Investigating changes in salivary oxytocin in horse with EGUS

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 Gastric ulcers are common in horses, with studies indicating their presence in approximately 60% of sport horses and up to 90% of Thoroughbred racehorses in training.

Gastric ulcers have been associated with various non-specific clinical signs, including weight loss, reduced appetite, poor physical condition, dullness, colic, diarrhea, poor performance, and behavioural changes. However, many adult horses with gastric ulcers exhibit no obvious signs.

Equine gastric ulcer syndrome (EGUS) is categorised into two types: equine squamous gastric disease (ESGD) and equine glandular gastric disease (EGGD). A definitive diagnosis requires gastroscopy, a relatively straightforward yet costly procedure.

There is growing interest in identifying biomarkers to assess gastric health non-invasively. One such biomarker is oxytocin, a peptide hormone that plays a role in stress regulation and gastric protection. Salivary oxytocin has been explored as a potential welfare indicator due to its antiulcer and gastric antisecretory properties. It helps reduce acid production and promotes mucosal protection by enhancing blood flow to the stomach lining. Additionally, as oxytocin is involved in social bonding and stress regulation, it may help prevent stress-induced ulcers.

Researchers aimed to investigate differences in salivary oxytocin levels in horses with and without gastric ulcers while also validating an AlphaLISA-based immunoassay for measuring oxytocin in horse saliva. A report of the work is published by BMC Veterinary Research. 

The study involved 102 horses, which were divided into five groups:

·       25 horses with both ESGD and EGGD

·       23 horses with only EGGD

·       21 horses with only ESGD

·       19 horses with other diseases

·       14 healthy horses

Diseased horses were admitted to the Large Animal Teaching Hospital at the University of Copenhagen, Denmark, while healthy horses were sampled at the Veterinary Teaching Hospital of the University of Extremadura, Spain. All examinations took place between February 2022 and March 2023.

The research team found that the assay demonstrated high precision and accuracy for measuring oxytocin in equine saliva. They highlighted the advantages of the AlphaLISA method over conventional ELISA kits, including the elimination of washing steps and the need for a lower sample volume (10 µL vs. 100 µL for ELISA). They point out that this is makes it a more practical option in clinical settings.

Their results showed that healthy horses had higher salivary oxytocin levels compared to those with EGGD or both EGUS types. Horses with only ESGD also had higher oxytocin levels than those with EGGD or both forms of EGUS. Additionally, horses with other diseases had higher oxytocin levels than those with EGGD or mixed EGUS cases.

The findings suggest a potential link between lower oxytocin levels and EGGD or mixed EGUS cases. However, further research is necessary to fully understand oxytocin's role in EGUS development and progression.

For more details, see: 

 

Botía, M., Muñoz-Prieto, A., Martínez-Subiela, S., Martín-Cuervo,^, M.,  Hansen, S. ,  Manteca, X. , Joaquín Cerón, J.,  López-Arjona, M.

Oxytocin in horse saliva: validation of a highly sensitive assay and a pilot report about changes in equine gastric ulcer syndrome. 

BMC Vet Res (2025) 21, 90 

https://doi.org/10.1186/s12917-025-04569-3