April 03, 2019

Interpretive Summary: Exogenous carbohydrases in the starter diets of weaned pigs

Interpretive Summary: Exogenous carbohydrases added to a starter diet reduced markers of systemic immune activation and decreased Lactobacillus in weaned pigs.

By: Anne Wallace

Carbohydrases are enzymes that break down complex carbohydrates including non-starch polysaccharides (NSP). These enzymes subsequently improve nutrient utilization and animal performance; postweaning pigs may therefore benefit from carbohydrases added to their feed. As an additional benefit, degraded NSPs release various dietary fibers which serve as a food source (prebiotics) for good bacteria (probiotics) within the animal gut. 

Prebiotics are known to benefit both gut health and gut microbial ecosystems. The authors of this study therefore aimed to better characterize the effects of carbohydrases on gut immunity and the microbiota of weaned pigs in this paper published in the March 2019 Journal of Animal Science. 

Xylanase (X), and a cellulase, ß-glucanase, xylanase blend (EB) were the carbohydrases evaluated in this study. A total of 460 pigs were fed one of four diets (corn, soybean, wheat-based) for 28 days, as follows: (1) high fiber control diet (CON), (2) CON supplemented with 0.01% X, (3) CON supplemented with 0.01% EB, or (4) CON supplemented with both X and EBat 0.01%. Intestinal tissue and digesta were collected on the last day of the study, and samples of blood were periodically collected throughout the study. Digesta was analyzed with qPCR.

There was increased gene expression of anti-inflammatory markers and tight junction proteins (IL-17, occludin, claudin 3) in the colons of pigs fed both X and EB, compared to the control. The X/EB combination also noted decreased inflammatory markers TNFα and IL-1ß. A reduction in IL-8 occurred in pigs fed only EB. These changes overall suggest there may be potentially improved bowel epithelial barrier integrity and a reduction in immune-mediated inflammation. Gut microbiota changes were also noted, as follows: in pigs fed X, Lactobacillusin the lower ileum were decreased, whereas in the ileum and cecum, Enterobacteriaceae increased, compared to control. Lactobacillus and volatile fatty acids (microbial fermentation byproducts) were also decreased in pigs fed EB. 

The results of this study suggest that carbohydrases may have the potential to alter gut microbial composition and immunity in weaned pigs, particularly the X/EB combination. Additional studies to better characterize the effects of these changes on pig gut microbiota, microbial metabolites, performance, and immunity more comprehensively are warranted. 

To view the article, visit the Journal of Animal Science.