University of Minnesota swine nutritionists are studying whether distiller's dried grains with solubles (DDGS) can effectively treat ileitis.
To date, results have been positive, but the evidence is not ironclad. Researchers hope to prove, one way or another, whether high levels of insoluble fiber in DDGS alleviate the clinical effects of ileitis. Anecdotal evidence in the field suggests that adding the ethanol co-product to grow-finish diets improves a pig's ability to resist or recover from ileitis outbreaks.
One theory deals with the large amount of “spent” yeast in DDGS following the ethanol fermentation process. Yeast cells are an excellent source of mannan-oligosaccharides (MOS). Work in the late 1990s shows MOS provides alternative attachment sites for certain bacteria, thereby blocking attachment to the intestinal wall, and in the case of pathogens, eliciting an immune response.
Another theory is that feeding diets low in soluble, non-starch polysaccharides can reduce the proliferation of pathogenic organisms in the gastrointestinal tract. Providing less soluble and more insoluble fiber in the diet means less available substrate for organisms in the intestine, which may reduce pathogen load.
Any or all of these mechanisms may make it possible for the fiber or yeast cells remaining in DDGS to promote gastrointestinal health, says Minnesota researcher Mark Whitney. DDGS contains about 10% fiber, mostly insoluble.
To test the theory, Whitney and his major professor, Jerry Shurson, conducted two studies using an ileitis challenge model.
Experiment 1 looked at the effect of a 10% or 20% DDGS diet on growing pigs inoculated with Lawsonia intracellularis, the organism causing ileitis. Study pigs became much sicker than intended. A too-high dosage level was blamed, likely skewing any possible nutritional benefits from DDGS, Whitney explains.
Experiment 2 used a 10% DDGS level and an ileitis challenge level similar to exposure in commercial finishers. Researchers also compared DDGS diets to those containing antibiotics used to treat ileitis.
The 100 crossbred pigs were weaned at 17 days, allotted by sex and weight to one of five treatments and housed in isolation rooms. Pigs were fed either a corn-soybean meal diet or a corn-soybean meal-DDGS diet, with or without antibiotics. The antibiotic regimen consisted of continuous bacitracin methylene disalicylate (BMD) at 30 g./ton of mixed feed, along with pulsing of chlortetracycline at 500 g./ton from Day 3 pre-challenge to Day 11 post-challenge.
Lesion data at necropsy was a primary response criteria to evaluating the results, which showed:
Feeding the 10% DDGS diet appeared to reduce lesion length, severity and percentage of pigs exhibiting lesions in the ileum and colon.
Antibiotic treatment reduced severity and length of lesions and percentage of pigs exhibiting lesions in the jejunum.
Although the combination of DDGS and antibiotic regimen appeared to affect fecal shedding 14 days post-challenge, there were no dietary effects on shedding by 20 days post-challenge, and immuno-histochemistry (IHC) indicated no dietary effect on pigs testing positive.
IHC scores did indicate a positive effect of DDGS and antibiotic regimen on severity of infection.
Researchers concluded that the 10% DDGS diet may provide some protection and aid the pig in coping with ileitis. The beneficial effects they observed were similar to the results seen for an approved antibiotic regimen. Feeding both DDGS and BMD/chlortetracycline, however, did not appear to have an additive effect.