Feed supplemented with organic acids does not affect starch digestibility, nor intestinal absorptive or secretory function in broiler chickens

The current study aimed to determine the impact of acidified feed on apparent ileal starch digestibility, intestinal transport and barrier function and intestinal glucose transporter expression. The experiment included a control group and a treatment group with broilers fed a standard diet without or with 1.5% of a commercial organic acid product (64% formic acid, 25% propionic acid, 11% water). Broilers were fed with the experimental diets from hatching until days 32-35. Starch digestibility was determined using 0.2% titanium dioxide as ingestible marker. Gene expressions of the intestinal sodium glucose transporter 1 (SGLT-1) and glucose transporter 2 (GLUT-2) were analysed using qPCR analysis. Additionally, SGLT-1 function and chloride secretion were analysed in Ussing chamber experiments. Jejunal samples were sequentially exposed to 10mm glucose, 100m phloridzin, 100m histamine and 100m carbachol. Apparent ileal starch digestibility (+/- SEM) of the control group (97.5 +/- 0.35%) and the acid-treated group (97.0 +/- 0.59%) did not differ (p=0.674). The mean tissue conductance of intestinal samples obtained from the control group and the treatment group was similar [10.6mS/cm(2) (+/- 0.68) and 9.4mS/cm(2) (+/- 0.80) respectively (p=0.147)]. The mean short-circuit currents (I-sc) of the samples exposed to glucose, phloridzin, histamine and carbachol did not differ (p>0.05). Additionally, no differences in the expression of SGLT-1 and GLUT-2 could be observed (p=0.942, p=0.413). Based on this study, the consumption of feed supplemented with organic acids was not associated with effects on ileal starch digestibility and functional traits of jejunal tissues, indicating that these additives have no major impact on the small intestinal function in broilers.