Comparison of probiotics maintained by in vivo passage through laying hens and broilers

Cecal colonization by salmonellae may be greatly reduced by inoculating chickens with normal cecal microflora, a phenomenon known as competitive exclusion. Unfortunately, it has not been possible to reliably store active cecal microflora over long time periods, and it is difficult to obtain consistent experimental results with different batches of microflora. In order to overcome these problems, the present authors have maintained active cecal flora through a 2-yr period by in vivo passage through both broiler chicks and layers that were fed a diet containing 5% lactose. Competitive exclusion cultures maintained in laying hens worked as well as cultures from broilers. Cecal microflora from either source excluded both nonlactose-fermenting and lactose-fermenting Salmonella strains. Colonization by both types of Salmonella was reduced even when the competitive exclusion organisms were given as late as 3 days after oral challenge inoculation with Salmonella typhimurium.