Hydrolyzed diets, also called hypoallergenic diets, are all the rage in the pet food world.
With smaller particle sizes, protein hydrolysates are less likely to elicit immunoglobulin E (IgE)-mediated allergic reactions. More recently, the pet food industry has begun incorporating hydrolyzed proteins into diets for various reasons, such as increasing digestibility, enhancing palatability, reducing allergic responses, and/or providing nutraceutical effects. The lower molecular weight resulting from hydrolysis would require less enzymatic digestion in the small intestine and, therefore, potentially increase protein digestibility and absorption.
However, the functionality of a hydrolyzed protein depends on the type of hydrolysate. Therefore, a study, just published in the Journal of Animal Science, was conducted to evaluate the effect of chicken meat hydrolysates and chicken heart and liver hydrolysates on digestibility, gut, skin and coat health, oxidative stress and inflammation in healthy adult dogs.
Experimental design
The U.S. team , from the University of Illinois, tested five dog diets made with similar ingredients except for the test protein sources. The control diet was formulated with chicken meal, a traditional protein source in pet foods, while the other diets involved partial or complete replacement of chicken meal with the two types of protein hydrolysate. All diets were well accepted by the dogs, and all dogs remained healthy throughout the study.
The results
Mechanically separated chicken protein hydrolysate or chicken liver and heart could serve as a compatible protein source with potential physiological benefits over conventional chicken meal. In the group with the 25% chicken liver and heart hydrolysate diets, an increase in fecal butyrate concentration, a decrease in BCFAs and a decrease in phenols/indoles were observed, while in the 25% chicken hydrolysate diet group, an increase in fecal IgA was observed, indicating the possible anti-inflammatory and immunomodulatory properties of the protein hydrolysates. However, further research is needed to confirm the effect. Dietary treatment did not affect the alpha diversity of the fecal microbiota; however, in dogs fed 25 percent liver and heart hydrolysates there was a shift in the microbiota with a larger group of Bifidobacterium and Ruminococcus gauvreauii, both considered beneficial microorganisms. Overall, avian protein hydrolysates may promote gut health and support anti-inflammatory and immunomodulatory effects in adult dogs. However, their effects depend on the level of inclusion and are source-specific.
Reference
Clare Hsu, Fabio Marx, Ryan Guldenpfennig, Negin Valizadegan, Maria R C de Godoy, The effects of hydrolyzed protein on macronutrient digestibility, fecal metabolites and microbiota, oxidative stress and inflammatory biomarkers, and skin and coat quality in adult dogs, Journal of Animal Science, Volume 102, 2024, skae057, https://doi.org/10.1093/jas/skae057
