Ulvan Activates Chicken Heterophils and Monocytes Through Toll-Like Receptor 2 and Toll-Like Receptor 4

Responsiveness to invasive pathogens, clearance via the inflammatory response, and activation of appropriate acquired responses are all coordinated by innate host defenses. Toll-like receptor (TLR) ligands are potent immune-modulators with profound effects on the generation of adaptive immune responses. This property is being exploited in TLR-based vaccines and therapeutic agents in chickens. However, for administering the TLR agonist, all previous studies used in ovo, intra-muscular or intra-venous routes that cannot be performed in usual farming conditions, thus highlighting the need for TLR ligands that display systemic immune effects when given orally (per os). Here we have demonstrated that an ulvan extract of Ulva armoricana is able to activate avian heterophils and monocytes in vitro. Using specific inhibitors, we have evidenced that ulvan may be a new ligand for TLR2 and TLR4; and that they regulate heterophil activation in slightly different manner. Moreover, activation of heterophils as well as of monocytes leads to release pro-inflammatory cytokines, including interleukin1-β, interferon α and interferon γ, through pathways that we partly identified. Finally, when given per os to animals ulvan induces heterophils and monocytes to be activated in vivo thus leading to a transient release of pro-inflammatory cytokines with plasma concentrations returning toward baseline levels at day 3

Marine Sulfated Polysaccharide extract stimulates in vitro intestinal immune mediators, and enhances colostrum IgG and milk IgA in lactating sow

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Green algae ulvan fraction displays dual functions in gut protection via bacterial growth inhibition and immunomodulatory activity

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Macroalgae extracts limits Marek’s disease virus load and dissemination in vitro.

Marek’s disease (MD) is a highly contagious lymphoproliferative disease of chickens caused by an alphaherpesvirus, Marek’s disease virus (MDV). MD is presently controlled by systematic vaccination of animals, which protects efficiently against clinical disease. However, MDV vaccines do not prevent the multiplication and spread of MDV field strains generating immunosuppression. They may also favor the emergence of strains with increased virulence. Therefore, MDV persists to be a major problem for the poultry industry generating economic losses estimated at 1-2 billion dollars per year. The development of new sustainable alternative strategies to control MDV is needed. Macroalgae extracts have previously been shown to exert antiviral and immunomodulatory activities that could support the animals to better resist to this challenge.The objective of the study was to explore the effect of sulphated green macroalgae (Ulva sp.) extract (MSP®IMMUNITY) on MDV infection in vitro. To determine the impact on MDV lytic replication, chick embryo fibroblasts (CEFs) were infected and treated with increasing doses of the algae extract. The viral load was quantified at 24, 48, 72 and 96 hours post infection (hpi) by qPCR. The results showed the treatments significantly decreased MDV lytic replication in CEFs in a dose-dependent manner with the strongest effect observed with concentrations of 1ml/l. From 24 hpi, the viral load was reduced by about 80% with the algae extract at a concentration of 2ml/l and this is maintained over time and reached 94% at 96 hpi, A substantial decrease in MDV plaque size (from 2 to 3 fold) was demonstrated suggesting that macroalgae extract impede MDV cell-to-cell spread in vitro. This study provides the first evidence that the use of the macroalgae extracts could be a good alternative to limit MDV infection in poultry

The sulphated polysaccharides extract ulvans from Ulva armoricana limits Marek’s disease virus dissemination in vitro and promotes viral reactivation in lymphoid cells

International audienceBackground: Marek's disease (MD) is a highly contagious lymphoproliferative disease of chickens caused by an alphaherpesvirus, Marek's disease virus (MDV). MD is presently controlled by systematic vaccination of animals, which protects efficiently against the development of clinical disease. However, MDV vaccines do not prevent the multiplication and spread of MDV field strains and may favor the emergence of strains with increased virulence. Therefore, MDV persists to be a major problem for the poultry industry and the development of new alternative strategies to control MDV is needed. Seaweed extracts have previously been shown to exert immunomodulatory and antiviral activities, especially against herpesviruses. The objective of the present study was to explore the effect of Ulva armoricana extracts on MDV infection in vitro. Results: We could demonstrate that the ulvan extract as well as its vitamin-enriched formulation reduce the viral load by about 80% at 24 h post-infection in infected chicken fibroblasts at concentrations that are innocuous for the cells. We also observed a substantial decrease in MDV plaque size suggesting that ulvans impede MDV cell-to-cell spread in vitro. Moreover, we showed that ulvan extract could promote MDV reactivation in lymphoid cells. Conclusions: Our data provide the first evidence that the use of the ulvan extract could be a good alternative to limit MDV infection in poultry

Activités antibactérienne et immunomodulatrice d'un extrait d'algue verte riche en polysaccharides sulfatés

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Immunomodulating effect of a seaweed extract from Ulva armoricana in pig: Specific IgG and total IgA in colostrum, milk, and blood

International audienceThe transfer of passive immunity from sows to piglets can be improved through the administration of immuno-stimulating products before farrowing. This study evaluated the immuno-stimulating effect of an algal sulfated polysaccharide extract (MSP extract) from the green algae Ulva armoricana when administrated orally to sows at the end of gestation. Four diets were tested: Control (no MSP extract), MSP1 (2 g/day of MSP extract), MSP2 (8 g/day), and MSP3 (16 g/day). The experimental diets were provided in two periods: before the last atrophic rhinitis vaccine booster, and a week before farrowing. Anti-Bordetella IgG antibodies were recorded in blood, colostrum, and milk, and total IgA were measured in colostrum and milk. Titer kinetics between the blood sampled before farrowing and colostrum displayed an increase in specific IgG for MSP3. Moreover, the MSP2 diet increased the level of total IgA in milk compared to the control group. Although the immuno-stimulating effect of MSP extract on piglet performance was not concurrent across the different supplementation levels, the present study supports the use of natural algae extract (MSP) as an immunomodulating solution in swine production

Marine-Sulfated Polysaccharides Extracts Exhibit Contrasted Time-Dependent Immunomodulatory and Antiviral Properties on Porcine Monocytes and Alveolar Macrophages

Porcine respiratory complex syndrome has a strong economic impact on the swine breeding sector, as well as a clear repercussion on the wellbeing of the animals, leading to overuse of antimicrobial molecules. Algal extracts used in short-term treatments are empirically recognized by farmers as having a positive effect on pigs’ health, however, their mechanisms of action are not well known and more research is needed. Herein we studied the short and median term impact of three algal extracts, in vitro, on the pro-inflammatory and antiviral responses of porcine primary blood monocytes and alveolar macrophages, as well as the susceptibility of the treated cells to infection by Porcine Respiratory and Reproductive Syndrome Virus (PRRSV) and the Aujeszky’s Disease Virus (ADV). All extracts presented a pro-inflammatory short-term effect, associated for two of them, with an inhibition of the PRRSV replication. Conversely, the three extracts presented an anti-inflammatory median term effect, with no impact on PRRSV replication. The observed immune modulation prompts us to test, in vivo, the anti-PRRSV action of algal extracts and strengthen the interest for this natural resource