By Caleb Shull and Omarh Mendoza of The Maschhoffs
Gut health has received significant attention lately in both humans and animals. Although there are many exciting opportunities in the realm of gut health and the impact of the microbiome on the host species, there are just as many unknowns. In partnership with various companies and universities, we have collected thousands of pig microbiota samples and have run multiple research trials investigating the impact of microbial supplementation. These efforts have enabled us to garner some insights into this exciting field of study.
How can diet impact gut health?
It is generally accepted that a highly diverse microbial population in the gut is beneficial to the host, whether that be a pig or another species. In our internal work, we have seen that microbial community diversity changes significantly throughout the life of the pig. These changes are particularly pronounced during weaning when pigs are transitioned from a milk-based diet to a grain-based solid diet.
Microbial populations that were established and adapted to milk as the main substrate are diminished and new populations are established. We have also seen a profound effect of diet composition on the microbiome in growing pigs. In addition, the inclusion of feed-grade antibiotics can have a significant impact on microbial diversity and could impact the representation of certain beneficial species.
Even within specific populations of pigs, a significant amount of variation in the gut microbiome is typically observed. We and others have concluded certain microbial populations are associated with increased growth performance and carcass leanness, which is encouraging to say the least. The challenge, however, is to separate cause and effect of these associations.
Do microbial products make a difference?
Several commercially available microbial products have been developed based on their association with growth performance. We have experienced mixed results with these products, which suggests the impact of such organisms might be situation specific. Many of these products are based on Bacillus or Lactobacillus species, which are fairly resilient outside the host and can survive during the feed manufacturing process.
Other microbes that are more sensitive to external environments but potentially more impactful on pig growth performance have been evaluated as supplements and shown to successfully colonize the pig digestive tract. The benefit of these new microbial products needs to be established and weighed against the resources, namely labor, required for their use in a commercial setting.
An alternative use of microbial products is the use of microbes that prevent or inhibit harmful bacteria that cause disease or intestinal challenges. More work needs to be done in this area to determine the viability of the approach.
How does genetic selection factor in?
Another exciting finding is the potential for genetic selection for microbiome diversity. Recent work has shown moderate heritability for specific microbial populations that are correlated with pig growth and backfat. These genetic relationships offer the potential to explain more of the variation between animals and enhance genetic progress.
There is still a lot to be learned about the microbiome and its relationship with pig health and production parameters. However, it is clear ignoring the vast number of living organisms that reside in the digestive tracts of pigs would be a mistake.
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