Postnatal development of Peyer's patches in small intestine of pigs: A histomorphological study

The postnatal development of the jejunal Peyer's patches (jej-PP) and ileal Peyer's patches (il-PP) was studied in day-old adult life in dum variety p igs. The discrete jej-PP numbers increased from 20 in day-old to 24 in adul t pigs. The continuous il-PP increased 4-times in length in adult pigs than that of day-old piglets. Histomorphologically jej-PP and il-PP grew differ ently in the postnatal life. With the increase of gut antigens the size of the follicles and inter follicular areas (IFA) increased in adult pigs. The average length and breadth of the follicle of jej-PP in day-old (0.14 mm /- 0.06; 0.19 mm +/- 0.05 respectively) increased up to adult age (0.63 mm +/- 0.48; 0.47 mm +/- 0.39 respectively). The il-PP grew actively up to 3 m onths of age (0.56 mm +/- 0.17 in length) but reduced in length in adult pi gs (0.44 mm +/- 0.20 in length). The IFA in jej-PP was wider than that of i l-PP. The morphological difference between 2 types of PP is an indication t hat they develop differently in postnatal life.