Probiotic effects of marine Debaryomyces hansenii CBS 8339 on innate immune and antioxidant parameters in newborn goats.

Several marine Debaryomyces hansenii strains have shown probiotic effects on aquatic animals, and D. hansenii-derived ß-glucans have recently provided immunostimulant effects on goat leukocytes. This study assessed the probiotic effects of live yeast D. hansenii CBS 8339 on newborn goats administered orally, and subsequently challenged in vitro with Escherichia coli. D. hansenii CBS 8339 demonstrated the capacity to survive gastrointestinal tract conditions (bile salts and acid pH tolerance) and adhere to goat intestine. Twelve Saanen × Nubian crossbred newborn goats (2.9 ± 0.47 kg) were fed with a controlled diet or D. hansenii (0.7 g/kg body weight per day)-supplemented milk for 30 days. Blood samples of newborn goats were taken at days 15 and 30, and peripheral blood leukocytes were isolated for bacterial challenge, and immunological and antioxidant analyses. Despite cell viability was higher in leukocytes of goat kids fed with the yeast supplement, protection against E. coli challenge was not significantly affected. On the other hand, at day 15, oral administration of D. hansenii enhanced respiratory burst and catalase activity and increased superoxide dismutase activity after challenge. In contrast, at day 30, administration of the yeast supplement increased peroxidase activity and enhanced nitric oxide production and catalase activity after challenge. Finally, the yeast-supplemented diet upregulated the expression of the receptor genes TLR (2, 4, 6), modulator genes Raf.1, Syk, and Myd88, transcription factor gene AP-1, and cytokine genes IL-1ß and TNF-α only at day 15 in leukocytes from unchallenged goat kids. These results demonstrated that a short time (15 days) of orally administering the probiotic D. hansenii CBS 8339 to newborn goats stimulated innate immune and antioxidant parameters and the expression of immune-related gene signaling pathways.

Debaryomyces hansenii CBS 8339 ß-glucan enhances immune responses and down-stream gene signaling pathways in goat peripheral blood leukocytes.

Debaryomyces hansenii-derived ß-glucan has shown immunostimulant effect on aquaculture species and recently on goat peripheral blood leukocytes. Moreover, the marine yeast D. hansenii CBS 8339 has demonstrated to enhance fish immune response. Nonetheless, the associated immune signaling pathways induced by ß-glucan from this marine yeast have not been characterized yet. This study described the effects of ß-glucan from D. hansenii CBS 8339 against challenge with Escherichia coli and activation of possible mechanisms on goat peripheral blood leukocytes. The proton nuclear magnetic resonance spectra showed that D. hansenii had ß-(1,3)(1,6)-glucan. The phagocytic ability enhanced after E. coli challenge, and nitric oxide production increased before and after challenge in leukocytes stimulated with D. hansenii ß-glucan. In addition, an early gene expression stimulation was found related to ß-glucan recognition by TLR2 and Dectin-1 receptors, intracellular regulation by Syk, TRAF6, MyD88 and transcription factor NFκB, and effector functions of pro-inflammatory cytokine, such as IL-1ß and TNF-α. Interestingly, simulation with D. hansenii-derived ß-glucan increased leukocyte viability after E. coli challenge. In conclusion, ß-glucan from D. hansenii CBS 8339 reduced cytotoxic effects of E. coli and modulated signaling pathways and innate immune response in goat peripheral blood leukocytes.