Reduction Of Antibiotics Involved By Microorganisms In Livestock And Poultry Breeding

Veterinary antibiotic pollution is a major environmental problem in the development of livestock and poultry industry in China.Veterinary antibiotics are over-added to feed as growth promoters,and accompanied by animal manure entering the environment.Over the years,they pollute the environment and threaten human health.Feed microbial agents can be used as feed additive instead of antibiotic to reduce the use of antibiotic at source.In addition,for the residual antibiotics in livestock and poultry manure,the addition of highly effective antibiotic-degrading bacteria during aerobic composting is an effective terminal treatment method.Screening microorganisms beneficial to the intestinal microbial community of poultry or capable of degrading antibiotics from the nature can reduce antibiotic contamination at the source and the end,respectively.Four strains of Bacillus were screened to degrade cellulose and protein,Bacillus amyloliquefaciens,Bacillus tequilensis,Bacillus velezensis and Bacillus subtilis.And Bacillus velezensis and Bacillus subtilis were found to degrade aureomycin.A strain of lactic acid bacteria with strong inhibitory ability against e.coli and staphylococcus aureus was screened,Lactobacillus plantarum.An existing yeast strain,Cyberlindnera jadinii,was activated.Compound microbial agent 1 was prepared with Bacillus velezensis,Lactobacillus plantarum and Cyberlindnera jadinii and used as feed additives to feed laying hens.It promoted the growth and laying of laying hens,increased the diversity of microbial communities in cecum contents of laying hens,increased the relative abundance of beneficial bacteria such as Rikenellaceae_RC9_gut_group,Faecalibacterium,Olsenella,Bifidobacterium and Phascolarctobacterium,and inhibited the reproduction of enteropathogenic bacteria such as Campylobacter?Desulfovibrio,Escherichia-Shigella and Cronobacter.The results showed that compound microbial agent 1 could be used as feed additive instead of antibiotics,thus reducing antibiotic pollution from the source.Compound microbial agent 2 was prepared with Bacillus velezensis,Bacillus subtilis,Bacillus amyloliquefaciens and Bacillus tequilensis and used as aerobic composting additives.The degradation rate of chlortetracycline increased from 85.32% to 92.06%.In the composting process,it was found that adding compound microbial agent 2 could increase the heating rate and the highest temperature of the compost,prolong the high temperature period,increase the pH value during the decomposition period,reduce the C/N during the decomposition period,promote the transformation of ammonium nitrogen into nitrate nitrogen,increase the relative abundance of Bacillus during the high temperature period,kill pathogenic bacteria and promote rapid maturation.The results showed that adding compound microbial agent 2 could improve the degradation of chlortetracycline in aerobic composting process and promote the rapid maturation of fecal aerobic composting.It was an effective terminal treatment method for antibiotic contamination in livestock and poultry breeding process.