| Summary: | 博士 === 國立臺灣大學 === 動物科學技術學研究所 === 106 === According to the latest survey from the Food and Agriculture Organization of the United Nations, up to 50 percent of the grain were contaminated by mycotoxins. Mycotoxins have adverse effects on humans, animals, and crops that result in illnesses and economic losses. The supplementation of mycotoxin detoxifiers to the contaminated feed could be the most promising approach to reduce the loss. Our previous study showed that Bacillus licheniformis CK1 (CK1) decreased more than 98% of zearalenone in ZEN-contaminated corn meal medium after 36 hours of incubation, thus suggesting that CK1 might be the solution for ZEN contamination in feed. In addition, CK1 was non-hemolytic, non-enterotoxin producing, and was resistant to gastric acid and bile salts. Furthermore, CK1 could adhere to human epithelial cell line (Caco-2) and reduce the adhesion of pathogens, such as enterohemorrhagic Escherichia coli and Salmonella typhimurium to surfaces of Caco-2 cells. Therefore, all these data showed that CK1 can be qualified as a food probiotic.
Although CK1 is a candidate for mycotoxin detoxifier, we still need more evidence to assess its market potential. By comparing CK1 to a commercial inorganic adsorbent (Omniguard®) and a well understood microbial original adsorbent (Lactobacillus rhamnosus GG, LGG), CK1 exhibited approximately 30% and 25% higher performance in removing ZEN than LGG and Omniguard®, respectively. Furthermore, to reveal the detoxification mechanism of CK1, viable and non-viable (acid treated and heat treated) CK1 were used in a ZEN removing assay. The process of toxin removal by CK1 is rapid since approximately 75% of ZEN was removed from the liquid media within the 10-min centrifugation. Even after 24 hours of incubation, the removal rate is slightly increased (from 0.5% to 2.2%) in all samples of CK1 without any significant difference. Under these conditions, the ZEN removal mechanism of CK1 was concluded to be through adsorption but not through biotransformation.
Since CK1 had exhibited probiotic characteristics in in vitro experiments, we also evaluated its other potential functions in vivo. In BALB/c mouse model, we evaluated the non-specific immune functions, gastrointestinal functions, and gut-brain axis effects of CK1. In immune functions study, the results showed that granulocyte phagocytosis, splenocyte proliferation and natural killer (NK) cell activity were increased after oral administration of CK1. In gastrointestinal functions study, levels of harmful bacteria Clostridium perfringens in the intestine were significantly decreased. Moreover, serotonin levels in the brain were significantly increased which imply that CK1 could influence gut-brain axis.
In conclusion, our data showed that CK1 had the best ZEN removing ability compared to two other commercial adsorbents. Moreover, CK1 possesses immunomodulatory functions, improves gastrointestinal function, and may involves in affects gut-brain axis, thus, making it a super multi-functional probiotic. In the future, CK1 can be applied in preventing diseases as well as in reducing stress.
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