Submitted to: Poultry Science
Publication Type: Abstract Only
Publication Acceptance Date: 8/13/2002
Publication Date: N/A
Technical Abstract: Populations of digestive microflora change as chickens age and can be affected by diet, stresses, and performance enhancers. A mature digestive bacterial community is protective against colonization and infection by enteropathogens and other harmful bacteria. Most culture techniques used to profile predominant organisms in bacterial communities inadvertently select for some bacteria, while excluding others. Several molecular-based techniques have been used to profile mixed microbial populations on the basis of DNA extracted from the entire community. Denaturing gradient gel electrophoresis (DGGE) was used in the present study to examine PCR-amplified fragments (amplicons) of a 16s ribosomal DNA (rDNA) variable region from predominant digestive bacteria. The objective of the present study was to examine changes in digestive microbial communities of developing chicks, mature chickens after induced molt, and young broilers given a performance enhancer as a feed additive; some groups were given a commercial competitive exclusion culture (CE). Dendrograms of amplicon patterns indicated about 51% similarity correlation between layer chicks 20 days old and younger and chicks greater than 20 days old. Cecal communities in layer chicks given CE exhibited 20% correlation at all ages with those in control chicks. Non-molted and molted hens had 40% correlation between cecal communities, while diets with low calcium and zinc lessened population differences (90% correlation). The performance enhancer had a greater effect on broiler chicks at 10 days of age (56% and 73% in two replicates (control vs. treated)) than in chicks at 3 days of age (greater than 88% correlation). Results indicated the potential usefulness of the molecular-based DGGE to identify beneficial and performance enhancing digestive bacteria in poultry.