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© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

Rhizopus oryzae is a fungus used to ferment tempeh in Indonesia and is generally recognized as safe (GRAS) for human consumption by the USA FDA. We previously assessed the effect of a tempeh extract on cortisol levels in zebrafish but did not include behavioral studies. Here, we measured the GABA content in three strains of Rhizopus oryzae, two isolated by us (MHU 001 and MHU 002) and one purchased. We then investigated the effect of tempeh on cortisol and the gut microbiota in a zebrafish experimental model. GABA concentration was the highest in MHU 002 (9.712 ± 0.404 g kg−1) followed by our MHU 001 strain and the purchased one. The fish were divided into one control group fed a normal diet and three experimental groups fed soybean tempeh fermented with one of the three strains of Rhizopus oryzae. After two weeks, individual fish were subjected to unpredicted chronic stress using the novel tank diving test and the tank light–dark test. Next-generation sequencing was used to analyze gut microbial communities and RT-PCR to analyze the expression of BDNF (brain-derived neurotrophic factor) gene and of other genes involved in serotonin signaling/metabolism in gut and brain. Tempeh-fed zebrafish exhibited increased exploratory behavior (less stress) in both tank tests. They also had significantly reduced gut Proteobacteria (include E. coli) (51.90% vs. 84.97%) and significantly increased gut Actinobacteria (include Bifidobacterium spp.) (1.80% vs. 0.79%). The content of Bifidobacterium adolescentis, a “psychobiotic”, increased ten-fold from 0.04% to 0.45%. Tempeh also increases BDNF levels in zebrafish brain. Rhizopus oryzae MHU 001 greatly improved the anti-stress effect of tempeh and microbiota composition in zebrafish gut.

Details

Title
Effect of Tempeh on Gut Microbiota and Anti-Stress Activity in Zebrafish
Author
Chen, Yo-Chia 1   VIAFID ORCID Logo  ; Tao, Nha-Linh 1 ; Shao-Yang, Hu 1   VIAFID ORCID Logo  ; Hui-Yun, Tsai 2 ; Sin-Chung, Liao 3   VIAFID ORCID Logo  ; Wei-Lun Tsai 4 ; Chun-Yi, Hu 5   VIAFID ORCID Logo 

 Department of Biological Science and Technology, Pingtung University of Science and Technology, Pingtung 912301, Taiwan; [email protected] (Y.-C.C.); [email protected] (N.-L.T.); [email protected] (S.-Y.H.) 
 Department of Nutrition and Health Science, Fooyin University, Kaohsiung 831301, Taiwan; [email protected] 
 Department of Biotechnology, Meiho University, Pingtung 912009, Taiwan; [email protected] 
 Division of Gastroenterology and Hepatology, Department of Internal Medicine, Kaohsiung Veterans General Hospital, Kaohsiung 813414, Taiwan 
 Department of Food Science and Nutrition, Meiho University, Pingtung 912009, Taiwan 
First page
12660
Publication year
2021
Publication date
2021
Publisher
MDPI AG
ISSN
16616596
e-ISSN
14220067
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2608128438
Copyright
© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.