Objective: Comparing the efficacy of coccidiostat drugs, Diclazuril, Salinomycin, and Narasin on performance parameters of broiler chickens in experimental coccidial infection.
Design: Completely randomised block.
Animals:A total number of 300 male day-old Ross 208 broiler chickens.
Procedure: The chicks were randomly divided to 5 groups of 60 birds (3 replicates/treatment), and placed in battery cages. The groups were: 1) which did not receive any coccidiostatic drug or oocysts (negative control), 2) which did not receive any coccidiostatic drug but was challenged with oocysts (positive control), 3) Diclazuril, 4) Narasin, and 5) Salinomycin. Treatment groups received the related coccidiostats from the beginning of the rearing period up to 3 days before slaughter( 49 days of age). Birds in all groups (except group 1), were challenged with 105 of mixed inoculum of E. tenella, E. maxima, and E. acervulina. Eight days
post-challenge, fecal samples were taken and oocysts per gram of feces determined for five consecutive days. By weighing the chicks and their consumed feed at 28 (before challenge), 35,42 and 49 days (end of the rearing period), mean of body weight (BW), weight gain (WG), feed intake (FI) and feed conversion ratio (FCR) of all groups determined weekly.
Statistical analysis: Analysis of variance, Tukey's test.
Results: At 35 days old (1 week after challenge), the differences among WGs of treated and positive control groups were significant (P< 0.01). At the same age, there were not any significant differences
among FCR of treated and negative control groups, but FCRs of all groups were significantly better than positive control (P0.05). At 49 days old, FCR of Salinomycin was better than positive control (p< 0.05), but no significant differences observed among treatments(P>0.05). Diclazuril and Salinomycin significantly reduced the OPG in comparison with positive control (p< 0.001).
Conclusion: According to the results of this study, using these coccidiostats can improve the performance parameters of broiler chickens and their usage can be recommended specially when
coccidial infections may occure. Comparison the performance of treatment groups showed partial improvement of BW and FCR by Diclazuril and Salinomycin respectively. In addition these two coccidiostats reduced OPG significantly. J. Fac. Vet. Med. Univ.
Tehran. 58, 4: 377-381, 2003.