Immune Responses and Resistance against Vibrio parahaemolyticus Induced by Probiotic Bacterium Arthrobacter XE-7 in Pacific White Shrimp, Litopenaeus vannamei     

Jiqiu  Li Beiping  Tan  Kangsen  Mai  Qinhui  Ai  Wenbing  Zhang  Zhiguo  Liufu  Wei  Xu 《Journal of the World Aquaculture Society》2008,39(4):477-489

A 63-d feeding experiment was conducted to determine the effects of dietary supplementation of probiotic bacterium Arthrobacter XE-7 on immune responses and resistance against Vibrio parahaemolyticus in the Pacific white shrimp, Litopenaeus vannamei . The probiotic bacteria were administered orally at four different doses of 0, 10⁶, 10⁸, and 10¹⁰ colony-forming unit (CFU)/g feed for shrimp. On Day 50, the shrimp were challenged with Vibrio parahaemolyticus by bath. On Days 7, 21, 49, and 63, six shrimp per tank were sampled to take intestine and hemolymph. With increasing dietary supplementation of probiotic bacteria, shrimp mortality decreased from 63.16% (the control) to 55.9% (10⁶ CFU/g feed), 51.75% (10⁸ CFU/g feed), and 51.78% (10¹⁰ CFU/g feed), respectively. Vibrio counts in intestine of shrimp fed probiotic bacterium Arthrobacter XE-7 was generally lower than that in the control shrimp ( P  < 0.05). The probiotic bacteria generally increased the immune parameters in shrimp, that is, total hemocyte counts, percentage phagocytosis, respiratory burst activity, and serum phenoloxidase activity. The results showed that probiotic bacterium Arthrobacter XE-7 can be used as probiotic in shrimp feed.  相似文献   

Molecular cloning and functional characterization of a putative Elovl4 gene and its expression in response to dietary fatty acid profiles in orange‐spotted grouper Epinephelus coioides          下载免费PDF全文

Songlin Li  Óscar Monroig  Juan Carlos Navarro  Yuhui Yuan  Wei Xu  Kangsen Mai  Douglas R Tocher  Qinghui Ai 《Aquaculture Research》2017,48(2):537-552

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Relationship between the ultrasonographic findings of suspected superficial digital flexor tendon injury and the prevalence of subsequent severe superficial digital flexor tendon injuries in Thoroughbred horses: a retrospective study     

Mai IIMORI  Norihisa TAMURA  Kazuhiro SEKI  Yoshinori KASASHIMA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2022,84(2):261

The onset of severe injury to the superficial digital flexor tendon (SDFT) is extremely difficult to predict from slight changes in ultrasonographic findings in cases with no apparent clinical signs. This study investigated the relationship between an increased cross-sectional area (CSA) or edema in the subcutaneous tissue around the tendon and the subsequent onset of severe SDFT injury in Thoroughbred racehorses. Horses were classified into three groups based on ultrasound diagnosis (USD) findings: Group A included cases with enlarged tendons; Group B included cases with tendons of normal size but with prominent edema in the peritendinous tissue; and Group C (control group) included cases with no abnormal USD findings. The incidence of subsequent severe tendon injury was significantly higher in the horses in Groups A (25.7%, 28/101) and B (28.3%, 65/212) than in those in Group C (4.9%, 2/41). There were no significant differences in the median period and the median number of races from the first examination to the subsequent tendon injury between Groups A (140 days, 1 race) and B (120 days, 1 race). The results of this study revealed that horses with increased CSA and peritendinous edema are likely to suffer a subsequent severe tendon injury. Also, these two USD findings, i.e., increased CSA and peritendinous edema, indicate the risk of onset of severe SDFT injury.  相似文献   

Aurasperone A Inhibits SARS CoV-2 In Vitro: An Integrated In Vitro and In Silico Study     

Mai H. ElNaggar  Ghada M. Abdelwahab  Omnia Kutkat  Mohamed GabAllah  Mohamed A. Ali  Mohamed E. A. El-Metwally  Ahmed M. Sayed  Usama Ramadan Abdelmohsen  Ashraf T. Khalil 《Marine drugs》2022,20(3)

Several natural products recovered from a marine-derived Aspergillus niger were tested for their inhibitory activity against SARS CoV-2 in vitro. Aurasperone A (3) was found to inhibit SARS CoV-2 efficiently (IC₅₀ = 12.25 µM) with comparable activity with the positive control remdesivir (IC₅₀ = 10.11 µM). Aurasperone A exerted minimal cytotoxicity on Vero E6 cells (CC₅₀ = 32.36 mM, SI = 2641.5) and it was found to be much safer than remdesivir (CC₅₀ = 415.22 µM, SI = 41.07). To putatively highlight its molecular target, aurasperone A was subjected to molecular docking against several key-viral protein targets followed by a series of molecular dynamics-based in silico experiments that suggested M^pro to be its primary viral protein target. More potent anti-SARS CoV-2 M^pro inhibitors can be developed according to our findings presented in the present investigation.  相似文献   

三亚市10年间景观格局变化分析          下载免费PDF全文

林宁  关学彬  麦全法 《农学学报》2017,7(2):68-73

为了充分了解热带滨海城市发展过程中景观变化特征及其影响因素,利用基于SPOT的影像数据,应用RS、GIS 软件和景观生态学方法,以海南省三亚市作为研究对象,分析了2002—2012 年三亚市土地利用及景观格局的动态变化情况。结果表明：（1）三亚市仍以耕地和阔叶林为主,建设用地大幅度增加,各土地利用类型有相互转移表现,2002—2012 年,水田面积减少了25.75%,水库/坑塘减少6.21%;草丛、建设用地和旱地面积分别增加143.16%、86.89%和10.20%;（2）运用景观格局指数和转移矩阵分析,得出研究区域景观斑块总体数量减少,说明这期间三亚景观破碎化趋势降低,主要由于人类活动的干扰不断加强,城市化进程加快使原来分散的乡镇村落等居民集中地聚集成片,转变为城市化建筑群,从而导致了研究区域景观破碎化程度的下降。  相似文献   

基于注意力机制神经网络的荒漠区蒸散量模拟     

齐建东  买晶晶 《农业工程学报》2020,36(22):151-157

该研究对基于注意力机制的长短期记忆（Attention-Based Long Short Term Memory，AT-LSTM）模型对蒸散量（Evapotranspiration，ET）模拟的可行性和有效性进行验证，以提高环境数据缺失情况下的蒸散量模拟精度。基于盐池县2012-2017年的每30 min环境数据，利用不同环境因子组合构建基于注意力机制的LSTM模型，并将其与极限学习机（Extreme Learning Machine，ELM）模型、支持向量机（Support Vector Machine，SVM）模型、长短期记忆（Long Short Term Memory，LSTM）模型在日尺度、月尺度和季节尺度上进行对比分析。结果表明：与其他3种模型相比，当输入环境因子变化时，AT-LSTM模型模拟精度变化很小，模拟效果均较好。当输入空气温度、净辐射、相对湿度、土壤温度、土壤含水率所有环境因子时，基于AT-LSTM模型的模拟效果最好，均方根误差（Root Mean Square Error，RMSE）为0.013 mm/30 min，平均绝对误差（Mean Absolute Error，MAE）为0.006 mm/30 min，相关系数（Correlation Coefficient，R）值为0.905。且无论是从小时尺度、日尺度和月尺度来看，AT-LSTM模型的模拟效果均优于其他3种模型。在环境因子缺失的情况下，净辐射对盐池县ET的模拟贡献程度最大，仅输入净辐射时，AT-LSTM模型模拟得到的RMSE和MAE分别为0.014、0.007 mm/30 min，R为0.892，模型模拟精度较高，AT-LSTM模型模拟精度高，模型稳定性强，对蒸散量模拟预测具有一定的适用性，仅输入净辐射的AT-LSTM模型可以作为环境数据缺失条件下的蒸散量预测模型。  相似文献   

基于氮平衡的种养结合沼液资源化利用研究     

刘晗晓  关正军  麦翀  高立洪  尹恒 《农机化研究》2021,43(1):1-7

研究沼液经济性消纳对提高沼液资源利用率、维持沼气工程稳定运行、缓解养殖带来的环境压力、提升农业废弃物资源化利用效率和经济效益,推动种养循环一体化发展具有重要意义。为此,结合农业废弃物资源化利用方式,基于盈亏平衡分析和秸秆资源化利用模型,以沼液经济性消纳半径为核心,探究了沼气工程投资金额和处理规模之间的关系,提出了沼液经济性消纳模型。研究结果表明:沼气工程投资金额与处理规模之间关系性较强(R 2=0.9842);沼液经济性消纳半径R bsa选取的主要影响因素是运输费用和沼液中N含量,不同消纳区域农业生产系数的差异性也会对经济性消纳半径的评估产生影响。利用模型对江西新余南英垦殖场规模化沼气发电工程(SBPGP)沼液经济性消纳半径进行估算,在保证氮平衡基础下,其沼液最小消纳范围在31.94 km 2左右。沼液经济性消纳模型的构建,为以沼气工程为纽带的种养一体化循环模式提供了技术参考,从经济性视角为循环农业发展提供了理论依据,从而实现经济效益与环境效益协调发展的目标。  相似文献   

沙枣树胶对红葡萄树提取液抗氧活性保护作用的研究     

伊力哈木·托合迪  买吐孙·买吐肉孜  买买提艾则孜  买买提依明 《中国农学通报》2008,24(6):74-77

该文就沙枣树胶对红葡萄树提取液抗氧性的保护作用及其变化进行了初步研究,结果表明红葡萄树提取液具有极强的抗羟自由基(H0·)能力,而抗超氧阴离子自由基(O-2·)的能力较弱,即在空气中易氧化、抗氧活性迅速降低、消失;当加入沙枣树胶初期,其抗氧性能迅速降低,3d后开始上升,15d后其对超氧阴离子自由基清除率达到30%,60d后对羟自由基清除率达到68%,其后,一直保持稳定.在沙枣树胶的多糖活性成分的作用下,红葡萄树胶的抗氧活性显著增强,稳定性提高.研究结果初步表明,沙枣树胶对红葡萄树提取液的抗氧活性具有显著的保护作用.  相似文献   

主要养殖鲟鱼的生物学及养殖前景   总被引：10，自引：0，他引：10  

卢迈新  黄樟翰  肖学铮  吴锐全 《大连水产学院学报》2000,15(4):280-287

鲟鱼是世界上最古老的鱼类之一,现存鲟鱼种数有２５～２６种。由于多年的酷渔滥捕和生态环境恶化,鲟鱼资源日益衰退。１９９０年世界鲟鱼产量为２万ｙ,１９９３年下降到１万ｔ。本文作者综述了鲟鱼类的起源、地理分布、生态习性和生物学特性,分析和讨论了开展鲟鱼养殖应注意的问题及鲟鱼的养殖前景。  相似文献   

京西山地棕壤和淋溶褐土饱和导水率的分析   总被引：13，自引：0，他引：13  

马履一  翟明普  王勇 《林业科学》1999,35(3):109-112

导水率Ｋ（ｈｙｄｒａｕｌｉｃｃｏｎｄｕｃｔｉｖｉｔｙ）是表示孔隙介质透水性能的综合比例系数,即单位水力势梯度下水的通量密度或渗透流速。Ｋ值是土壤颗粒大小分布、固体物质的化学组成和土壤紧实度的函数。因此,对于不同的土壤或同一土壤的不同层次Ｋ值亦可能有差...  相似文献