Location: Food Animal Environmental Systems Research
Title: The Effect of Mono- and Di-Saccharides on the Microbiome of Dairy Cow Manure and Its OdorAuthor
![]() |
Loughrin, John |
![]() |
Agga, Getahun |
Submitted to: Microorganisms
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/28/2024 Publication Date: N/A Citation: N/A Interpretive Summary: In a previous experiment we showed that the odor of cow manure could be improved by incubation with the sugars glucose, lactose, and sucrose. This improvement was due to reductions in the concentrations of the malodorants most typical of animal wastes and the production of compounds of other compounds with fruit-like aromas. Due to large concentrations of lactic acid produced by the sugar amended manure, we inferred that lactic acid bacteria were involved in improving the manure odor. Here through microbiome analysis to characterize the microbial communities of the manure, we show that lactic acid bacterial growth was promoted by the addition of all three sugars. Lactic acid bacteria are commonly used to ferment foods such as sauerkraut and yoghurt. Bacteria in the genus Lactobacillus were stimulated by sugar addition whereas bacteria in the order Clostridiales were not noticeably affected. Many Clostridiales have been implicated in the production of manure malodor. It is possible that the environmental conditions in the sugar supplemented manure were unfavorable for the production of malodors. We conclude that lactic acid bacteria are the primary bacteria involved in reducing malodorants in dairy cow manure and present strategies to enhance their abundance in animal wastes. Technical Abstract: In a previous experiment, we showed that the odor of Bos taurus manure slurries could be improved by anaerobic incubation with the sugars glucose, lactose, and sucrose. This improvement was due to reductions in the concentrations of malodorants, including dimethyl disulfide, p-cresol, p-ethylphenol, indole, and skatole, and a shift to the production of fruity esters, including ethyl butyrate and propyl propanoate. Due to large concentrations of lactic acid produced by the sugar-amended manure slurries, we inferred that lactic acid bacteria were involved in improving the manure slurry odor. Here, through 16S rRNA amplicon sequencing for microbiome analysis, we show that lactic acid bacterial growth was promoted by the addition of all three sugars. Lactobacillus buchneri and an unknown Lactobacillus sp. were the most prominent lactic acid bacteria stimulated by sugar addition. Lactobacillales were found only in trace abundances in unamended manure slurries. The relative abundance of orders such as Clostridiales, Bifidobacteriales, and Erysipelotrichales were not noticeably affected by sugar amendment. However, the disaccharides lactose and sucrose seemed to increase the relative abundance of Bifidobacterium, whereas the monosaccharide glucose did not. We conclude that lactic acid bacteria are the primary bacteria involved in improving odor in dairy cow manure slurries and present strategies to enhance their abundance in animal wastes. |