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

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.

Digestibilidade, produtos da fermentação e compostos voláteis nas fezes de cães Bulldog francês alimentados com diferentes fontes proteicas

“…In addition to the proteins being precursors of BCFA, it is also a precursor to the offensive odors compounds such as phenols, indoles, sulfur, ammonia and amines Hwang;. In the present study, the presence of two sulfide compounds were detected in two different animals in the T0 treatment, the dimethyl trisulfide and dimethyl disulfide, this result agrees with that observed by Lowe et al (1997b), who found dimethyl trisulfide in a single sample of dog feces.…”

“…Short chain fatty acids (SCFA) are mainly a result of carbohydrate fermentation, whereas branched chain fatty acids (BCFA) are the product of the fermentation of proteins Hwang et al, 2016). In this study SCFAs were very common, however, the BCFAs were not frequent, this result may indicate a greater availability of energy from carbohydrates, and less availability of amino acids and nitrogen in the intestine, although there was no statistical difference in the treatments in relation to this result.…”

“…The phenol and indole proportions are related to fecal pH, being that phenols are produced in the presence of low pH, while the indole at high pH (Hwang et al, 2016).…”

“…Nenhum dos produtos da fermentação intestinal apresentou diferenças significativas entre as dietas. A baixa fermentação no presente estudo pode ser explicado pelo menor fluxo de proteínas não digeridas no intestino grosso, indicando uma quantidade constante de glucose como fonte de degradação dos microrganismos intestinais proveniente de carboidratos, e baixo conteúdo de aminoácidos e nitrogênio devido ao pouco conteúdo de proteínas nas dietas e a alta digestibilidade das mesmas (HWANG et al, 2016 0,54 T0, Dieta com farinha de vísceras de frango; T1, Dieta com glúten de trigo; T2, Dieta com farinha de vísceras de frango e glúten de trigo e T3, Dieta com farinha de vísceras de frango, glúten de trigo e proteína hidrolisa; EPM, erro padrão da media; n = 8 cães por dieta; a,b,c Médias nas linhas seguidas de letras iguais não diferem entre si (p˃0,05).…”

“…intestinal, e da exposição à contaminantes químicos (GARNER et al, 2007). As proporções de fenóis e indóis estão relacionadas com o pH fecal, sendo que os fenóis são produzidos em presença de pH baixos, enquanto os indóis em pH alto (HWANG et al, 2016). Em média o pH intestinal em cães é de 7,3 (LUI et al, 1986).…”