Evaluation of the Effect of In Ovo Applied Bifidobacteria and Lactic Acid Bacteria on Enteric Colonization by Hatchery-Associated Opportunistic Pathogens and Early Performance in Broiler Chickens

Probiotics have been used to promote pioneer colonization by beneficial bacteria in poultry. The purpose of the present study (four trials) was to determine if an in ovo injection with Bifidobacterium saeculare (B2-2, B3-4) and/or lactic acid bacteria (LAB18, LAB46) at d18 of embryogenesis reduced Enterococcus and Gram-negative bacterial colonization in the gut at hatch. An environmental challenge model was used to simulate microbial contamination in large-scale hatch cabinets in a laboratory setting. In all trials, gut homogenates obtained from chicks at hatch were plated to enumerate relevant bacterial populations. Performance was evaluated in trials two and four. The top treatments in trial one were selected for further testing in trials 2–4. The significance level for all analyses was set at p < 0.05. A meta-analysis of gut bacterial recovery for trials 2–4 revealed that the administration of probiotic treatments increased LAB and/or bifidobacteria at hatch compared to non-treated groups. LAB46 + B2-2 was more effective at reducing Gram-negative bacteria and Enterococcus in the gut compared to other probiotic treatments. All treatments improved d14 BW and d0–14 BWG compared to non-treated groups. These results indicate that exposure to beneficial bacteria during late embryogenesis can prevent colonization by opportunistic pathogens associated with contamination in commercial hatch cabinets and may also improve early performance in broiler chickens.