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991.
本文利用BIOLOG自动微生物鉴定系统对所分离保存的罗非鱼致病菌株进行生化鉴定,确定为无乳链球菌(Streptococcus agalactiae),进而测定虎杖、五倍子、地榆、黄连、大黄、白头翁、黄芩等14种中草药单用及联用复方对该致病菌株的抑菌效果。结果表明,从14种中草药中筛选出6种中草药(中草药A、中草药B、中草药C、中草药D、中草药E、中草药F)对无乳链球菌有良好的抑制作用;随后考察此6种中草药组合成双联用、三联用及四联用复方的抑菌效果,其中双联用中的2种复方具有显著协同作用,4种复方具有协同作用;三联用中的8种复方具有显著协同作用,3种复方具有协同作用;四连用中的1种复方具有显著协同作用,1种复方具有协同作用。 相似文献
992.
993.
Guozhi Luo Zefeng Liu Jinfang Gao Zhiwei Hou Hongxin Tan 《Aquaculture International》2018,26(3):773-784
A denitrification reactor packed with polycaprolactone (PCL) as a carbon source and biofilm carrier was developed to remove nitrate nitrogen (\( {\mathrm{NO}}_3^{-}-\mathrm{N} \)) from the water of a recirculating aquaculture system for 115 days. The hydraulic retention time was set to 6 h, and the water flow rate was 0.95 L h?1. The removal rates of \( {\mathrm{NO}}_3^{-}-\mathrm{N} \) ranged from 34.67 to 155.7 g \( {\mathrm{NO}}_3^{-}-\mathrm{N} \) m?3 day?1 when the effluent \( {\mathrm{NO}}_3^{-}-\mathrm{N} \) concentrations ranged between 1.62 and 72.25 mg L?1. No obvious changes in the Fourier transform infrared spectra of the PCL before and after use were observed. Bacterial community structure in the biofilm of the PCL granules was analyzed using Illumina MiSeq sequencing technology. Proteobacteria and Bacteroidetes were predominant in the biofilm, with relative abundances of 63.9 and 27.4%, respectively. Three genera, Acidovorax, Azospira, and Diaphorobacter, were capable of both denitrification and PCL degradation. This study indicates that PCL-packed reactors may be used and optimized for removing nitrate from aquaculture effluents. 相似文献
994.
To better understand the endocrine- and immune-response pattern during reproduction in a fish species having parental care behaviors and also to accumulate the endocrine- and immune-related data for future explanations of the low reproductive efficiency in seahorse species, the variations of immune factors and sex steroids in the plasma of the male lined seahorse Hippocampus erectus at different breeding stages, i.e., pre-pregnancy, pregnancy (early, middle, and late periods), and post-pregnancy, were investigated in the present study. The immune factors included monocytes/leucocytes (M/L), leucocyte phagocytic rate (LPR), immunoglobulin M (Ig M), interleukin-2 (IL-2), interferon-α (IFN-α), and lysozyme (LZM). The sex steroids included testosterone (T), 11-ketotestosterone (11-KT), 11β-hydroxytestosterone (11β-OHT), 17α-methyltestosterone (17α-MT), 17β-estradiol (E2), and 17α-hydroxy-20β-dihydroprogesterone (17α-20β-P). Moreover, the immune metabolic activity of epithelium cells in the brood pouch at different breeding stages was also analyzed through ultrastructural observations of the abundance of cytoplasmic granules, mitochondria, endoplasmic reticulum, lysosomes, and exocytosis. The results show that a higher immune level was observed during pregnancy, particularly in the early and middle periods, and a lower immune level was noted during pre-pregnancy. Correspondingly, the epithelium cells in the brood pouch also showed a stronger immune metabolic activity during pregnancy and weaker activity during pre-pregnancy. Four sex steroids of T, 11β-OHT, 17α-MT, and E2 were higher during pre-pregnancy and lower during post-pregnancy, whereas 11-KT and 17α-20β-P, which were positively correlated with part immune factors, were higher during pregnancy. No negative correlations between sex steroids and immune factors were observed. In conclusion, the higher immune competence during pregnancy may indicate that parental care could improve immunity, which may be the major factor for no immunosuppressive effect of sex steroids during reproduction in the seahorse H. erectus, unlike noncaregiving fishes in which inhibitions of sex steroids on immunity are frequently observed. Moreover, higher 11-KT and 17α-20β-P during pregnancy than during pre-pregnancy and post-pregnancy may suggest that these two steroids are also involved in parental care regulation. 相似文献
995.
RAPD技术在鱼类研究中的应用 总被引:3,自引:0,他引:3
RAPD(Random Amplified Polymorphic DNA, 随机引物扩增多态DNA)技术是1990年由Williams和Welsh两个研究小组同时发展起来的一项DNA多态检测技术.RAPD技术与其他分子标记技术相比具有独特的优势,在生物种群遗传结构分析、遗传多样性检测、物种亲缘进化关系鉴定、基因连锁图谱的构建和基因定位与分离等得到了广泛应用,在鱼类研究中也有了一定应用,并取得相应成果,主要表现在以下方面. 相似文献
996.
鳗鲡仔,幼鱼年龄生长的研究 总被引:3,自引:0,他引:3
辽东半岛黄海北部沿岸河口4—6月溯河的白仔鳗,全长53.5—64.5毫米,平均58.83毫米,体长频率高峰位于57.1—59.0 毫米体长组,其体长体重呈直线相关。白仔鳗与幼鳗群体的体长、体重则是指数相关,其方程为W=1.136×10~(-7) L~(3.3871)。12尾白仔鳗耳石平均日轮数为146.3,据此对其产卵期进行了推测,观察证实,在不同生态条件下生活过的幼鳗耳石的环纹有过渡带存在。 相似文献
997.
为了建立鳜传染性脾肾坏死病毒(ISKNV)疫苗抗原含量的ELISA检测方法,制备了3株抗ISKNV主衣壳蛋白(MCP)的单克隆抗体,鉴定了其生物学特性。将大肠杆菌表达的重组MCP纯化复性后,连续3次免疫BALB/c小鼠,然后将免疫小鼠的脾细胞与SP2/0细胞融合,经过克隆、筛选,获得3株能稳定分泌抗ISKNV MCP蛋白的单克隆抗体阳性细胞株,分别命名为5F1、3D9和5B4,均为Ig G1亚型。间接ELISA实验表明,3株单抗可特异性识别ISKNV,与鳜弹状病毒、大鲵虹彩病毒等无交叉反应。将5F1株免疫小鼠后制备腹水,以重组MCP和ISKNV细胞培养物上清液为检测抗原,ELISA检测腹水效价分别为1∶51 200和1∶400。间接免疫荧光(IFA)和Western Blotting鉴定结果显示,5F1能够与ISKNV病毒发生特异性反应,并初步确定5F1单抗株制备的腹水用于IFA的使用浓度为1∶200、Western Blotting的使用浓度为1∶1000。结果证实,成功制备了抗ISKNV MCP的单克隆抗体,可特异性识别ISKNV病毒粒子和MCP蛋白,为建立ISKNV疫苗抗原含量检测方法奠定了基础。 相似文献
998.
Effects of dietary selenium on growth performance and oxidative stress in juvenile grass carp Ctenopharyngodon idellus
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L.W. Liu X.‐F. Liang J. Li J.G. Fang X.C. Yuan J. Li M.S. Alam 《Aquaculture Nutrition》2018,24(4):1296-1303
An 8‐week feeding trial was conducted to investigate the effect of dietary selenium (Se) on feed intake, weight gain and antioxidant activity in juvenile grass carp (11.2 ± 0.03 g). Six Se levels (0.13, 0.41, 0.56, 1.12, 2.18 and 4.31 mg/kg) of semi‐purified diets were assayed in triplicate. The maximum weight gain, specific growth rate and feed intake were obtained in fish fed with 1.12 mg Se/kg diet. Hepatic glutathione peroxidase activity was markedly increased when dietary Se ≤1.12 mg/kg diet and reached a plateau when dietary Se ≥1.12 mg/kg diet. Hepatic superoxide dismutase and serum catalase activities in juvenile grass carp fed with 0.56, 1.12 and 2.18 mg Se/kg diets were all significantly higher than those in the other groups. The malondialdehyde content in liver and serum was firstly decreased and then increased with increasing dietary Se content, and the lowest content was observed in fish fed with 1.12 mg Se/kg diet. With the increase in Se level, the activities of serum alanine aminotransferase and aspartate aminotransferase were reduced. In addition, serum alkaline phosphatase activity and albumin content were highest in fish fed with 1.12 mg Se/kg diet. This study indicated that both the Se deficiency and excess of Se caused negative effect on the oxidative stress in juvenile grass carp and suggested that the health‐giving concentration of dietary inorganic Se was 1.12 mg/kg diet. Moreover, based on the broken‐line regression analysis of weight gain, the optimal concentration of dietary inorganic Se was 0.83 mg/kg for juvenile grass carp. 相似文献
999.
野生牙鲆亲鱼摄食驯化技术 总被引:5,自引:0,他引:5
以活鱼为诱饵对捕获的3批野生牙鲆亲鱼进行摄食驯化培育,解决了野生牙鲆捕后在人工培育条件下拒食的难题,并利用牙鲆摄食的诱导性、使后期捕获的野生鱼在已驯化了的亲鱼带动下主动摄食人工投喂的鲜铒。 相似文献
1000.
从自然感染发病的美洲鲥肝脏、肾脏和肠道中分离出1株细菌,经革兰染色镜检及PCR鉴定,确定为维氏气单胞菌(Aeromonas veronii)。用该菌株接种健康美洲鲥,鉴定其致病力,从人工感染50 g左右的健康美洲鲥发现,菌株具有很强的致病力,试验鱼在感染后72 h内全部死亡,且患病症状与自然发病的鱼症状一致。进一步采用药敏纸片法测定分离菌株对多种抗生素的敏感性,结果发现:维氏气单胞菌对恩诺沙星、氧氟沙星、头孢噻吩三种药物极为敏感,对红霉素、头孢唑啉中度敏感,对青霉素、氨苄西林、阿莫西林、四环素、链霉素不敏感。 相似文献