Lymphoid tissues of the small intestine of swine from birth to one month of age
Chu, R.M.; Glock, R.D.; Ross, R.F.; Cox, D.F.
American Journal of Veterinary Research 40(12): 1713-1719
1979
ISSN/ISBN: 0002-9645 PMID: 316657 Document Number: 142226
Interepithelial lymphocytes (IEL) and aggregated lymph nodules (ALN; Peyer's patches) in 6 portions of the small intestines of pigs were studied at ages of 0 (4-10 h), 1, 5, 15 and 31 days; the microscopic anatomy of the small intestines was also examined. The numbers of IEL increased significantly (P < 0.05) from 3.3 .+-. 0.6/100 absorptive epithelial cells at 0 days of age to 38.9 .+-. 3.5 at 31 days of age. The cranial portion of the small intestine contained more IEL than the caudal portion. In general, most of the IEL (55.6%) in all age groups were found in the subnuclear position below the nuclear level of absorptive epithelial cells. As animals got older, supranuclear IEL decreased and subnuclear IEL increased while nuclear level IEL remained stable. Many histologically normal lymphocytes and degenerated cells were also adjacent to the mucosal epithelium of the small intestine. Small ALN with relatively well-defined germinal centers and loosely arranged domes were observed in the youngest group of pigs (4-10 h after birth). The size of ALN increased several times from day 0-31 days of age. The dome epithelium of ALN usually contained relatively more IEL that tended to group together in cords of cells, while in other epithelial areas, IEL were randomly dispersed. Eosinophilic globules which may represent absorbed protein from colostrum or milk were found in the cytoplasm of absorptive epithelial cells only through 5 days of age. More globules were located in the supranuclear cytoplasm in 0-day and 1-day groups, as opposed to a subnuclear predominance in the 5-day group. Highly vacuolated cytoplasm was seen in the absorptive cells of the caudal 2/3 of the villi in the caudal portion of the small intestine at 0, 1, 5 and 15 days of age. The vacuolation was most prominent at 5 and 15 days of age.