Date of Graduation

7-2026

Document Type

Thesis

Degree Name

Master of Science in Poultry Science (MS)

Degree Level

Graduate

Department

Poultry Science

Advisor/Mentor

Parsons, Benjamin

Committee Member

Owens, Casey

Second Committee Member

Kidd, Michael

Keywords

Corn Fermented Protein; DDGS; Metabolizable Energy; Phytase

Abstract

The purpose of this research was to determine the availability of energy and phosphorous (P) in dry-grind corn co-products in chickens was assessed. In the first objective, the determination of energy availability, both a precision-fed rooster assay and an ad libitum fed broiler chicken assay were used in order to elucidate energy availability in corn co-products. There were 8 samples of corn fermented protein (CFP) and 2 samples of conventional distillers dried grains with solubles (CDDGS) evaluated for metabolizable energy (ME). The CFP contained a mean CP and crude fat of 55 and 3.7% (DM basis), respectively, compared with 30 and 8.5% in CDDGS, respectively. For precision-fed roosters, the mean nitrogen-corrected true ME (TMEn) for CFP was 3,305 kcal/kg DM compared with 3,152 kcal/kg DM for CDDGS. In ad libitum-fed broiler chickens, the mean nitrogen-correct apparent ME (AMEn) of CFP was 2,777 kcal/kg DM, which was greater (P < 0.05) compared with 2,568 kcal/kg DM in CDDGS. The ME values among CFP samples were generally consistent; albeit ME was correlated with crude fat (R = 0.77 to 0.78). For assessment of P availability, three methods were used, and these were a precision-fed rooster assay, and two ad libitum fed broiler chicken assays. For this objective, dry-grind corn co-products were sourced from ethanol plants using and not using phytase during simultaneous saccharification and fermentation. Five samples were evaluated: CDDGS from an ethanol plant using phytase (CDDGS-phytase), CFP from an ethanol plant using vs. not using phytase (CFP ± phytase), and the remaining fractionated DDGS left after CFP recovery from an ethanol plant using vs. not using phytase (FDDGS ± phytase). Phytic acid (myo-inositol 1,2,3,4,5,6) was lower in samples produced at ethanol plants using phytase. In precision-fed roosters, phytic acid (myo-inositol 1,2,3,4,5,6) disappearance was on average 34 percentage units greater for phytase vs. no phytase samples (P < 0.05). The P bioavailability based on bone ash and ileal P digestibility showed similar trends, where on average values were 32 to 36 percentage units higher for phytase vs. no phytase samples (P < 0.05). Results from these studies demonstrate that the nutritional value of dry-grind corn co-products for poultry is improved by fractionation, due to increased CP, reduced fiber, and increased ME, and by phytase use at ethanol plants, which reduces phytate-P, increases phytic acid disappearance in birds, and improves both P bioavailability and P digestibility.

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