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Abstract
Summary
A total of 310 intestines of freshly dead and sacrificed broiler chickens aged 2-7 weeks-old were collected from Sohag, Assuit and El-Minia provinces. The collected samples were classified to 3 major groups according to viral, bacterial and coccidial infestations. Collected samples were examined bacteriologically for possible recovery of C. perfringens.
The current study revealed the following results:
• A number of 108 C. perfringens isolates were successfully isolated with an incidence of 34.8%. All these isolates were morphologically and biochemically identified
• The incidence of C. perfringens was higher (43%) in the group of birds showing NE and positive for coccidiosis than in the group of birds showing NE and negative for coccidiosis (25%).
• According to the age susceptibility, the highest incidence of C. perfringens was detected in older birds (43-49 days) of age, while the incidence was low in young birds (15-22).
• The incidence of C. perfringens was higher in broiler flocks fed on animal protein ration contain 72% fish meal than in broiler flocks fed on plant protein ration contain 6.4% .
• The isolation of C. perfringens from eggshell revealed that 34 samples were positive out of 84 samples(40%). In chick fluffs, isolation of C. perfringens revealed that 12 samples were positive out of 48 samples (25%).
• The isolation of C. perfringens from one-day-old chicks revealed that 20 samples were positive out of 62 samples (32%).The isolation of C. perfringens from breeder hens at time of laying egg revealed that 4 samples were positive out of 72 samples (5.5%).
• In normally appearance chickens, incidence of C. perfringens was higher (23%) in Native flocks than in broiler flocks (19%).
The pathogenicity of more common recovered strains of C. perfringens was proved in 21-day-old broiler chicks by oral route of inoculation. The mortality rate among groups of chicks inoculated with toxigenic C. perfringens were 60%, while in the chicks inoculated with non-toxigenic C. perfringens were 35%. All deaths occurred within 2 weeks post infection. Clinical signs and PM lesions and reisolation of inoculated organism were described and discussed.
Evaluation the effect of some avilable feed additives (growth promoters) on experimentally infected chicks feed ration with Lincomycin , Salinomycin and Enramycin. Also use anticoccidial vaccine as Coccivac-D, or Porbiotics (Lactobacillus) indicated that the use of Lactobacillus as a propiotics were superior in protection (100%) against challenge with coccidia oocysts and toxigenic C. perfringens. On the other hand, the combined use of Lincomycin with Salinomycin and the use of Lincomycin only given mortality rate of 10% , while the use of Salinomycin only given mortality rate of 20% which more than the use of Enramycin in which the mortality rate was 15% .
All feed additives were effective in protection against challenge with toxigenic C. perfringens except the use of Coccivac-D as the anticoccidial vaccine did not protect from coccidiosis and the vaccinated group showed mortality rate (50%) which was higher than the mortality rate (35%) of non-medicated control birds .
The sensitivity of some isolated C. perfringens strains were tested against antibiotics in vitro. Tetracycline, Erthromycin, Enrofloxacin, Colistin was found to be of a moderate effect. Oxytetracycline, Amoxycillin and Ampecillin were found to be highly effective, while Gentamycin and Neomycin were found to be highly non effective