Quantification of Odorants in Animal Feeds at Commercial Swine and Poultry Operations

Abstract. Odorants in animal feeds may affect feed flavor and taste, and serve as the indicators for feed quality. These odorants come from various processes such as fermentation and decay of feed ingredients, contamination by fecal materials, and adsorption of volatiles in the air of animal houses. This study collected 37 feed samples from 14 swine and poultry operations, and quantitated a total of 54 organic odorants with gas chromatography-mass spectrometry (GC-MS), including fatty acids, alcohols, aldehydes, ketones, phenols, and nitrogen-containing compounds. Those compounds together accounted for 0.46±0.20% wet feed mass, with the highest percent (0.54±0.19%) found at visited layer hen houses and the lowest percent (0.38±0.14%) at swine farrowing houses. Acetic acid and ethanol were most abundant, accounting for 0.22±0.13% and 0.13±0.07% wet feed mass, respectively. Fecal indicators including indole and skatole were <5 ppm by mass. The odorant composition of feed samples showed no significant effect by animal operation type; while a gradual seasonal change was noted. This study is expected to help better understand the causes of odorants in animal feeds and their implications to animal health and production performance.