两种微藻浓缩液保藏效果的比较

本试验研究了不同冷冻保护剂和降温方式处理下,眼点拟微球藻(Nannochloropsis oculata)浓缩液(2×109cells/mL)在4℃和-18℃下保藏3个月,以及钝顶螺旋藻(Spirulina platensis)浓缩液(7%干重)在-18℃下保藏3个月的效果。结果表明,采用-18℃速冻、不添加保护剂,保藏3个月后眼点拟微球藻的相对细胞活性最高,达到新鲜细胞对照的48.17%,显著高于其他处理组(P<0.05);同样条件下,眼点拟微球藻浓缩液的蛋白和EPA损失率分别为3.42%和2.73%,钝顶螺旋藻浓缩液的蛋白和总脂肪酸损失率分别为4.17%和19.33%,综合比较各处理,该方法是这两种微藻浓缩液低温保藏的优选方法。     

三聚氰胺在凡纳滨对虾中的残留消除规律研究

在室温(23~29℃)条件下,凡纳滨对虾用普通饲料驯化7d后再用含有不同剂量的三聚氰胺的饲料连续投喂25d,研究三聚氰胺在凡纳滨对虾血液、肌肉和肝胰腺组织中的残留消除规律。结果表明:凡纳滨对虾投喂含有三聚氰胺的饲料后,三聚氰胺在对虾血液、肌肉和肝胰腺组织中均有残留,当饲料三聚氰胺含量为800mg/kg时,对虾中三聚氰胺残留量最高部位是肝胰腺,其残留量达到6.10mg/kg;停喂含有三聚氰胺的饲料后,三聚氰胺在对虾血液、肌肉和肝胰腺组织中消除时间分别为1、4、6d;三聚氰胺在凡纳滨对虾体内可代谢为三聚氰酸,当饲料中三聚氰胺含量为200~800mg/kg时,三聚氰酸只在肝胰腺组织中检出,在血液和肌肉中均未检出,在肝胰腺组织中消除时间为3d。因此,肝胰腺可作为凡纳滨对虾体内三聚氰胺残留监控的靶器官。     

天然植物复合提取物对凡纳滨对虾生长及抗病力的影响

为研究在饲料中添加天然植物复合提取物对凡纳滨对虾生长、饲料利用、体组成成分以及对虾非特异性免疫指标的影响,设计了5个天然植物复合提取物浓度梯度的等氮等能饲料,饲料中天然植物复合提取物的添加量分别为0、0.05%、0.1%、0.2%和0.3%.实验用对虾初始体重为0.57g,经过8周的投喂实验.结果表明,饲料中添加天然植物复合提取物对凡纳滨对虾的增重率和成活率的影响显著,其中以添加天然植物复合提取物0.2%组的增重率最高,成活率则随着饲料中天然植物复合提取物添加浓度的提高而显著上升.天然植物复合提取物对凡纳滨对虾饲料系数和蛋白质效率的影响显著,其中以添加0.2%组饲料系数最低,蛋白质效率最高.对凡纳滨对虾全虾蛋白质、脂肪、灰分和水分的分析表明,饲料中添加天然植物复合提取物对凡纳滨对虾全虾组成成分的影响不显著.对虾血清溶菌酶活力、酚氧化酶活力以及血浆中红细胞总数受饲料中添加天然植物复合提取物的影响显著,然而血清超氧化物歧化酶活力不受饲料中天然植物复合提取物添加水平的影响.以对虾生长、成活率以及血清中酚氧化酶活力为指标,凡纳滨对虾饲料中天然植物复合提取物的适宜添加量为0.1%～0.2%.     

对虾饲料中木薯粉替代小麦粉对对虾生长性能的影响

研究饲料中以不同水平的木薯粉替代配方中相应的高筋小麦粉对凡纳滨对虾的生长速度、成活率和饵料系数的影响.结果表明:替代水平3％的组,凡纳滨对虾增重率最高(3 401.25％),但与对照组比差异不显著(P＞0.05);随着木薯粉替代水平的提高,增重率呈下降趋势且均显著低于对照组(P＜0.05),替代水平达12％的组,增重率降至最低(3 170.00％).试验组凡纳滨对虾成活率均显著高于对照组(P＜0.05).添加木薯粉可以降低凡纳滨对虾的饵料系数,3％组饵料系数(1.12)显著低于对照组(P＜0.05).     

T-2毒素对凡纳滨对虾的经口急性毒性效应研究

通过T-2毒素微胶囊毒饵料一次性染毒凡纳滨对虾,采用模型拟合法测定T-2毒素对凡纳滨对虾经口LD50,并分析Ca2+-ATPase、多酚氧化酶(PPO)活力以及肌肉病理组织学变化,进而探明T-2毒素对凡纳滨对虾急性毒性效应。结果表明,T-2毒素对凡纳滨对虾的急性毒性经口一次性暴露的LD50为1.22 mg/(kg·bw),T-2毒素对PPO酶活性和Ca2+-ATPase活性的急性毒性效应ED50分别为0.05和3.22 mg/(kg·bw),比较风险评估指数RI可知,PPO活性可作为生物学效应标记描述T-2毒素对对虾的急性毒性效应,且比Ca2+-ATPase更加灵敏。T-2毒素急性暴露可导致肌纤维间隙面积比增大,可导致对虾肌肉品质劣化。采用LC-MS/MS定量检测染毒对虾肌肉中的T-2毒素,但是没有发现游离态T-2毒素残留,说明对虾中T-2毒素急性暴露不会引起物质蓄积,但却产生功能蓄积,可能是T-2毒素以隐蔽态形式存在,导致初始轻微损伤逐渐累加的结果。     

酶解小麦对凡纳滨对虾生长性能的影响

研究了体外酶解凡纳滨对虾饲料原料中小麦粉的适宜酶解用量及酶解后对凡纳滨对虾生长性能的影响.结果表明:小麦经酶解处理后,试验组的成活率比对照组有所提高,饵料系数降低,平均增重率、特定生长率和总表观消化率均提高显著,且β-葡聚糖酶、纤维素酶和木聚糖酶3种酶复合的使用效果要优于用单一酶的使用效果.     

山梨醇对凡纳滨对虾无水运输中呼吸和能量代谢的影响

将驯化后体质量(12.86±0.80)g的凡纳滨对虾(Litopenaeus vannamei)随机分为两组,分别在13℃的3.5%山梨醇溶液或清水(对照)中浸泡3 min,至全部对虾侧卧水底呈休眠状态后,取30只一组装入聚氯乙烯(polyvinyl chloride,PVC)袋(220 mm×320 mm),充纯氧后密封,置于15℃的恒温箱中无水运输。10小时后将全部对虾转移至的清水(20℃～25℃)中复苏。测定休眠5、10 h和复苏1 h状态下凡纳滨对虾血清血蓝蛋白、乳酸、葡萄糖浓度、乳酸脱氢酶(lactate dehydrogenase,LDH)、肝胰腺琥珀酸脱氢酶(succinate dehydrogenase,SDH)活力和肝糖原含量的变化,以探究山梨醇对凡纳滨对虾无水运输存活率的影响及其作用机理。结果发现,模拟无水运输10小时后,山梨醇组对虾存活率为88.89%,显著高于对照组(71.11%)(P 0.05);休眠状态下,山梨醇组血蓝蛋白、乳酸、血糖浓度和SDH、LDH活力显著高于对照组(P 0.05),肝糖原浓度显著低于对照组(P 0.05);复苏1小时后,两组对虾的乳酸、血糖浓度及对照组SDH活力仍与新鲜状态差异显著(P 0.05),其他参数恢复正常水平。结果表明,3.5%山梨醇可提高对虾有氧和无氧呼吸强度及存活率,缓解低、缺氧和能量不足的胁迫。     

超微浒苔对凡纳滨对虾消化酶活力的影响

目的研究超微浒苔的不同添加量对凡纳滨对虾消化酶活力的影响。方法取凡纳滨对虾幼虾450尾,采用简单随机抽样的方法分成18个组放入18个相同规格的养殖水箱中。对照组不添加浒苔,Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ组浒苔添加量分别为1%、2%、3%、4%、5%,各组饲粮营养水平除代谢能有微小差异外均完全一致。试验期42 d,于42日龄进行凡纳滨对虾胃肠道消化酶活性的测定。结果 2%、3%、4%的浒苔添加量可显著提高凡纳滨对虾的胃蛋白酶、胃脂肪酶、胰肠蛋白酶和胰肠脂肪酶的活性。各浒苔添加水平对胃、肠淀粉酶的活性影响均不显著。结论本试验条件下,以凡纳滨对虾饲料中超微浒苔添加量为3%最好。     

大豆肽产品替代鱼粉对凡纳滨对虾生长性能、消化酶活力及肠道组织结构的影响

本实验研究大豆肽替代凡纳滨对虾饲料中的鱼粉对其生长性能、消化酶活力及肠道组织结构的影响。配制大豆肽替代鱼粉量分别为0%(FM),10% (FSM10),20% (FSM20),30% (FSM30),40% (FSM40),100% (FSM100)的6种等氮等能饲料。挑选健康凡纳滨对虾(初重为1.53±0.36 g)在网箱中养殖50d,实验共6组,每组3个重复。结果表明：(1)大豆肽替代鱼粉量小于20%时,凡纳滨对虾的增重率、特定生长率和饲料系数与对照组均无显著差异(P>0.05),但替代量超过20%时成活率显著低于对照组(P＜0.05)。(2)大豆肽显著降低凡纳滨对虾肝胰腺中淀粉酶活力,FM组显著高于其他各实验组(P＜0.05),但各组间胰蛋白酶和脂肪酶活力差异并不显著(P＞0.05);(3)大豆肽对凡纳滨对虾肠组织中淀粉酶活力影响不显著(P＞0.05),但胰蛋白酶和脂肪酶活力随大豆肽替代量的增加呈先上升后下降的趋势。(4)大豆肽对凡纳滨对虾肠组织结构影响显著,肠绒毛高度、宽度随着鱼粉替代量的增加呈现出先上升后下降的趋势,且FSM100组会损伤肠组织绒毛,导致绒毛长度最低(P＜0.05)。综上所述,本实验条件下大豆肽替代20%以内的鱼粉对凡纳滨对虾生长性能、消化酶活力和肠组织圴无不良影响,但替代100%鱼粉会损伤小肠组织。     

不同微藻对缢蛏稚贝肉质风味的影响

通过固相微萃取-气相色谱-质谱联用技术,对投喂了6种养殖常用饵料微藻的缢蛏稚贝进行肉质风味的检测分析,研究不同的微藻饵料对缢蛏稚贝肉质风味的影响。研究发现:不同饵料微藻投喂组的缢蛏稚贝中检测到挥发性化合物在种类和数量上存在差异。共检测到71种化合物,其中醛、酮、烃种类最多(共43种),占总化合物种类的60.56%,其中,醛类占总化合物种类的22.54%、酮类占21.12%、烃类占16.90%;此外,还有一些醇类、醚酯类等化合物,但其种类和相对含量均不高。3-甲基-正丁醛以相对含量61.37%~77.28%存在于假微型海链藻、威氏海链藻和角毛藻这3种硅藻饵料投喂组中,认为3-甲基-正丁醛是影响硅藻投喂缢蛏稚贝风味的主要物质;此外,二甲基硫含有特殊气味,在球等鞭金藻和青岛大扁藻的投喂组中相对含量最高,分别为29.39%和51.53%。     

Studies of bioavailability of different food sources of selenium in experiment

The selenium bioavailability in selenium enriched Spirulina (Arthrospira platensis), phycocyanin containing (Se-PC) protein isolate, separated from this micro algae and in sodium selenite was studied and compared in rats. The daily dose of selenium per one animal was 5 microgram in all experimental groups. The average selenium levels in blood serum and liver of animals that received sodium selenite during 14 days were the highest. The average selenium level in blood serum of animals fed with selenium enriched Spirulina platensis after 14 days of receiving was the same with the control group, but the average concentration of selenium in their liver was rather high and close to this parameter of sodium selenite animal group. The animals which were fed with Se-PC showed better results. Their average selenium level in blood serum was higher than in Spirulina group, but lower than in sodium selenite group. The average concentration of selenium in the liver of these animals was the same with sodium selenite animal group. As regards to animals that were fed with selenium enriched Spirulina, Se-PC and sodium selenite for 21 days, the average selenium levels ratio in their blood serum and liver was higher than in control group, but these results were not significantly different among each other. The concentrations of selenium in seminal glands in all groups of animals including control group both after 14 and 21 days feeding were close to each other.     

无水运输温度和时间对南美白对虾肌肉品质及生理应激的影响

为探讨南美白对虾无水保活运输的适宜温度和时间,本文研究了对虾低温休眠温度,测定了4、10 ℃条件下模拟运输不同时间段的存活率,分析了对照组、休眠组、运输组和运输后复水唤醒30 ?min?,4种状态下对虾肌肉品质以及生理应激指标。结果表明,南美白对虾的休眠温度为（10.0±0.2）℃;模拟运输12 h内,两温度组存活率均为100%,36?h后两组存活率均低于30%。不同运输温度对肉质指标影响不显著（P>0.05）;除蒸煮损失率,相同温度下运输应激对水分、粗蛋白、粗脂肪含量影响均不显著（P>0.05）。生理应激指标中,两种温度下模拟运输24 h后,肌糖原、琥珀酸脱氢酶（succinate dehydrogenase,SDH）、乳酸脱氢酶（lactate?dehydrogenase,LDH）和丙二醛（malondialdehyde,MDA）含量与对照组相比均发生显著变化（P<0.05）,且复水后也均不能恢复到对照组水平。南美白对虾可以通过低温诱导休眠的方式进行无水保活运输,10 ℃适于18 ?h内短途运输,长途运输则可选用4 ℃。     

Biomass Nutrient Profiles of Three Microalgae: Spirulina platensis, Chlorella vulgaris, and Isochrisis galbana

ABSTRACT: Nutritional composition was determined for Spirulina platensis, Chlorella vulgaris , and Isochrisis galbana cultures. Data include the proximate composition, energy value, mineral elements, and fatty acid composition. Sixteen strains of these microalgae were obtained as a percentage of total fat. Total PUFA, SFA contents, n -3/ n -6 ratios, and eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) ratios were obtained. Protein content was high in Spirulina samples, whereas Isochrisis had the highest ash content. Spirulina is a rich source of γ-linolenic acid (GLA); Chlorella was an important source of PUFAs. Spirulina is a rich source of K, Chlorella is rich in P, and Isochrisis is a good source of Ca and Mg. Se content of Isochrisis is higher than in the other microalgae.     

Design and implementation of a continuous microwave heating system for ballast water treatment

A continuous microwave system to treat ballast water inoculated with different invasive species was designed and installed atthe Louisiana State University Agricultural Center. The effectiveness of the system to deliver the required heating loads to inactivate the organisms present was studied. The targeted organisms were microalgae (Nannochloropsis oculata), zooplankton at two different growth stages (newly hatched brine shrimp-Artemia nauplii and adult Artemia), and oyster larvae (Crassosstrea virginica). The system was tested at two different flow rates (1 and 2 liters per min) and power levels (2.5 and 4.5 kW). Temperature profiles indicate that, depending on the species present and the growth stage, the maximum temperature increase will vary from 11.8 to 64.9 degrees C. The continuous microwave heating system delivered uniform and near-instantaneous heating at the outlet proving its effectiveness. The power absorbed and power efficiency varied for the species present. More than 80% power utilization efficiency was obtained at all flow rate and microwave power combinations for microalgae, Artemia nauplii and adults. Test results indicated that microwave treatment can be an effective tool for ballast water treatment, and current high treatment costs notwithstanding, this technique can be added as supplemental technology to the palette of existing treatment methods.     

水产养殖增氧消毒剂在对虾育苗中的应用

将研究的水产养殖增氧消毒剂在对虾育苗生产中进行了应用研究和生产性试验,结果表明,增氧消毒剂能促使对虾蜕皮,用药８小时后蜕皮率达５８％,增加幼虫活力;吸附沉淀有机悬浮物、氨氮及硫化氢等,从而改善育苗池池底状况。镜检发现,虾幼体可直接摄食该增氧消毒剂,使之成为幼虫营养性和肠道消炎等药物的载体     

碳酸氢铵为氮源对螺旋藻培养的影响

以碳酸氢铵作为氮源,研究在分批培养及流加培养条件下其对螺旋藻生长的影响。结果表明：当培养液中碳酸氢铵浓度小于5mmol/L时,螺旋藻生长正常;碳酸氢铵浓度超过5mmol/L时,螺旋藻生长受到抑制,解体死亡。采用生物量反馈补料的流加策略可以使培养液中螺旋藻生物量达到3.08g/L,产率达到0.26g/(L ·d),藻体中蛋白质及叶绿素含量分别达到65.06%和13.37mg/g,结果证实了碳酸氢铵为氮源高密度培养螺旋藻的可行性。     

三种饵料微藻半连续培养条件的研究

文章从起始密度和更新率两个方面对三种经济饵料微藻:小球藻、牟氏角毛藻和小新月菱形藻进行半连续培养条件的研究。实验表明,三种饵料微藻均可实现半连续培养;小球藻的最佳半连续培养条件是细胞起始密度4.2×107个/mL,日更新率为30%;牟氏角毛藻的最佳半连续培养条件是起始密度3.8×106个/mL,日更新率为40%;小新月菱形藻的最佳半连续培养条件是起始密度7.8×106个/mL,日更新率为40%。     

盐藻多糖对熟制南美白对虾冻藏期间品质变化的影响

研究了0.06%盐藻多糖处理对冻藏南美白对虾品质的影响。以菌落总数、TVB-N值、TBA值、色差(L~*、a~*和b~*)、质构(硬度和弹性)和水分含量作为评价指标,分析盐藻多糖处理对冻藏对虾新鲜度和品质的影响。结果表明,熟制南美白对虾冻藏期间新鲜度没有超标,但虾体水分含量降低幅度较大,硬度迅速增加,弹性降低,L~*、a~*和b~*值降低,对虾整体品质随着贮藏时间的增加而下降。盐藻多糖处理提高了对虾的新鲜度,且保持了虾体水分,改善了对虾的硬度和弹性,抑制了对虾褪色,起到了一定的保水和护色作用。     

The hepatoprotective potential of Spirulina and vitamin C supplemention in cisplatin toxicity

Spirulina platensis is a microalgae with potent dietary phyto-antioxidant, anti-inflammatory and anti-carcinogenic properties. We investigated the mechanism of cisplatin induced hepatotoxicity and whether this natural antioxidant provided protection against cisplatin hepatotoxicity. The study was carried out in a mice model where the animals were segregated into different groups according to their treatments, e.g. control group with no treatment, cisplatin treated, cisplatin + Spirulina treated, cisplatin + vitamin C treated and cisplatin + Spirulina + vitamin C treated. The liver marker enzymes were found to be elevated following cisplatin treatment, signifying hepatotoxicity. The supplementation of Spirulina and vitamin C could effectively bring down the levels of these enzymes. Light microscopy also showed that cisplatin treatment induced liver injury and that histopathological abnormalities were prevented by Spirulina and vitamin C supplementation. This protective effect was further substantiated by the estimation of antioxidant levels and extent of lipid peroxidation in the Spirulina, vitamin C and Spirulina + vitamin C supplemented groups as compared to cisplatin alone.     

螺旋藻富碘培养效果及现状

螺旋藻生长速度快,培养方便,具有较强的富集金属离子的能力,可将无机碘转化为人体易吸收的有机碘,从而获得富含有机碘的螺旋藻,提高螺旋藻的品质和开发高附加值产品.该文从螺旋藻的富碘机理入手,简要介绍了螺旋藻的富碘效果及研究现状.