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Deng Y.F.,South China Agricultural University | Liao X.W.,South China Agricultural University | Liao X.W.,Guangdong Enterprise Laboratory of Healthy Animal Husbandry and Environment Control | Wang Y.,South China Agricultural University | And 5 more authors.
Italian Journal of Animal Science | Year: 2015

The objective of this study was to examine the effects and role of prebiotics, such as inulin, fructo-oligosaccharides (FOS) and galacto-oligosaccharides (GAS), to mitigate sulfur-containing odour gases, hydrogen sulfide (H2S) and methyl mercaptan (CH3SH) using pigs as in vitro study model. Inocula obtained from pigs were incubated at 39°C for 24 h using 550 mg sterilised substrate (caecal contents supplemented with or without 50 mg prebiotics). Production of total gas, H2S and CH3SH were determined. The results showed that total gas production for the caecal content of pigs was 57.3 mL, and that for H2S and CH3SH was 220.2 and 15.2 ^L, respectively. The total gas production increased (P<0.05), whereas concentrations of H2S and CH3SH decreased (P<0.05) with supplementation of prebiotics. Among the prebiotics, inulin was the most effective in mitigating H2S and CH3SH productions, reducing the two malodorous gases by 14.7 and 19.8%, respectively. The reduction of the above two sulfur-containing gases was supported by lower sulfate-reducing bacteria population and higher sulfate radical concentrations in the prebiotics, particularly that of inulin supplementation group. © Y.F Deng et al., 2015.

Huang L.,South China Agricultural University | Wen X.,South China Agricultural University | Wang Y.,South China Agricultural University | Wang Y.,Guangdong Enterprise Laboratory of Healthy Animal Husbandry and Environment Control | And 7 more authors.
Journal of Environmental Sciences (China) | Year: 2014

Effects of antibiotic residues on methane production in anaerobic digestion are commonly studied using the following two antibiotic addition methods: (1) adding manure from animals that consume a diet containing antibiotics, and (2) adding antibiotic-free animal manure spiked with antibiotics. This study used chlortetracycline (CTC) as a model antibiotic to examine the effects of the antibiotic addition method on methane production in anaerobic digestion under two different swine wastewater concentrations (0.55 and 0.22mg CTC/g dry manure). The results showed that CTC degradation rate in which manure was directly added at 0.55mg CTC/g (HSPIKE treatment) was lower than the control values and the rest of the treatment groups. Methane production from the HSPIKE treatment was reduced (p <0.05) by 12% during the whole experimental period and 15% during the first 7days. The treatments had no significant effect on the pH and chemical oxygen demand value of the digesters, and the total nitrogen of the 0.55mg CTC/kg manure collected from mediated swine was significantly higher than the other values. Therefore, different methane production under different antibiotic addition methods might be explained by the microbial activity and the concentrations of antibiotic intermediate products and metabolites. Because the primary entry route of veterinary antibiotics into an anaerobic digester is by contaminated animal manure, the most appropriate method for studying antibiotic residue effects on methane production may be using manure from animals that are given a particular antibiotic, rather than adding the antibiotic directly to the anaerobic digester. © 2014.

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