Interactions Between Dietary Fibre and the Intestinal Mucosa and Their Effect on the Gut Health of Young Pigs

Diet can have a major influence on animal health. This impact can be beneficial or harmful if it leads to a proliferation of pathogenic bacteria. Dietary fibre (DF) is a component  of the diet that can have a major impact on gut health. DF is not readily digested by young pigs and forms the main substrate for bacterial fermentation in the intestinal tract. Various components in DF can either improve gut health or alternatively irritate the gut and cause diarrhea as a result. Thus, it is important to know how DF interacts with the intestinal mucosa to protect against or enhance enteric infections.

Since the use of antibiotics for growth promotion is being actively discouraged, alternative methods to control enteric bacterial pathogens have been investigated. Dietary manipulation of the fermentation in the hind gut is one method that can be used to improve “gut health.” Gut health is a complex entity comprised of three components (diet, the gut mucosa and microflora). Since DF is the main substrate for bacterial fermentation and interacts with both the mucosa and the micorflora, it has an important role in the control of “gut health.”

The effects of DF on amino acid digestibility, endogenous losses and digestibility of other nutrients is well documented. Soluble fibre increases transit time, delays gastric emptying  and slows absorption whereas insoluble fibre decreases transit time, enhances water holding capacity and assists faecal bulking. The reductions in nutrient digestibilities can be considered to be anti-nutritive effects and are important considerations for young pigs however DF might help to protect against the build up of pathogenic bacteria.

Some authors have suggested that DF can help to overcome some of the post weaning growth lag seen in young weaned pigs. Fibre from oats, wheat and barley are supposed to have some benefit, however this is not always true and depends on the part of the grain that is used. As a result little DF is added to diets or young pigs.

Dietary fibre has a major effect on gut development by increasing the size and length of various organs such as the small intestine. DF can also influence the villus height/crypt depth ratio and this might lead to an increase in the absorptive capacity in the small intestine. If the ingestion of DF improves the absorption of both food and liquid, this may help to reduce the incidence of diarrhea.

Ultimately, the interaction between dietary fibre and the intestinal mucosa is complex. Diet does have an important role to play in disease and health. For young pigs, DF may have some benefits for gut health such as reducing the severity of diarrhea and assisting with rehydration. DF influences gut health by a series of complex interactions with the intestinal epithelium, the mucus and the microflora. There is still much to learn regarding these interactions.

Reference: 2003. Animal Feed Science and Technology 108:95-117.

Prepared by: Ian R. Seddon, Ph.D.

Published by Manitoba Agriculture, Food and Rural Initiatives
Nutrition Update (Volume 15 No.1)