NUTRITION ▶▶▶


Further research has been conducted in poultry models in order to demonstrate the ability of MSP Immunity to en- hance innate and adaptive immune response of broilers through activation of heterophils and monocyte. Heterophils are functionally equivalent to mammalian neutrophils and are a critical component of innate immunity. Their activity can be evaluated by measuring the oxidative burst (release of reactive oxygen species (ROS) with bactericidal activity) and/or by conducting a degranulation assay, assessing the enzymatic activity of glucuronidase also able to degrade vi- ruses and bacteria. Monocytes are important phagocytes in poultry, playing a critical role in both innate immunity (bac- tericidal activity via nitric oxide (NO) production) and initia- tion of the adaptive immune response via their role as antigen- presenting cell. The effect of this green algal extract (MSP Immunity) on birds’ monocytes and heterophils (purified from peripheral blood of 28 day-old broilers) was evaluated in vivo. Three different concentrations of MSP Immunity (10, 25, 50mg/L) were given orally (per os) at day 0 (first day of the trial) for 24 hours and compared with the negative control. The experiments lasted four days in total. Results showed that MSP Immunity in- duced the activation of monocytes and heterophils. A dose and time response was observed for nitric oxide release by monocytes with a peak at day 1, swiftly declining, with values no longer statistically different from that of the negative con- trol at day 3 (Figure 1). In parallel, the ability of MSP Immunity to induce glucuronidase activity in heterophils was also oc- curring in a time and dose-dependent manner (Figure 2).


Figure 1 - Nitric oxide release by monocytes with different concentrations of MSP®IMMUNITY during 4 consecutive days.


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Additional in vitro experiments, using specific PRR inhibitors, showed that MSP Immunity activates monocytes and hetero- phils through recognition by TLR2 and TLR4 confirming the results obtained by Berri et al. (2017) in a porcine model. Moreover, the study showed that the activation of monocytes and heterophils led to a transient increase of immune media- tors transcription, including interleukin 1-β, interferon-α and interferon-γ. These cytokines are produced during innate im- mune responses and play an important role as activators of adaptive immune responses via the differentiation of Th1 cells that will determine cell-mediated immunity: antigen presentation activity of macrophages and induction of lymphocytes B to synthetise opsonizing antibodies.


Conclusion


The study highlights the potent role of MSP Immunity to sup- port the development of adaptive immune response in broil- ers. This innovative bioactive compound can thus play an im- portant role within the reduction of antibiotics in feed. Complementary trials in research centres or in the field have confirmed that when distributed continuously to broilers dur- ing starter and grower phases, MSP Immunity (associated with another Olmix MSP in a commercial product named Al- gimun), can accelerate the shift from innate to adaptive im- munity (decreased heterophil to lymphocyte ratio), improve gut protection (higher plasmatic IgA levels) and improving technical performance.


References available upon request.


Figure 2 - Glucuronidase activity by heterophils with different concentrations of MSP®IMMUNITY during 4 consecutive days.


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The data in figure 1 and 2 represents the mean ± SEM of three independent experiments with 25 chickens per group. Differ- ent letters with the same colour indicate statistically different values for the different doses at the same time with p < 0.05, different symbols with the same colour indicate statistically different values for the different doses at the same time with *p < 0.05, **p < 0.01, and ***p < 0.005 when values are statistically different for the same dose at different times.


▶ POULTRY WORLD | No. 4, 2019 27 * * c * * d


PHOTO: OLMIX


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