Responsiveness to invasive pathogens, clearance via the inflammatory response, and activation of appropriate acquired responses are all coordinated by innate host defenses. We have previously demonstrated that a purified ulvan extract of Ulva armoricana is able to activate avian heterophils and monocytes in vitro and in vivo , leading to in vivo release of cytokines including interleukin 1 β (IL1β), interferon α (IFNα) and interferon γ (IFNγ), in a transient and dose-dependent manner. In this study, we used the same protocol to evaluate a formulated version of this extract, called Searup ® . Our experiments showed that a single oral administration of this product at the dose recommended for use in the farm, results in heterophils and monocytes activation. In heterophils, activation was evidenced by β-D-glucuronidase release and increased mRNA expression of IL1β, IFNα and IFNγ. In monocytes, the expression of IFNγ and inducible nitrite oxide synthase (iNOS) were also up-regulated. Finally, plasmatic NO increased significantly on day 1, decreased on day 2 and was no longer significant at day 3. A similar pattern was observed for β-D-glucuronidase and for the modifications of the transcription profiles in monocytes as well as in heterophils. The only notable exception is gene transcription of 2'-5' Oligoadenylate Synthase, which is maximal at day 2 in monocytes. Due to its protective role in virus infection, this may constitute an additional layer of protection for this class of pathogens. Together our results show that the formulated solution, Searup ® , similarly to the purified extract allow to activate monocytes and heterophils but with some variations in the cytokines profiles and may provide protection against a larger variety of pathogens.
Activation of Heterophils and Monocytes in Chicken with a Formulation Containing a Seaweed Extract from Ulva armoricana
