Identification of factors which affect competitive exclusion culture establishment and efficacy in commercial poultry

Abstract

The present investigation was performed to evaluate the establishment and efficacy of a commercially available competitive exclusion (CE) culture (Preempt[]) in egg-laying or broiler chickens under conditions similar to those found under commercial rearing conditions. Since antibiotics are routinely used in the commercial poultry industry to control infection and disease by bacterial pathogens, and since CE cultures, by definition, are bacterial cultures of normal intestinal microflora used for disease prophylaxis in poultry, evaluation of establishment and efficacy of CE cultures under conditions of antibiotic use seems prudent. We evaluated the effect of in ovo (day 18E), day-of-hatch subcutaneous (SQ), or maternal administration of antibiotics commonly used by the commercial poultry industry on Preempt[] establishment as measured by 48 h cecal propionic acid concentration. Additionally, since CE cultures and modified-live vaccines each represent viable means for controlling the food-borne pathogen Salmonella in commercially reared poultry, additional experiments were performed which evaluated the computability of these two products under conditions of near-simultaneous administration.