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.

ABSTRACT

Research on protein hydrolysates has observed various properties and functionalities on ingredients depending on the type of hydrolysate. The objective of this study was to evaluate the effects of hydrolyzed chicken protein that was incorporated into diets on digestibility, gut health, skin and coat health, oxidative stress, and intestinal inflammation markers in healthy adult dogs. Five complete and balanced diets were manufactured (1) CONd 25% chicken meal diet; (2) 5% CLHd 5% chicken liver and heart hydrolysate plus 20% chicken meal diet; (3) CLHd 25% chicken liver and heart hydrolysate diet; (4) 5% CHd 5% chicken hydrolysate plus 20% chicken meal diet; (5) CHd 25% chicken hydrolysate diet. A replicated 5 × 5 Latin square design was used which included 10 neutered adult Beagles. Each of the 5 periods consisted of a 7-d washout time and a 28-d treatment period. All diets were well accepted by the dogs. Fecal butyrate concentration was higher while fecal isovalerate and total phenol/indole were lower in dogs fed CLHd than CONd (P < 0.05). Dogs fed CHd had higher fecal immunoglobulin A concentration when compared with CLHd (P < 0.05); however, both groups were comparable to the CONd. There was no difference among groups in serum cytokine concentrations, serum oxidative stress biomarkers, or skin and coat health analyses (P > 0.05). Fecal microbiota was shifted by CLHd with higher abundance in Ruminococcus gauvreauii group as well as lower Clostridium sensu stricto 1, Sutterella, Fusobacterium, and Bacteroides when compared with CONd (P < 0.05). There was also a difference in beta diversity of fecal microbiota between CLHd and CHd (P < 0.05). In conclusion, chicken protein hydrolysate could be incorporated into canine extruded diets as a comparable source of protein to traditional chicken meal. The test chicken protein hydrolysates showed the potential to support gut health by modulating immune response and microbiota; however, functional properties of protein hydrolysates are dependent on inclusion level and source.

Research has been exploring various functional properties of hydrolyzed protein to benefit the health of animals. However, the functionality of a hydrolyzed protein depends on the type of hydrolysate. Therefore, this study was conducted to evaluate the effect of hydrolysates from chicken meat and hydrolysates from chicken heart and liver on digestibility, gut health, skin and coat health, oxidative stress, and inflammation in healthy adult dogs. Five canine diets were manufactured with similar ingredients except for the test protein sources. The control diet was formulated with chicken meal, a traditional protein source in pet food, and the other diets had a partial or complete substitution from the chicken meal with the two types of protein hydrolysate. The diets were all well accepted by the dogs and all dogs maintained healthy throughout the study. Dogs fed the hydrolysate from chicken meat showed lower inflammatory biomarkers in the feces. On the other hand, dogs fed the hydrolysate from chicken liver and heart demonstrated a shift in gut microbiota with more abundant beneficial bacteria. In conclusion, poultry-originated protein hydrolysates showed the potential in making positive changes in inflammatory state, immune response, and microbiota in healthy adult dogs.