Browsing by Author "Fang, Qiao"

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    Environmental concentrations of antibiotics impair zebrafish gut health.
    (Elsevier, 2018-01-04) Li, Zhou; Samwel Mchele Limbu; Fang, Qiao; Zhen-Yu, Du; Meiling, Zhang
    Antibiotics have been widely used in human and veterinary medicine to both treat and prevent disease. Due to their high water solubility and low bioavailability, many antibiotic residues have been found in aquatic environments. Fish are an indispensable link between the environmental pollution and human health. However, the chronic effects of environmental concentrations of antibiotics in fish have not been thoroughly investigated. Sulfamethoxazole (SMX) and oxytetracycline (OTC) are frequently detected in aquatic environments. In this study, zebrafish were exposed to SMX (260 ng/L) and OTC (420 ng/L) for a six-week period. Results indicated that exposure to antibiotics did not influence weight gain of fish but increased the metabolic rate and caused higher mortality when treated fish were challenged with Aeromonas hydrophila. Furthermore, exposure to antibiotics in water resulted in a significant decrease in intestinal goblet cell numbers, alkaline phosphatase (AKP), acid phosphatase (ACP) activities, and the anti-oxidant response while there was a significant increase in expression of inflammatory factors. Antibiotic exposure also disturbed the intestinal microbiota in the OTC-exposed group. Our results indicated that environmental antibiotic concentrations can impair the gut health of zebrafish. The potential health risk of antibiotic residues in water should be evaluated in the future.
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    Influence of Long-Term Feeding Antibiotics on the Gut Health of Zebrafish
    (Zebrafish, 2018-08-01) Li, Zhou; Samwel Mchele Limbu; Fang, Qiao; Zhen-Yu, Du; Meiling, Zhang
    The use of antibiotics for anti-infection and growth promotion has caused the overuse of antibiotics in aquaculture. However, the benefit or risk of the long-term use of antibiotics on fish growth or health has not been fully addressed. In the present study, zebrafish were fed with sulfamethoxazole (SMX) or oxytetracycline (OTC) at the therapeutic concentrations (100 and 80 mg/kg body weight per day, respectively) for 6 weeks to mimic the long-term use of antibiotics. The digestive enzyme activities were higher in both antibiotic treatments, and higher oxygen consumption rate was found in OTC treated group. As a result, SMX increased the weight gain of zebrafish, and OTC treatment did not show significant prompting effect on growth. The mortality was higher in SMX or OTC treated group on 2nd–4th day after exposure to Aeromonas hydrophila. Lower alkaline phosphatase (AKP) and acid phosphatase (ACP) activities were found in OTC treated group, while higher malondialdehyde (MDA) content was found in the intestine of both SMX and OTC treated zebrafish. Furthermore, feeding OTC decreased the intestinal microbial richness. This study revealed that long-term use of legal aquaculture concentrations of antibiotics caused systemic adverse effects on fish gut health; stringent policy for use of antibiotics in fish is urgent.
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    The Physiological and Metabolic Differences between Visceral and Subcutaneous Adipose Tissues in Nile tilapia (Oreochromis niloticus).
    (The American Physiological Society, 2017-11-09) Ya-Wen, Wang; Ji-Lei, Zhang; Jian-Gang, Jiao; Xiao-Xia, Du; Samwel Mchele Limbu; Fang, Qiao; Mei-Ling, Zhang; Dong-Liang, Li; Zhenyu, Du
    Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SCAT) have different structures and metabolic functions and play different roles in the regulation of the mammal endocrine system. However, little is known about morphology and physiological and metabolic functions between VAT and SCAT in fish. We compared the morphological, physiological, and biochemical characteristics of VAT and SCAT in Nile tilapia and measured their functions in energy intake flux, lipolytic ability, and gene expression patterns. SCAT contained more large adipocytes and nonadipocytes than VAT in Nile tilapia. VAT had higher lipid content and was the primary site for lipid deposition. Conversely, SCAT had higher hormone-induced lipolytic activity. Furthermore, SCAT had a higher percentage of monounsaturated and lower polyunsaturated fatty acids than VAT. SCAT had higher mitochondrial DNA, gene expression for fatty acid β-oxidation, adipogenesis, and brown adipose tissue characteristics, but it also had a lower gene expression for inflammation and adipocyte differentiation than VAT. SCAT and VAT have different morphological structures, as well as physiological and metabolic functions in fish. VAT is the preferable lipid deposition tissue, whereas SCAT exhibits higher lipid catabolic activity than VAT. The physiological functions of SCAT in fish are commonly overlooked. The present study indicates that SCAT has specific metabolic characteristics that differ from VAT. The differences between VAT and SCAT should be considered in future metabolism studies using fish as models, either in biomedical or aquaculture studies.
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    The presence or absence of intestinal microbiota affects lipid deposition and related genes expression in zebrafish (Danio rerio).
    (Frontiers Media SA, 2018-05-29) Yi, Sheng; Hui, Ren; Samwel Mchele Limbu; Yuhong, Sun; Fang, Qiao; Wanying, Zhai; Zhen-Yu, Du; Meiling, Zhang
    Understanding how intestinal microbiota alters energy homeostasis and lipid metabolism is a critical process in energy balance and health. However, the exact role of intestinal microbiota in the regulation of lipid metabolism in fish remains unclear. Here, we used two zebrafish models (germ-free and antibiotics-treated zebrafish) to identify the role of intestinal microbiota in lipid metabolism. Conventional and germ-free zebrafish larvae were fed with egg yolk. Transmission electron microscopy was used to detect the presence of lipid droplets in the intestinal epithelium. The results showed that, microbiota increased lipid accumulation in the intestinal epithelium. The mRNA sequencing technology was used to assess genes expression level. We found majority of the differentially expressed genes were related to lipid metabolism. Due to the limitation of germ-free zebrafish larvae, antibiotics-treated zebrafish were also used to identify the relationship between the gut microbiota and the host lipid metabolism. Oil-red staining showed antibiotics-treated zebrafish had less intestinal lipid accumulation than control group. The mRNA expression of genes related to lipid metabolism in liver and intestine was also quantified by using real-time PCR. The results indicated that apoa4, hsl, cox15, slc2a1a, and lss were more related to intestinal bacteria in fish, while the influence of intestinal microbiota on the activity of fabp6, acsl5, cd36, and gpat2 was different between the liver and intestine. This study identified several genes regulated by intestinal microbiota. Furthermore, the advantages and disadvantages of each model have been discussed. This study provides valuable information for exploring host-microbiota interactions in zebrafish in future.
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    Soybean and cottonseed meals are good candidates for fish meal replacement in the diet for juvenile Macrobrachium nipponense. , 26(1): 309–324.
    (Springer, 2017-11-13) Yujuan, Huang; Nannan, Zhang; Wujiang, Fan; Yanyan, Cui; Samwel Mchele Limbu; Yunlong, Zhao; Fang, Qiao; Liqiao, Chen; Zhenyu, Du; Dong-Liang, Li
    Macrobrachium nipponense is a new aquaculture species with high market demand and is preferred as food by Asian consumers. However, its nutrient requirements and optimal dietary sources have not been fully evaluated. In the present study, we examined four common plant protein sources (soybean meal, cottonseed meal, rapeseed meal, and peanut meal) as partial replacement for 25% fishmeal protein in five isonitrogenous and isocaloric diets in M. nipponense for 8 weeks. The nutritional effects of the four plant protein sources were compared by means of growth performance, feed efficiency, histology, biochemical composition, oxidative stress, total hemocyte count, and in vitro digestion. Prawns fed the diets containing soybean (730.96 ± 33.50%) and cottonseed meals (672.32 ± 74.52%) had higher weight gain than those fed on rapeseed (503.71 ± 50.85%) and peanut (507.79 ± 52.10%) meal diets (p < 0.05). Similarly, the feed conversion ratios of prawns fed on soybean (1.66 ± 0.12%) and cottonseed (1.88 ± 0.06%) meal diets were significantly lower than those fed on rapeseed (2.37 ± 0.10%) and peanut (2.77 ± 0.16%) (p < 0.05) meal diets. No significant differences were found among groups in the hepatopancreas and intestinal histological characteristics, activities of antioxidant enzymes, and hemocyte number. The amino acid composition in diets and prawn muscles was comparable among groups. Soybean meal showed the highest in vitro digestibility. Taken together, soybean and cottonseed meals could be good candidates for partial fishmeal replacement in M. nipponense diets.