Researchers compared healthy dogs that regularly ate faeces with dogs whose owners had never seen them do so. They found no significant differences in the core faecal microbiota, dysbiosis index, or carriage of the enteropathogens tested.
The researchers recruited 44 clinically healthy dogs through the Universities of Milan and Parma. All underwent a physical examination, haematology, and biochemistry before inclusion.
Twenty-three dogs were classed as coprophagic, based on owners repeatedly seeing them eat their own faeces or those of other animals. The remaining 21 were included only if their owners reported never having seen them eat, or attempt to eat, faecal material.
There was plenty of variety in what the coprophagic dogs were eating. Around a third ate their own faeces, while others ate faeces from dogs, cats, horses, wildlife, or humans. More than half ate more than one type.
Faecal samples were then analysed using quantitative PCR. The researchers calculated the canine dysbiosis index and measured several bacterial groups associated with a healthy or disrupted gut microbiome. The dysbiosis index was similar, as were the individual bacterial groups measured. Most dogs in both groups remained within the expected reference intervals for healthy animals.
The researchers also looked for several potential enteropathogens, including Clostridium perfringens, Clostridioides difficile, Campylobacter jejuni, Salmonella spp. and canine parvovirus.
Again, coprophagic dogs were no more likely to test positive than dogs that did not eat faeces.
Neither Salmonella nor canine parvovirus was detected in any dog. C. difficile and C. jejuni were detected infrequently and, interestingly, only in dogs in the non-coprophagic group, although numbers were too small for this difference to be significant.
The C. perfringens enterotoxin gene was relatively common in both groups. The authors point out that this is consistent with previous work showing that healthy dogs can carry the gene, so its presence alone should not be interpreted as evidence of disease.
However, this study only screened for selected bacterial and viral enteropathogens. It did not assess intestinal parasites, and the authors highlight that coprophagy can still complicate faecal parasite testing. Ingested eggs may pass through the gastrointestinal tract and potentially result in a positive test without the dog itself being infected.
This was a relatively small study, and there are a few reasons not to conclude that coprophagy has no effect on gastrointestinal health.
Whether a dog was coprophagic relied on owner observation. A dog placed in the non-coprophagic group could therefore have indulged when nobody was looking.
The researchers also did not measure how often dogs ate faeces, how much they consumed, or how recently they had done so before the sample was collected. That means a short-lived effect after coprophagy, or an effect related to how much is eaten, could have been missed. Diet was not controlled either.
The type of faeces eaten also varied considerably, making it difficult to separate the effects of eating a dog’s own faeces from those of eating faeces belonging to another dog or another species.
So the findings are probably best interpreted quite narrowly: in this group of otherwise healthy dogs, habitual coprophagy was not associated with measurable changes in the core faecal microbiota or increased carriage of the enteropathogens tested.
There is another potential use for the findings.
Faecal microbiota transplantation is increasingly being investigated in dogs, but selecting a suitable donor means ruling out factors that could make the donated material less safe or less useful.
Current donor guidelines do not specifically exclude dogs that practise coprophagy. The authors say their results suggest coprophagy alone may not be a reason to reject an otherwise healthy donor, provided the dog meets all the other recommended screening criteria.
Full article available here.