[Toxic effects of AFB_1/T-2 toxin and intervention effects of Meyerozyma guilliermondii in dried Lutjanus erythopterus on mice].

OBJECTIVE: In order to investigate the effect of yeast on reducing mycotoxin damage in dried fish. METHODS: A strain of Meyerozyma guilliermondii MH 211588. 1(MG-81) was mixed and fermented 48 h with dried Lutjanus erythopterus which contaminated aflatoxin B_1(AFB_1) and T-2 toxin(T-2). The toxin concentration in fermentation at different time was detected by LC-MS/MS, and fermentation was fed with mice by intragastric administration(7 d). Blood routine and four liver function enzymes were measured by hematology analyzer and microplate spectrophotometer respectively. The elimination effect of MG-81 isolate on mycotoxin damage in dried fish was evaluated by the toxin concentration at different time and its toxic effect on mice. RESULTS: The removal rates of AFB_1 and T-2 in dried fish fermentation showed a parabolic linear growth trend with the prolongation of fermentation time. The removal rates of AFB_1 and T-2 in dried fish fermentation broth tended to be stable at 36 h(the removal rates of AFB_1 and T-2 were 83. 7%±1. 3% and 78. 5%±0. 8%). This indicated that 36 h was the optimal time for MG-81 to remove mycotoxins in dried fish. At the same time, it was found that there was no significant change in the indexes of MG-81 dried fish fermentation compared with the control group(P>0. 05), while the same dose of AFB_1 and T-2 dried fish fermentation(without MG-81), the leucocytes, lymphocytes, erythrocyte, hemoglobin, platelet and mean platelet volume of mice were significantly lower than those of control group(P>0. 05), showing obvious hemotoxicity and immunotoxicity. The activity of four liver enzymes was increased significantly(P<0. 05), showing obvious hepatotoxicity. CONCLUSION: The fermentation of MG-81 for 36 h can effectively remove AFB_1 and T-2 from dried fish and eliminate their hazards.

Correlation of vitamin D with inflammatory factors, oxidative stress and T cell subsets in patients with autoimmune hepatitis.

Correlation of vitamin D with inflammatory factors, oxidative stress and T cell subsets in patients with autoimmune hepatitis were investigated. Patients with liver diseases (n=635) treated in The Sixth People's Hospital of Qingdao City from March 2015 to January 2018 were selected, among which 80 cases diagnosed with autoimmune hepatitis were included into observation group, and 80 healthy cases were included into control group. Patients with autoimmune hepatitis were further divided into normal 25-hydroxyvitamin D [25-(OH) D] group (n=40) and abnormal 25-(OH) D group (n=40) according to the level of 25-(OH) D, and divided into normal liver function group (n=40) and abnormal liver function group (n=40). 25-(OH) D, liver function, inflammatory factors, oxidative stress level and T cell subsets were compared. In the observation group, levels of 25-(OH) D, superoxide dismutase (SOD), total antioxidant capacity, and T cell subsets were lower than those in the control group (P<0.05), while levels of total bilirubin (TBIL), indirect BIL (IBIL), direct BIL (DBIL), aspartate aminotransferase (AST), alanine aminotransferase (ALT), inflammatory factors and malondialdehyde (MDA) were higher than those in the control group (P<0.05). In the normal 25-(OH) D group, levels of inflammatory factors and oxidative stress factor were lower than those in the abnormal 25-(OH) D group (P<0.05), while the SOD level, total antioxidant capacity and T cell subset counts were higher than those in the abnormal 25-(OH) D group (P<0.05). Moreover, the 25-(OH) D level in patients with autoimmune hepatitis was negatively correlated with hs-CRP, tumor necrosis factor-α (TNF-α), ALT and MDA, but positively correlated with CD3+ and CD4+ counts, SOD and total antioxidant capacity. Patients with autoimmune hepatitis, especially those with decreased level of vitamin D, are more prone to enhanced inflammatory and stress responses, decreased levels of T cell subsets and decline in immunity.

Diversity and succession of microbial communities and chemical analysis in dried Lutianus erythropterus during storage.

The population, diversity and succession of microbial communities and chemical characteristics of dried crimson snapper (Lutianus erythropterus) during storage for 50 days were investigated. The population of bacteria, yeasts and filamentous fungi in the samples were enumerated by culture methods using appropriate agar media. The amplicons of the 16S rRNA of bacteria and the ITS region of fungi were sequenced and compared with gene libraries to obtain the identity and abundance of microorganisms in the community. Free amino acids and several other chemical characteristics were determined by HPLC and corresponding chemical reaction methods. Before storage, the average counts of bacteria, yeasts and filamentous fungi in the dried fish were 3.2, 2.5 and 2.2 log CFU/g, which increased to 4.6, 3.6 and 3.9 log CFU/g, respectively after storage. Major succession in the bacterial > fungal communities occurred during storage as evidenced by a significant decline in the number and diversity of microbial communities. Predominant bacterial genera were Phytobacteria, Vibrio, Acinetobacter and Macrococcus in the freshly dried fish, which were replaced by Bacillaceae, Halomonas, Lentibacillus, Alkalibacillus after storage. The fungal community of the freshly dried fish consisted of Penicillum > Yamadazyma, Malassezia, Candida and Eurotiales with Penicillum being the most dominant. Penicillium camemberti was the most abundant fungal species in the dried fish before storage with most dominant after storage and accounted for >96% of the abundance. The succession in the microbial community was accompanied by major changes in chemical characteristics with a significant decrease in fat, and an increase in total free amino acids and total volatile basic nitrogen (TVB-N).