Supplementation of Xylanase and Mannanase Influences in Vitro Fermentation Characteristics of DDGS in the Large Intestine of Swine

Fermentation substrate modulates the composition of the microbial community and the end-products of microbial metabolism; hence, substrate may influence nutritional, physiological and immunological function in pigs. After arabinoxylan, mannan is the second most abundant hemicellulosic polysaccharide present in corn distillers dried grain with solubles (DDGS), which is not degraded by endogenous enzymes in swine, and subsequently reduces the digestibility of other nutrients. Utilization of byproducts like DDGS in swine feeding can be enhanced by supplementing with enzymes. DDGS with three enzymatic treatments (xylanase, mannanase, and xylanase + mannanase) and without enzymes along with inulin and a blank as a positive and negative control, respectively, were used in this in vitro study to evaluate the effect of supplemental enzymes on fermentation characteristics of DDGS in the large intestine of swine. After a 2-step enzymatic digestion, residues were fermented using fresh pig feces as a microbial inoculum and gas production was recorded periodically for 72 h by means of a pressure transducer. Gas production was then modeled mathematically. The VFA in the fermented liquid phase was measured by gas chromatography. Supplementation with xylanase significantly increased (P < 0.05) total gas production (223 to 256 ml gas/g sample incubated). Supplementation with xylanase also significantly increased (P < 0.05) production of acetate, total VFA, and propionate, i.e. excess propionate produced would provide energy to the animal via gluconeogenesis. Conversely, mannanase supplementation significantly increased production of butyrate (P < 0.05), signifying its role in providing energy to colonocytes and supporting gut health.