscope. Results: Drastic changes in histomorphometrical parameters of lymphoid tissues were observed in peripuberty, prominently in cloacal bursa and thymus as demonstrated by the significant decrease in all assayed parameters. Involutionary changes were also observed in oesophageal and pyloric tonsils. Conclusion: Involution occurs in bursa and thymus of partridges around puberty rather than their juvenile stages. These changes are also appreciable in CT, oesophageal and pyloric tonsils, whereas the spleen keeps the same histological features before and around puberty.