Dietary conjugated linoleic acid ameliorates intestinal inflammation in pigs

Bassaganya-Riera, J., R. Hontecillas, and M.J. Wannemuehler (2001) Dietary conjugated linoleic acid ameliorates intestinal inflammation in pigs. Proceedings of the 82^nd Annual Meeting of the Conference of Research Workers in Animal Diseases; Nov 11-13; St. Louis, MO; (Abstract #113).

Saturated fatty acids and/or excess linoleic acid intake enhance mucosal inflammatory responses; conversely, ω-3 polyunsaturated fatty acids have generally been sought as beneficial towards preventing inflammation. Conjugated linoleic acid (CLA) has also been shown to be effective in preventing diseases with a common inflammatory pathogenesis (i.e., colorectal cancer, diabetes, and atherosclerosis). Chemically, CLA is a mixture of positional (9,11; 10,12; or 11,13) and geometric (cis or trans) isomers of octadecadienoic acid (C18:2) with conjugated double bonds. The present study aimed to investigate the molecular basis underlying the possible anti-inflammatory properties of dietary CLA in pigs using a model of bacterial induced colitis (i.e., swine dysentery). Soybean oil (e.g., predominantly linoleic acid) or CLA was supplemented in diets of healthy pigs in two separate studies using a total of 64 pigs. Feeding trials were designed as 2 × 2 (i.e., eight blocks of two littermates) and 2 × 3 (i.e., sixteen blocks of three littermates) factorial arrangements within split-plot designs. In the first study two dietary treatments (sub-plot) and two infective status (whole plot) were utilized, whereas in the second study a vaccination treatment was included in addition to the dietary treatments and challenged groups. To induce colonic inflammation, half of the blocks were challenged with Brachyspira hyodysenteriae. Growth rate was determined weekly prior to and after bacterial challenge. Using tissue samples collected at postmortem, interferon-γ (IFN-γ) and interleukin-10 (IL-10) message expression in colonic lymph nodes draining the affected mucosa was assessed by reverse transcriptase-polymerase chain reaction. Colonic tissues recovered from pigs were histologically-evaluated. Dietary conjugated linoleic acid supplementation prior to the induction of colitis (1) ameliorated the damage of the colonic mucosa; (2) maintained cytokine profiles that resembled those of the non-infected pigs; and (3) attenuated growth failure. The present results suggest a possible role for lipid nutrition in modulating the course of enteric inflammatory diseases.