Study On The Toxicity Of Toltrazuril And Its Efficacy Against E.Tenella In Chicken

Toltrazuril,a triazinetrione derivative, is synthesized by us now. The toxicity of toltrazuril in mice and prevention and treatment of coccidiosis in chicken were studied in this paper.Acute toxic test in mice was determined by improved Karber method. The oral LD50 of toltrazuril was 5011 mg.kg~-1.bw~-1, and the confidence areas of 95% were 3715 ~ 6761 mg kg~-1bw~-1. Accumulation toxic test was determined by dose-increased every 4 days. The results showed that the K of toltrazuril in mice was 4.26, and it belonged to the medium accumulation. Mice were administered with toltrazuril at the dosage of 500, 100, 20 mg kg~-1bw~-1 in order to investigate subchronic toxicity. In the 500 mg.kg~-1bw~-1 dose WBC were decreased and mainly affected the liver in the body ; At the 20 and 100 mg kg~-1bw~-1 dose the viscera pathology symptoms and blood routine were not significantly changed. Sperm abnormality test on the male mice reproduction cells showed that toltrazuril was non-genotoxic. These results showed that toltrazuril was practical non- toxicity.In order to evaluate the prime time of effect of toltrazuril on E. tenella in chickens, toltrazuril at doses of 50 X 10~-6 mg.L~-1 was administered in coccidian devepolment stages, the results showed that toltrazuril administered 12~144h after infection was effective, the prime time of effect of toltrazuril was 36~60h after infection .The efficacy of toltrazuril against E. tenella were researched in chickens via drinking warter at the dosage of 50 X 10~-6mg.L~-1 25 X 10~-6 mg.L~-1, 12.5 X 10~-6mg.L~-1 and 6.25 X 10~-6 mg.L~-1 respectively ,for 2 consecutive days. The results showed that the ACI of the 50 X 10~-6 mg.L~-1 and 25 X 10~-6 mg.L~-1 groups were 190.22 and 187.12, kept in high effect against coccidiosis. The ACI of 12.5 X 10~-6 mg.L~-1 and 6.25 X 10~-6mg.L~-1 groups was 158.36 and 122.58, kept in low effect. It suggested that toltrazuril could be used via drinking water at doses of 25X10~-6 mg.L~-1 for 2 consecutive days.The efficacy for preventive treatment of toltrazuril were researched via drinking and feeding at the dosage of 25 X 10~-6 mg.L~-1 .The ACI were 179.0 and 167.7 respectively.Efficacy were researched against E. tenella in 21 day-old AA broiler chickens with toltrazuril at doses of 25 X 10~-6 mg.L~-1 in drinking water, Baycox at doses of 25 X 10~-6 mg.L~-1 in drinking water, diclazuril at doses of 1 X 10~-6 mg.kg~-1 in feeding and VO 150X10~-6 mg.kg~-1 in feeding. The results showed that the anticoccidial index of toltrazuril, Baycox, diclazuril and VO were 192.98,186.02,141.48 and 161.98 respectively.Efficacy were researched against E.tenella in 21 day-old Lohmann cocks with the combinations of toltrazuril respectively with diclazuril, maduramicin and Zoalene. Anticoccidial indexes(ACI) were used as the criteria of evaluating anticoccidial efficacy. The results showed that the ACI of toltrazuril combinated with diclazuril, maduramicin and Zoalene were 187.29, 182.78, 171.38 respectively. The combinations of toltrazuril with diclazuril and maduramicin were high effective.