| Popis: |
Extensive usage and the limited number of approved poultry anticoccidial drugs has led to some degree of resistance being developed to all drugs. Three independent battery trials were conducted to evaluate the anticoccidial drug sensitivity (AST) of species/strains of Eimeria within three commercial coccidia vaccines. The vaccines used for these studies were Immucox 3® (broiler vaccine) (IM3), Immucox 5® (broiler breeder vaccine) (IM5), and Immucox T® (turkey vaccine) (IMT). Each trial used a randomized block design with six replications. Each cage contained eight male Cobb 500 broilers (IM3 and IM5) or eight male Hy-Line turkeys (IMT). At 12 days of age (D0), birds were group weighed, allocated to treatment cages, and issued weighed treatment feeds. Birds and remaining feed were weighed on D8 (20 days of age) (IM3 and IM5) or D9 (21 days of age (IMT)). Anticoccidial drugs were blended at commercial use levels. The treatments were as follows. IM3: 1) Nonmedicated nonchallenged (NMNC); 2) Nonmedicated challenged (NMC); challenged and medicated with 3) robenidine 33 parts per million (ppm); 4) decoquinate 30 ppm; 5) clopidal 125 ppm; 6) zoalene 125 ppm; 7) diclazuril 1 ppm; 8) amprolium 125 ppm; 9) salinomycin 66 ppm; 10) narasin 39.6 ppm + nicarbazin 39.6 ppm; and 11) narasin 74.25 ppm. IM5 used the same IM3 treatments 1-11 plus 12) nicarbazin. IMT: 1) NMNC; 2) NMC; 3) lasalocid 79.2 ppm; 4) monensin 66 ppm; 5) amprolium 125 ppm; 6) zoalene 125 ppm; and 7) nicarbazin 125 ppm. The challenge for each vaccine was 100 times the commercial recommended dose given orally on D2 (14 days of age). For trials IM3 and IM5, on D8 (6 days postchallenge) all chickens were coccidia lesion scored. IMT oocysts per gram (D7-9) and dropping scores (D8) were determined instead of lesion scores. For IM3 and IM5 vaccines, the results showed that all strains were sensitive to all anticoccidial drugs. For turkey IMT vaccine, the results showed that all strains were highly sensitive to all anticoccidial drugs. This information can serve as a foundation for the use of these coccidia vaccines in the restoration of coccidia sensitivity in the field. |
