Pakistan is basically an Agricultural country whose economy largely hinges upon its animal wealth. Poultry industry which Is recognized as one of the major emerging fields In the country is confronting with many a baffling malady which often leave the Industry at a growing disadvantage. Escherichla coil, one of the most abundantly Incriminated organism in avian ailments, is reckoned to be one of the major culprits that wreaks havoc on the steeply proliferating poultry industry.

The present project made an effort to study the efficacy of different drugs on various prevalant strains of E. coll isolated from broilers that were submitted for postmortem at V.R.I. and C.V.S. Lahore.

Twelve different antibacterial drugs which Included doxycycline, Inoxyl, oxytertracycline, ampicillin, colistin, trimethoprim, flumequlne, furazolidone, tylosin, furadantin clamoxyl and gentamicin were used to observe the sensitivity of the isolates. In-vitro gentamicin, -flumequine, inoxyl and clamoxyl emerged as drugs of choice in order of their decreasing importance in this experiment.

The pathogenicity of the isolated strains was tested In Swiss white mice. After viable count, ten mice were injected intraperltonenily with the suspension of the Isolated strain at a dose rate of 0.25 ml having 3x10'8 bacteria while ten mice were kept as controls.

The four best drugs were further tested for their efficiency in protecting the birds from E. coil infection. A total of 180 birds reared upto four weeks of age were divided into six groups viz. A to F, each consisting of 30 birds. Group A was kept as uninfected and untreated while to the group B infection was given but no treatment. The remaining groups I .e. C, 0, E and F after infection were treated with Inoxyl, gentamicin, clamoxyl and fiuinequine respectively. All the groups were kept under close observation and their mortality and feed efficiency was recorded. Maximum mortality was recorded in group B i.e. 54.5'l% while in the group C, 0, E and F the mortality recorded was 25%, 42.85%, 40.90% and 27.77% respectively.

According to this trial Inoxyl afforded maximum protection against the Infection and proved best In relation to F.C.R. Flumequlne stood in second in the list while clamoxyl was next best drug in furnishing protection against the Infection whereas gentamicin was the least best drug in this regard.