A horse's gut microbiome communicates with its host by sending chemical
signals to its cells, which has the effect of helping the horse to extend
its energy output, finds a new study published in Frontiers in Molecular
Biosciences. This exciting discovery paves the way for dietary supplements
that could enhance equine athletic performance.
"We are one of the first to demonstrate that certain types of equine gut
bacteria produce chemical signals that communicate with the mitochondria in
the horse's cells that regulate and generate energy," says Eric Barrey,
author of this study and the Integrative Biology and Equine Genetics team
leader at the National Research Institute for Agriculture, Food and
Environment, France. "We believe that metabolites - small molecules created
by breaking down bigger molecules for food or growth - produced by these
bacteria have the effect of delaying low blood sugar and inflammation in the
cells, which in turn extends the horse's athletic performance."
Links to disease
Mitochondria, which can be briefly described as the energy provider of
cells, have been shown in recent studies to be interdependent with gut
bacteria. In fact, many diseases associated with mitochondrial dysfunction
in humans, such as Parkinson's and Crohn's have been linked to changes in
the gut microbiome in many previous studies.
"Studying horses is a good way to assess the link between gut bacteria and
mitochondria, because the level of exercise, and thereby mitochondrial
function, performed by a horse during an endurance race is similar to that
of a human marathon runner," explains Dr Nuria Mach, first author of this
paper, also based at the National Research Institute for Agriculture, Food
and Environment, France.
She continues, "For this study we gained permission for veterinary doctors
to take blood samples from 20 healthy horses of similar age and performance
level, at the start and end of the International Endurance Competition of
Fontainebleau, an 8-hour horse race in France. These samples provided
information about the chemical signals and expression of specific genes,
which is the process by which DNA is converted into instructions for making
proteins or other molecules. To understand the composition of the horse's
gut bacteria metabolites, we obtained fecal samples at the start of the
race."
The researchers found that certain bacteria in the gut were linked to the
expression of genes by the mitochondria in the cells. Furthermore, the genes
that were expressed, or "turned on", were linked to activities in the cell
that helped it to adapt to energetic metabolism.
Evolutionary explanation
"Interestingly, mitochondria have a bacterial origin - it is thought they
formed a symbiotic relationship with other components to form the first
cell. This may explain why mitochondria have this line of communication with
gut bacteria," says Barrey.
Mach concludes, "Improving our understanding of the intercommunication
between the horse and the gut microbiome could help enhance their individual
performance, as well as the method by which they are trained and dietary
composition intake. Manipulating the gut microbiota with probiotic
supplements as well as prebiotics, to feed the good bacteria, could be a way
for increasing the health and balance of the microbiome and horses, to
better sustain endurance exercise."
Reference:
Mach N, Moroldo M, Rau A, Lecardonnel J, Le Moyec L, Robert C and Barrey E
(2021) Understanding the Holobiont: Crosstalk Between Gut Microbiota and
Mitochondria During Long Exercise in Horse. Front. Mol. Biosci. 8:656204. doi:
10.3389/fmolb.2021.656204