Cinnamon bark oil and coconut oil emulsions modified small intestinal motility and barrier function in laying hens in an ex vivo experiment

1. Plant extracts and oils are supplemented in diets for chickens due to their antimicrobial capacities; however, little information exists whether they influence intestinal motility and barrier function. 2. The present study aimed to determine the effect of increasing levels of cinnamon bark oil (CBO; 0, 0.038, 0.076 and 0.151) and coconut oil emulsions prepared with soy and sunflower lecithin on the contractile function of enteric wall muscles in the jejunum and ileum and jejunal barrier function in laying hens. 3. For testing muscle contraction, mid-jejunal and ileal segments (n = 4 each per hen) from four laying hens were placed in a longitudinal orientation into isolated organ baths filled with Krebs buffer and fastened to force transducers. Muscle segments were induced to contract with acetylcholine and the effects of the oil emulsions on contraction were measured. 4. For barrier function, distal jejunal pieces were stripped of serosa before mounting into Ussing chambers and recording changes in short-circuit current (ISC) and transepithelial tissue conductivity (GT) before and after addition of the respective emulsion. 5. The CBO decreased the muscle tone, representing a relaxation of on average 36.2 and 42.6 for the jejunum and ileum, respectively, compared to before the addition (P < 0.001). Moreover, CBO linearly decreased the ISC and GT of the jejunal mucosa, indicating a greater absorption of anions and increased barrier function (P < 0.001). Only the coconut oil-sunflower lecithin emulsion relaxed the muscles, whereas both coconut oil-lecithin emulsions increased the ISC but reduced the GT of the jejunal mucosa, which suggested an increased cation absorption and decreased paracellular permeability, respectively (P < 0.05). 6. In conclusion, CBO and coconut oil-lecithin emulsions showed the potential to increase jejunal barrier function, whereas CBO may be more efficacious to slow down digesta passage in the small intestine.