Saccharomyces cerevisiae genetically engineered to enhance butanol production will be used in a manufacturing process similar to that of fuel ethanol production, including co-production of distillers products for animal feed. A poultry feeding trial was conducted with simulated isobutanol-derived dried distillers grains with solubles (bDDGS), comprising non-fermentable corn solids and heat-inactivated Butamax modified yeast (BMY), to determine potential health effects. Simulated dried distillers grains were produced in 2 variants: bDDGS containing 10% (B10) or 50% (B50) BMY. The BMY concentrations were selected based on a conservative estimate from ethanol-derived distillers grains (eDDGS) approximating 2.5 and 12-fold margins of exposure. The B10 and B50 DDGS were evaluated in a 42-day feeding trial using male Ross 708 broiler chickens fed diets containing eDDGS, B50 DDGS, or B10 DDGS without or with isobutanol, 2,3-butanediol, and isobutyric acid metabolites each at target concentrations of 2 (B10-2), 5 (B10-5), or 10 (B10-10) times the anticipated specification limit in the commercial product. Diets were fed (n = 50 broilers/treatment) in 3 phases: starter phase with 8% DDGS and grower and finisher phases each with 15% DDGS. No statistically significant differences or diet-related effects on mortality, clinical pathology, or organ weights, and no microscopic observations associated with consumption of diets containing B10, B50, or B10 supplemented with metabolites at any targeted exposure level were observed. A lower (P < 0.05) mean absolute bursa of Fabricius weight in the B10-10 group compared to the B10 group was considered to be within the range of biological variability. A non-significant trend toward lower weight, gains, and feed intake, and higher feed:gain ratio was observed in the B10-10 group, and was considered a non-adverse palatability effect of consuming high concentrations of metabolites. These results demonstrate that consumption of phase diets containing simulated DDGS from a novel isobutanol production process was well-tolerated., Competing Interests: K.S. Reidinger is an employee of Butamax Advanced Biofuels, LLC, the funding entity for the work presented within the manuscript, and the producer of Butamax Modified Yeast. A. Chen is an employee of DuPont Industrial Biosciences, a related entity to Butamax Advanced Biofuels, LLC. J.M. Roper and J.M. Caverly Rae are employees of DuPont Haskell Global Center for Health Sciences (DuPont Haskell). B.L. Smith, E. Huang, and C.A. Walker are employees of DuPont Pioneer. J.L. McNaughton is an employee of AHPharma, Inc. DuPont Pioneer, DuPont Haskell, and AHPharma, Inc. received financial support from Butamax Advanced Biofuels, LLC for materials, resources and consulting expertise related to the design, conduct, analysis and interpretation of the studies presented within this manuscript. These disclosed commercial affiliations do not alter the authors’ adherence to PLOS ONE policies on sharing data and materials. The authors declare no additional potential competing interests.