Unformulated oligodeoxynucleotides (ODN) containing CpG motifs (CpG-ODN) have been shown to stimulate the innate immune system against a variety of bacterial, viral, and protozoan infections in a variety of vertebrate species. We have previously shown that in ovo delivery of unformulated CpG-ODN was able to significantly protect neonatal broiler chickens against Escherichia coli or Salmonella Typhimurium infections. The objectives of this study were to examine the safety and immunoprotective effects of CpG-ODN formulated with 2 types of carbon nanotubes (CNTs) or 2 types of lipid-surfactant (LSC) delivery systems in neonatal broilers against E. coli septicemia. Embryonated eggs, which had been incubated for 18 days, received either 50 µg of CNT-CpG-ODN, 50 µg of LSC-CpG-ODN, 50 µg of unformulated CpG-ODN, or saline. Four days after exposure to CpG-ODN (day 1 posthatch), 1 × 104 or 1 × 105 colony-forming units of a virulent strain of E. coli isolated from a turkey with septicemia were inoculated subcutaneously in the neck. Clinical signs, pathology, bacterial isolations from the air sacs, and mortality were observed for 8 days following challenge with E. coli. Bacterial isolations and pathologic observations were conducted immediately after birds were dead or euthanatized. The survival rate of birds in groups receiving saline following E. coli infection was 20% to 30%. In contrast, birds receiving CpG-ODN formulations had a significantly higher survival rate of 60% to 80% (P < 0.01). Bacterial loads and clinical scores were significantly lower (P < 0.05) in groups treated with CNT- or LSC-CpG-ODN compared to the groups receiving CpG-ODN or saline. Moreover, there is no evidence of any adverse effects of these formulations in any organs or in growth rates of birds until 42 days of age. This is the first time that CpG-ODN formulated with CNT and LSC have been demonstrated to have an immunomodulatory effect against an E. coli infection in neonatal broiler chickens following in ovo delivery.
Protección temprana en pollos de engorde después de la aplicación in ovo de oligodesoxinucleótidos que contienen motivos CpG (CpG ODN) formulados con nanotubos de carbono o liposomas.
Se ha demostrado que los oligodesoxinucleótidos (ODN) no formulados que contienen motivos CpG (CpG-ODN) pueden estimular el sistema inmune innato contra una variedad de infecciones por protozoarios, bacterias y virus en una variedad de especies de vertebrados. Se ha demostrado previamente que la aplicación in ovo de CpG-ODN no formulados fue capaz de proteger significativamente a pollos de engorde contra infecciones tempranas por Escherichia coli o Salmonella typhimurium. Los objetivos de este estudio fueron examinar la inocuidad y los efectos inmunoprotectores de CpG-ODN formulados con 2 tipos de nanotubos de carbono (CNT) o dos tipos de sistemas de administración de lípidos surfactantes (LSC) en pollos recién nacidos contra la septicemia por E. coli. Los huevos embrionados, que habían sido incubados durante 18 días, recibieron o bien 50 µg de CNT-CpG-ODN, 50 µg de LSC-CpG-ODN, 50 µg de CpG-ODN no formulados, o solución salina. Cuatro días después de la exposición a los CpG-ODN (día 1 después de la eclosión), se inocularon con 1 × 104 o 1 × 105 unidades formadoras de colonias de una cepa virulenta de E. coli aislada de un pavo con septicemia por vía subcutánea en el cuello. Se analizaron los signos clínicos, patología, aislamiento bacterianos de los sacos aéreos, y la mortalidad durante ocho días después de la inoculación con E. coli. Los aislamientos bacterianos y las observaciones patológicas se llevaron a cabo inmediatamente después de que las aves murieron o se les practicó la eutanasia. La tasa de supervivencia de las aves
