Abstract
Exogenous enzymes are routinely added to diets for non-ruminant animals, mainly to help enhance energy and nutrient utilization, thus contributing to efficient and sustainable production systems. Also, feed enzymes allow for effective utilization of non-traditional feedstuffs (e.g. co-products) in non-ruminant diets, with potential to mitigate feed cost. In addition to increased nutrient utilization, however, feed enzymes, through their impact on the gastrointestinal environment and microbial composition, can have a profound effect on indices of gut health and function. These effects may explain the reported reductions in medication costs and variability in animal performance and mortality rates observed with dietary enzyme supplementation. By acting on their target substrates, feed enzymes reduce the availability of non-digested substrates and in the case of carbohydrate-degrading enzymes can produce short-chain oligosaccharides with potential prebiotic effects. These changes are known to modulate the gut microbiome in favor of bacteria associated with a healthy gut, while reducing the population of pathogenic bacteria, which explains the reduced incidences of diarrhea that have been attributed to enzyme supplementation. Also, feed enzymes may reduce oxidative stress and enhance the functional capacity (e.g. maintaining barrier function) of the gastrointestinal tract. Feed enzymes by themselves may never be a single solution to mitigate gut health challenges in livestock production systems, but clearly there is a mounting body of evidence to support the role of feed enzymes in this regard. Therefore, their benefits will be maximized when used as part of an integrated solution approach for containing enteric pathogens of economic importance and eliminating the negative effects of dietary components with potential to compromise intestinal integrity.
The role of feed enzymes in maintaining broiler intestinal health through modification of the microbiota
