Age-related changes in the anatomical characteristics of Peyer's patches in small intestine of Bactrian camels (Camelus bactrianus)

Abstract

The distribution, size, and appearance of Peyer's patches vary according to species. In order to determine the anatomical characteristics of Peyer's patches in small intestine of Bactrian camel, and age-related changes in the number of Peyer's patches, 40 Bactrian camels of the following four age groups were studied: young (0.5-2 years), pubertal (3-5 years), middle-aged (6-16 years), and old (17-20 years). The exact number of Peyer's patches was recorded, and the appearance of Peyer's patches was described in detail. The results indicated that Peyer's patches of Bactrian camels not only have a particular anatomical location and distinct appearance but also change with age. They were distributed in the whole small intestine and there were four distinct types of Peyer's patches: nodular, faviform, cup-shaped, and cystic form Peyer's patches. However, the nodular and cystic form Peyer's patches are specific to Bactrian camel, which have not been found in other animals including Dromedary camel. In addition, the distribution density of Peyer's patches in ileum was the maximum, then was jejunum and duodenum. Further statistical analysis showed that the number of Peyer's patches was altered with age. The number peaked in 5-year-old camels and declined subsequently with age. However, there was little change in the size of Peyer's patches in different age groups; no age-related macroscopic variations in the shape or size of the Peyer's patches were found. Results obtained from this study provide the basic information to further study on the gastrointestinal mucosal immunity of Bactrian camel.

Morphologic Observation of Mucosa‐Associated Lymphoid Tissue in the Large Intestine of Bactrian Camels (Camelus bactrianus)

“…Some PPs were found in the first third of the colon but they were different in shape from the scrotiform PPs observed in the ileocecal orifice. They looked very similar to the cup‐shaped or faviform PPs described previously in the ileum (Qi et al, ). The lamina propria was rich in lymphocytes, forming lymphoid follicles, the muscularis mucosa was incomplete, and the submucosa contained aggregated lymphatic nodules (Fig.…”

“…The highest number of PPs were found in the ileocecal orifice. Different forms of PPs were also observed in the mucosa of the small intestine in the Bactrian camel (Qi et al, ), but they were not as well‐developed as those in the ileocecal orifice, suggesting that the mucosal immune inductive sites in the gastrointestinal tract of the Bactrian camel are mainly located in the ileocecal orifice. Compared to the ileocecal orifice, lower numbers of PPs were present in both the middle and posterior segments in the cecum, which is in agreement with the findings in yaks and sheep.…”

“…Previous studies have shown that the abomasum, one of two stomachs of the Bactrian camel, contains unique structures of mucosa‐associated lymphoid tissue (MALT) (Wang, ; Xu et al, ; Zhang et al, ). MALT was also rich in the small intestinal mucosa and was mainly distributed in the oncoides portion of the duodenum, jejunum, and ileum (Qi et al, ). In contrast, cattle and sheep have a significantly lower amount of lymphoid tissue in the gastric mucosa.…”

Distribution of immunoglobulin G antibody secretory cells in small intestine of Bactrian camels (Camelus bactrianus)

“…The IgG ASCs density was the highest from middle segment of duodenum to middle segment of jejunum, and then in distal segment of jejunum and initial segment of ileum, the lowest was in initial segment of duodenum, in middle and distal segment of ileum. However, the results of the research on the distribution of the Bactrian camel intestinal Peyer’s patches (PPs) showed that the PPs were mainly distributed in the Ileum and there were less in the duodenum and jejunum [ 17 ]. Moreover, this distribution characteristics were similar to those in human, rat, cow and sheep’s intestine [ 29 ].…”

Ileal and jejunal Peyer’s patches in buffalo calves: Histomorphological comparison

“…In 6-month-old calves, the number of layers of elliptical lymphoid follicle in ileum reduced to 1 or 2 ( Figure-10 ). Only the ileal Peyer’s patch regressed to small scattered follicles in older pigs [ 24 ] and the reduction in size of ileal follicles was observed in adult dogs [ 25 ] and in Bactrian camel [ 26 ] also, after 5 years of age. Similarly in red deer, from 6 months of age, the ileal Peyer’s patch follicles began to round up, the interfollicular area in ileal Peyer’s patch also increased and resembled the morphology of the jejunal Peyer’s patch [ 17 ].…”