Pet food processing methods are known to have an impact on nutrient digestibility and are thought to affect animal health, but this correlation is still understudied.
Therefore, the objective of the recent study from the University of Illinois was to determine the digestibility of raw, frozen, freeze-dried, fresh and extruded dog foods and to evaluate their effects on blood and fecal parameters of healthy adult dogs.
Raw dog food is an increasing format, with growth of 14.14% from 2021 to 2022 and a U.S. market share of 3.91% in 2022. Raw dog food is generally processed into frozen and freeze-dried formats; these segments account for 1.65% and 1.43% of market share in 2022, with growth of 19.10% and 14.50% from 2021 to 2022, respectively.
Ten healthy dogs were used to test the following diets: extruded diet (EXT), fresh diet (FRSH), raw frozen diet (FRZN), hybrid freeze-dried raw diet (HFD) and freeze-dried raw diet (FD). After consuming them for 35 days, blood and feces were collected for analysis.
Significant differences were found between the groups. The EXT diet group had higher fecal output than all others. In general, the EXT diet had the lowest digestibility values, while FRZN, FD and HFD had the highest. Fecal scores were increased (softer feces) in dogs fed EXT or FRSH compared with those fed FRZN or FD. In general, dogs fed the HFD diet had higher protein fermentation indicators than those fed EXT or FRSH.
Conclusions
Fecal microbiota populations differed dramatically between diets. The diets tested were distinctive, but further research is needed to understand how ingredient source, processing method and macronutrient composition contribute to the different responses.
Reference
Elizabeth L Geary, PatrÃcia M Oba, James R Templeman, Kelly S Swanson, Apparent total tract nutrient digestibility of frozen raw, freeze-dried raw, fresh, and extruded dog foods and their effects on serum metabolites and fecal characteristics, metabolites, and microbiota of healthy adult dogs, Translational Animal Science, Volume 8, 2024, txae163, https://doi.org/10.1093/tas/txae163
