| Coccidiosis is a parasitic protozoal disease caused by several Eimeria species parasitized in the chicken intestinal mucosal cells. Coccidiosis is the highest incidence in all kinds of poultry diseases that cause serious harm to the poultry industry, and the Eimeria tenella is the most common with the most pathogenicity to chickens. With the development of aquaculture, drug residues, microbial resistance and food safety issues associated with the line, especially the emergence of superbugs, all of them heavily strike the public nerve. Research in recent years have shown that artemisinin (ARS) can reduce the output of oocyst from the infected chicken and the sporulation rate of oocysts, so ARS shows a certain anti-coccidial effect. Some literatures indicate that sulfasalazine (SASP), one of chronic rheumatic drugs, has a good therapeutic effect on ulcerative colitis in a clear dose-dependent manner. Whether can the drug be used as a preventive agent for chicken coccidiosis? While for the national restrictions on food additives in animal feed regulations, we want to know whether combination of them can obtain the acceptable therapy against Eimeria tenella under the premise of reducing the dose of sulfa drugs? To explore these issues, this study carried out the following experiments.1. Efficacy and safety of ARS and SASP for the Eimeria tenella. Healthy1-day-old chickens were chosen as test animals, insect attack carried out in accordance with normal operation, then the control effect of SASP, ARS and artemether on chicken coccidiosis will be observed in this study. At the end of the trial, all chickens were weighted and sacrified by vervical dislocation, and then the necessary samples were collected. Meanwhile, physical examinations, such as blood and serum biochemistries, gross and histopathological lesions were also examined. Anticoccidial index (ACI) is calculated for each experimental group. The results confirmed that SASP have a good therapeutic effect on Eimeria tenella, and the ACI reached188.5, in addition, the preventive effects appears an obvious dose-dependent relationship. However, artemisinin was less effective, unless it combinated with SASP. This combination can improve anticoccidial activities even if reducing the dose of sulfa drugs, so it shows a prospective development in clinical practice. Artemether has no anti-coccidial effect, conversely, it showed a certain side effects to chicken’s liver and kidney, so it is not recommended in clinical use as a coccidiostat. Target animal safety indicated that the sulfasalazine was safe as a control measure for coccidiosis of chickens.2. Determination of SASP residue in muscular tissue of chickensTissues were extracted sequentially using acetonitrile, and liquid-liquid extraction by hexane. Then the residues were dissolved with mobile phase for HPLC detection. The mobile phase was acetonitrile:water:formate=35:65:0.2(V/V/V), with UV detection wavelength as365nm. The result showed that the concentration of SASP had a good liner coefficient relation (R2=0.9997) in the range of2.5～20μg/mL. The limit of detection was0.1mg/kg, and the limit of quantitation was0.5mg/kg. When spiked level were1,2and4mg/kg in chicken muscle from tissues assay, the average recovery rate was up to74.76%. The experimental detection method is simple, rapid, accurate and reliable, which is suitable for SASP residual detection in chicken tissues. |
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