Effects Of OTC On Enzyme Activities And Microbial Community Metabolic Profiles

As the farms of domestic animals become more and more intensive and larger andlarger in scale, they administer great amounts of antibiotics to their animals, which dischargethese antibiotics along with their dung and urine, hence causing severe environmentalpollutions. Adding different concentration of oxytetracycline to pig manure mixed with wheatstraw to produce organic fertilizer. Studying the effect of oxytetracycline on the activity ofenzyme and microbial community metabolism in the composting process by the activity ofenzyme analysis method and Biolog micro-plate culture method. Studying the effect oforganic fertilizer containing oxytetracycline on the activity of enzyme and microbialcommunity metabolism in the soil by the activity of enzyme analysis method and Biologmicro-plate culture method. In order to provide evidence of effectively harmless disposal ofanimal manure containing oxytetracycline and reasonable utilization of resource. The mainresults are as follows:1. The results showed that composting temperature lasted for5days on treatmentwithout addition of oxytetracycline (0mg/kg), which could meet the need of the requirementof harmlessness. Other treatments failed to meet the need of the requirement of harmlessnessduring the composting.2. In the first composting day, the cellulose enzyme activity is significantly lower in withaddition of35mg/kg oxytetracycline than that in CK, then cellulose enzyme activity ofaddition of35mg/kg oxytetracycline treatment and CK ware not significant difference. Thecellulose enzyme activity of addition of35mg/kg oxytetracycline treatment at a relatively lowlevel after the third composting day, showed that e addition of140mg/kg oxytetracyclinegreatly inhibited the activity of cellulase. The activity of urease was increased by addition ofoxytetracycline in the first3days, since then on, it was decreased. The activity of ueease washighest in the addition of105mg/kg of oxytetracycline treatment. Then, oxytetracyclineinhibited the activity of urease. From day1to day18, oxytetracycline promoted the activityof catalase, then oxytetracycline inhibited the activity of catalase.3. By analysising the composting process of microbial community metabolism, wefound that AWCD value of CK was higher than other treatments during the rasing anddropping temperature period, while the addition of70mg/kg oxytetracycline treatment of AWCD value was the highest in the high temperature period. Shannon index results suggestedthat the oxytetracycline addition could reduce the functional diversity of microbialcommunities during the rasing temperature period, in contrast, it could increase the functionaldiversity of microbial communities during the high and dropping temperature period. Thecarbon source utilization data showed that the addition of140mg/kg oxytetracycline couldsignificantly change the types of carbon sources used by microorganisms.4. It showed that oxytetracyline inhibited during the first day of pot culturing period,and then promoted urease activity; it had evident inhibitory effect on alkaline phosphataseactivity but presented promoting effects on catalase activity.5. The analysis with the Biolog EcoPlateTMshowed that at the96th incubation hour, theAWCDs of soil microbe decreased by12.22%and15.66%where oxytetracyline was addedat35mg/kg and70mg/kg, increased by2.05%and8.31%where oxytetracyline was addedat105mg/kg and140mg/kg, compared to where oxytetracyline was not added, respectively.the analysis on the Shannon indexes of the soil microbe communities showed that theShannon indexes were significantly lower where oxytetracyline was added at35mg/kg,70mg/kg,105mg/kg and140mg/kg than not added. The principal components analysis showedthat where its oxytetracyline content was as high as70mg/kg, pig dung still could exertinfluence on carbon sources for the metabolisms of soil microbes.