Microanatomical aspects of the intestines and gut-associated lymphoid tissue of meat rabbits

Cite this article: Gavrilіn, P. M., & Nikitina, M. O. (2019). Microanatomical aspects of the intestines and gut-associated lymphoid tissue of meat rabbits. Theoretical and Applied Veterinary Medicine, 7(1), 42‒46. doi: 10.32819/2019.71008 Abstract. In the paper, we consider the morphology of intestine structures and gut-associated lymphoid tissue of meat rabbits. The investigation was carried out for the rabbits of the following ages: 1, 10, 20, 30, 60 and 90 days of postnatal development. In accordance with the age groups, the samples of small and large intestines were taken and stained with hematoxylin eosin. As the result of microscopy investigations, the morphology of intestines and lymphoid tissues was studied. We found out that the most area of a microscopic section was taken up by mucosa, whereas lymphoid cells were detected mainly in lamina propria and somewhat in epithelium. We observed that immune structures of 30-day rabbits were formed in lamina propria hardly breaking the submucous layer. For the 1-day rabbits, the lymphoid tissue was detected in sacculus rotundus and vermiform appendix. Starting from the 20-th day of postnatal development, the lymphoid tissue was also observed in lamina propria and other intestinal tracts. We found specific types of lymphoid tissue and immune structures, which were typical of each age group of the rabbits. Besides, we studied the traits of lymphatic nodule development within the selected ages as well as assessing differentiation periods of lymphoid tissue. We determined that lymphoid tissue could be detected for the newborn rabbits, viz. lymphatic nodules and aggregated lymphoid nodules (Peyer’s patches) begin growing from the 20-th day of postnatal development, whereas germinal centers are observed in lymphatic nodules of 60-day rabbits. With age, the number of lymphatic nodules is increasing in lymphoid plaques whereas the amount of lymphoid tissue is decreasing between the plaques. Since birth, lymphatic nodules are mostly circular-shaped. However, irregular-shaped lymphatic nodules, which are arranged in two rows, are appearing in the lymphoid plaques starting from 30-day age. On the 90th day of postnatal development, almost all lymphatic nodules within the lymphoid paques have irregular shape and may be arranged in three rows. A well-developed bloodstream vessel cab be observed in the proximity of the lymphoid tissue and lymphoid structures of each rabbit age group.