Performance of broilers fed a broader spectrum antibiotic (virginiamycin) or a narrower spectrum antibiotic (bacitracin methylene disalicylate) over 3 consecutive grow-out cycles

Differences in major bacterial populations in the intestines of mature broilers after feeding virginiamycin or bacitracin methylene disalicylate

“…One of the goals of this study was to test the hypothesis that feeding broiler chickens virginiamycin has a more pronounced effect on the GI tract microbiota than feeding BMD (LaVorgna et al . ). Our results support this, as we observed that virginiamycin significantly reduced diversity in the caecum compared to the control diet ( P = 0·023), whereas BMD did not ( P > 0·05).…”

“…perfringens levels in the poultry environment have been reported (LaVorgna et al . ). We attempted to model our experiment after the aforementioned study in order to determine if a similar result was observed for levels of this pathogen in the GI tract.…”

“…Recently, a feeding trial was conducted to examine the effect of feeding virginiamycin or BMD over multiple flocks, or grow‐out cycles, of broilers raised under typical commercial conditions (LaVorgna et al . ). Although significantly better feed efficiency (i.e.…”

“…Observations from previous work (LaVorgna et al . ) led us to hypothesize that virginiamycin would have a broader impact, compared with BMD, on GI bacterial populations important for protecting the host from the outgrowth of opportunistic pathogens, e.g . Cl.…”

Stress as a Normal Cue in the Symbiotic Environment

“…Fermentation by the beneficial microbe B. thetaiotaomicron produces s uccinate, whose accumulation within the antibiotic-perturbed mouse gut creates an additional source of nutrition for enteropathogens like C. difficile [69], E. coli, and C. rodentum [70]. A similar phenomenon has been observed in the antibiotic-treated guts of broiler hens [71, 72], and is a well-known aspect of rumen microbial ecology [14]. In addition, pumpkins have a native microbiota (including members of both the γ-proteobacteria and Gram-positive bacilli) that is antagonistic towards bacterial pathogens of this plant [73], although the nature of the antagonism is not yet known.…”