| A cylinder plate microbiological assay with Escherichia Coli,StaphylococcusAureus,Bacillus Pumilus and Bacillus Subtilis was developed for determination ofMonensin,Salinomycin and Maduramicin residues in different tissues(mucle,liver andkidney) of chicken. And the appropriate bacterium was screen out to examine thedrugs'residues in different tissues of chicken.1 The establishment of microbiological method for three PEs'residues and thecollection of sensitive bacterium.1.1 The collection of the feasible inoclum concentration of seed ager witn the four bactriaand pH of substrate.The concentration of bacteria and pH of substrate were confirmed by the inhibitionzone diameters and the definition at different moment.The results showed: When theinoclum concentration were 2%(16×105cfu·mL-1),0.5%(10×106 cfu·mL-1),0.12% (6×106cfu·mL-1) and 0.004%(6×105 cfu·mL-1) of the Escherichia Coli,Staphylococcus Aureus,Bacillus Pumilus and Bacillus Subtilis respectibely, the inhibition zone diameters were thebiggest of the center concentration, and the edges were clearly. And the best PH ofsubstrate was 6.5.1.2 The limit detection of three Polyether ionophores in Phosphate-Buffered Saline(PBS).The limit detection were confirmed by the determination of the inhibition zonediameters with three drugs and four bacteria. The results: In PBS, there were differencesamong the limit detection of the same drug with the different bacteria; and there were thedifferences among the limit detection of the different drugs with the same bacterium. Withthese four bacteria, the limit detection of MON was 1.0～2.0μg·mL-1, and the limitdetection of SAL was 0.25～2.0μg·mL-1, and the limit detection of MAD was 1.5～2.5μg·mL-1.1.3 The preparation of the standard response curves of three Polyether ionophores inPhosphate-Buffered Saline(PBS).The research prepared the standard response curves of three Polyether ionophores tofour bacteria in PBS, and the range of concentration were the 1/2 times of the limitdetection to the 16 times. The results: The coefficients variations (C.V.) of the slopes werebelow than 10%; and the correlation variation were above than 0.99. These showed that theexperiment had good repetition, and the inhibition zone diameters with the logarithm ofdrug concentration had good linear relation.1.4 The filtration of the sensitive bacterium of microbiological method for three Polyetherionophores.The sensitive bacterium was screen out across the limit detection of three drugs withfour bacteria. The results: The limit decetion of MON was lowest to 1.0μg·mL-1 with Staphylococcus Aureus and Bacillus Subtilis. And the limit decetion of SAL was lowest to0.25μg·mL-1 with Bacillus Subtilis. The limit decetion of MAD was lowest to 1.5μg·mL-1with Bacillus Pumilus and Bacillus Subtilis.2 The establishment of microbiological determination method for three PEs'residuesin tissues of chickens.2.1 The preparation of the standard response curves of three Polyether ionophores intissues of chickens.The research put the criterion drugs diluted into six concentration used the distillsolution of blank tissues, and prepared the the standard response curves by sensitivebacteria. The results: The coefficients variations (C.V.) of the slopes were below than 10%;and the correlation variation were above than 0.99. These showed that the experiment hadgood repetition, and the inhibition zone diameters with the logarithm of drug concentrationhad good linear relation.2.2 The recovery rate of three Polyether ionophores in tissues.The research used the sensitive bacteria to determine the reclaim and the precisionwith adding different drug concentration in every tissue. The results were given as follow:the recoveries rates of MON,SAL and MAD were between 62.9%～87.7%,64.1%～87.8% and 61.8%～85.6% separately; and the C.V. were were between 4.2%～14.2%,4.6%～14.2% and 3.1%～14.8% separately, which the recovery rate were higher slowly asthe accession level increased.2.3 The limit detection of three Polyether ionophores in blank tissues.The results showed that the limit detection of three Polyether ionophores in musclewere 0.4～2μg·g-1; which lower than 0.6～2.5μg·g-1 in liver and in kidney. The BacillusSubtilis was the best.3 The residues detection of three Polyether ionophores in chicken tissues.The detection of residues of three drugs: the residues of three drugs in different timewere detected with microbiological method in tissues of boiler. The results showed that theresidues of MON were all below than the limit detection in muscle and kidney, and theresidue was the highest in 6 hours, and the residues after 18 hours were undetectable inliver. The residues of SAL were undetectable after 24 hours,48 hours and 24 hours inmuscle,liver and kidney separately. Then the residues of MAD were undetectablecompletely.It was concluded that Bacillus Subtilis was the best bacterium. This method waspractical, fast, steady and easy to perform, which can be used in the detection of thePolyether ionophores residues of in the tissues of broiler.
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