Effect of Storage Period on the Changes of Odorous Compound Concentrations and Bacterial Ecology for Identifying the Cause of Odor Production from Pig Slurry.

Ok Hwa Hwang,Jeong Hoon Kwag,Sung Back Cho,Sung Kwon Park,Deug Woo Han,Sang Ryoung Lee,Hiroaki Matsunami

doi:10.1371/journal.pone.0162714

Ok Hwa Hwang, Jeong Hoon Kwag + Show 5 more

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https://doi.org/10.1371/journal.pone.0162714

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Abstract

Odor from buildings where pigs are housed is generated by anaerobic fermentation of undigested materials in pig slurry stored for several weeks in pit. The objective of this study was to investigate the effect of storage period on the level of odorous compounds in pig slurry and on its bacterial community. A slurry sample (15 L) was taken from the pit of a finisher pig building and incubated in acryl chambers for six- weeks. Slurry for analysis was sampled every two-week. Levels of odorous compounds in the slurry sample were drastically changed after two weeks of storage period; levels of phenols and short chain fatty acids (SCFAs) were decreased (P<0.05), whereas indoles and branched-chain fatty acids (BCFAs) were increased (P<0.05). Among dominant bacteria, Bacteroides and Porphyromonadacese_uc_g revealed a strong positive correlation with the levels of phenols and SCFAs. Populations of AC160630_g, Acholeplasmatales_uc_g, Mollicutes_uc_g and Cloacamonas_f_uc_g positively correlated with indole and BCFAs content. Taken together, levels of odorous compounds were increased after two weeks of storage, possibly because of changes in the predominant bacterial groups to those that use protein as a carbon source in the hypo-carbohydrate conditions.

Highlights

Large amounts of pig slurry are generated by intensive animal farming and industrial livestock production; in South Korea, the amount increased from 4,370 million tons in 2009 to 4,724 million tons in 2013 [1]
Changes in the bacterial community structure during 6 weeks slurry storage period were analyzed by the multiplex bar-coded pyrosequencing technique based on 16S rRNA gene sequences (Table 2)
Our results demonstrate that the storage period of pig slurry in a pit significantly affects the composition of odorous compounds produced as well as the bacterial community

Summary

Introduction

Large amounts of pig slurry are generated by intensive animal farming and industrial livestock production (factory farming); in South Korea, the amount increased from 4,370 million tons in 2009 to 4,724 million tons in 2013 [1]. Swine farming accounts for more than 54% of civil complaints about odor from livestock facilities in South Korea [2]. Odor emissions from pig farms are mainly affected by the type of pig house; in South Korea, 76% of pig houses are built with an open ventilation system and 52% with a slurry storage system [2]. Identify the Cause of Odor Production from Pig Slurry PLOS ONE | DOI:10.1371/journal.pone.0162714 September 19, 2016

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