No abstract

Modified-masked T-2 toxin (mT-2) formed during metabolism in edible aquatic animals may go undetected by traditional analytical methods, thereby underestimating T-2 toxicity. The effects of T-2 on growth and antioxidant capacity and histopathological changes in the hepatopancreas were studied in Pacific white shrimp Litopenaeus vannamei exposed for 20 d to 0, 0.5, 1.2, 2.4, 4.8, and 12.2 mg/kg of T-2 in their feed. The concentration of mT-2 in the hepatopancreas was detected by liquid chromatography-tandem mass spectrophotometry before and after trifluoroacetic acid (TFA) treatment that converted mT-2 to free T-2. A dose-dependent increase in mT-2 concentration was observed in the hepatopancreas. Dietary exposure to T-2 significantly decreased (P < 0.05) shrimp growth and survival rate compared with the controls. The malondialdehyde (MDA) concentration was significantly increased in shrimp exposed to feed with ≥2.4 mg/kg T-2 (P < 0.05). The antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GPx), total antioxidant capacity (T-AOC), and also glutathione (GSH) content increased in shrimp dosed with 2.4-4.8 mg/kg T-2 but declined at the highest dose (12.2 mg/kg), probably indicating an inability to cope with high concentrations of reactive oxygen species (ROS) as evident from a marked increase in MDA (P < 0.05) culminating in cellular toxicity. Histopathological changes in the hepatopancreas were dose dependent, with cell autophagy evident at the highest exposure dose. This is the first report in shrimp of a dose-dependent increase in ROS, SOD enzyme activity, and T-AOC at low T-2 exposures, and associated histopathological changes in the hepatopancreas, in response to dietary T-2. Received January 26, 2016; accepted October 9, 2016.

Brucellosis is a prevalent zoonotic disease worldwide. However, the spatiotemporal patterns evolution and its driving factors of Brucellosis have not been well explored. In this study, spatiotemporal scan statistics were applied to describe the spatiotemporal pattern of evolution in Brucellosis from 2003 to 2019 in mainland China, and GeoDetector analysis was further conducted to explore the driving effects of environmental, meteorological, and socioeconomic factors. We identified a distinct seasonal pattern for Brucellosis, with a peak in May and lowest incidence between September and December. High-risk clusters were first observed in the northwestern pastoral areas and later expanded to the southern urban areas. The spatiotemporal heterogeneity was mainly explained by total SO2 emissions, average annual temperature, sheep output, and consumption of meat per capita with explanatory powers of 45.38%, 44.60%, 40.76%, and 30.46% respectively. However, the explanatory power changed over time. Specifically, the explanatory power of average annual temperature tended to decrease over time, while consumption of meat per capita and total output of animal husbandry tended to increase. The most favorable conditions for the spread of Brucellosis include 0.66–0.70 million tons of SO2 emissions, 9.54–11.68 °C of average annual temperature, 63.28–72.40 million heads of sheep output, and 16.81–20.58 kg consumption of meat per capita. Brucellosis remains more prevalent in traditional pastoral areas in Northwest China, with the tendency of spreading from pastoral to non-pastoral, and rural to urban, areas. Total SO2 emission, average annual temperature, sheep output, and consumption of meat per capita dominated the spatial heterogeneity of Brucellosis with changes in explanatory power over time.

Vibrio parahaemolyticus (Vp), a major food-borne pathogen, is responsible for severe infections such as gastroenteritis and septicemia, which may be accompanied by lifethreatening complications. While studies have evaluated factors that affect the virulence of the pathogen, none have investigated the interaction of Vp with gut microbiota. To address this knowledge gap, we compared the effect of Vp on gut bacterial community structure, immunity, liver and kidney function, in pseudo germ-free (PGF) mice and normal (control) mice. Significant damage to the ileum was observed in normal mice compared with the PGF mice. The inflammatory factors IL-1β, IL-6, and TNF-α in normal mice were ∼2.5-fold higher than in the PGF mice, and liver (ALT, AST, ALP) and kidney (BUN) function indices were ∼1.6-fold higher. The Vp infection substantially reduced species composition and richness of the gut microbial communities. In particular, there was a shift in keystone taxa, from protective species of genera Bacteroides, Lactobacillus, Bifidobacterium, and Akkermansia in the gut of control mice to opportunistic pathogens Enterobacteriaceae, Proteus, Prevotella, and Sutterella in Vp-infected mice, thus affecting microbiota-related biological functions in the mice. Specifically, pathways involved in infectious diseases and ion channels were significantly augmented in infected mice, while the pathways involved in metabolism, digestion and cell growth declined. We propose that the normal mice are more prone to Vp infection because of the alteration in gut-microbe-mediated functions. All these effects reduce intestinal resistance, with marked damage to the gut lining and pathogen leakage into the blood culminating in liver and kidney damage. These findings greatly advance our understanding of the mechanisms underlying interactions between Vp, the gut microbiota and the infected host.

Mycotoxins are secondary metabolites produced by fungi. These contaminate dried seafoods during processing and storage and represent a potential health hazard for consumers. A sensitive, selective and accurate liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was established for simultaneous quantification of four common mycotoxins (aflatoxin B1 (AFB1), T-2 toxin (T-2), ochratoxin A (OTA) and deoxynivalenol (DON)) in dried shrimp, dried fish and dried mussel products. Mycotoxins were extracted from dried seafood samples by acetonitrile/water (85/15, v/v), subjected to ultrasound for 60 min at 20 °C and cleaned up by defatting with n-hexane. The sample matrix affected the linearity of detection (R2 ≥ 0.9974). The limit of detection (LOD) and limit of quantification (LOQ) in dried seafood products varied from 0.1 to 2.0 µg·kg−1 and 0.3 to 5.0 µg·kg−1, respectively. The method was validated by spiking samples with specific mycotoxin levels, and the recoveries, intra-relative standard deviation (RSDs) and inter-RSDs ranged between 72.2–98.4%, 2.8–10.6%, and 5.5–15.4%, respectively. This method was used to analyze 40 dried seafood products purchased from the Zhanjiang seafood market. Results of this product sampling showed that while no DON was detected, AFB1, T-2 and OTA were detected in 30.8%, 17.5% and 33.3% of the samples, respectively. AFB1, T-2 and OTA concentrations varied at 0.58–0.89, 0.55–1.34 and 0.36–1.51 µg·kg−1, respectively. Relatively high frequency of contamination and the presence of AFB1, OTA and T-2 residues indicate the need to monitor mycotoxins in dried seafood products.

Modulation of the intestinal barrier, inflammation, and gut microbiota by Pediococcus pentosaceus zy-B (zy-B) in Vibrio parahaemolyticus (Vp)-infected C57BL/6J mice was studied. Mice intragastrically pretreated with 10 8 colony-forming units (CFU) zy-B significantly alleviated Vp infection as evidenced by maintaining body weight and reduced disease activity index score and intestine ratio. In addition, zy-B reduced the Vp load in the ileum and cecum, significantly reduced the load in the colon, prevented colonic atrophy, and strengthened mucosal integrity. Mechanistically, zy-B ameliorated intestinal barrier dysfunction by upregulating tight junction protein expression, which in turn reduced the lipopolysaccharide, D-lactic acid (D-LA), and diamine oxidase concentrations and downregulated the cannabinoid receptor 1 (CB1) and CB2 mRNA expressions. Moreover, zy-B systemically reduced inflammation by decreasing interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α levels, and increased interleukin-10 (IL-10), immunoglobulin M (IgM), and immunoglobulin G (IgG) levels in the colon and serum. Furthermore, zy-B markedly altered the gut microbiota composition by enriching Bif idobacterium, Akkermansia, and Lactobacillus in the colon. Overall, zy-B appears to act as a probiotic to alleviate Vp infection by protecting the intestinal barrier, reducing inflammation, and promoting the growth of "beneficial" gut microbiota.

Dried fish are important dietary protein and income sources in Zhanjiang, China. Mycotoxins produced by pathogenic fungi that contaminate fish during processing can cause considerable hazard to consumer health. This study reports fungal diversity, total fungal counts and mycotoxin contamination of dried fish sold at the seafood market in Zhanjiang. Seven dried fish products (Hemibarbus maculatus, Pseudosciaena crocea, Lutjanus erythopterus, Thunnus thynnus, Scomberomorus niphonius, Eleutheronema tetradactylum, Trichiurus lepturus, n = 10) from seven retailers were analyzed for contaminated fungal species, occurrence frequency and residues analysis of four mycotoxins. Using potato dextrose agar (PDA) plate purification, morphology observation, internal transcribed spacer (ITS) sequence analysis, 25 fungal strains representing 12 genera from dried fish were systematically isolated and identified. Three dominant genera in dried fish were Fusarium sp. (80.4%), Penicillium sp. (70.7%) and Aspergillus sp.(63.9%). Other fungal genera were Neoscytalidium sp.(38.1%), Cutaneotrichosporon sp. (38.1%), Trichoderma sp.(20.3%), Naganishia sp.(15.3%), Kodamaea sp. (10.8%), Phialemoniopsis sp.(9.2%), Nigrospora sp.(7.3%), Ceriporia sp.(6.3%), Phellinus sp.(4.5%). Aspergillus flavus contamination was the higher and ranged from 1.10 × 10 3 to 2.40 × 10 4 cfu/g. The mean fungal contamination of other fungal species in dried fish ranged from 1.07 × 10 2 to 4.58 × 10 4 cfu/g. The total fungal counts of Fusarium sp. ranged from 1.09 × 10 2 to 2.11 × 10 4 cfu/g, but the occurrence frequency is relatively high. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses showed that mycotoxin residues were present in 12 out of the 25 dried fish tested. Aflatoxin B 1 (AFB 1) was the most frequently detected and the concentration ranged from 0.03 to 3.52 μg/kg. T-2 toxin (T-2), ochratoxin A (OTA), and deoxynivalenol (DON) concentrations ranged from 0.21 to 1.53, 0.03-2.21 and 0.71 μg/kg respectively. High occurrence of fungal populations and mycotoxins in dried fish sold in the Zhanjiang market pose a potential threat to consumer health. It is recommended that in future, advanced processing methods and controlled storage condition need to be used to minimize and if possible eliminate fungal contamination during dried fish processing.

T-2 toxin (T-2), a naturally occurring mycotoxin that often accumulates in aquatic animals via contaminated feed, is toxic to animals, including humans. In this study, six groups of shrimp (n = 30 shrimps/group) were given T-2 in feed at concentrations of 0–12.2 mg/kg for 20 days. T-2 accumulation, intestinal histopathology, digestive enzyme activities and subsequent effects on shrimp are reported. Compared to the control, T-2 significantly reduced weight gain, specific growth rate, and survival. The histopathology of shrimp intestine showed concentration-dependent degenerative and necrotic changes in response to dietary T-2. Progressive damage to the microstructures of shrimp intestine occurred with increasing dietary T-2 concentrations, with initial inflammation of the mucosal tissue at T-2 concentrations of 0.5 and 1.2 mg/kg, progressing to disappearance of intestinal villi and degeneration and necrosis of the submucosa at 12.2 mg/kg. Intestinal amylase and protease activities increased at low T-2 concentrations but showed significant inhibition at high concentrations; however, the opposite trend occurred for lipase activity. Collectively, these results indicate that digestive enzyme activities and mucosal structures are markedly affected by exposure to T-2, and these may have contributed to the lower survival rate of shrimp.