Influence of oligosaccharides and fish oil on gastrointestinal tract characteristics and metabolic profiles of humans, pigs, and rats

Experiments were conducted to evaluate oligosaccharides (OS) and fish oil on gastrointestinal tract characteristics and metabolic profiles of humans, pigs, and rats. Experiment 1, thirty healthy human adult males were assigned to one of two enteral diets, a control (n = 10) and an ulcerative colitis nutritional formula (UNCF; n = 20). The UCNF contained supplemental OS, gum arabic, and fish oil. Formulas contained comparable levels of protein, fat, and carbohydrates. The UCNF was considered safe due to no untoward effects on serum metabolites, hematology, and urinalysis compared to the control. Ingestion of the UCNF resulted in increased plasma and RBC levels of the n-3 fatty acids (FA) with a concomitant decrease in n-6 FA. Bifidobacteria were unaffected by treatment. Experiment 2, forty-eight barrows were assigned to the enteral diets used in the human study to assess effects on bifidobacteria, serum metabolites, hematology, urinalysis, phospholipid FA, and eicosanoids. Plasma phospholipid FA were higher in n-3 FA and lower in n-6 FA due to the UCNF. Similar effects were noted in RBC and colonic and cecal mucosa. Proinflammatory prostaglandins were reduced due to the UCNF compared to the control, while leukotrienes were unaffected. Serum metabolites, hematology, urinalysis, bifidobacteria, and histology were unaffected by treatment. Experiment 3, fifty rats were assigned to one of five diets to examine OS on cecal and colonic short chain FA (SCFA), pH, and gut microbiota. The diets consisted of: (1) elemental diet (ED); (2) ED + 5% microcrystalline cellulose; (3) treatment 2 + 6% fructooligosaccharides; (4) treatment 2 + 6% oligofructose; and (5) treatment 2 + 6% xylooligosaccharides. The OS diets resulted in increased cecal SCFA and decreased pH. Cecal bifidobacteria and total anaerobes were increased while total aerobes were decreased due to OS ingestion. Similar microbiota effects were noted in the colon. Experiment 4, pigs were used to develop chronic inflammation induced by peptidoglycan-polysaccharide (PG-PS) injections in the distal colon. In a pilot study, one pig was given both saline and PG-PS injections subserosally in different areas of the colon. No inflammation was noted; however, the colonic lymph nodes draining the PG-PS-treated area had severe subacute lymphadenitis. Three additional pigs were given saline, PG-PS, or Freund's complete adjuvant injections separately and deeper in the colon. The saline and PG-PS pigs had little or no inflammation while the Freund's complete adjuvant pig had focal granulomatous inflammation. In summary, the inclusion of OS and fish oil in nutritional formulas may be beneficial to gastrointestinal tract health via maintenance of intestinal integrity and alterations of inflammation, gut microbiota, and energy sources in the large bowel.U of I OnlyETDs are only available to UIUC Users without author permissio