Respiratory Tract Associated Lymphoid Tissues in Native Chicken (Gallus gallusdomesticus) of Bangladesh

Abstract

The respiratory system of birds exhibits unique adaptations, including the presence of air sacs. Birds, particularly those in scavenging management systems, face constant challenges from inhaled particles, microorganisms, and aerosols. To combat these challenges, the avian respiratory mucosa is equipped with immune-competent cells and various lymphoid tissues. This study focuses on the role of Respiratory tract associated lymphoid tissue (RALT) in the immune response to respiratory pathogens and the postnatal development of RALT in native scavenger chickens (Gallus gallus domesticus) as they age. Histological examinations of the trachea and lung in male and female native chickens at different age groups (Day 1, 30, 90, and 180) were conducted. Significant variations in IELs were observed at Day 180 in trachea of both male and female chickens (P≤0.05). Also, there was significant variations in IELs at Day 180 in lungs of male native chickens. This increase in IELs may be attributed to their scavenging nature and continuous exposure to pathogens. Additionally, aggregated lymphoid tissues were present in the lamina propria of the respiratory tract, but significant variations were observed only in the trachea of female native chickens at Day 180. This study contributes to a better understanding of avian respiratory immunology. It highlights the unique immune responses and lymphoid structures in the respiratory system of native scavenger chickens and underscores the importance of considering these factors in chicken health management