Impact of increasing the levels of insoluble fiber and on the method of diet formulation measures of energy and nutrient digestibility in growing pigs

Abstract

The objective of this study was to determine the differences in response to distillers dried grains with solubles (DDGS) level under constant nutrient or floating nutrient concentrations. A total of 21 ileal-cannulated gilts (33.1 ± 0.4 kg body weight) were randomly allotted to one of seven dietary treatments in a 3-period incomplete Latin square design (n = 9). Treatments consisted of a 0% DDGS basal diet, plus diets containing 15%, 30%, or 45% DDGS. Diets were formulated using one of two different formulation methods: 1) constant nutrient (CNU) where nutrients were held equal to the basal diet or 2) constant ingredients (CIN) where DDGS were added at the expense of corn and all other ingredients remained constant, so nutrient levels were allowed to “float.” Chromic oxide was added to the diets at 0.5% as an indigestible marker. Increasing the level of DDGS decreased the apparent ileal digestibility (AID) of dry matter (DM), gross energy (GE), starch, dispensable amino acids (AA), and fiber components (P < 0.050). The decrease in the AID of Lys, Met, Thr, and Trp was more pronounced under CNU compared with the CIN formulation method (P < 0.050). The decrease in the AID of hemicellulose was less pronounced under CNU compared with the CIN formulation method (P = 0.045). There was a DDGS level × formulation method interaction for the AID of acid hydrolyzed ether extract (AEE; P = 0.015); for the CNU formulation method, increasing level of DDGS decreased the AID of AEE from 0% to 30% and remained similar from 30% to 45% DDGS, whereas the CIN had no effect on the AID of AEE. Increasing the level of DDGS decreased the apparent total tract digestibility (ATTD) of DM, GE, and fiber components (P < 0.050), except for acid detergent fiber, which was not affected. The decrease in the ATTD of insoluble dietary fiber and total dietary fiber was less pronounced under CNU compared with CIN (P < 0.050). The ATTD of AEE decreased for CNU compared with CIN (P < 0.010). In conclusion, increasing the insoluble fiber level in the form of DDGS decreased the digestibility of most dietary components, including DM, GE, starch, insoluble fiber, and AA. The CNU and CIN formulation methods are equivalent when evaluating the digestibilities of DM, GE, starch, crude protein, and AA (when they were not added in purified synthetic forms). Differences between CNU and CIN formulation methods were detected for the digestibility of insoluble fiber, fat, and essential AA (when added as crystalline AA).

Xylanase increased the energetic contribution of fiber and improved the oxidative status, gut barrier integrity, and growth performance of growing pigs fed insoluble corn-based fiber

“…Non-starch polysaccharides ( NSP ) are often considered an antinutritional factor in swine diets associated with reduced energy and nutrient utilization, decreased growth performance, and reduced carcass yield ( Weber et al, 2015 ; Acosta et al, 2020 ). Approximately, 49% of the NSP in corn and corn distiller’s dried grains ( DDGS ), primary sources of fiber in many U.S. swine diets, are arabinoxylans ( Jaworski et al, 2015 ).…”

Can the digestibility of corn distillers dried grains with solubles fed to pigs at two stages of growth be enhanced through management of particle size using a hammermill or a roller mill?

“…However, in the case of corn DDGS, this difference from the whole grain products might be the result of the multiple processes involved in its production. Additionally, the elevated level of insoluble fiber in corn DDGS can be a limiting factor in its utilization since pigs have limited fermentation capacity ( Acosta et al, 2020c ). Thus, although reducing the PS of corn DDGS is an effective way to increase the digestibility of numerous nutrient fractions, it does not seem to be a viable strategy to enhance the utilization of insoluble fiber in growing pigs.…”

Xylanase supplementation in corn-based swine diets: a review with emphasis on potential mechanisms of action

“…When reduced-oil DDGS are included in diet formulations at the expense of corn, the nutrient composition will change along with net energy ( NE ; Patience and Petry, 2019 ). This can be visualized by estimating the NE content and composition of NE of the constant ingredient formulation in a study by Acosta et al (2020) . In this study, for every 15% increase in reduced-oil-corn DDGS included at the expense of corn, dietary acid-hydrolyzed ether extract increased by nearly 17%, NDF increased by 34.2%, CP increased by 27%, starch decreased by 20% ( Figure 1A ), and estimated NE decreased by 83 kcal/kg or 3.5% ( Figure 1B ).…”

“…Reduced-oil DDGS contain less fat and greater NSP than conventional DDGS and as such contain less dietary energy ( Li et al, 2017 ). Typically, corn–soybean meal-based diets contain between 7% and 10% neutral detergent fiber ( NDF ), but with every 5% addition of reduced-oil DDGS in place of corn, dietary NDF will increase by approximately 1% ( Acosta et al, 2020 ).…”

“…NSP, or more simply called fiber, has taken on many definitions over the past century but has been most recently defined in the context of animal nutritionists by the Codex Alimentarius Committee of the Food and Agriculture Organization of the United Nations (2010) “as those carbohydrate polymers with ten or more monomeric units which are not hydrolyzed by the endogenous enzymes nor absorbed in the small intestine.” Indeed, pigs lack the endogenous carbohydrases needed to digest NSP and rely on microbial fermentation for NSP utilization ( Varel and Yen, 1997 ), and corn-based NSP is poorly fermentable due to its insolubility ( Gutierrez et al, 2013 ). Insoluble NSP is often touted as an antinutritive factor, as increased dietary insoluble NSP will decrease nutrient and energy digestibility, impact pig performance, and reduce carcass yield ( Weber et al, 2015 ; Acosta et al, 2020 ). However, utilizing exogenous carbohydrases may partially ameliorate these antinutritive effects.…”