Study on Geographical Strains of Eimeria maxima II.The Pathogenicities of Eleven Geographical Strains of Eimeria maxima

Suqiu Yellow chickens were used to study the pathogenicities of eleven geographical strains of Eimeria maxima,assessed by clinical symptom,gross pathology,weight gain,lesion score and mortality.The results were as follows:The clinical symptoms and the gross intestinal pathology were similar in birds infected with all the strains and died of coccidiosis.The body weights in all infected groups were affected,and except the groups at 0.1×10~4/bird,the weight gains were significantly different from that of the control groups(P0.05).When the dose was 10×10~4/bird,the weight gains were the lowest in groups infected with Shanghai strain and the largest in groups infected with Suzhou strain and Longyan strain,but there were no significant differences(P0.05).And the lesion scores were the lowest in groups infected with Suzhou strain or Longyan strain and largest in groups infected with Yangzhou strain,but except Suzhou strain,there were no significant differences(P0.05).The infections with Yangzhou strain,Lianyungang strain,Fuzhou strain,Guangzhou strain and USA strain at dose of 10×10~4/bird caused a mortality of 20%,10%,10%,10% and 10%,respectively.It suggested that Yangzhou strain and Shanghai strain were the highest pathogenic,and Suzhou strain and Longyan strain were the least pathogenic among all the strains.