Browsing by Author "Assey, Remmy John"

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    Development of the intestinal tract lymphatic system in goats
    (Sokoine University of Agriculture, 1989) Assey, Remmy John
    Gross and microscopic studies of the Gut-Associated Lymphoid Tissue (GALT) and Mesenteric Lymph Nodes (MLN) were performed on ten fifteen 3 months old kids and fifteen 8-12 months old goats. Morphological changes of the intestinal tract lymphatic system with age, the relationship of morpholo­ gical changes between and within intestinal lymphoid organs in particular the Peyer's patches and the MLN during growth, possible role of the Peyer's patches in the immune system of the caprine and lymph flow from the intestine were studied. Kids were born with an average of 35 histologically mature Peyer's patches in the jejunum (Jejunal Peyer's patches-JPP) which ranged in size from five follicles to 4.5 cm. long patches. A long Peyer's patch whose width was not uniform was also found in newborn kids. j e j unum It was broader caudally and it extended from the to the ileocecocolic junction (Jejunal-Ileal Peyer's Patch-JIPP). The average length of the JIPP was 0.83 m. Two round Peyer's patches were found in the colon (Colon Peyer's Patches - CPP ). The Peyer's patches were present on 17% of the intestine length. The shape of the follicles and the interfollicular area breadth were different in the JPP, JIPP and CPP. Interepithelial lymphocytes (IEL) number on domes decreased from cranial end to caudal end of the intestine. The trend was not observed on the villi epithelium. Intestinal tract villi epithelial cells in kids which had not suckled were columnar and had their nuclei in the apices. In average newborn kids had 5(1— 10) jejunal, 1 (1 - 3) Their total ileocecocolic and 3 (2 - 6) colic lymph nodes. was 0.11% of post-slaughter animal body weight corrected weight for stomach compartments weight. The MLN were immature. Wi thin twelve hours after birth and colostrum ingestion, secondary lymphoid nodules appeared on the MLN. At three months age, kids had about 38 JPP with size ranging from five follicles to patches 5.4 cm. long. The width of the JIPP was also not uniform, and it was 1.4 tn. long. There were 2 Peyer's patches were present on about 18% of the intestinal CPP. length. There were 3 (1 - 9) jejunal, 1 (1 - 2) ileocecocolic and 3 (2 - 5 ) colic lymph nodes. Their total weight was 0.29% of the post-slaughter animal body weight corrected for stomach compart- ments weight. The MLN were histologically mature. Goats of 8 - 12 months age had about 33 JPP and 2 CPP. In a single observation, three snail patches were found in the cecum. JIPP had grossly atrophied and measured about 1.5 m. in length. Peyer's patches were present on about 13% of the intestine length. There were 5 (1 - 12) jejunal, 2 (1 - 4) ileocecocolic and 4 (2 - 5 ) colic lymph nodes. Their total weight was 0.16% of the post-slaughter animal body weight corrected for stomach compartments weight. mature. The MLN were histologically There was a general trend of a decrease of IEL number on the demes and villi from cr«iiial end to caudal end of the intestinal tract. Domes epithelia were columnar and had a mean of 1.2 + 0.3, 1.8 + 0.5 and 0.2 + 0.1 goblet cells per dome in the newborn, 3 IEL nunber on months and 8-12 months old goats, respectively. dome and villi showed a general increase with age. There was no significant difference (P > 0.05) between the means of the JPP number of the three age groups.There was also no significant correlation neither betweenlength of Peyer's patches and intestine length nor between MLN and body weights. There was no significant difference ( P >0.05) between the proportion of intestine on which the Peyer's patches were present in newborn and 3 months old kids, while there was significant difference ( P < 0.05) between these two months old group. groups and the 8-12 There was significant difference (P < 0.05) between the means of the MLN weight of the three age groups and there was also significant difference (P < 0.05 ) between the means of MLN-body weight proportion of the three age groups. The JPP, JIPP and CPP had a common character of being histologically mature at birth, but differed in their follicular histology and life history. The JPP follicles were short, broad and pear-shaped, had large interfollicular areas and did not show signs of atrophy with age. The JIPP follicles were cylindrical or sac-shaped and atrophied with age like the thymus and avian Bursa of Fabricius. The atrophy of the JIPP started at the mid portion of the patch. Similarity between the caprine JIPP and the avian Bursa of Fabricius with regard to their prenatal maturation, their proximity to the gut and their postnatal involution is compatible with the assumption that the caprine JIPP is the equivalent of the avian Bursa Fabricii. A bean-shaped jejunal lymph node cdudaily located on the group chain was found in three out of seven animals. The node with the single ileocecocolic node drained the JIPP. Efferent from the bean-shaped jejunal node joined efferent of the ileoce­ cocolic lymph node and the vessel formed joined the efferent of the colic lymph nodes to form the colic trunk. In three animals, efferents of one or two colic lymph nodes drained into the ileocecocolic lymph node. The colic trunk confluenced with the jejunal trunk to form the intestinal trunk which emptied into the cisterna chyli. Goats did not have visceral trunk.