Adult dogs fed puppy-level portions developed some of the same digestive characteristics observed in younger puppies, including softer stools and lower apparent protein digestibility, according to research results published in the Journal of Veterinary Internal Medicine.
Researchers at the Federal University of Paraná conducted two experiments using the same commercial extruded dry food formulated for growing dogs. The first followed eight Beagles at 2, 5, 8 and 11 months, with six evaluated at 14 months.
The second compared two groups of six 14-month-old Beagles fed either maintenance portions or larger portions matching the younger puppies’ intake relative to metabolic body weight.
In the second experiment, apparent crude protein digestibility was 74.2% in dogs receiving puppy-level portions, compared with 77.1% in dogs receiving maintenance portions. Apparent digestibility measures the proportion of an ingested nutrient that is not recovered in feces.
Dogs receiving larger portions also produced more feces, averaging 363.7 grams daily compared with 202 grams in the maintenance group. Their stools contained less dry matter and received lower firmness scores.
Higher intake increased fecal ammonia and total branched-chain fatty acids, compounds associated with protein fermentation. The larger portions also changed bacterial communities, including greater abundance of Streptococcus and lower abundance of Blautia.
These results suggest that some digestive differences between puppies and adults reflect the greater amount of food puppies consume to support growth, rather than age alone.
The longitudinal experiment also showed that digestion did not change uniformly as dogs matured. Apparent crude protein digestibility increased with age, while apparent fat and dry matter digestibility declined. The diet’s estimated metabolizable energy value also declined with age.
Fecal bacterial communities changed during early growth but did not differ significantly among the 8-, 11- and 14-month assessments. This suggests that the overall microbial community became more stable around 8 months in these Beagles. Older dogs also had higher fecal concentrations of short-chain fatty acids, including acetate, propionate and butyrate.
The researchers identified protein digestibility and energy density as potential considerations for puppy food development.
“Based on the results observed, highly digestible protein sources associated with a higher caloric diet density are recommended for growing dogs,” they wrote.
However, the experiments did not directly compare protein sources or diets with different energy densities. The small sample, single breed and single diet limit broader application.
The authors acknowledged Dalpet for supplying the diet and Institute PremieRpet for financing the project.
