Salmonella exclusion in broiler chicks by the competitive action of adult gut microflora.

A series of experiments was carried out to investigate the efficacy of the competitive exclusion technique in the control of Salmonella in broiler chicks. Anaerobic overnight culture obtained using 10(-3) g ml-1 caecal material in VL-broth medium provided total exclusion of a moderate S. enteritidis challenge (1.2 x 10(2) cells/chick). Increasing the challenge level resulted in less protection, but significant protection occurred at an excessive S. enteritidis challenge level of 1.5 x 10(6) cells/chick. The effectiveness of protection using both moderate and excessive challenges was monitored in newly hatched chicks until they were 22 days old. An improvement in growth performance in terms of higher body weight, feed consumption and feed conversion, in addition to lower mortality, was observed. The use of other control measures such as antimicrobial feed additives or lactose sugar (1.5% w/v) in the drinking water in combination with the competitive microflora treatment resulted in a better overall protection and performance.