Respiratory and urogenital tract associated lymphoid tissues in native chicken (Gallus gallus domesticus) of Bangladesh

Abstract

This study specifies the morphological features and distribution of lymphoid tissues in the respiratory and urogenital tract to establish the impact of chicken age significance on tract-associated lymphoid tissues. The different organs of the respiratory and urogenital tract of 1-day, 30-day, 90-day, and 180-day-old male and female native chickens were freshly taken and stained with hematoxylin and eosin (H & E). The mean of intraepithelial lymphocytes (IELs) in the trachea of male and female native chickens has a significant variation in 180 days of age (P≤0.05). The mean of IELs in the lungs of male native chickens has a significant variation with their age (P≤0.05). The mean of aggregated lymphoid tissues in the lungs of male native chickens has a significant variation between 90 days and 180 days of age (P≤0.05). The mean of IELs in the kidneys of both male and female native chickens and ureters only in female native chickens has a significant variation with their age (P ≤ 0.05). The mean of IELs in the infundibulum, isthmus, and uterus of female native chickens has a significant variation between 90 days and 180 days (P≤0.05). A higher number of IELs in the uterus compared to other segments of the oviduct was observed at 180 days of chicken. There was a significant variation in the mean of IELs in the urogenital tract of female chickens from male chickens. There was no significant variation (P>0.05) of aggregated lymphoid tissues based on age in the native chicken. The IELs were in various sizes, from small lymphocytes with little cytoplasm to larger cells with obvious cytoplasm. The aggregated lymphocytes were a distinct, distinguishable structure under bright-field light microscopy. It was in the lamina propria, typically immediately below the basement membrane. The aggregates did not allow for the definite identification of germinal centers. These results suggest that the distribution of lymphoid tissue in the respiratory and urogenital tract of native chickens increases with aging and is relatively high in specific parts of the tract.