Many travelers or dieters have experienced for themselves how an abrupt diet change can influence the intestines. While the sudden shift in digestive system functioning can be uncomfortable and inconvenient, it’s generally not dangerous. Likewise, changing a pet’s diet can cause digestive disruption, but isn’t hazardous to the animal’s health as long as the foods are nutritious. Researchers used this temporary gut upset caused by diet shifts as a model for true illness in order to evaluate feed ingredients aimed at enhancing gastrointestinal stability in companion animals. Their study examined how abrupt dietary changes in dogs can serve as a controlled method to study gut microbiota resilience and test digestive health additives.
“This model offers potential for evaluating the efficacy of additives in fostering a resilient microbiota, thereby promoting strategies to enhance canine digestive health,” the researchers wrote in the Journal of Animal Science.
Experiment using dietary shift to induce digestive upset in dogs
The research involved 24 adult Beagles going from kibble to a high-protein wet dog food. Researchers first fed the dogs a standard extruded dry kibble containing 26% protein, 12% fat and 52% carbohydrates. The Beagles ate that diet for 29 days. The experimenters then abruptly transitioned the dogs to a high-protein canned formulation with 43% protein, 29% fat and only 16% carbohydrates, which they consumed for another 29 days.
This sudden dietary difference resulted in measurable physiological and microbiological changes. Apparent total tract digestibility of dry matter, organic matter, crude protein and gross energy increased. However, digestibility and the diet’s metabolizable energy declined, suggesting a trade-off between macronutrient absorption and energy utilization.
Fecal consistency also shifted. After the diet switch, dogs produced wetter, less formed stools. On a microbial level, the transition reduced beneficial genera such as Turicibacter and Lactobacillus, while opportunistic and potentially pathogenic bacteria including Fusobacterium, Peptacetobacter hiranonis, Escherichia coli and Clostridium perfringens proliferated. These shifts were reflected in a temporary spike in the dysbiosis index and inflammatory biomarkers such as plasma immunoglobulin A and C-reactive protein.
Metabolically, the change in diet led to significant alterations in fecal short-chain fatty acid profiles and increased fecal ammonia concentrations. Polyamines, typically linked to gut cell health, declined under the wet diet, while monoamines such as indole and indole-3-acetic acid rose, further indicating microbial stress or turnover.
However, several indicators began normalizing by the end of the study, suggesting an adaptive microbial response to the new diet. The researchers noted that this adaptive capacity points to the utility of this model in evaluating the performance of functional ingredients intended to enhance gut resilience.
While the study reinforces the importance of gradual dietary transitions for digestive stability, it also offers a framework to assess how specific additives might support or accelerate microbial adaptation, without relying on genuinely sick dogs that need treatment instead of experimentation.