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91.
多孔高分子载体固定化微生物厌氧流化床处理低浓度废水的研究 总被引:14,自引:0,他引:14
本文报道用厌氧流化床反应器处理低浓度有机废水的可行性研究结果。采用多孔高分子载体固定厌氧微生物和流态化技术强化传质过程,可克服低浓度有机废水甲烷化能力低的障碍。实验表明,在35±1℃条件下,处理COD浓度为1600mg/L的人工葡萄糖废水,床层最优膨胀率为50%,容积有机负荷率为19.2gCOD/(L·d),COD去除率达70%;处理COD浓度为220~250mg/L的城市污水,容积有机负荷率为2.4~2.6gCOD/(L·d),COD去除率为54%~56%。 相似文献
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本实验利用四只带有永久性瘤胃瘘管的延边半细毛羊,采用交叉实验设计进行测试.体内实验表明,瘤胃液氨浓度实验组比对照组明显降低(P<0.01),实验组的PH值比对照组显著降低(P<0.05),VFA的变化不显著(P>0.05).原虫蛋白浓度(P<0.05)、细菌蛋白浓度(P<0.05)和TCA-P(P<0.01)较对照组都明显提高,瘤胃温度没有发现变化;体外实验表明,实验组的产气性能明显高于对照组(P<0.01),而瘤胃液中除淀粉酶(P<0.05)有显著提高外,脂酶、脲酶和纤维素酶的活性均无变化.在原虫种类的变化上,实验组的内毛虫数量较对照组明显增高,但双毛虫却明显降低(P<0.01). 相似文献
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Elva Mayra Toledo‐Cuevas Francisco J Moyano López Dariel Tovar Ramírez Carlos A Strüssmann Carlos Alfonso Álvarez‐González Carlos Cristian Martínez‐Chávez Carlos A Martínez‐Palacios 《Aquaculture Research》2011,42(6):776-786
The early development of the digestive biochemistry of three cultured Atherinopsids (two Odontesthes species and Chirostoma estor) was investigated. Relatively high lipolytic and high alkaline proteolytic activities were found in all species. In addition, gene expression of lipase and trypsin during the early development of C. estor not only indicates an early onset of the lipase activity but also demonstrates a major importance of protein digestion in this species. However, despite all of them share similar habitats, differences in their digestive activities were evident. The rise in the activities of brush border membrane enzymes correlated with the decrease in cytosolic activities, used as indicator of maturation of the digestive tract, was detected in both species of Odontesthes at 9 weeks after hatching. In contrast, no similar signs were measured in C. estor, this being in agreement to the long weaning period (nearly 5 months) reported for this species. 相似文献
96.
Temperature modulates liver lipid accumulation in Atlantic salmon (Salmo salar L.) fed low dietary levels of long‐chain n‐3 fatty acids 下载免费PDF全文
N.H. Sissener B.E. Torstensen M.A.G. Owen N.S. Liland I. Stubhaug G. Rosenlund 《Aquaculture Nutrition》2017,23(4):865-878
Atlantic salmon (Salmo salar) were fed five graded levels of eicosapentaenoic acid (EPA, 20:5n‐3) and docosahexaenoic acid (DHA, 22:6n‐3), from 1.4 to 5.2% of total fatty acids (FA, 5–17 mg kg?1 feed), and grew from ~160 g to ~3000 g, with the period from 1450 g onwards conducted both at 6 °C and at 12 °C. All fish appeared healthy, and there were no diet‐related differences in haematological or plasma parameters, as well as intestinal histological or gut microbiota analysis. Fish reared at 6 °C had higher accumulation of storage lipids in the liver compared to fish reared at 12 °C. Liver lipids also increased with decreasing dietary EPA + DHA at 6 °C, while there was no such relationship at 12 °C. Gene expression of SREBP1 and 2, LXR, FAS and CPT1 could not explain the differences in liver lipid accumulation. In liver polar lipids, DHA was found to be reduced when dietary EPA + DHA was <2.7% of FAs, while the level of EPA in the membranes was not affected. In conclusion, reducing dietary EPA + DHA from 5.2 to 1.4% of total FAs had a minor impact on fish health. Temperature was the factor that most affected the liver lipid accumulation, but there was also an interaction with dietary components. 相似文献
97.
Changes in the gut microbiome of the Chinese mitten crab (Eriocheir sinensis) in response to White spot syndrome virus (WSSV) infection 下载免费PDF全文
Intestinal microorganisms play important roles in maintaining host health, but their functions in aquatic animal hosts have yet to be fully elucidated. The Chinese mitten crab, Eriocheir sinensis, is one such example. We attempted to identify the shift of gut microbiota that occurred in response to infection of white spot syndrome virus (WSSV), an emerging viral pathogen in the crab aquaculture industry. The microbiota may exert some control over aspects of the viral pathogenesis. We investigated the changes in composition and structure of the crab gut microbiome during various WSSV infection stages of 6 h post‐infection (hpi) and 48 hpi, using a 16S rRNA approach on the MiSeq Illumina sequencing platform. Four phyla (Firmicutes, Proteobacteria, Tenericutes and Bacteroidetes) were most dominant in the gut of E. sinensis regardless of the WSSV infection stages. However, further analysis revealed that over 12 bacterial phyla, 44 orders and 68 families were significantly different in abundance at various states of WSSV infection. Several intriguing aspects of E. sinensis gut bacteria that had not been previously reported were also uncovered, such as class Mollicutes was dominant here, but absent in crabs from Yangtze River estuary and Chongming Islands. Overall, this study provided the first evidence that changes in gut microbiome were closely associated with the severity of WSSV infection and that indicator taxa could be used to evaluate the crab health status. 相似文献
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Effect of Bacillus cereus as a water or feed additive on the gut microbiota and immunological parameters of Nile tilapia 下载免费PDF全文
Miao Wang Guanbin Liu Maixin Lu Xiaoli Ke Zhigang Liu Fengying Gao Jianmeng Cao Huaping Zhu Mengmeng Yi Deguang Yu 《Aquaculture Research》2017,48(6):3163-3173
We evaluated the effects of Bacillus cereus, as an additive in water and feed, on the gut microbiota and immunological parameters of Nile tilapia (Oreochromis niloticus) fingerlings. Experiments were performed in tanks and net cages respectively. Experiment 1: Tilapia were housed in tanks for 42 days, and B. cereus was added to the water at 1.0 × 104 cfu mL?1 (Treatment 1) and 1.0 ×105 cfu mL?1 (Treatment 2) weekly. For the control, no probiotic was added. Experiment 2: Tilapia were housed in cages for 42 days, and the feed was supplemented with B. cereus at 1.0 × 107 cfu g?1 (Treatment 1) and 1.0 × 108 cfu g?1 (Treatment 2) weekly. For the control, no probiotic was added. Each treatment contained three replicates, with 50 male tilapias per replicate. The fish from the probiotic treatments in both tank and cage experiments had significantly higher serum lysozyme and peroxidase activities than the control. In the cage experiment, alkaline phosphatase and total superoxide dismutase activities in tilapia were significantly higher in probiotic treatments compared with the control. The results of polymerase chain reaction‐denaturing gradient gel electrophoresis showed that B. cereus supplementation in the feed and water affected the autochthonous gut bacteria community of tilapia and stimulated various potentially beneficial bacteria. Therefore, B. cereus, as a water or feed additive, could enhance the immune status and affect the gut microbiota of tilapia. Bacillus cereus was more effective as a feed supplement rather than a water additive for enhancing the immune status of tilapia. 相似文献
100.
Jing Zhang Fan Xiong Gui‐Tang Wang Wen‐Xiang Li Ming Li Hong Zou Shan‐Gong Wu 《Aquaculture Research》2017,48(9):4934-4944
To elucidate the influence of different diet on the intestinal microbe and bile acids, we characterized the microbiota and bile acids in the hindgut content of grass carp fed on formula feed (FF group) or Sudan grass (SG group). Fusobacteria and Proteobacteria were significantly more represented in FF group than in SG group whereas Bacteroidetes was significantly more abundant in SG group than in FF group. Simpson diversity was significantly higher in FF group than in SG group (t = 2.33, P < 0.05). Chenodeoxycholic acid (CDCA) was the most abundant primary bile acid in the two groups, with average concentrations of 1.03 ± 0.62 and 4.44 ± 1.80 ng mg?1 in SG and FF group respectively. The most abundant secondary bile acid was deoxycholic acid (DCA) in SG group and ursodeoxycholic acid (UDCA) in FF group, with average concentrations of 0.17 ± 0.06 and 2.67 ± 0.88 ng mg?1 respectively. UDCA is significantly more abundant in FF group than in SG group, and the total bile acids were higher in FF group than in SG group. Cetobacterium and Fusobacteriaceae U114 were significantly related with the concentrations of CDCA (r = 0.85, P < 0.05 and r = 0.82, P < 0.05 respectively) and UDCA (r = 0.92, P < 0.01 and r = 0.92, P < 0.01 respectively). However, Bacteroides was negatively related with the concentration of UDCA (r = ?0.67, P < 0.05). Overall, there existed certain relationship between the intestinal microbes and the faecal bile acids, and they were both influenced by the diet. 相似文献