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Synthetic DNA containing CpG motifs (CpG-ODN) are potent innate immune stimulators in neonatal and adult broiler chickens against bacterial septicemia. We have recently demonstrated that intrapulmonary (IPL) delivery of CpG-ODN as microdroplets under laboratory conditions can protect neonatal chickens against lethal Escherichia coli septicemia. The objectives of this study were to develop a commercial-scale poultry nebulizer (CSPN) that can deliver CpG-ODN as microdroplets in neonatal broiler chicks in the hatcheries and study the efficacy of CSPN in inducing immune-protective effects under different environmental conditions in 2 geographical locations in Canada. Three field experiments were conducted in commercial poultry hatcheries during different seasons of the year in Saskatchewan and British Columbia, Canada. Neonatal broiler chicks (n = 8,000/experiment) received CpG-ODN by the IPL route in the CSPN chamber for 30 min, and control chicks received distilled water (DW) for 30 min. Broiler chicks (CpG-ODN—240 chicks/experiment and DW—40 chicks/experiment) were randomly sampled from all locations of the CSPN after nebulization and challenged with a lethal dose of E. coli to examine the CpG-ODN nebulization induced protection. We found a significant level (P < 0.05) of protection in broiler chicks against E. coli challenge, suggesting that the newly built CSPN successfully delivered CpG-ODN via the IPL route. We found that when the CSPN was maintained at humidex 28°C or below and relative humidity (RH) between 40 and 60%, neonatal birds were significantly (P < 0.05) protected against E. coli septicemia after IPL delivery of CpG-ODN. By contrast, protection in chicks was adversely affected when the CSPN was maintained at the humidex of 29°C or higher and RH of 70%. Overall, the present study successfully built a CSPN for CpG-ODN delivery in chicks at the hatchery and revealed that the temperature, humidity, and humidex were critical parameters in CSPN for efficient delivery of CpG-ODN. [ABSTRACT FROM AUTHOR]

The emergence of enterococcal infections in neonatal broiler chickens in the poultry industry has become common in many countries, including Canada. The objective of this study was to examine the bacterial infections in nonviable broiler chicken embryos in three western Canadian poultry hatcheries using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The pattern of embryo mortality that occurred during incubation and the breakout analysis results were similar in all three hatcheries. The majority of embryo mortality occurred during the late stage of incubation (35.08%), followed by the early stage of incubation (15.35%). The breakout analysis showed that 65.82% of swabs had at least one type of bacterial growth while 34.17% of swabs were negative for bacterial isolation. Of those 65.82% swabs with bacterial growth, 34.3% of swabs yielded a mixed bacterial population while 31.52% yielded one type of bacterial growth. The frequency of bacterial isolation from hatch debris (60%-75%) increased with the age of broiler breeders. MALDI-TOF MS was able to provide genus-level identification of 83.13% of isolates among all bacterial types isolated. MALDI-TOF MS identified Enterococcus and Escherichia coli isolates with 97.18% and 100% accuracy at species level, respectively, whereas Staphylococcus species were identified with 62.59% accuracy. The congruence between MALDI-TOF MS identification and 16S rRNA or cpn60 universal gene target sequencing was 100% or 90%, respectively. Of all bacteria isolated, Enterococcus species (29.71%) were the most prevalent, followed by E. coli (19.46%). About 56% of E. coli-infected samples were coinfected with Enterococcus species. Among all Enterococcus species isolated, Enterococcus faecalis (79.58%) was the most prevalent, followed by Enterococcus faecium (8.1%). Overall, our study showed that Enterococcus-associated embryo mortality was predominant in all three hatcheries investigated and suggests that MALDI-TOF MS technology can be applied to identify bacteria such as Enterococcus species isolated from poultry.