EFFECT OF SPECTINOMYCIN ON ESCHERICHIA-COLI INFECTION IN 1-DAY-OLD DUCKLINGS

Two-challenge trials and one confirmation trial were conducted to eval uate the efficacy of spectinomycin in the treatment of 1-day-old duckl ings infected with Escherichia coli. In the challenge trials, duckling s were injected in the right posterior thoracic air sac with 0.2 cm3 o f broth containing 10(8) colony-forming units E. coli (strain 078, E38 )/ml. Spectinomycin at dosage levels of 2.5 mg, 5.0 mg, and 10.0 mg of activity was injected subcutaneously 6 hours following infection. The confirmation trial was conducted to confirm the challege trials; proc edures were similar to those used in the challenge trials, except that only the 5.0 mg of activity dosage of spectinomycin was used. In both types of trials, spectinomycin-treated ducklings had significantly lo wer mortality and higher average weight gain, average daily gain, and feed consumption than infected unmedicated controls. These results ind icate that spectinomycin is effective in treating ducks for experiment ally induced colibacillosis caused by E. coli (strain 078, E38).