Campus Units
Animal Science
Document Type
Article
Publication Version
Published Version
Publication Date
2018
Journal or Book Title
Journal of Animal Science and Biotechnology
Volume
9
First Page
4
DOI
10.1186/s40104-017-0226-9
Abstract
Xylose, as β-1,4-linked xylan, makes up much of the hemicellulose in cell walls of cereal carbohydrates fed to pigs. As inclusion of fibrous ingredients in swine diets continues to increase, supplementation of carbohydrases, such as xylanase, is of interest. However, much progress is warranted to achieve consistent enzyme efficacy, including an improved understanding of the utilization and energetic contribution of xylanase hydrolysis product (i.e. xylooligosaccharides or monomeric xylose). This review examines reports on xylose absorption and metabolism in the pig and identifies gaps in this knowledge that are essential to understanding the value of carbohydrase hydrolysis products in the nutrition of the pig. Xylose research in pigs was first reported in 1954, with only sporadic contributions since. Therefore, this review also discusses relevant xylose research in other monogastric species, including humans. In both pigs and poultry, increasing purified D-xylose inclusion generally results in linear decreases in performance, efficiency, and diet digestibility. However, supplementation levels studied thus far have ranged from 5% to 40%, while theoretical xylose release due to xylanase supplementation would be less than 4%. More than 95% of ingested D-xylose disappears before the terminal ileum but mechanisms of absorption have yet to be fully elucidated. Some data support the hypothesis that mechanisms exist to handle low xylose concentrations but become overwhelmed as luminal concentrations increase. Very little is known about xylose metabolic utilization in vertebrates but it is well recognized that a large proportion of dietary xylose appears in the urine and significantly decreases the metabolizable energy available from the diet. Nevertheless, evidence of labeled D-xylose-1-14C appearing as expired 14CO2 in both humans and guinea pigs suggests that there is potential, although small, for xylose oxidation. It is yet to be determined if pigs develop increased xylose metabolic capacity with increased adaptation time to diets supplemented with xylose or xylanase. Overall, xylose appears to be poorly utilized by the pig, but it is important to consider that only one study has been reported which supplemented D-xylose dietary concentrations lower than 5%. Thus, more comprehensive studies testing xylose metabolic effects at dietary concentrations more relevant to swine nutrition are warranted.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Copyright Owner
The Author(s)
Copyright Date
2018
Language
en
File Format
application/pdf
Recommended Citation
Huntley, Nichole F. and Patience, John F., "Xylose: absorption, fermentation, and post-absorptive metabolism in the pig" (2018). Animal Science Publications. 713.
https://lib.dr.iastate.edu/ans_pubs/713
Included in
Agriculture Commons, Animal Sciences Commons, Biochemical Phenomena, Metabolism, and Nutrition Commons
Comments
This article is published as Huntley, N.F., Patience, J.F. Xylose: absorption, fermentation, and post-absorptive metabolism in the pig. J Animal Sci Biotechnol 9, 4 (2018). doi: 10.1186/s40104-017-0226-9.