Searup®, based on macroalgae extracts (MSP®IMMUNITY) activates broiler’s immune cells (heterophils and monocytes), improving their resistance to challenges.

A single administration of Searup^® at 1 ml/l of drinking water, the dose recommended for the use in the farm, activates two innate immune avian cell types, heterophils and monocytes, via the activation of the TLR2 and TLR4 receptors.

Heterophils and monocytes play a crucial role in defending animals against invasive pathogens via both direct action (innate immune response) and by inducing the appropriate acquired immune responses. Monocytes can differentiate into dendritic cells and macrophages, and thus play an important role in the development of innate and adaptive immune response by phagocytic and antigen-presenting activities respectively. The heterophils are the avian neutrophils, when they are activated, they can produce immune mediators as well as antiviral enzymes.

Additionally, different cytokines involved in innate and adaptive immunity were transiently upregulated in response to Searup^®, such as interferon-α, interferon-γ, IL1 β and OAS (Oligoadenylate synthase) for heterophils and interferon-γ, IL1 β and OAS for monocytes. These cytokines participate in several activities of the immune response as IL1 β acts on the proliferation and the differentiation of immune cells, interferon-γ activates macrophages and antibodies production by B cells while interferon-α and OAS protect against virus. This is in adequation with previous similar study with MSP®_IMMUNITY  (a macroalgae extract rich in sulfated polysaccharides), a key ingredient of Searup^® where the expression of the above cytokines was also upregulated (Guriec et al, 2018).

Moreover, Searup^® triggered an upregulation of the gene expression of immune mediators which are involved in both cellular immune responses against intracellular and extracellular pathogens. This suggests that Searup^® might support the adaptive immune response and modulate the pathogens response.