Synergism Of Earthworm And Lactobacillus In The Degradation Of Tetracycline In Sheep Feces And Its Mechanism

Currently,tetracycline antibiotics are widely used in animal husbandry industry,but the phenomenon of overuse of antibiotics makes antibiotics become a new global pollutant.Currently,the degradation of tetracycline in livestock and poultry feces is mainly concentrated in fermentation treatment,and the research objects are mostly cow manure,pig manure,chicken manure,etc.In this study,on the basis of the digestion of sheep manure by earthworms,lactobacillus was added,and different tetracycline residual concentrations of sheep manure were set.The degradation rate of tetracycline was taken as the main index,and earthworm,lactobacillus and earthworm were added to investigate the degradation mechanism of tetracycline residual tetracycline in sheep manure.The main results were as follows:(1)The residual tetracycline concentration of sheep manure was 11.25mg/kg before fermentation and 6.63 mg/kg after 18 days of fermentation.Fermentation treatment could degrade tetracycline residue in sheep manure,but it still could not meet the environmental standards.The addition of earthworm treatment could significantly reduce the residual tetracycline in sheep manure,with the highest degradation rate reaching 64.61%,and the lower the residual concentration of tetracycline,the more obvious the degradation effect.The effect of earthworm and lactic acid bacteria on the degradation of tetracycline residue in sheep manure after fermentation was better than that of earthworm alone.The higher the amount of lactic acid bacteria was,the more significant the degradation rate was(2)The total nitrogen and total phosphorus content in the worm dung formed by earthworm eating sheep dung increased significantly,and the pH value decreased from 10.3 to about 9.5.The change of electrical conductivity increased first and then decreased with the increase of tetracycline residual concentration.The earthworm could adjust the pH and electrical conductivity of its surrounding environment to make the environment more suitable for its survival.The total nitrogen and phosphorus content of earthworm+lactic acid bacteria in the experimental group also increased significantly,and the improvement effect was better than that of earthworm treatment(the average nitrogen and phosphorus content of earthworm treatment was N:11.36g/kg,P:3.88g/kg).The average content of nitrogen and phosphorus treated by earthworm+lactic acid bacteria:N:15.30 g/kg,P:3.76 g/kg).(3)In the static treatment group,the lower the residual concentration of the fourth ring,the higher the activity of the lignin peroxidase(S-Lip)and the higher the degradation rate of the corresponding tetracycline,proving that S-Lip has the ability to degrade tetracycline.Tetracycline stress for a long time is bad for the growth of earthworms,earthworms body cut down the content of soluble protein(SP)and superoxide dismutase(SOD)activity and catalase(CAT)activity to reduce the amplitude is larger,add lactic acid bacteria can helps relieve the stress of high concentration of tetracycline on earthworms,increase the earthworm biomass,at the same time,the earthworm body antioxidant enzyme activity increased significantly.(4)The structure and composition of the bacterial community of earthworm coelenterum and the bacterial community of earthworm feces were significantly different from that before treatment.Earthworms in the process of the degradation of residual tetracyclines in dung,coelenteron earthworm and wormcast microbial communities are complementary to each other,wormcast main species level actinomycosis door,door thick wall,door,the door of metarhizium bending deformation bacteria,earthworm coelenteron major species of horizontal gate of actinomycetes,thick wall ascomycetes door,the door deformation bacteria,green door and bacteroidetes,under the environment of high concentration of tetracycline residues,antibiotic-resistant bacteria dominant bacteria genera,such as bacillus and yellow bacillus,the bacillus of tetracycline resistance,and earthworm lumbrukinase dung coelenteron associated with tetracycline degradation bacteria genera in the dominant bacteria genera,This may be the result of the self-regulation of the microecosystem of earthworm-sheep dung-tetracycline-bacteria.The fecal abundance of firmicutes increased significantly after the addition of lactic acid bacteria.The bacterial community structure of earthworm coelenterum treated with earthworm and lactic acid bacteria did not change much compared with that treated with earthworm.In summary,earthworm+lactic acid bacteria synergistic treatment has a significant degradation effect on the residual tetracycline in sheep manure,and the nutrient content of the formed worm feces is high,earthworm+lactic acid bacteria synergistic treatment can be applied to the harmless treatment of livestock feces.