Study On The Detection Methods,residue Characteristics And Risk Of Antibiotics In Non-antibiotic Pig Breeding

With the rapid development of pig breeding industry,veterinary drugs such as antibiotics are widely used in breeding industry to prevent diseases and promote animal growth.However,the long-term massive use and abuse of antibiotics has caused severe bacterial resistance and multiple resistance in the environment,which has gradually become the focus of attention.Therefore,the Ministry of agriculture has proposed that the non-antibiotic breeding to alleviate the antibiotic pollution of livestock and poultry,which is forbidden to use growth promoting antibiotic feed additives in the breeding process.Nevertheless,previous studies mainly focused on conventional breeding,and there was lack of research after the implementation of non-antibiotic breeding.In order to evaluate the potential risks of antibiotics for animal diseases prevention and treatment to the environment and human health under the background of non-antibiotic breeding,26 common typical antibiotics in pig breeding were selected as target antibiotics.The 26 antibiotics analysis methods were established to detect typical antibiotics in feed,manure and commercial pork available for non-resistant pig farms in Shanghai area,respectively,to explore their residual characteristics and conduct environmental health risk assessments.The main research conclusions are as follows:（1）The analysis methods for 7 kinds of 26 antibiotics in feed,pig manure and pork was established.All antibiotics were linear in the range of 1.37～500μg·L^-1.The correlation coefficient R~2 was greater than0.9944.The instrument limits of detection were 0.04～5.51μg·L^-1and limits of quantification were 0.14～18.35μg·L^-1.MAE-SPE was used as the pretreatment method of feed samples.The volume ratio of methanol:acetonitrile mixed solution（V:V=1:1）and EDTA-Mc Ilvaine buffer solution was 1:1 as the extraction solution.When the microwave extraction temperature was 65℃and the extraction time was 15 min,the recoveries were 56.73%～127.37%;Based on the pretreatment of feed samples,manure samples obtained great and stable recovery when 100 mg PSA and 50 mg C18 were added,and the recoveries were58.13%～129.77%;Pork samples were pretreated with ATPE,0.2%formic acid acetonitrile:Na2 EDTA（V:V=7:3）was selected as the extraction solution,and（NH₄）₂SO₄was used as the phase separation salt,the recoveries were 56.60%～133.80%.（2）Antibiotics with different residual levels were detected in non-antibiotic breeding pig farms.The detection amount of antibiotics in feed was 0～63.52μg·kg^-1.Chloramphenicols were the main antibiotic in conservation feed,macrolides（51.24%）and quinolones（48.76%）were the main antibiotics in fattening feed;The detection amount of antibiotics in manures was 12.12～103804.20μg·kg^-1,DOX in tetracyclines was the main antibiotic,with the highest concentration of 96.45 mg·kg^-1.The results showed that the levels of antibiotics used and produced by pigs in the nursery stage were higher than those in the fattening stage;At present,antibiotic intake through feed addition was not the main utilization way in non-antibiotic breeding farms.Injection and drinking water addition may be the main sources of antibiotic pollution in farms.（3）The overall level of antibiotics detected in commercial pork available from the above farms was low.Only three antibiotics were detected,and the detection concentration from high to low was FLOR(130.39μg·kg^-1)>CP(74.85μg·kg^-1)>TP(21.34μg·kg^-1).The results were in accordance with national food safety standards.As there were a small amount of antibiotics detected in pork,there were certain safety risks and the relevant departments ought to further strengthen the regulation of antibiotic use in livestock and poultry breeding industry.（4）Antibiotics detected in manures from pigs at different stages of growth that showed different degrees of risk.The risk of antibiotics in nursing pig manure was higher than fattening pig manure.Although the above antibiotics had not caused serious consequences,the continuous accumulation of antibiotics would cause potential risks on the ecological environment and human health.Antibiotics residues in pork had little risk to human health and were at an acceptable safety level;At the same age stage,the risk of antibiotics to human health was that the food safety index of men higher than women.Although the food safety index of pork was less than 1,the risk of illegal use of antibiotics in the process of livestock and poultry breeding,the supervision of antibiotic use in livestock and poultry breeding industry should be further strengthened.