#14-234

Complete

Date Full Report Received

09/30/2016

Date Abstract Report Received

09/30/2016

Investigation

Institution:
Primary Investigator:

This project speaks directly to the objective of the National Pork Board to “enhance nutrient extraction from low energy feedstuffs including but not limited to the effect of dietary factors on digestibility, gut function, and enzyme supplementation.” With the growing demand for corn from ethanol and other industries, pork production has been using and will continue to use increased corn co-products in swine diets. These co-products are lower in energy and higher in fiber compared to corn. Therefore, the industry as a whole is presented with the challenge of maintaining productivity while feeding lower energy feedstuffs. Xylanases are enzymes that break down the hemicellulose component in plant fibers. By supplementing xylanase enzymes in the diet, it is hypothesized that the dietary fibers will be broken down, allowing the pig’s natural enzymes access to trapped nutrients as well as the smaller broken down fiber fragments, thereby increasing digestibility. Improving digestibility of these lower energy, high fiber feedstuffs would allow pork producers to maintain production while feeding lower quality, cheaper feedstuffs. Understanding how the enzyme works within the body of the pig can help ensure the most appropriate use for the xylanase enzyme to achieve the best possible return on investment. This research will also help to determine whether an adaptation period is necessary for the xylanase enzyme to be effective, as has been previously suggested. Overall, this project aims to better understand how the xylanase enzyme works within the pig in order to provide the pork industry with guidance on when and how to use the enzyme most effectively.

Thirty-two gilts surgically fitted with T-cannulae at the end of the small intestine were randomly allotted into one of four dietary treatments on d 0 of the experiment, and remained on the same diets throughout the trial. Experimental diets were arranged in a 2 × 2 factorial with the first factor being fiber level (corn-SBM vs corn-SBM-30% DDGS), and the second factor being enzyme inclusion (no enzyme vs xylanase enzyme added at industry standard level). Three 5-day collections occurred during the trial (d 8 to 12, d18 to 22, d 38 to 42), each of which consisted of a 2-day fecal collection followed by a 3-day ileal collection. These collection times corresponded to body weights of approximately 4o kg, 60 kg and 80 kg.

This research found that xylanase inclusion increased energy digestibility in low fiber diets, but had no effect on energy digestibility in high fiber diets. Xylanase inclusion actually decreased fiber digestibility in the small intestine, regardless of fiber level in the diet. The inclusion of xylanase altered the pattern of energy digestibility
over the course of the trial; however the xylanase and non-xylanase treatments did not significantly differ from one another at any of the three collection periods. Xylanase inclusion did increase energy digestibility from d 20 to 40, whereas the non-xylanase treatment did not increase significantly. The question remains if this increase would have continued after 40 days, allowing the xylanase treatment to surpass the non-xylanase treatment.