81 Measuring biomarkers to assess the effect of diet on the mucosal integrity of the equine large intestine

Abstract

Alterations in the integrity of the intestinal mucosa can lead to severe health issues, which can manifest as an increase in mucosal permeability and/or in malabsorption of nutrients. In horses, the hindgut acidosis and the disbalance of the intestinal microbiota caused by excessive starch intake may jeopardize mucosal integrity. In other species, studies suggest that polyphenols could play a protective role for maintaining mucosal integrity. Thus, the objective of this study was to evaluate the integrity of the mucosa of the large intestineby measuring biomarkers of intestinal permeability and absorption in horses fed either a high-fiber or a high-starch diet, combined with a polyphenol-rich plant (sainfoin) supplementation. Twelve adult geldings (7 ± 2 years old,515 ± 53 kg BW) were enrolled in a 4 periods × 4 diets Latin square design, including 4 21 d experimental periods separated by 21 d wash-out periods. The 4 iso-caloric and iso-nitrogenous rations included either high-fiber (HF; 18.5g DM hay/kg BW) or high-starch meals (HS; 8.0g DM hay+6.3g DM barley/kg BW; 1.9g starch/kg BW/meal), and were supplemented with ether control (CONT; 3.1g DM sunflower meal+hay/kg BW) or sainfoin pellets (SF; 3.1g DM Equifolia [Multifolia]/kg BW). Feces and blood were sampled at theend of each experimental period to measure fecal and plasma acetate concentrations, and plasma lipopolysaccharides (LPS) concentration. Mixed effect models were used to assess the effect of the diet (HF vs HS), supplementation (CONT vs SF), and their interaction on these parameters. When horses were fed the diet HS, higher concentration of fecal acetate (P < 0.001) and lower concentration of plasma acetate (P = 0.007) were observed compared with diet HF. This might indicate a decreased absorption capacity through the intestinal wall with diet HS. However, no significant effect of the diet was observed on plasma LPS concentration which suggests that the permeability of the intestinal mucosa is not modified after 21 d with these diets. Adding sainfoin to the ration did not alter the monitored parameters related to mucosal integrity. The next step would be to monitor mucosal permeability and absorption for longer periods of time (longer that the 21-d monitoring done here). This might allow to have a better insight on the effect of diet on mucosal integrity.