Study summary · Dogs · Food processing · Algya et al., 2018
Digestibility is one part of a food’s performance.
Selected foods differed in digestion and stool measurements. This short experiment does not establish which format produces better lifelong health.
Why this study matters
“More digestible” sounds like an overall quality rating, but it answers a narrower question about nutrient recovery. To judge a health claim, look for the health outcome itself as well as digestion measurements.
How the study worked
Participants
Healthy adults; average age 3.6 years.
What happened?
Dogs rotated through four commercial foods.
The comparison
Extruded kibble, two roasted refrigerated foods and a raw food.
What was measured?
Digestibility, faecal measures, microbiota, blood chemistry, urine and activity.
What the researchers found
| Outcome | Reported result | How to read it |
|---|---|---|
| Digestibility | Protein and fat digestibility favoured both roasted foods over kibble (P < 0.05). | A nutrient measurement is not a disease outcome. |
| Stools | Scores did not differ; raw feeding produced lower faecal pH and dry matter. | Different stool chemistry need not mean better health. |
| Triglycerides | Lower with grain-free roasted and raw food than kibble; within reference ranges. | A lower normal value is not automatically a clinical benefit. |
Source access: abstract-based summary. University research record.
What strengthens the evidence?
The crossover design lets the same dogs contribute observations under different feeding conditions. This helps reduce the influence of stable differences between individual animals. Measuring several outcomes also helps readers avoid judging a food from a single result.
What limits the conclusions?
Eight dogs cannot represent the full variety of pets. Four weeks on a food is a short window for judging lifelong suitability. Comparing complete recipes does not isolate cooking from ingredients and nutrient composition. This entry was checked against the published abstract and university record; detailed methods and the complete disclosure statement have not been verified.
What the researchers concluded
The authors described the tested diets as well tolerated and digestible.
Evidence.pet interpretation
Use this as a comparison of the particular foods studied, rather than a league table of raw, fresh and dry feeding. A processing claim needs a comparison that separates the processing step from everything else that changed in the recipe. Microbiome shifts are descriptions of a community; calling them beneficial requires evidence connecting them to an outcome that matters to the animal. Likewise, this experiment cannot settle microbiological safety. Digestibility, nutritional completeness, contamination control and long-term health are separate questions, so evidence supporting one should not be used to answer all four.
Funding and author interests
Co-author Lynn Lye was affiliated with Freshpet. Full funding and conflict declarations remain unverified.
Read the original research
Algya KM, Cross TWL, Leuck KN, et al. Apparent total-tract macronutrient digestibility, serum chemistry, urinalysis, and fecal characteristics, metabolites and microbiota of adult dogs fed extruded, mildly cooked, and raw diets. Journal of Animal Science. 2018;96(9):3670–3683. doi:10.1093/jas/sky235.
Evidence.pet editorial summary · Study ID STU-002 · Source checked 22 September 2026. Strengths, limitations and interpretation are our editorial assessment, not a formal evidence grade.
Sources checked: published abstract and University of Illinois research record. Full-text appraisal pending.