磺胺二甲嘧啶及其加入方式对猪粪厌氧消化的影响

为研究磺胺二甲嘧啶(SMZ)残留对猪粪厌氧消化系统的影响,采用两种加入方式,即经体内代谢法(加入经饲SMZ后所获含SMZ的猪粪)和直接加入法(加入空白猪粪+SMZ),并比较分析了两种研究方法间的差异。试验在有效容积为1 300 mL的厌氧消化系统模型中恒温30℃进行,为期28 d,前7 d为加药期,后21 d为停药期,在加药期每天加入SMZ浓度为56.04 mg/kg和47.10 mg/kg的猪粪。结果表明:(1)两种加入方式对厌氧消化系统中SMZ及其代谢产物N4-ACE-SM2浓度影响差异不显著(P>0.05);(2)分别加入SMZ浓度为56.04 mg/kg和47.10 mg/kg的猪粪时,在加药期经体内代谢组的产甲烷量分别比同浓度的直接加入组显著降低了17.36%和23.60%(P<0.05),在停药期直接加入组比同浓度的经体内代谢组显著降低了13.79%和16.34%(P<0.05),且经体内代谢组与空白组无显著差异(P>0.05);(3)经体内代谢组产甲烷菌多样性变化趋势与空白组相似,而与直接加入组不同,试验结束时,经体内代谢组产甲烷菌群落结构与空白组相似性为1,而与直接加入组相似性为0.86。由此可知,在本试验条件下,两种加入方式下SMZ对猪粪厌氧消化系统的影响不同,采用经体内代谢法评估SMZ对厌氧消化系统的影响更具合理性。

Effect of Sulfamethazine and the Addition Methods on Anaerobic Digestion of Swine Manure

To study the effect of sulfamethazine(SMZ) on the anaerobic digestion system of swine manure, two addition methods were used and compared in this paper,which were the in vivo metabolic method(using manure collected from swine fed with diet containing SMZ) and the direct addition method(antibiotic-free manure directly added with SMZ). The experiment was conducted with laboratory model anaerobic reactors with an effective working volume of 1.3 L at 30℃ for 28 consecutive days. The first 7 days were the medicated period, followed by 21 days as the withdrawal period. Two SMZ concentrations of 56.04 mg/kg and 47.10 mg/kg swine manure were added into anaerobic reactors during the medicated period. The results are as follows:(1) The concentration of SMZ and N4-ACE-SM2 had no significant difference between two addition methods(P>0.05);(2) Under two SMZ concentrations of 56.04 mg/kg and 47.10 mg/kg, compared with the direct addition group, the methane production of the in vivo metabolic group was respectively significantly decreased by 17.35% and 23.60% in the medicated period(P<0.05);the direct addition group was significantly lower than the in vivo metabolic group by 13.79% and 16.34% in the withdrawal period(P<0.05), and there was no significant difference between the in vivo metabolic group and the blank group(P>0.05);(3) The diversity of methanogenic bacteria in the in vivo metabolic group was similar to that of the blank group, but different from the direct addition group;At the end of the experiment, the similarity of the methanogen community structure was 1 between the in vivo metabolic group and the blank group, and the similarity was 0.86 between the in vivo metabolic group and the direct addition group was 0.86. Results of the present study demonstrated that under the experimental conditions, the effects of SMZ on the anaerobic digestion system of swine manure are different. It is more reasonable and accurate to evaluate the effect of SMZ on anaerobic digestion system by the in vivo metabolic method.