Page 656 - Veterinary Immunology, 10th Edition

dominated by members of two phyla, the Firmicutes and the
VetBooks.ir Bacteroidetes, with lesser numbers of Actinobacteria and

Proteobacteria and many minor phyla such as the Fusobacteria and
the Verrucomicrobia. It has been estimated that the canine small

intestine harbors more than 200 different bacterial species, while the
canine colon may house up to a thousand (Fig. 21.4).

FIG. 21.4 The enormous diversity of the gut microbiota in the dog
is well seen in this comparison of the composition of the colon
microbiota in normal dogs and dogs with inflammatory bowel
disease. (Courtesy Dr. P. Xenoulis.)

Each individual animal's microbiota is unique and its

composition is determined by management, diet, genetics,
antibiotic exposure, and environmental factors. The composition of

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