Effect of avilamycin, tylosin and ionophore anticoccidials on Clostridium perfringens enterotoxaemia in chickens.

In order to study the prophylactic and metaphylactic effect of antomicrobial growth promoters and ionophorous anticoccidials on the incidence of Cl. perfringens enterotoxaemia in chickens, experimental attempts were performed with 675 chickens in 27 trials. The birds were intraduodenally infected with Cl. perfringens type A (ATCC 3624). The following antimicrobial growth promoters and ionophore anticoccidials were used either on their own or in combination: avilamycin, narasin, monensin and tylosin. While infected and non-medicated trials showed an average incubation period of 1 week, clinical symptoms occurred 2-4 days later in infected and medicated birds. Avilamycin medicated birds had the longest incubation period. In the infected and non-medicated trials, a mortality rate of 16%-36% was noted within 3 weeks post infection. The avilamycin trials showed a mortality rate of 0-8% (0-2 birds died) and the narasin and monensin a mortality rate of 0-8%, respectively. In the combination groups (monensin + avilamycin or narasin + avilamycin), the mortality rate ranged from 0 to 4%. Tylosin showed a very good metaphylactic/therapeutic effect against Cl. perfringens enterotoxaemia. Following infection, medicated birds showed a significantly better bodyweight gain than the chickens, whose feeds had not been supplemented. From epidemiological point of view, the systematic prevention of coccidiosis is a key in the control of Cl. perfringens enterotoxaemia in chickens.