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Unravelling Faecal Microbiota Variations in Equine Atypical Myopathy: Correlation with Blood Markers and Contribution of Microbiome
by
, , , , , , , ,
Anne-Christine François
1,*,†,
Carla Cesarini
2,†,
Bernard Taminiau
3,
Benoît Renaud
1
,
Caroline-Julia Kruse
4,
François Boemer
5,
Gunther van Loon
6
,
Katrien Palmers
7,
Georges Daube
3,
Clovis P. Wouters
1,
Laureline Lecoq
2,
Pascal Gustin
1 and
Dominique-Marie Votion
1 1
Department of Functional Sciences, Faculty of Veterinary Medicine, Pharmacology and Toxicology, Fundamental and Applied Research for Animals & Health (FARAH), University of Liège, 4000 Liège, Belgium
2
Equine Clinical Department, Faculty of Veterinary Medicine, Fundamental and Applied Research for Animals & Health (FARAH), University of Liège, 4000 Liège, Belgium
3
Department of Food Sciences–Microbiology, Faculty of Veterinary Medicine, Fundamental and Applied Research for Animals & Health (FARAH), University of Liège, 4000 Liège, Belgium
4
Department of Functional Sciences, Faculty of Veterinary Medicine, Physiology and Sport Medicine, Fundamental and Applied Research for Animals & Health (FARAH), University of Liège, 4000 Liège, Belgium
5
Biochemical Genetics Laboratory, CHU, University of Liège, 4000 Liège, Belgium
6
Department of Internal Medicine, Reproduction and Population Medicine, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium
7
De Morette Equine Clinic, 1730 Asse, Belgium
*
Author to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Animals 2025, 15(3), 354; https://doi.org/10.3390/ani15030354
Submission received: 18 December 2024
/
Revised: 15 January 2025
/
Accepted: 18 January 2025
/
Published: 26 January 2025
(This article belongs to the Special Issue Pasture-Associated Poisoning in Grazing Animals)
Simple Summary
Equine atypical myopathy is a severe intoxication caused by protoxins synthesised by certain maple trees, notably sycamore maple (Acer pseudoplatanus). These protoxins are activated into harmful toxins that disrupt lipid metabolism by inhibiting specific steps of fatty acid β-oxidation, leading to the accumulation of acylcarnitines in the blood. This activation process is catalysed mainly by specific mitochondrial enzymes, which are also present in some bacteria. Horses grazing in close proximity to affected animals have shown differences in their faecal microbiota composition, suggesting that the role of gut microbiota in atypical myopathy could be more substantial than previously understood. Recently, blood analyses have demonstrated the existence of subclinical cases among these cograzers. The present study compares the faecal bacteria of horses affected by atypical myopathy, their cograzers, and a group of toxin-free horses serving as a control group. Results show significant differences in faecal bacterial diversity and composition between groups, particularly for certain bacterial genera. Additionally, blood levels of specific compounds appear to be associated with these bacterial changes. The theoretical presence of the enzymes involved in the protoxin activation process was also studied. These results highlight the importance of comprehensively studying intestinal microbiota to better understand its role in this generally fatal poisoning.
Abstract
Hypoglycin A and methylenecyclopropylglycine are protoxins responsible for atypical myopathy in equids. These protoxins are converted into toxins that inhibit fatty acid β-oxidation, leading to blood accumulation of acylcarnitines and toxin conjugates, such as methylenecyclopropylacetyl-carnitine. The enzymes involved in this activation are also present in some prokaryotic cells, raising questions about the potential role of intestinal microbiota in the development of intoxication. Differences have been noted between the faecal microbiota of cograzers and atypical myopathy-affected horses. However, recent blood acylcarnitines profiling revealed subclinical cases among cograzers, challenging their status as a control group. This study investigates the faecal microbiota of horses clinically affected by atypical myopathy, their cograzers, and a control group of toxin-free horses while analysing correlations between microbiota composition and blood parameters. Faecal samples were analysed using 16S amplicon sequencing, revealing significant differences in α-diversity, evenness, and β-diversity. Notable differences were found between several genera, especially Clostridia_ge, Bacteria_ge, Firmicutes_ge, Fibrobacter, and NK4A214_group. Blood levels of methylenecyclopropylacetyl-carnitine and C14:1 correlated with variations in faecal microbial composition. The theoretical presence of enzymes in bacterial populations was also investigated. These results underscore the critical need to investigate the potential role of intestinal microbiota in this poisoning and may provide insights for developing prevention and treatment strategies.
Keywords:
equine atypical myopathy; microbiota; gut microbiota; faecal Microbiota; microbiome; faecal microbiome; horses; equine; hypoglycin A; methylenecyclopropylacetyl-carnitine; MCPA-CoA; acylcarnitines; 16S rRNA gene sequencing; next generation sequencing; NGS; blood metabolites; toxin; poisoning
