The aim of the present study was to examine the vaccine immune response in ewes supplemented with Bacillus toyonensis BCT-7112 during a period of 5-day supplementation before vaccination against a recombinant Clostridium perfringens epsilon toxin (rETX).
Ewes were vaccinated with 200 µg of rETX adjuvanted with 10% aluminum hydroxide. The treat group was orally supplemented with B. toyonensis BCT-7112 (3 × 10 viable spores) for 5 days prior to the first and second vaccination. Ewes supplemented with B. toyonensis BCT-7112 showed higher neutralizing antibody titers than the non-supplemented ewes (P < 0.05), with an increase in serum levels for total IgG anti-rETX by 3.2-fold (P < 0.0001), and for both IgG isotypes IgG1 and IgG2 by 2.1-fold and 2.3-fold (P < 0.01), respectively, compared with the control group. The peripheral blood mononuclear cells of ewes in the supplemented group had a higher (P < 0.05) cytokine mRNA transcription levels for IL-2 (6.4-fold increase), IFN-γ (2.9- fold increase) and transcription factor Bcl6 (2.3-fold increase) compared with the control group.
We conclude that a 5 days of supplementation with B. toyonensis BCT-7112 prior vaccination is sufficient to significantly improve the humoral immune response of ewes against C. perfringens recombinant ETX vaccine.
These findings open a new perspective in the utilization of B. toyonensis BCT-7112 as an immunomodulator since a 5 days period of probiotic supplementation is sufficient to improve the vaccine immune response.
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