The ileal, total tract and postileal digestibility of compound feeds either rich in wheat or rye in an ileo-caecal fistulated minipig model.

Environmental issues and concerns about animal welfare display current challenges in animal husbandry and feeding. Rye, a cereal that has scarcely been used in animal feed in recent decades, could help address some of the challenges in pig feeding as a climate friendly and health promoting feed ingredient. Distinct constituents of rye - especially its non-starch-polysaccharides (NSP) - are fermented in the large intestine while short chain fatty acids (SCFA) are produced in that process. This can promote gut health and the feeling of satiety in pigs. To examine the site of the digestion of rye within the digestive tract in comparison to wheat as a widely used ingredient in pig diets, two diets with high shares of either wheat or rye (each 69.0%) were fed to ileo-caecally fistulated, adult minipigs. Ileal digesta and faeces were collected and ileal, total tract and postileal digestibility rates were calculated. In the apparent ileal digestibility (AID), significant differences were only found for organic matter (OM) and Nitrogen-free extract (NfE) with lower values for the rye-rich diets (77.2 ± 2.00 vs. 73.8 ± 2.01% and 79.8 ± 2.56 vs. 75.3 ± 2.61%, respectively). These differences could not be recovered for the total tract digestibility (ATTD - 90.2 ± 2.16 vs. 89.8 ± 1.94% and 93.0 ± 1.69 vs. 92.8 ± 1.37%, respectively), resulting in an elevated postileal digestibility which was significant for NfE (13.2 ± 2.42 vs. 17.5 ± 2.77%). Therefore, rye can be used to promote hindgut fill and fermentation in pig feeding, especially in restrictively fed animals such as pregnant sows.