Fiber Fortification and Functionality in Innovative Companion Animal Nutrition Products

Introduction

Historically, fiber-containing ingredients when incorporated into a pet food have been associated with grain by-products. Thus “fiber” has been associated with the nutritional term “crude fiber, and has been looked upon as a more negative component in pet foods. In recent years, a better understanding of the nutritional and physiological functions of fiber has made it an important nutrient in the formulation of companion animal foods and treats.

Fiber Forms and Functions

Fiber as a nutrient falls into one of two categories: insoluble “bulking” fibers and soluble “fermentable” fibers. Both of these types of fibers provide significant nutritional benefits to companion animals. Insoluble fibers, will reduce the rate of passage through the digestive tract, by increasing the non-digestible bulk of GI tract digesta, or increase the viscosity of the digesta. A slower rate of GI tract passage will allow more time for water re-absorption, which has a positive effect on stool quality. Ingredients such as brans, beet pulp and gums, which are high in pectin, have proven to either reduce digesta transit time or increase fecal volume.

A second important function of fibers is to provide a positive growth / fermentation substrate for GI tract microorganisms. The large intestine is a fermentation chamber, where food ingredients that have not been enzymatically digested and absorbed are then fermented by intestinal microorganisms. These organisms function mainly to break down insoluble fibers. Thus slowly digested food substrates that allow for a consistent fermentation produce the best “digestive health”. Soluble fibers like pectin, psyllium, guar gums, and beet pulp produce a slow consistent fermentation, and can help stabilize the digestion of high protein or high fat super premium pet foods.

In addition, there are novel fibers, often referred to as “prebiotic fibers” that besides providing a positive fermentation substrate, can provide other nutritional and health benefits. These fiber times include fructooligosaccharides, galactooligosaccharides, lactulose and maltodextrins. These fibers will modify the microbial population of the GI tract, which produces a more consistent fermentation that reduces the potential for digestive distress. A proper fermentation will reduce the production of compounds that are harmful to the mucosal lining of the GI tract, and produces more consistent stool quality.

Summary

The optimal level and type of fiber needed in a pet food will vary greatly depending on the overall ingredient composition of the product. Different protein and carbohydrate sources will differ in there effects on rate and extent of nutrient digestion. This needs to be considered when looking for a fiber type and level that will produce the desired nutrient digestibility and digestive tract health. Fiber sources can be blended to achieve a balance between fermentable and non-fermentable fiber. Fiber levels effect nutrient digestibility: insoluble fibers will reduce total nutrient digestibility. This may be of a benefit for a “weight control” diet, but a negative for a high-energy performance pet food.