Spectroscopy able to detect emergence of fatigue in horses – study

The use of Raman spectroscopy on blood serum samples from athletic horses identified metabolic changes involved in the emergence of fatigue, researchers report.

Raman spectroscopy is a technique for the analysis of biological fluids. It has been proven effective for the analysis of proteins. The technique is widely used in the study of human biofluids, such as tears, urine and sweat.

Researchers at the University of Messina in Italy said the evaluation of performance levels in athletic horses is important to prevent sports injuries.

The scientists, writing in the journal Animals, set out in their prospective study to evaluate the use of Raman spectroscopy to assess changes in serum metabolic biomarkers collected before and after a jumping course completed by five regularly trained Italian Saddle Horse geldings aged 8 to 10.

All horses were healthy and had undertaken the same level of training under the same training program.

The obstacle course consisted of a 350-metre trail with eleven 1.25-metre jumps.

Four blood samples were collected from each horse for analysis – one before the course was undertaken, one immediately after, and further samples 30 minutes and 1 hour after its completion.

Analysis by Raman spectroscopy revealed metabolites involved in the rise of fatigue. Lipids and tryptophan were identified in one frequency band, while leucine, glycine, isoleucine, lactic acid, tripeptide, adenosine, and beta carotene were identified in another.

“A significant effect of exercise was recorded on all the sub-bands,” Giuseppe Acri and his fellow researchers reported. “In particular, a change immediately after exercise versus before exercise was found.”

The average lactic acid concentration was positively correlated with the Raman area of the sub-band assigned to lactic acid.

“In this context, the application of Raman spectroscopy on blood serum samples represents a useful technique for secondary-structure protein identification to investigate the metabolic changes that occur in athletic horses during physical exercise,” they said.

Raman spectroscopy analysis is a technique that has been shown to be easy to perform, rapid, reproducible, and non-invasive, the authors said. “It does not require special chemical diagnostic kits, it is non-destructive, and the limit of the analysis is only represented by the degradation of the sample itself.

“Our results can be considered a starting point for further studies on larger numbers of horses to confirm our results.”

They continued: “It seems only right to emphasize that each amino acid spectrum is unique, and if it is exposed to a different environment because of conformational changes in the protein upon binding, this will appear in the Raman spectrum.

“As this study demonstrated, this technique provides useful information for understanding horses’ responses to physical exercise, to monitor training programs, and to obtain an early poor-performance diagnosis, which can be performed in the field.”

In particular, there is potential for the use of hand-held Raman and stimulated Raman scattering devices, they said.

The study team comprised Acri, Barbara Testagrossa, Giuseppe Piccione, Francesca Arfuso, Elisabetta Giudice and Claudia Giannetto, all with the University of Messina.

Acri, G.; Testagrossa, B.; Piccione, G.; Arfuso, F.; Giudice, E.; Giannetto, C. Central and Peripheral Fatigue Evaluation during Physical Exercise in Athletic Horses by Means of Raman Spectroscopy. Animals 2023, 13, 2201. https://doi.org/10.3390/ani13132201

The study, published under a Creative Commons License, can be read here.