The Horse Gut Microbiome Responds in a Highly Individualized Manner to Forage Lignification
Authors: Gomez Andres, Sharma Ashok Kumar, Grev Amanda, Sheaffer Craig, Martinson Krishona
Summary
# Editorial Summary: Individualized Microbiome Responses to Forage Lignification in Horses Whilst the equine microbiome's role in forage digestion is well established, how changes in forage lignin content affect individual horses remains poorly understood. Researchers fed six horses a crossover diet of reduced-lignin and conventional alfalfa hay (differing by 7 g/kg in acid detergent lignin content, matched for protein, fibre and digestible energy), collecting faecal samples over 24-hour periods for bacterial community profiling via 16S rRNA sequencing. Contrary to expectations, reduced-lignin alfalfa did not produce a consistent microbiome signature across all horses; instead, each animal's microbial community responded uniquely in terms of diversity changes and specific bacterial populations, with taxa including *Akkermansia*, *Fibrobacter succinogenes*, *Treponema* and *Paludibacter* fluctuating in horse-specific patterns, alongside differential impacts on dry matter digestibility and faecal particle size. These findings suggest that seemingly minor variations in hay quality may trigger substantial but highly individualised shifts in microbial ecology, which could meaningfully influence nutrient extraction and metabolic health—though translating these microbiome changes into practical performance outcomes requires further investigation. For practitioners formulating feeds or managing forage selection, this work underscores that nutritional responses to hay quality are unlikely to be uniform across horses, potentially explaining variable results in feeding trials and individual variation in digestive efficiency.
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Practical Takeaways
- •Don't assume all horses will respond identically to forage quality changes; individual monitoring of digestive health and performance is warranted when switching hay sources
- •Small differences in hay lignin content (7 g/kg difference tested here) can significantly affect individual horses' digestive efficiency, suggesting hay analysis and individualized feeding strategies may be beneficial
- •Monitor individual horses for changes in manure quality, body condition, and performance when introducing new forage batches, as microbiome adaptation appears highly individualized
Key Findings
- •Reduced lignin alfalfa did not produce uniform microbiome changes across all horses, indicating highly individualized responses
- •Each horse's microbiome responded differently to lignin content in terms of alpha and beta diversity over time
- •Horse-specific taxonomic changes occurred in Akkermansia, Fibrobacter succinogenes, Treponema, and Paludibacter abundance depending on individual
- •Individual microbiome traits correlated with dry matter digestibility and feed particle size in a horse-specific manner