Goonewardene KB, Popowich S, Gebhardt S, Gunawardana T, Gupta A, Kurukulasuriya S, Karunarathna R, Liu M, Chow-Lockerbie B, Ayalew L, Ahmed KA, Kamali H, Tikoo SK, Foldvari M, Willson P, Boire J, Roberts K, Ambrose N, Simonson C, Gomis S. Aerosol delivery of synthetic DNA containing CpG motifs in broiler chicks at hatch under field conditions using a commercial-scale prototype nebulizer provided protection against lethal Escherichia coli septicemia.
Poult Sci 2021;
100:100934. [PMID:
33652543 DOI:
10.1016/j.psj.2020.12.031]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 11/26/2020] [Accepted: 12/16/2020] [Indexed: 12/21/2022] Open
Abstract
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.
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