饲料中灵芝提取物对异育银鲫生长、饲料利用、免疫应答及抗病的影响

通过生长实验探求饲料中添加灵芝提取物饲料对异育银鲫（6.720.11） g生长、饲料利用及免疫应答的影响,以及停止灵芝提取物饲料后,使用效果的持续性。在实验进行的第21天（D21）、第46天（D46）、第65天（D65）进行取样,结果表明所有的灵芝提取物组的特定生长率在饲喂65d后与对照组无显著差异（P0.05）。摄食率随着灵芝提取物在饲料中含量的增加而增加（P0.05）,饲料效率则有着相反的趋势（P0.05）。在D46和D65时,随着灵芝提取物的含量增高,吞噬活力略有增高,但无显著差异（P0.05）。在D21、D46和D65时,呼吸暴发活力随着灵芝提取物的含量增高而增高（P0.05）,在D21时,（0.6%-21d、0%-44d）处理组和（3%-21d、0%-44d）处理组其呼吸暴发活力高于对照组（P0.05）。在D65时,（0.6%-21d、0%-44d）处理组和（3%-21d、0%-44d）处理组其呼吸暴发活力仍高于对照组（P0.05）,但差异不显著。D21、D46和D65时,替代途径补体溶血活力随着灵芝提取物的增高而降低（P0.05）。所有处理组溶菌酶活力在D21时没有产生显著差异。在D46时,对照组溶菌酶活力比最高添加组低但高于低添加组（P0.05）,（3%-1d、0%-44d）处理组也仍高于对照组（P0.05）。在D65时,所有添加组的溶菌酶活力均低于对照组（P0.05）。在D65时,髓过氧化物酶活力随着灵芝提取物的添加剂量升高而升高（P0.05）,（0.6%-21d、0%-44d）处理组仍高于对照组（P0.05）。灵芝提取物的能提高白细胞呼吸暴发活力,且在在高剂量摄入21d后（D46时）,仍可以保持较高的活力,说明灵芝提取物对免疫应答有一定时间延续效应。随着灵芝提取物添加量的升高,异育银鲫在经爱德华氏菌攻毒后的存活率显著提高。最高存活率组为3%添加组,显著高于对照组（P0.05）。实验周期为65d时,饲料中灵芝提取物推荐添加剂量为3%。       

一株维氏气单胞菌发酵培养基优化及其制备疫苗免疫效力比较

采用单因素试验、响应面试验法对维氏气单胞菌(Aeromonas veronii)发酵培养基的氮源、碳源、无机盐和磷酸盐成分及用量进行优化组合,确定优化培养基组成：胰蛋白胨10.8 g/L,葡萄糖5.0 g/L,牛肉膏3.0 g/L,磷酸二氢钾2.0 g/L,硫酸镁0.4 g/L,NaCl 5.0 g/L。并与基础培养基的发酵活菌数、制备的灭活疫苗免疫效力进行比较,经过验证试验绘制维氏气单胞菌在优化培养基条件下的7 L发酵罐生长曲线。在优化发酵培养基条件下,维氏气单胞菌活菌数为5.94×10⁹ cfu/mL,比基础培养基增幅43.13%;制备的灭活疫苗相对保护率为77.78%,比基础培养基提高了14.81%。7 L发酵罐发酵培养10 h,活菌数达到最大8.85×10⁹ cfu/mL。通过对发酵培养基的优化,可以获得低成本、优质高效的维氏气单胞菌发酵菌液,为今后维氏气单胞菌灭活疫苗规模化发酵培养提供参考。     

三种淡水鱼类在中国南北两个地区的肠道菌群差异比较

山东省德州市禹城市和湖南省长沙市望城区分别属于我国北方和南方地区,环境和气候差异明显。本试验以禹城市和望城区两地的草鱼(Ctenopharyngodon idella)、鲫鱼(Carassius auratus)和鲤鱼(Cyprinus carpio)为研究对象,对肠道中的菌群进行16s rRNA V4高变区扩增,基于IonS5 TM XL测序平台进行测序,并对相关数据进行分析。结果表明,在门水平上鲫鱼、鲤鱼、草鱼的肠道优势菌主要为变形菌门(Proteobacteria)、梭杆菌门(Fusobacteria)、硬壁菌门(Firmicutes),拟杆菌门(Bacteroidetes),各组中这四种菌门所占比之和均在80%以上;基于Bray-Curtis距离值的秩次进行组间差异显著性检验,山东草鱼组和湖南草鱼组比较中组间差异大于组内差异(R=0.307,P<0.05),且线性判别分析显示湖南草鱼组的特征性菌群为弧菌属,而山东草鱼组的为梭菌纲,推测特征性菌群差异与环境的影响有关;有害菌种的统计分析表明,湖南鲫鱼组和鲤鱼组的嗜水气单胞菌属相对丰度明显高于对应的山东鲫鱼组和鲤鱼组,山东草鱼组和鲤鱼组的弧菌属相对丰度高于对应的湖南草鱼组和鲤鱼组,可能受外界环境的影响,不同地区抵御外来有害细菌的能力也不一样。本研究对两地的淡水鱼类肠道微生物群落结构进行了比较和分析,为进一步的鱼类发育研究奠定基础。     

Fish hypnosis: Induction of an atonic immobility reflex

An immobility reflex may be induced in fish by a vigorous flow of water through the branchial chamber. The reflex was observed in 22 species representing bony and cartilaginous fishes from diverse habitats, and was invariably characterised by loss of caudal muscle tone and limp posture. The immobilised state may be maintained for many hours, and revival is instantaneous. The critical flow rate for induction increases with increasing body size in the snapper, Pagrus auratus, and heart rate falls below the resting rate. In addition, haematological parameters, and plasma lactate after 6?h were typical of resting fish. Although the mechanism is unclear, and the selective advantage for the fish unknown, pressure-sensitive receptors in the branchial chamber are likely to be involved. Application in live fish transport, and recovery from handling and exercise stressors is suggested.     

Fabrication of Nano-engineered Transparent Conducting Oxides by Pulsed Laser Deposition

Nanosecond Pulsed Laser Deposition (PLD) in the presence of a background gas allows the deposition of metal oxides with tunable morphology, structure, density and stoichiometry by a proper control of the plasma plume expansion dynamics. Such versatility can be exploited to produce nanostructured films from compact and dense to nanoporous characterized by a hierarchical assembly of nano-sized clusters. In particular we describe the detailed methodology to fabricate two types of Al-doped ZnO (AZO) films as transparent electrodes in photovoltaic devices: 1) at low O₂ pressure, compact films with electrical conductivity and optical transparency close to the state of the art transparent conducting oxides (TCO) can be deposited at room temperature, to be compatible with thermally sensitive materials such as polymers used in organic photovoltaics (OPVs); 2) highly light scattering hierarchical structures resembling a forest of nano-trees are produced at higher pressures. Such structures show high Haze factor (>80%) and may be exploited to enhance the light trapping capability. The method here described for AZO films can be applied to other metal oxides relevant for technological applications such as TiO₂, Al₂O₃, WO₃ and Ag₄O₄.     

Twice Daily Melatonin Peaks in Siberian but not Syrian Hamsters under 24 h Light:Dark:Light:Dark Cycles

The daily pattern of blood-borne melatonin varies seasonally under the control of a multi-oscillator circadian pacemaker. Here we examine patterns of melatonin secretion and locomotor activity in Siberian and Syrian hamsters entrained to bimodal LDLD8:4:8:4 and LD20:4 lighting schedules that facilitate novel temporal arrangements of component circadian oscillators. Under LDLD, both species robustly bifurcated wheel-running activity in distinct day scotophase (DS) and night scotophase (NS) bouts. Siberian hamsters displayed significant melatonin increases during each scotophase in LDLD, and in the single daily scotophase of LD20:4. The bimodal melatonin secretion pattern persisted in acutely extended 16 h scotophases. Syrian hamsters, in contrast, showed no significant increases in plasma melatonin during either scotophase of LDLD8:4:8:4 or in LD20:4. In this species, detectable levels were observed only when the DS of LDLD was acutely extended to yield 16 h of darkness. Established species differences in the phase lag of nocturnal melatonin secretion relative to activity onset may underlie the above contrast: In non-bifurcated entrainment to 24 h LD cycles, Siberian hamsters show increased melatonin secretion within ～2 h after activity onset, whereas in Syrian hamsters, detectable melatonin secretion phase lags activity onset and the L/D transition by at least 4?h. The present results provide new evidence indicating multi-oscillator regulation of the waveform of melatonin secretion, specifically, the circadian control of the onset, offset and duration of nocturnal secretion.     

异育银鲫GABAB受体1亚基 cDNA部分序列的克隆及组织表达分析

为了确定γ-氨基丁酸B受体（gamma-aminobutyric acid B receptor,GABABR）基因在异育银鲫（Carassius auratus gibelio）不同组织中的表达,本实验分别对异育银鲫不同组织中GABABR1基因进行RT-PCR扩增,并进行了克隆和测序,在与GenBank基因库中已知GABABR1序列进行同源性比对的基础上采用邻接法构建系统发育树,并进一步分析其在异育银鲫不同组织内的表达水平。结果：经克隆获得异育银鲫GABABR1基因CDS区序列383bp,编码127个氨基酸。荧光定量PCR结果显示GABABR1基因在异育银鲫脑、肝、肾、心、肠、鳔、鳃、肌、鳍、脾、卵巢、精巢组织中均有表达,且在不同组织中的表达水平由高到低依次是：脑>尾鳍>精巢>心、肠、鳔> 卵巢、脾、鳃、肌>肝、肾。本研究证实了GABABR1基因在异育银鲫各组织中的表达的广泛性,且有明显的组织特异性。     

Circadian Phase Dependent Thermal Stimulation of Ovarian Recrudescence in Indian Catfish,Clarias batrachus

Female Clarias batrachus acclimated to long photoperiod (13L:11D), were subjected to 30º ± 1ºC thermopulses of either 6-hour or 12-hour duration at different phases of the LD cycle during the late resting phase (first week of January) of their annual reproductive cycle. Six-hour pulses were given either at 0600 or 1200 or 1800 or 0000. Twelve-hour thermopulses were given at 0600 or 1800. The long photoperiods were started at 0530 and that of ambient at 0630 coinciding with the average timing of sunrise that prevailed during the period of the study. The results indicate that exposure to long photoperiod or constant high temperature induced gonadal growth (GSI) and elevated testosterone and oestradiol levels in plasma. The high temperature was significantly more effective in its action. Further, combination of long photoperiod and high temperature produced the strongest gonadal stimulation as gauged from GSI and the levels of steroid hormones. Interestingly, 30ºC thermopulses of 12-h duration when given at 0600 to fish held under long photoperiod induced gonadal development of comparable magnitude as observed in response to constant high temperature under long photoperiod. Thermopulses (30ºC) of 6-h duration given at 0600 or 1200 also induced significant gonadal recrudescence but of much lesser magnitude. Thermopulses either of 6-h or 12-h duration at 1800 failed to elicit any change in the variables under study. The results of cosinor analysis performed on the responses to 6-h thermopulses also substantiate that there is a rhythm in the sensitivity of C. batrachus to thermopulses. Thus it appears that in this species temperature-induced gonadal recrudescence would occur only following coincidence of high temperature with the thermoinducible phase. The underlying mechanism of this phenomenon might be circadian in nature.     

饲料脂肪水平对长养殖周期异育银鲫“中科3号”生长和脂代谢的影响

实验以初重为(11.33±0.03) g的异育银鲫(Carassius auratus gibelio)为研究对象,分别投喂脂肪水平为4%(L4)、8%(L8)、12% (L12)、16% (L16)和20% (L20)的5种等氮饲料进行为期340d的长养殖周期实验,以探究饲料脂肪水平对长养殖周期异育银鲫生长性能、消化酶活性和脂代谢的影响。期间共取样5次,生长阶段分为63d(D63,幼鱼期)、110d(D110,养成前期)、223d(D223,越冬期)、275d(D275,越冬后)和340d(D340,养成中后期)。实验结果显示,以增重率为评价指标,幼鱼期D63的异育银鲫适宜脂肪水平为8%,养成前期D110的异育银鲫适宜脂肪水平为12%,而其他生长阶段饲料脂水平对增重率无显著影响。饲料脂肪水平对幼鱼期异育银鲫肠道消化酶活性有显著影响,脂肪酶活性随脂肪水平的升高呈现先降低后升高的趋势,幼鱼期(D63)异育银鲫肠道胰蛋白酶和淀粉酶活性高于越冬期和养成中后期的异育银鲫,表明幼鱼期的异育银鲫对脂肪的利用较低。幼鱼期(D63)异育银鲫脂肪合成相关基因pparγ和fas的表达量饲料脂肪水平升高呈先升高后下降的趋势,且在L8组表达量最高,而脂解基因lpl和cpt1a的表达量在低脂组L4显著低于其他各组。pparγ和cpt1a在越冬后期(D275)的表达量随饲料脂肪水平的升高呈现先上升后下降,而fas表达量在L4组显著高于其他组,表明不同生长阶段异育银鲫对饲料脂肪摄入的响应策略不一致,摄入过高或过低均会导致代谢紊乱。适宜的脂水平(8%—12%)可促进幼鱼期和养成前期异育银鲫的生长,增强脂肪利用率和脂代谢能力,而较大规格的异育银鲫对脂肪的变化不敏感。     

鲫幼鱼耳石荧光标记效果

为确认茜素络合物对鲫（Carassius auratus）耳石进行有效标记的可行性,以便为鲫甚至其他鲤科鱼类标志放流技术的开发及效果评估提供一定的借鉴,本研究以孵出后90 d的鲫幼鱼为研究对象,设置单一浓度（100 mg/L）的茜素络合物浸泡标记5 d,分析茜素络合物在耳石上的沉积情况以及不同耳石在不同后续饲养天数的动态变化。结果表明,矢耳石、微耳石和星耳石上在可见光、绿色和蓝色激发光下都检测到了良好的茜素络合物标记环,标记率和存活率均为100%。但不同耳石的茜素络合物标记效果不同,荧光下,星耳石的标记效果最显著,微耳石次之;可见光下,微耳石的标记效果最好,星耳石次之。随着后续饲养天数的延长,可见光下标记逐渐减弱,至20 d时基本消失,而在绿色和蓝色激光下标记环荧光强度无减弱迹象,能长久保持,且在蓝色激发光下标记环更易被观测到。上述结果结合鲫生长、存活和行为正常等情况综合显示,在100 mg/L茜素络合物溶液中浸泡标记鲫幼鱼5 d,其耳石可以获得满意的标记效果。