The pig microbiome is an intriguing area of science. How does it function? In what ways does it impact pig performance? While many discoveries have been made in this area, we’re just scratching the surface and don’t yet have a full understanding of the microbiome’s influence.  

The microbiome is composed of all the microflora (bacteria, viruses, protozoa and fungi) that live on or within a host organism. As researchers continue to learn about the pig microbiome, we’re finding more and more ways it can impact the animal.

One of the more common associations with the pig microbiome is the immune system – specifically related to the gut. The gut contains about 70% of the pig’s immune system. As gut function declines, the potential risk increases for disease and performance loss. Much of the industry research to date has focused on ways to support the gut microbiome, strengthening defenses to better address pig health challenges.      

A less talked about area of research is the role of a pig’s microbiome in functional digestion.

Feed efficiency can improve when the gut microbiome is balanced. Both good and bad bacteria are a natural and important part of a balanced gut microbiome. The good bacteria break down fiber from the diet and turn it into short-chain fatty acids that the pig can use for energy. When the gut microbiome is in dysbiosis (or out of balance) and doesn’t contain enough good bacteria, the feed doesn’t stay in the gut as long as it should, and the pig doesn’t capture as much energy from feed, affecting growth potential.

The microbiome’s impact on nursery pigs

When we think about the microbiome being out of balance, we usually think about nursery pigs and newly weaned pigs. In these phases, pigs are more susceptible to disease because their immune systems are underdeveloped.

Growth in this phase sets the foundation for grower pig and finishing pig performance, making it critical to maintain pig health for optimal finishing potential. Research at the Purina Animal Nutrition Center showed that weaning weights and end-of-nursery weights are strong predictors of finishing weights. In an 18-month study involving 1,770 pigs, results indicated each additional pound at weaning was correlated to an increase of 1.8 pounds at Day 32. Each additional pound at Day 32 post-weaning correlated to 2.1 additional pounds at finishing on Day 110.^[1]

Industry research is looking into how we can “seed” a pig’s microbiome early to influence the microbiome composition – potentially boosting average daily gain and supporting the pig's immune system in the nursery phase.

For example, can we better prepare the pig’s gut to transition from a liquid-only diet to a dry-feed diet? Can we influence the microbiome early on to improve fermentation and energy absorption in newly weaned pigs? What is the ideal gut microbiome composition to help support immune function? These are the questions researchers are investigating today.

The evolution of pig microbiome research

In the past, scientists relied heavily on culture methods to identify bacterial populations in various samples. However, this methodology has many limitations when trying to identify the scope and abundance of bacteria present. For example, many bacteria are unculturable or have not been fully characterized, making identification difficult.

Yet recent technological advances have drastically improved the speed and cost of analyzing the microbiome. At Purina’s state-of-the-art Emerging Technology Center and Center for Animal Metabolism and Microbiology, we have the capabilities to do everything from culturing pathogenic bacteria to whole genome sequencing. Our research scientists are able to identify different types of bacteria and quantify how many of each are present in a particular microbiome – and then compare changes in that population either across time or between animals. 

Why is this important?

By analyzing multiple microbiome samples, we can build a data set that identifies commonalities and differences between high-performing pigs and low-performing pigs. If we can get down to the specifics to understand which microbiome composition is the most effective for a weaned pig, or a sow or a finishing pig, we can develop customized solutions that help support and develop an optimal microbiome population in pigs.

Considering the trillions of microflora that can make up a pig’s microbiome, this will be a long process that will take many years to fully explore and understand.

One of the first steps towards this larger goal is the development of the Microbiome Quotient™ service for the commercial poultry industry – a service that allows our team to analyze microbiome samples from individual operations and identify customized solutions to optimize performance. We are working on developing a similar program for the swine industry in the future. 

Connect with a Purina swine nutritionist to learn more.