Relationship of Dietary Antimicrobial Drug Administration with Broiler Performance, Decreased Population Levels of Lactobacillus salivarius, and Reduced Bile Salt Deconjugation in the Ileum of Broiler Chickens

Abstract

Straight-run broiler chickens were raised either in floor pens or wire-floored cages (trial 1) or in floor pens only (trials 2, 3, and 4). Birds raised in floor pens had lower BW and feed intakes than those raised in cages. The administration of bacitracin in the feed increased feed intake from d 12 to d 35, decreased the feed conversion ratio during the same period in trial 2, and improved the weight gain of broilers from d 0 to 10 in trial 3. The concentrations of conjugated bile salts (taurocholic and taurochenodeoxycholic acids) were higher in the ileal contents of broilers administered the antimicrobials compared with untreated birds. Supplementation of the feed with monensin increased fat digestibility in the ileum of the birds. Although total numbers of bacteria in ileal contents were the same regardless of whether antimicrobials were administered or not, the bacterial community differed qualitatively. Populations of Lactobacillus salivarius were reduced in birds fed antimicrobials relative to untreated broilers. A representative ileal isolate of L. salivarius deconjugated bile salts in pure culture in the laboratory and in the ileal contents of ex-Lactobacillus-free chickens maintained in a protective environment and colonized by the Lactobacillus isolate. These observations provide a link between bile salt deconjugation in the ileum by L. salivarius and decreased weight gain of broilers. Lactobacillus salivarius populations could be targeted in future studies aimed at modification of the ileal bacterial community to achieve growth promotion of broilers without the administration of antimicrobial drugs.

Allelic Variation of Bile Salt Hydrolase Genes in Lactobacillus salivarius Does Not Determine Bile Resistance Levels

“…Inactivation of bshB in L. acidophilus NCFM revealed that the strain lost hydrolytic activity for tauroconjugated bile salts (40). Given that lactobacilli are the main contributors to Bsh activity in the murine and chicken intestinal tracts (26,56) and could be physiologically important when produced by lactobacilli in the human gut, biochemical characterization of the corresponding Bsh enzymes is desirable.…”

“…This strain harbors a 242-kb megaplasmid, pMP118, that interdigitates with chromosomally encoded functions to confer metabolic flexibility (35,44). L. salivarius is common in the GI tracts of many animals, including humans (1) and chickens (26), but its survival mechanisms in vivo are poorly understood. In this study, therefore, we examined the contributions of allelic variants of bsh to the bile resistance of L. salivarius, as well as other bile resistance mechanisms.…”

Effects of Acidified Yeast and Whey Powder on Performance, Organ Weights, Intestinal Microflora, and Gut Morphology of Male Broilers

“…E. coli counts were performed on McConkey agar and incubated for 24h at 37°C. After incubation, colonies formed on the respective media were counted and expressed as Log (CFU) per g of intestinal content (Guban et al, 2006). All microbiological analyses were performed in triplicate, and average values were used for statistical analyses.…”

<b>Appraisal of purple coneflower (<i>Echinacea purpurea</i>) extract on production performance, internal organs, and gut microflora of japanese quail

“…Each sample was serially diluted. Using these diluted sub samples, Lactobacillus was enumerated on De Man-RogosaSharpe (MRS) agar after incubation at 37°C in an anaerobic chamber for 48 h (Guban, Korver, Allison, & Tannock, 2006). Coliforms was counted on CHROM agar ECC (EF322-Paris France) after incubation at 37°C in an aerobic chamber for 48 h (Sallam, 2007).…”