Interpretive Summary: Impact of increasing the levels of insoluble fiber and on the method of diet formulation measures of energy and nutrient digestibility in growing pigs
By Anne Wallace
High fiber pig feed is cost effective yet poorly digested due to an excess of insoluble fiber. Excess insoluble fiber may unfortunately negatively impact digestibility as it cannot be broken down by digestive enzymes and also impairs the digestibility of starch. Corn distillers dried grains with solubles (DDGS) is one such ingredient. However, DDGS is a valuable ingredient despite its high insoluble fiber content as it is both cost effective and increases the nutrient value of pig feed.
The authors of this June 2020 Journal of Animal Science study hypothesized that increased DDGS would reduce both energy and nutrient digestibility in growing pigs. They also evaluated constant ingredient (CIN) versus constant nutrient (CNU) formulations in order to determine if one formulation was preferable to the other.
Pigs were fed one of seven different diets with concentrations of DDGS ranging from 0% to 45% of basal feed. Results indicated that the apparent ileal digestibility (AID) of dry matter (DM), gross energy (GE), starch, and amino acids (AA) were all decreased with increased DDGS. The apparent total tract digestibility (ATTD) of DM, GE and fiber were also decreased with increased DDGS. There was no notable difference between CIN versus CNU formulations, except with insoluble fiber, fat (CNU method recommended), and purified-synthetic AA (CIN method recommended).
Overall, the results of this study support the authors’ hypothesis that increased DDGS reduces the digestibility of feed in growing pigs. The data from their results may be useful for determining a balance between cost effectiveness and digestibility when adding DDGS to pig feed. Further studies looking at the impacts of DDGS on digestibility are warranted.