A. G. Hollister

Effect of a Defined Continuous-Flow Derived Bacterial Culture and Dietary Lactose on Salmonella typhimurium Colonization in Broiler Chickens

A defined bacterial culture protective against Salmonella typhimurium cecal colonization in broiler chicks was derived utilizing a continuous-flow (CF) culture apparatus. Chicks receiving the CF culture in combination with a diet containing dietary lactose were protected against cecal colonization by S. typhimurium. The culture consisted of a mixture of gram-positive and gram-negative facultative and strictly anaerobic bacteria. The isolates were identified as Enterococcus avium, two strains of Enterococcus faecalis (designated A and B), Lactococcus lactis, Lactobacillus animalis, a Lactobacillus that could not be identified to species level (designated strain CMS), Citrobacter freundii, Escherichia coli, E. fergusonii, Bifidobacterium animals, and Propionibacterium acidipropionici. Results indicated that CF cultures can be used as a tool to identify bacteria which are antagonistic to S. typhimurium in the chick cecum.

Inoculation of broiler chicks with a continuous-flow derived bacterial culture facilitates early cecal bacterial colonization and increases resistance to Salmonella typhimurium

Experiments were conducted to examine the effect of a continuous-flow (CF) derived bacterial culture and of dietary lactose on colonization level by anaerobic bacteria in the ceca of broiler chicks. Cecal facultative and strictly anaerobic bacteria colony forming units (CFU), total volatile fatty acid (TVFA), lactic and propionic acid concentrations in 3-d-old chicks, and cecal log10 Salmonella typhimurium colonization and propionic acid concentrations in 10-d-old chicks were measured. Treatment groups were control diet, 2% lactose diet, CF culture + control diet, and CF culture + 2% lactose diet. Groups inoculated with CF culture had decreased (P < 0.05) Salmonella in cecal contents at 10 d of age. The level of Salmonella protection was significantly (P < 0.05) correlated with increased cecal bacteria CFU, TVFA, and propionic acid concentrations in 3-d-old chicks. Results indicated that inoculating newly hatched chicks with CF culture containing cecal microflora originally obtained from adult chickens, facilitates early cecal colonization by native cecal microflora, and this is associated with protection against Salmonella .

Competitive Exclusion of Salmonella enteritidis in Leghorn Chicks: Comparison of Treatment by Crop Gavage, Drinking Water, Spray, or Lyophilized Alginate Beads

The protective effect of cecal bacteria cultures on Salmonella enteritidis cecal colonization was evaluated. Competitive-exclusion cultures were administered by crop gavage, in first drinking water, by whole body spray, or encapsulated in alginate beads and provided in feed pans. Leghorn chicks were treated with cultures of cecal bacteria on the day of hatch and challenged orally with 10(4) S. enteritidis 2 days after treatment. Salmonella cecal colonization was evaluated 7 days after challenge. No Salmonella organisms were detected in the ceca of chicks treated with cecal cultures by crop gavage. Chicks treated with cecal cultures in the drinking water or by spray application showed comparable protection and significant decreases (P < 0.05) in the number of Salmonella in the cecal contents compared with untreated controls. The consumption of cecal bacteria encapsulated in alginate beads significantly decreased (P < 0.05) Salmonella cecal colonization compared with control treatment, but it provided less protection than the other treatment methods evaluated.

Effect of a characterized continuous-flow culture of cecal bacteria on Salmonella typhimurium crop colonization in broiler chicks

Broiler chicks were inoculated orally at 1 day of age with a continuous-flow (CF) culture of anaerobic cecal bacteria and challenged with 10(4) Salmonella typhimurium 48 hr (at 3 days old) after inoculation to determine the effect of the CF culture (CF3) on Salmonella crop colonization. Chicks were assigned to four groups: 1) untreated control chicks, 2) challenged at 3 days old with Salmonella, 3) inoculated at 1 day old (day-of-hatch) with CF3, and 4) inoculated at 1 day old with CF3 and challenged at 3 days old with Salmonella. Crop pH decreased significantly (P < 0.05) 24 hr after inoculation in chicks provided with CF3. The pH of crops at 24 hr from control chicks (group 1) was 5.4 and the pH of crops from inoculated chicks (group 3) was 4.7. Decreased pH was accompanied by a significant increase (P < 0.05) in corp lactic acid from approximately 0.1 mmol/ml in control chicks to about 0.2 mmol/ml in chicks given the culture. Salmonella crop colonization decreased (P < 0.05) 4 hr after challenge from a 2.6 log10 colony-forming units (cfu) in Salmonella-control (group 2) chicks to 0.6 log10 cfu in CF3-inoculated (group 4) chicks. Although at 4 and 8 hr after challenge, there were decreased (P < 0.05) numbers of crops testing culture-positive for Salmonella regardless of treatment, Salmonella colonization decreased (P < 0.05) in chicks inoculated with CF3 as compared with controls. The results indicated that CF3 can effectively reduce Salmonella crop colonization.