The field of equine metabolomics is being under-utilized, according to scientists, who say opportunities to develop diagnostic tools and select animals for more desirable traits are being bypassed.
Metabolomics is the scientific study of the set of metabolites – they’re the substances formed in metabolism – that are present within an organism, cell, or tissue.
Advanced analytical chemistry techniques allow scientists to comprehensively measure large numbers of small-molecule metabolites in cells, tissues and biofluids.
The ability to rapidly detect and quantify hundreds or even thousands of metabolites within a single sample is helping scientists paint a far more complete picture of system-wide metabolism and biology.
It is now routinely used in biomedical, nutritional and crop research. It is also being increasingly used in livestock research and livestock monitoring.
Researchers from Canada’s University of Alberta set out to review available scientific literature on livestock metabolomics for five of the most common livestock species – cattle, sheep, goats, horses and pigs.
Seyed Ali Goldansaz and his colleagues identified 149 manuscripts covering all five species that met the criteria for their review.
Most livestock metabolomic studies focused on issues related to animal health, nutrition and production, they reported.
“However, we were surprised to see relatively few efforts focused on metabolomic characterization of healthy animals with the aim of identifying baseline values for different metabolites in different biofluids or tissues. In fact, only 16 studies (10%) of this kind were reported.
“These ‘referential surveys’ are foundational and are often needed before biomarker studies could/should be undertaken or fully understood,” the study team reported in the open-access peer-reviewed journal PLOS ONE.
“The least studied group were horses with only five reported equine metabolomic studies.” This represented just 3% of the papers considered suitable for inclusion in the review.
The primary focus for equine metabolomics has been on drug discovery and doping detection, specifically for Thoroughbred horses, they said.
“Given the large sums of money directed to horse racing, this is not unexpected. However, compared to the widespread applications of metabolomics in other livestock species for other purposes, it is clear that equine metabolomics is being under-utilized.
“Certainly, equine metabolomics could be used to select more desirable traits and higher value or higher performing animals, similar to what is being done for bovine metabolomics.
“Likewise, metabolomics could serve as a diagnostic or prognostic tool for improving equine health and disease resilience (as it has for essentially all other livestock species).”
They said they found no metabolomic studies looking at common diseases in horses such as equine flu, equine herpes, Equine Eastern Encephalitis, anemia, laminitis and azoturia (tying up).
“Livestock metabolomics studies also appear to be missing a number of opportunities currently being pursued in human biomedical research.
“One of particular note is the use of metabolomics to predict (as opposed to diagnose) or detect subclinical forms of disease. While disease diagnosis is useful, often it is too late or too costly to perform useful veterinary interventions.”
The authors found that coverage of the cattle metabolome was quite extensive. In contrast, there was an obvious gap in terms of the coverage of other livestock species, with goat and equine metabolomes being very poorly characterized.
“Much more work is needed on goat and horse metabolomes to bring them up to the level seen in the bovine metabolome,” they said.
The review team comprised Goldansaz, An Chi Guo, Tanvir Sajed, Michael Steele, Graham Plastow, and David Wishart.
The authors also compiled data on the known composition of the livestock metabolomes for the five species, now available through an open access, comprehensive livestock metabolome database.
The database will enable livestock researchers and producers to conduct more targeted metabolomic studies and to identify where further metabolome coverage is needed.
Goldansaz SA, Guo AC, Sajed T, Steele MA, Plastow GS, Wishart DS (2017) Livestock metabolomics and the livestock metabolome: A systematic review. PLoS ONE 12(5): e0177675. https://doi.org/10.1371/journal.pone.0177675