|Mcgarvey, Jeffery - Jeff|
Submitted to: American Society for Microbiology General Meeting
Publication Type: Abstract only
Publication Acceptance Date: 1/11/2011
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Sodium bisulfate (SBS) is commonly used in the poultry industry, and is beginning to be used on dairies, to acidify animal waste for the reduction of ammonia emissions. However, little is know about the effects of SBS on the bacterial populations in waste. Methods: SBS was applied at 0, 50, 100, 150 g/m2 to dairy cow waste as it accumulated on the floors of four cattle pen enclosures, housing eight dairy cattle each. Cultural and 16S rRNA gene sequence analysis was used to analyze the bacterial population structure of the waste. Results: We observed significant decreases in the pH of the waste in all treatments after day one; however, the pH of the waste receiving 50 g/m2 returned to control levels by day four, while the others remained significantly lower. Aerobic plate counts revealed that all levels of treatment caused a drop in bacterial concentration; however, the bacterial numbers returned to control levels in all of the treatments by day four. The 16S rRNA gene libraries revealed SBS treatment caused significant reductions in sequences associated with the phyla Bacteroidetes and Firmicutes and significant increases in those associated with the Proteobacteria, Actinobacteria and Spirochaetes (P<0.01); however, over time the number of these sequences reverted to the control levels. Interestingly, the percentage of sequences associated with E. coli increased by several orders of magnitude after SBS application; however, they too reverted to control levels over time. Conclusions: Sodium bisulfate is effective at reducing the emissions of various volatile organic compounds but care must be taken when beginning application as it may result in increases in E. coli levels.