Degree Type

Dissertation

Date of Award

1985

Degree Name

Doctor of Philosophy

Department

Veterinary Pathology

Abstract

The effects of age, diet, and selected microflora on the large intestinal mucosa of newborn and gnotobiotic piglets aged 4 to 54 days were evaluated in order to extend our knowledge of the development of the cecum and colon and the effects of those factors postulated to impact on the susceptibility to Treponema hyodysenteriae. Gnotobiotic piglets were divided into 3 groups: one group was maintained on milk, one group on solid food, and one was maintained on solid food and inoculated with 6 strains of microflora selected because they had been found in high numbers in pigs with swine dysentery. Tissues from cecum, proximal colon, and spiral colon were evaluated morphologically, histochemically, and morphometrically;The cecum and colon of newborn piglets contained numerous villus-like structures. The luminal two-thirds of these structures were covered with vacuolated epithelial cells. These vacuolated epithelial cells disappeared between day 0 and 4. From day 4 to 14, the surface epithelial cells of gnotobiotic piglets contained fat droplets. The numbers of droplets at 14 days were much lower than those at 4 days;Goblet cells from the cecum and colon of newborn and gnotobiotic piglets were morphologically identical and similar to goblet cells from the intestine of other species. Occasionally, pale goblet cells interpreted to be a less active form of goblet cells were found in the crypts of all three sites of the large intestine. Swollen goblet cells were present in the mid crypt region of the cecum of many gnotobiotic piglets. The incidence was lower in the group of animals on solid food and not infected with selected microflora. More goblet cells with a prominent cytoplasmic rim were present on the surface of all three large intestinal sites in pigs on solid food with or without selected microflora;Solid food and selected microflora caused an increase in the volume fraction of the intracellular mucin content per unit volume of the large intestinal epithelium after a temporary reduction. Neither solid food alone nor in combination with selected microflora caused any changes in the degree of goblet cell mucin sulfation. The degree of sulfation decreased as the animals got older. The cecum had less sulfomucin-producing goblet cells than the proximal and spiral colon.

DOI

https://doi.org/10.31274/rtd-180813-8706

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Supote Methiyapun

Language

en

Proquest ID

AAI8604497

File Format

application/pdf

File Size

157 pages

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