Dietary fish oil alters the sensitivity of guinea pig ileum to electrically driven contractions and 8-iso-PGE2

Dietary fish oil rich in n-3 polyunsaturated fatty acids (PUFA) have been positively implicated in bowel health. This was investigated in relation to newborn guinea pig growth, caecal digesta pH and SCFA profile, ileal total phospholipid fatty acid content and particularly for in vitro ileal contractility. A newly formulated commercial rice porridge (congee) preparation supplemented with essential nutrients, standard chow for palatability and 3% fat as safflower oil or tuna fish oil was fed to new born guinea pigs and their mothers. After two months of feeding, while the mean body weight and weight and length of small intestine of the fish oil supplemented group were significantly lower (P < 0.05) compared to the safflower supplemented group there was no difference in final small intestine density. Substitution of safflower oil with tuna fish oil led to significantly lower oleic acid content of ileum total phospholipid with a concomitant increase in the n-3 PUFA ALA, EPA and DHA (P < 0.05). The fish oil supplemented group had a significantly higher caecal digesta pH (P < 0.03) with a significantly lower propionate concentration (P < 0.04). Significantly less voltage was required to initiate contraction of the ileum of the fish oil supplemented group (P < 0.03). There was no significant difference in the sensitivity (EC₅₀) and maximal contraction induced by acetylcholine, histamine, serotonin, and prostaglandins PGE₂ or PGF₂. However, the sensitivity to the isoprostane, 8-iso-PGE₂ of the fish oil supplemented group was significantly reduced (P < 0.04). These results warrant further investigation into the physiological role that dietary n-3 PUFA may play in bowel contractility and health.