Characterization of Intestinal Microbiota and Response to Dietary Virginiamycin Supplementation in the Broiler Chicken

Abstract

The inclusion of antibiotic growth promoters, such as virginiamycin, at subtherapeutic levels in poultry feeds has a positive effect on health and growth characteristics, possibly due to beneficial effects on the host gastrointestinal microbiota. To improve our understanding of the chicken gastrointestinal microbiota and the effect of virginiamycin on its composition, we characterized the bacteria found in five different gastrointestinal tract locations (duodenal loop, mid-jejunum, proximal ileum, ileocecal junction, and cecum) in 47-day-old chickens that were fed diets excluding or including virginiamycin throughout the production cycle. Ten libraries (five gastrointestinal tract locations from two groups of birds) of approximately 555-bp chaperonin 60 PCR products were prepared, and 10,932 cloned sequences were analyzed. A total of 370 distinct cpn60 sequences were identified, which ranged in frequency of recovery from 1 to 2,872. The small intestinal libraries were dominated by sequences from the Lactobacillales (90% of sequences), while the cecum libraries were more diverse and included members of the Clostridiales (68%), Lactobacillales (25%), and Bacteroidetes (6%). To assess the effects of virginiamycin on the gastrointestinal microbiota, 15 bacterial targets were enumerated using quantitative, real-time PCR. Virginiamycin was associated with increased abundance of many of the targets in the proximal gastrointestinal tract (duodenal loop to proximal ileum), with fewer targets affected in the distal regions (ileocecal junction and cecum). These findings provide improved profiling of the composition of the chicken intestinal microbiota and indicate that microbial responses to virginiamycin are most significant in the proximal small intestine.

Microbial shifts in the swine distal gut in response to the treatment with antimicrobial growth promoter, tylosin

“…A positive relation between the increase in abundance of Lactobacillus spp. population and an increase in weight gain has been shown in other animal models (18,21).…”

The Gut Microbiota: Ecology and Function

“…There have been additional studies of the bacterial composition of the gut in other animals, including chickens (Dumonceaux et al, 2006), mice (Yap et al, 2008), pigs (Hill et al,8 2005), and cows (Hernandez et al, 2008). These studies have revealed that each animal species has a gut microbiota that is unique and representative of that species.…”

Characteristics of Lactic Acid Bacteria Isolated from Gastrointestinal Tract of Cemani Chicken and Their Potential Use as Probiotics

“…The number of LAB was not influenced by the pH value. There were many other factors affecting such as diet, age, presence of barrier in the intestine and different physiological functions within the organ system (Dumonceaux et al, 2006).…”