Table 2.

Effects of specific factors on equine intestinal organism abundances

Factor	Effect on organism abundance	Organisms in enteral microbiome	Reference
highly concentrated (grain) feed	increase	lactic acid bacteria, especially Streptococcus spp. and Lactobacillus spp.	[181] [31]
high-starch fed	increase	Succinivibrio	[28]
high-starch fed	decrease	Clostridiales, Lachnospiraceae	[28]
haylage	putative increase	Fibrobacter succinogenes, Fibrobacter intestinalis	[106]
grass-based diet	increase	Bacteroidetes, Lachnospiraceae Bacillus, Lactobacillus, Streptococcus	[181]
grass-based diet	decrease	Fibrobacter, Ruminococcus	[181]
high oil and high starch diets	increase	Proteobacteria	[28]
increasing age	increase	Euryarchaeota, Actinobacteria, Bacteroidetes, Chlamydiae, Chloroflexi, Planctomycetes, Spirochaetes, TM7, Verrucomicrobia	[182]
increasing age	decrease	Proteobacteria, Gammaproteobacteria, Enterobacteriaceae, Enterococcus	[182]
domestication	lower	Methanocorpusculum	[101]
pH below 6.0	decrease	Ruminococcus albus, Fibrobacter succinogenes	[6]
pH below 6.0	increase	Streptococcus bovis, Lactobacillus spp., Mitzuokella spp.	[6]
parasite egg burden	decrease	Bacteroides, Clostridium XIVa, Ruminococcus, unclassified Lachnospiraceae	[178, 183]
parasite egg burden	increase	Clostridium IV, Coprococcus, Anaerovibrio, Agreia, Oscillibacter, Turicibacer, unclassified Cystobacteraceae, Campylobacter, Bacillus, Pseudomonas	[178, 183]
laminitis	increase	Lactobacilli, Escherichia coli	[138, 184]