Quantitative analysis of the intestinal bacterial community in one- to three-week-old commercially reared broiler chickens fed conventional or antibiotic-free vegetable-based diets
Open Access
- 11 September 2006
- journal article
- Published by Oxford University Press (OUP) in Journal of Applied Microbiology
- Vol. 102 (4), 1138-1149
- https://doi.org/10.1111/j.1365-2672.2006.03153.x
Abstract
To explore the effect of drug-free poultry production on the intestinal microflora of broiler chickens, the bacterial community of this environment was quantitatively profiled in both conventionally reared birds and birds reared without antibiotic growth promotants (AGPs) on a vegetable-based diet. Quantitative, real-time PCR with group-specific 16S rDNA primer sets was used to enumerate the abundance of the following chicken gastrointestinal (GI) tract phylogenetic groups: the Clostridium leptum-Faecalibacterium prausnitzii subgroup (Clostridium genus cluster IV), the Clostridium coccoides - Eubacterium rectale subgroup (Clostridium cluster XIVa and XIVb), the Bacteroides group (including Prevotella and Porphyromonas), Bifidobacterium spp., the Enterobacteriaceae, the Lactobacillus group (including the genera Leuconostoc, Pediococcus, Aerococcus and Weissella), the Clostridium perfringens subgroup (Clostridium cluster I), Enterococcus spp., Veillonella spp., Atopobium spp., Campylobacter spp. and the domain Bacteria. A species-specific 5'-nuclease (Taqman) assay was also employed to specifically assess Cl. perfringens abundance. Ten birds were sampled from each of two commercial chicken houses, one in which feed was supplemented with AGPs and exogenous animal protein, and the other vegetable-based and drug-free, at 7, 14 and 21 days of age. The ileal community was dominated by two large populations, the lactobacilli and the Enterobacteriaceae, with those taxa much more numerous in drug-free vegetable-based diet fed birds than those conventionally reared at the 7- and 14-day time periods. The progressive changes in microflora in both the conventional and drug-free caeca were similar to each other, with the Enterobacteriaceae sequences dominating at day 7, but being replaced by obligate anaerobe signature sequences by day 14. Of note was the finding that all the day 14 and day 21 replicate caecal samples from the drug-free house were positive for Campylobacter spp. averaging >10(8) 16S rDNA gene copies per gram wet weight. Quantitative, real-time PCR indicates that the effects of drug-free rearing on the chicken GI tract microbial community are most pronounced in the ileal region, but AGPs may be important in controlling Campylobacter colonization of the caecum. A quantitative taxonomic understanding of the shifting microbial ecology of the broiler chicken gut microbiota is important in the light of AGP withdrawal. AGP withdrawal has occurred in response to concerns over the transfer of antimicrobial-resistant bacteria to humans via the food production chain.Keywords
This publication has 50 references indexed in Scilit:
- Microflora Ecology of the Chicken Intestine Using 16S Ribosomal DNA PrimersPoultry Science, 2004
- Characterization of Bacterial Communities in Feces from Healthy Elderly Volunteers and Hospitalized Elderly Patients by Using Real-Time PCR and Effects of Antibiotic Treatment on the Fecal MicrobiotaApplied and Environmental Microbiology, 2004
- Percent G+C Profiling Accurately Reveals Diet-Related Differences in the Gastrointestinal Microbial Community of Broiler ChickensApplied and Environmental Microbiology, 2001
- Removal of antibiotic growth promoters from poultry diets: implications and strategies to minimise subsequent problemsWorld's Poultry Science Journal, 2000
- Epidemiology of vancomycin-resistant enterococci in the community and the relevance of farm animals to human infectionJournal of Hospital Infection, 1997
- Farm animals as a putative reservoir for vancomycin-resistant enterococcal infection in manJournal of Antimicrobial Chemotherapy, 1994
- Evidence for an animal origin of vancomycin-resistant enterococciThe Lancet, 1993
- The Intestinal Microflora of Poultry and Game Birds During Life and After StorageJournal of Applied Bacteriology, 1979
- The avian intestinal flora with particular reference to the possible ecological significance of the cecal anaerobic bacteriaThe American Journal of Clinical Nutrition, 1972
- The intestinal flora of the chicken in the period 2 to 6 weeks of age, with particular reference to the anaerobic bacteriaBritish Poultry Science, 1972