Study summary · Dogs · Food processing · Cai et al., 2022
Processing changed digestion and gut measurements.
Eighteen healthy Beagles ate one of three versions of a similar recipe: raw, pasteurised or high-temperature sterilised. After eight weeks, the researchers found differences in protein digestibility, blood measurements and faecal bacteria. These results do not establish which processing method produces the healthiest dog over a lifetime.
Why this study matters
When two commercial foods differ in both recipe and processing, it is difficult to know which difference explains a result. This experiment is useful because it compared foods prepared from the same ingredients. It addresses a more focused question about processing, while leaving important questions about disease, food safety and long-term nutrition unanswered.
How much confidence should you place in this study?
Using a common ingredient formulation makes this a more focused processing comparison than a trial of unrelated retail recipes. Random allocation is reported, but concealment and blinded outcome assessment are not established. Six dogs per group provide limited precision, and many laboratory endpoints were tested. Inconsistent wording between the abstract and main report reduces confidence in some numerical and microbial claims. Public sequence data improve transparency, but we have not independently reanalysed them. The findings are exploratory evidence about short-term biological responses, not a ranking of foods by overall health benefit.
Full-text editorial appraisal completed 23 September 2026. This assessment considers design, measurement, missing data, applicability and funding. It is not a formal certainty grade or a systematic review.
How the study worked
Participants
Eighteen healthy three-year-old Beagles from a college training base in Shanghai: nine males and nine females. Researchers randomly allocated six dogs to each group, with three males and three females per group. The dogs were housed individually under controlled conditions.
What happened?
All three foods used rice, chicken breast, corn, sugar beet meal, meat and bone meal, chicken fat and a palatability enhancer. The raw version was mixed and packaged without the final heating step. The pasteurised version was heated at 80°C for 20 minutes. The high-temperature sterilised version was autoclaved at 121°C for 30 minutes. Foods were stored at -20°C. Following one week of adaptation, each dog received 750 g daily for 56 days. The term raw here describes this experimental preparation; some component ingredients were already commercially processed.
The comparison
Three parallel groups received the raw, pasteurised or high-temperature sterilised version. Each dog remained on its assigned food. There was no commercial dry-kibble comparison group in the reported methods.
What was measured?
Blood counts and serum chemistry were measured at baseline and day 56. Faeces collected on days 54 to 56 were used to estimate apparent total-tract digestibility, describe bacteria by 16S rRNA sequencing, and measure short-chain fatty acids. Food intake and body weight were also assessed. These measurements describe digestion and physiological responses, not lifetime disease risk.
What the researchers found
| Outcome | Reported result | How to read it |
|---|---|---|
| Protein digestibility | The detailed results report higher crude-protein digestibility in the high-temperature group than in the other groups (P < 0.05). | A digestion measure does not establish superior long-term health. We have not repeated the ambiguous percentage comparison in the abstract. |
| Blood measurements | Triglycerides were higher in the high-temperature group. Routine blood counts were reported within normal levels before and after the trial. | A difference between groups is not automatically a clinical abnormality. |
| Bacterial richness | Chao1 and observed-species indices were lower in the high-temperature group. Raw and pasteurised groups did not differ significantly on the reported diversity indices. | More bacterial types are not necessarily better. These indices do not measure disease prevention. |
| Fermentation products | Faecal acetate, propionate, butyrate and total acids were lower in the raw group (P < 0.05). | A stool concentration reflects production, absorption and other factors. It cannot establish whether the gut received more or less benefit. |
What strengthens the evidence?
Random allocation and equal numbers of males and females in each group help reduce some differences between the groups. Using the same ingredient recipe improves the ability to investigate processing compared with a trial of unrelated commercial foods. The study measured several types of response rather than relying on owner impressions alone. The authors provide a public sequencing-data accession.
What limits the conclusions?
There were only six dogs per group, all the same breed and age, with eight weeks of follow-up. This limits applicability to other breeds, puppies, older dogs, cats and animals with disease. Many endpoints were examined in a small sample, so individual statistically significant findings need replication. Faecal bacteria and fermentation products are indirect indicators of health. The study did not establish infection risk or the long-term nutritional adequacy of any feeding approach. Reporting is inconsistent: the abstract refers to dry food although the methods describe three wet preparations, and some bacterial directions differ between the abstract and main text. For that reason, we do not use those disputed details to rank the foods.
What the researchers concluded
The authors concluded that processing affected digestibility, blood measurements, faecal bacteria and short-chain fatty acids. Although they discussed these as health-related changes, they also acknowledged that it was difficult to determine whether the microbiome changes were beneficial or harmful.
Evidence.pet interpretation
This experiment suggests that processing can influence how dogs respond to a food even when the ingredient recipe is similar. It does not support a simple rule that less heat is always better, or that greater digestibility guarantees better overall health. A change in bacterial richness is not a diagnosis, and a lower amount of a fermentation product in stool does not directly show lower production throughout the gut. Treat the findings as a small, short-term experiment with reporting limitations. They are not evidence for choosing a particular retail product or a substitute for a complete assessment of nutrition and safety.
Funding and author interests
The paper reports support from the Scientific Research Project of Shanghai Vocational College of Agriculture and Forestry (KY2-0000-19-01) and the Shanghai Academy of Agricultural Sciences Run Up programme (ZP19171). The authors declared no competing interests. Shanghai Weita Pet Products manufactured the experimental foods. Sequence data are deposited under BioProject PRJNA733866.
Read the original research
Cai X, Liao R, Chen G, Lu Y, Zhao Y, Chen Y. The influence of food processing methods on serum parameters, apparent total-tract macronutrient digestibility, fecal microbiota and SCFA content in adult beagles. PLOS ONE. 2022;17(1):e0262284. doi:10.1371/journal.pone.0262284.
Evidence.pet editorial summary · Study ID STU-003 · Source checked 23 September 2026. Strengths, limitations and interpretation are our editorial assessment, not a formal evidence grade.
Adapted from Cai and colleagues under CC BY 4.0, with original Evidence.pet interpretation.
Creative Commons Attribution 4.0 licence. The source has been condensed and reorganised.