Resistance of eimeria field isolates to combined anticoccidial drugs

Many researchers express concern about the emergence of stable forms of eimerias and the breadth of resistance, because this determines the duration of "life" of anticoccidial products. The field isolates of the emery were isolated from the biological material (litter) from broiler chickens from poultry farms of the Russian Federation, typed to species and propagated according to the generally accepted method. Typing of the emmeries was carried out according to the morphological features of the oocysts, the duration of the prepatent period, and pathomorphological changes in the intestinal tract after the challenge of the susceptible bird. Sporulated ovocysts were stored in a solution of 2.5% potassium di-chromate at a temperature of 4-6 ° C until the time of the study. The sensitivity of the field crops to the active ingredients and their combinations was determined on broiler chickens at the age of fourteen days, grown under conditions appropriate to age and excluding their spontaneous infection with infectious and parasitic diseases. In the present work, the species composition of the field isolates of Eimeria circulating in poultry-farming enterprises of the Russian Federation and the Republic of Belarus and their sensitivity to combined anticoccidial drugs are investigated. The species composition of the field isolates of chicken Eimeria in six cases is represented by a mixture of E. acervulina and E. tenella, and in three cases - E. acervulina, E. tenella, and E. maxima. The low sensitivity of the field isolates of chicken Eimeria to ionophore antibiotics and to their combination with nicarba-zin has been established. One isolate of three is sensitive to narasin, two of six to monensin, one to four to maduramicin, two of seven to a combination of narasin + nicarbazin, one in eight to a combination of monensin + nicarbazin and one of two to a combination of maduramicin + nicarbazin. Three field isolates, presented as a mixture of E. acervulina and E. tenella, and a mixture of E. acervulina, E. tenella and E. maxima, showed partial resistance to all the drugs studied.

эймерии, комбинированные ант икокцидийные препарат ы, противококцидийный индекс, резистентность, Eimeria, combined anticoccidial drugs, anticoccidial index, resistance

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