Safety Evaluati On Of Diclazuril And Toltrazuril To Broilers

The effects of Diclazuril and Toltrazuril on broilers growth and slaughter performance, immune action, sera biochemical indices, histology of some organs were researched, and the dose effect and elimination of Diclazuril and Toltrazuril’s deposition in muscle and liver of broilers were also studied in this experiment to investigate the safety of the drugs to broilers.5041d AA Broilers were divided into7treatments with6replicates of12broilers in each replicate. Group1(the control group) was supplied with the basal diets, while the treatments (group2, group3and group4) were supplemented with1mg/kg,2mg/kg and4mg/kg Diclazuril in the basal diets respectively at8～35days old, and the other treatments (group5, group6and group7) were supplemented with25mg/L,50mg/L and100mg/L Toltrazuril in tap water respectively at8-10days old.The experiment lasted for49days. The results showed that:1. Study on the effects of Diclazuril and Toltrazuril on growth, slaughter performance and immune action of broilersThere was no significant effect on the growth and slaughter performance of broilers fed with Diclazuril and Toltrazuril in the basal diets and water (P>0.05). The transformation rates of peripheral T lymphocyte of group3and group4were significantly lower than group1(P<0.05or P<0.01). The immune organs indices of group4was significantly higher than group1(P<0.05), but the serum antibody titre of NDV of this group was significantly lower than group1(P<0.05) at28d. The thymus index and the spleen index of group5and group6were significantly higher than that of group1(P<0.05), the bursa index of group7was significantly lower than that of group1at28d (P<0.05); The transformation rates of peripheral T lymphocyte of group6was significantly higher than that of group1(P<0.05).2. Study on the effects of Diclazuril and Toltrazuril on sera biochemical indices and the deposition of the drugs in muscle and liver of broilersThe activities of AMS of group3and group4were significantly lower than that of group1(P<0.05or P<0.01), while the activities of T-SOD were significantly higher than that of group1at28d (P<0.05or P<0.01); The activity of T-SOD of group4was significantly lower than that of group1and the other experimental groups at35d and42d (P<0.05or P<0.01). The activities of AMS, the content of total protein and T-SOD of group6and group7were significantly lower than that of group1(P<0.05or P<0.01).The deposition amount of Diclazuril in muscle and liver of group4was significantly higher than that of group2and group3(P<0.05or.P<0.01). The deposition amount of Toltrazuril in muscle and liver of group7was significantly higher than group5and group6(P<0.01or P<0.05). The deposition amount of the two drugs in liver was significantly higher than that of the muscle (P<0.05or P<0.01). With the extension of time after withdrawal, the elimination trend of the two drugs in muscle and liver was accorded with index function model. According to the model prediction, the Diclazuri’s deposition amount in muscle and liver of group2, group3and group4attenuated to the limit of detection of HPLC (249.60ng/g) at18.42day,23.01day,28.17day and25.65day,29.17day,33.49day after withdrawal respectively; the Toltrazuril’s deposition amount in muscle and liver of group5, group6and group7attenuated to the limit of detection of HPLC (74.45ng/g) at3.42day,4.74day,5.73day and5.02day,6.10day,6.59day after withdrawal respectively.3. Study on the effects of Diclazuril and Toltrazuril on histology of broilers’liver, spleen and renalThe liver, renal and spleen of the control group all developed normally, but that of the test groups all had different pathological changes. The lesion degree of the organs appeared obviously to be correlated to the dosage of drug concentration and administration time. The pathological changes of the test groups showed that:The liver showed symptoms of cells swelling, hemorrhage, congestion, inflammatory cell infiltration. The spleen showed symptoms of hemorrhage, inflammatory cell hyperplasia, and the renal showed hemorrhage, congestion, cells swelling, lumen reduced or total occlusion. The pathological changes of the groups with Diclazuril were more severe than that of the groups with Toltrazuril.