| The objective of this dissertation was to investigate the impact of diet composition on gastro-intestinal health of swine experimentally infected with Lawsonia intracellularis, the causative organism for proliferative enteropathy, or ileitis. Two preliminary growth trials were conducted to determine maximal inclusion level of corn distiller's dried grains with solubles (DDGS) in nursery diets. Increasing level of DDGS reduced feed intake of pigs weighing less than 7 kg, while growth performance of heavier pigs was unaffected up to 25% DDGS.;Three disease challenge experiments were conducted in growing pigs. Weaned pigs (17 d of age) were allotted to treatments, fed experimental diets during a 4-wk pre-challenge period, orally inoculated with L. intracellularis , and maintained on diets for three weeks. Feces were collected on d 14 and d 20 post-challenge and analyzed by PCR to determine shedding of L. intracellularis. On d 21 post-challenge, pigs were euthanized, lesions of intestinal mucosa evaluated, and ileal tissue samples analyzed by immunohistochemistry to determine presence of L. intracellularis .;In the first experiment, diets contained 0, 10, or 20% DDGS. Inoculation dose was 1.5 x 109 L. intracellularis per pig. Feeding DDGS did not reduce lesion length, prevalence, proliferation of L. intracellularis, or severity of lesions, but did increase fecal shedding. The second trial evaluated diets containing 10% DDGS and/or antimicrobial therapy (33 g/tonne BMDRTM in the diet, while pulsing 550 g/tonne AureomycinRTM from d 3 pre-challenge to d 11 post-challenge). Inoculation dose was 8.0 x 108 L. intracellularis per pig. Feeding DDGS reduced ileum and colon lesion length and prevalence and reduced severity of the lesions. Antimicrobial regimen reduced prevalence and severity of lesions in the jejunum, and tended to reduce overall lesion length. In the third experiment, dietary inclusion of 20% DDGS, 5% soybean hulls, or 5% soybean hulls sprayed with a polyclonal antibody product specific for L. intracellularis were evaluated. Inoculation dose was 8.0 x 108 L. intracellularis per pig. Diet did not affect lesion parameters. Overall, it appears that dietary inclusion of DDGS provides some benefit to growing pigs subjected to a moderate ileitis challenge, but not during a severe infection. |
