Interpretive Summary: Flaxseed meal and oat hulls supplementation: impact on dietary fiber digestibility, and flows of fatty acids and bile acids in growing pigs
By: Anne Wallace
In this study published in the January 2019 Journal of Animal Science, researches supplemented nutritionally balanced pig feed with flaxseed meal (FM) and oat hulls (OH). Their goal was to determine how fiber rich components (like FM and OH) might affect dietary fiber (DF) digestibility, and fatty acid (FA) and bile acid (BA) gastrointestinal flow and utilization in growing pigs. Previous studies have noted diets high in fiber with added fat can reduce performance in pigs even though they are fed nutritionally balanced diets.
A total of 12 barrows of similar body weight were fed two treatment diets (two-period cross-over design). During each period, 8 pigs were fed a treatment diet, and 4 pigs were fed a control diet. The diets were formulated as follows: nutritionally balanced corn-soybean meal-based basal diet with no FM or OH (control diet), basal diet with added FM (FM diet) or basal diet with added OH (OH diet). Samples of fecal material and ileal digesta (from cannula ports) were collected and analyzed for contents during the study period.
It was found that pigs fed OH and FM diets excreted more BA in feces than the control pigs. FA digestibility was also significantly reduced in pigs fed both the FM and OH diets, compared to the control diet. The OH pigs also had greater gastrointestinal flow of FAs and short-chain fatty acids compared to pigs fed FM and control diets.
Overall, the results of this small study suggest that addition of OH and FM to nutritionally balanced pig feed, which are both high in soluble and insoluble fibers, do appear to affect the digestibility of FA as well as the excretion and flow of BA and FA. Repeat studies to include a larger number of animals and replicate these results is justified. More in-depth studies to confirm the authors’ hypothesis about potential mechanisms responsible for the reduced digestibility influencing gut fermentation e.g. dietary fiber bulking, viscosity, or alteration to gut microbiota, is also warranted.
To view the article, “Flaxseed meal and oat hulls supplementation: impact on dietary fiber digestibility, and flows of fatty acids and bile acids in growing pigs,” visit the Journal of Animal Science.