A six-month feeding trial has demonstrated the safety and nutritional efficacy of chicken protein produced through precision fermentation for use in dog food, according to research published in Frontiers in Veterinary Science.
The study, conducted by scientists at the University of Illinois Urbana-Champaign in partnership with Bond Pet Foods, evaluated a protein ingredient created by inserting chicken DNA sequences into Saccharomyces cerevisiae (brewer's yeast) genome. The resulting biomass was harvested, heat treated and spray dried to produce an inactivated yeast-containing chicken protein for kibble formulation.
Thirty-two healthy adult dogs participated in the trial, with test groups receiving diets containing 15%, 30% or 40% of the brewed chicken protein. A control group received a standard diet based on chicken by-product meal and brewer's rice.
"It was highly digestible and there were some beneficial changes to the dogs' gut microbes and metabolites," said Kelly Swanson, professor and director of the Division of Nutritional Sciences at the University of Illinois, who served as corresponding author with Tomas Belloso, vice president of regulatory affairs at Bond Pet Foods.
Precision fermentation process
The fermentation process used industrial-scale stainless-steel tanks similar to those used in brewing operations. Bond Pet Foods' research team identified abundant proteins in chicken muscle tissue, cross-referenced their DNA sequences, and inserted them into specific sites in the yeast genome for protein expression.
Blood, fecal and urine analyses throughout the 26-week study period showed no adverse effects on body weight, physical condition, blood chemistry or other health markers. Dogs consuming the brewed protein showed beneficial increases in fecal concentrations of short-chain fatty acids including butyrate, propionate and valerate, which are associated with reduced inflammation.
While fat digestibility decreased somewhat with inclusion of the brewed protein, overall digestibility remained high. Fecal volume and dry matter decreased proportionally with higher inclusion rates, though stool quality remained acceptable across all treatment groups.
"When we were formulating these diets, we knew there was a lot of soluble fiber in them, and that was one thing I was a little nervous about — if it would cause loose stools or constipation, which is not a nice outcome for pets or their owners," Swanson said. "And I was happy to see that the stool quality was not affected."
Benefits of brewed protein, yeast
The research represents the first study to use precision fermentation to produce a combined yeast-chicken protein and assess its safety in pet food applications. Precision fermentation technology has been used for nearly 50 years to produce manufacturing ingredients including cheese enzymes, vanilla and vitamin B12.
S. cerevisiae yeast products are already common in commercial pet food formulations, typically serving as palatants to enhance aroma and taste. Beyond protein content, brewer's dried yeast provides B vitamins, amino acids and minerals.
Previous research by Swanson and colleagues has shown yeast products in pet foods can increase beneficial fecal bacteria concentrations and immunoglobulin A levels, supporting immune function in the intestinal tract.
"The main goal was to provide foundational protein for pet health, but it looks like there could be a secondary benefit from the soluble, fermentable fibers in the whole cell product for the dogs' large intestines as well," said Belloso with Bond Pet Foods. “We’re thrilled to see such positive results from the University of Illinois study. It reinforces the promise of brewed chicken protein as a safe, effective and sustainable option for pet nutrition."
The study was co-authored by University of Illinois animal sciences professor Patricia M. Oba and alumni Julio Moto and Meredith Smola, along with Bond Pet Foods co-founder and chief technical operations officer Pernilla Audibert.
Source: University of Illinois at Urbana-Champaign
