Control of Salmonella typhimurium Colonization in Broiler Chicks with a Continuous-Flow Characterized Mixed Culture of Cecal Bacteria

Abstract

A continuous-flow culture system was used to isolate and maintain a mixed culture of cecal bacteria from adult broilers composed of 29 bacterial strains representing 10 genera. Broiler chicks were treated with the mixed culture in the drinking water on the day of hatch and challenged orally with 10(4) Salmonella typhimurium 2 d after treatment. The experiment was repeated in four separate trials using newly hatched chicks. The concentration of propionic acid and total volatile fatty acid (VFA) in the cecal contents was determined 2 d after treatment and at 10 d of age. Compared with controls, the number of treated chicks that were cecal culture-positive for Salmonella decreased (P < .01) in each of the trials. Additionally, the number of Salmonella in the cecal contents of the treated chicks at 10 d of age was decreased (P < .005) compared with controls in each trial. The decreased number of Salmonella in the cecal contents of the 10-d-old treated chicks was correlated with elevated concentrations of propionic acid (P < .05) and total VFA (P < .1) in the cecal contents of the treated chicks 2 d after treatment. The results indicated that VFA-producing bacteria present in the mixed culture became rapidly established in the ceca of the treated chicks and effectively increased resistance to S. typhimurium challenge.

Veillonella magna sp. nov., isolated from the jejunal mucosa of a healthy pig, and emended description of Veillonella ratti

“…In the gastrointestinal tract, strains of the genus Veillonella thereby constitute an essential link with indigenous lactic acid bacteria in a natural microbial food-chain (Marounek & Bartos, 1987;Pacheco Delahaye et al, 1994;Kolenbrander, 2006). Mixed cultures of veillonellae and, inter alia, lactic acid bacteria, isolated from the caeca of chickens, are inhibitory to enteropathogenic bacteria (Hinton et al, 1991;Hinton et al, 1992;Corrier et al, 1995). One such mixed culture is commercially available as a health-promoting competitive exclusion culture for poultry production (Nisbet, 2002).…”

Modeling the survivability ofSalmonella typhimuriumin the chicken cecae using an anaerobic continuous-culture of chicken cecal bacteria

“…On Day 3, approximately 48 h post CE treatment, and immediately prior to Salmonella challenge, 10 chicks in each group were randomly selected and euthanatized by cervical dislocation. The concentrations of VFA (acetic +propionic+bu-tyric+ isobutyric +valeric+isovaleric) in the cecal contents were determined by gas liquid chromatography as reported previously (16). The remaining 25 chicks in each group were orally challenged by crop gavage with 10 2 , 10 4 or 10 6 CFU S. typhimurium.…”

“…To mimic the approximate turnover time of the avian cecae a dilution rate of 0.0416 h − 1 corresponding to a flow rate of 0.80 ml/minute and a vessel turnover time of 24 hr was chosen. After achieving steady state conditions the culture as described previously (16) …”

“…The development of the culture has been described in detail previously (16). Briefly, the intact cecae were obtained from four adult broilers maintained on a corn-soybean-based diet that contained no antibiotics.…”

“…Recently, a continuous-culture containing 29 different bacterial isolates was developed by the continuous-culture of cecal bacteria obtained from adult chickens (16). This culture has been reported to be stable and reproducible (25) and when provided at day-of-age, increases the chick's resistance to cecal colonization by enteropathogens such as Salmonella typhimurium similar to that provided by the host normal mature microflora (16,25,26). We hypothesize that since the protective effect of the chicken cecal microflora maintained in this stable continuous-culture and the microflora in the cecae of mature chickens is similar, this in 6itro culture may serve as a useful model to understand how the host microflora protect against enteropathogen colonization.…”