In ovo administration of L. animalis, B. licheniformis, or their combination influences Ross 708 broiler chick hatch performance and immuno-physiological parameters

There is a demand for novel pathogen mitigation strategies in antibiotic-free poultry production, which has triggered the development of various probiotic application methods. One application method is the in ovo (in egg) administration of probiotics on incubation day (d) 18, where the unhatched chick consumes a probiotic before hatch and prior to being exposed to environmental pathogens. Therefore, the objective of this study was to evaluate the influence of in ovo L. animalis, B. licheniformis, or L. animalis + B. licheniformis (10⁶ cfu/50 μL each) administration on hatch performance (N = 21 egg flats/treatment, 30 eggs/flat), live performance (N = 12 pens/treatment), and d of hatch immuno-physiological parameters (N = 12 birds/treatment) among Ross 708 broiler chicks. Data were analyzed by 1-way ANOVA with significance established at P ≤ 0.05. All in ovo probiotic treatments had greater % hatch than the control treatment, and eggs in ovo-administered with B. licheniformis had lower % late dead and % culled-pipped eggs. However, all in ovo probiotic treatments had lower average chick weights compared to those of the HVT vaccine control group. At hatch, chicks administered with B. licheniformis or L. animalis + B. licheniformis had greater relative ceca weight and lower peripheral blood leukocyte levels compared to those belonging to the control group. There were no effects on live performance during the first 2 wk post-hatch. These results show that B. licheniformis and L. animalis are effective candidates for in ovo probiotic administration, but further investigations regarding immuno-physiological responses to in ovo B. licheniformis administration are necessary.