A rapid and simple method for the quantitative determination of volatile fatty acids (VFAs; propionic acid, n-butyric acid, i-valeric acid and n-valeric acid) and indoles (phenol, p-cresol, 4-ethyl phenol, indole and skatole) in pig slurry and dog excrement using solid-phase micro-extraction (SPME) coupled to gas chromatography was evaluated. 50/30 ㎛ DVB/CAR/PDMS (Divinylbenzene/Carboxen/Polydimethylsiloxane) fiber was used to extract the target compounds in aqueous media. Sample amount and adsorption time was standardized for the routine analysis. Detection limits were from 0.11 to 0.15 ㎍/L for VFAs and from 0.12 to 0.28 ㎍/L for indoles and the correlations observed (R 2 ) were 0.975~1.000. This method was applied to the pig slurry, fertilizer, compost and dog excrement. In nearly all cases, the indoles were detected in concentrations of higher than their limits of detection (DOLs). But the VFAs in swine manure were below their DOLs.
This study was performed to compare the level of odorous compounds in feces and urine of finishing pigs. Feces and urine from 16 finishing pigs were separately collected for 28-d. Concentrations of volatile organic compound (VOC; phenols and indoles) and volatile fatty acid (VFA; SCFA and BCFA) were measured in feces and urine. Amount of phenols and p-cresol was higher (P<0.05) in urine than in feces. Urinal levels of phenols and p-cresol were 257.8 ppm and 250.9 ppm, and those of fecal phenols and p-cresol were 0.50 ppm and 0.05 ppm, respectively. There was no difference in concentration of indoles from feces (1.0 ppm) and urine (1.8 ppm). Short chain fatty acid (SCFA) level in urine was higher (P<0.05) than in feces showing 4,547 ppm and 863 ppm, respectively. Proportion of acetic acid to total SCFA was higher in urine (94%) than in feces (66%). However, level of branched fatty acid (BCFA) was greater in feces (118 ppm) compare to that of urine (87 ppm). Odorous compounds analyzed in the current study, phenols and SCFA, were contained more in urine than in feces. Greater amount of VFA is typically found in feces than in urine since it is generated in the large intestine. However, urine contained more VFA than feces in the current study. Therefore, it will be necessary to exploit odor reducing techniques especially for pig urine as grassland fertilizer.
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