New study compares digestibility of animal and plant-based dog foods

A new study has compared the digestibility of different dog foods using animal and vegan protein sources. Researchers evaluated for the apparent total tract digestibility (ATTD) of the diets and tested for their effects on factors such as serum metabolites and faecal characteristics, metabolites, and microbiota of twelve healthy adult dogs.

The four diets were all formulated to be nutritionally complete but used four different protein sources: 

• fresh deboned, dried, and spray-dried chicken (DC)
• chicken by-product meal (CBPM)
• wheat gluten meal (WGM)
• corn gluten meal (CGM)

The four diets performed differently depending on the outcome being measured.

• Dogs being fed the animal protein diets had slightly higher faecal scores overall (firmer stools), but all faecal scores for all diets remained within an appropriate range. 
• The dry matter apparent total tract digestibility was highest for the fresh chicken and wheat gluten meal groups. 
• Crude protein apparent total tract digestibility was highest for the wheat gluten meal group.
• Dogs fed the chicken by product meal had lower nutrient and energy digestibility's than all other diets, with protein digestibility being highest in the wheat gluten meal group. 
• Additionally, the chicken by product group had lower organic matter, crude protein, and energy apparent total tract digestibility than those fed the other diets.
• Faecal metabolites and microbiota were different between diets, with the animal-based protein diets increasing faecal protein metabolites. 
• Overall, all diets were complete and balanced and performed well. Future research comparing plant and animal-based protein sources would be beneficial to further understand the differing effects on canine digestion. 

As the top performers for each analysis varied, and because all diets performed well overall, the results of this study suggest that it may not be necessary to rely on animal proteins in dog feeds as plant-based proteins can perform on par in terms of digestibility.

Read the study here!

Kelly M Sieja, Patrícia M Oba, Catherine C Applegate, Christine Pendlebury, Janelle Kelly, Kelly S Swanson, Evaluation of high-protein diets differing in protein source in healthy adult dogs, Journal of Animal Science, Volume 101, 2023, skad057, https://doi.org/10.1093/jas/skad057