饲料添加剂硒和谷胱甘肽对微囊藻毒素胁迫下罗非鱼肝脏去毒相关基因诱导表达的影响

为从分子水平探讨饲料添加剂硒(Se)和谷胱甘肽(GSH)对淡水养殖鱼类肝脏微囊藻毒素胁迫下去毒分子机理的影响,实验杂交罗非鱼一组喂食含0.15 mg/kg Se的富硒酵母粉饲料,一组喂食含普通酵母粉的饲料,喂食一个月以上;实验尼罗罗非鱼一组喂食含1 g/kg GSH的饲料,一组喂食普通饲料,两组均饱食10 d.所有实验组再均分两组,一组腹腔注射磷酸缓冲液(PBS),一组按体质量注射腹腔注射50μg/kg微囊藻毒素-LR(MC-LR),24 h后分离肝脏组织.以β-肌动蛋白作为外参照,采用半定量RT-PCR方法研究Se和GSH分别对罗非鱼肝脏去毒相关基因转录水平的诱导改变.结果表明,未喂食Se的实验组,杂交罗非鱼肝脏alpho-可溶性谷胱甘肽S-转移酶(sGSTA)和谷胱甘肽过氧化物酶(GPX)基因mRNA表达水平在腹腔注射50μg/kg MC-LR 24 h后,均较PBS组有诱导趋势;Se+MC-LR组sGSTA和GPX基因mRNA表达水平,均较Se+PBS组略低,可能与添加剂的低剂量添加相关.喂食GSH的实验组,尼罗罗非鱼腹腔注射MC-LR组,肝脏sGSTA基因mRNA表达水平较PBS组有诱导趋势;Se+MC-LR组GPX基因mRNA表达水平,较Se+PBS组有升高趋势,而sGSTA和rho-可溶性谷胱甘肽S-转移酶(sGSTR)基因mRNA表达水平则轻微降低.本实验首次从基因表达水平比较研究了Se和GSH对罗非鱼微囊藻毒素压力情况下,肝脏去毒酶基因表达的影响变化,为Se和GSH饲料添加剂在鱼类饲料中的合理添加提供分子水平的理论依据.     

Influence of dietary conjugated linoleic acid on growth, fatty acid composition and hepatic lipogenesis in large yellow croaker (Pseudosciaena crocea R.)

We examined the effects of conjugated linoleic acid (CLA) on growth, fatty acid composition and enzyme activity of fatty acid oxidation in the liver of large yellow croaker. We divided 1600 fish (average initial weight 150 g) into 4 groups and reared them in 8 cages. Four dietary treatments were formulated to contain 0%, 1%, 2% and 4% (w/w) CLA, respectively. The fish were fed for 10 weeks ad libitum twice daily. We found that the dietary CLA had no effect on growth, biometric parameters and whole body proximate (P>0.05), but showed some significant effects on the fatty acid composition in both muscle and the liver. The activities of lipogenic enzymes were slightly depressed in fish fed with increasing levels of CLA when compared with control (P>0.05). Dietary CLA supplementation had no effects on liver lipid content, but significantly increased the contents of saturated fatty acids (SFA) and polyunsaturated fatty acids (PUFA) (P<0.05) and decreased monounsaturated fatty acid (MUFA) content in both muscle and the liver. Dietary CLA inclusion resulted in significant increases of the biologically active cis-9, trans-11 and trans-10, cis-12 isomers in both tissues (P<0.05). The total accumulation of CLA was higher in the liver (3.83%, w/w) than in muscle (3.77%, w/w) when fed with 4% (w/w) CLA. This study demonstrates that large yellow croakers are capable of absorbing and depositing CLA and long-chain n-3 PUFA in the liver and muscle, showing that this species fed with CLA could be an important human food source for these healthful fatty acids.     

黑鲷NKCC1分子特征及其对急性盐度胁迫的表达响应

为了解黑鲷(Acanthopagrus schlegelii)在盐度胁迫过程中的适应机制,本研究利用基因扩增、聚类分析、荧光定量PCR等技术对NKCC1基因进行生物信息学分析以及在不同组织中的表达特征研究,并探讨其在急性盐度胁迫下的表达机制.结果表明NKCC1基因的开放阅读框(Open Reading Frame,OR...     

Paleodietary changes by penguins and seals in association with Antarctic climate and sea ice extent

Positioned near the top of the food web, the dietary composition of Antarctic penguins and seals can be an excellent indicator of the regional food web and thus the status of the marine ecosystem. The dietary composition of modern penguins and seals has been well investigated; a long-term time series of data on penguin and seal diets, however, are rare. Such data, especially any predating the initiation of human harvesting of fish, whales and seals in Antarctica, are crucial for understanding and predicting responses of regional marine food webs to natural climate changes. Here we review recent progress on research of paleodietary change in Antarctic penguins and seals, specifically the Adelie penguin （Pygoscelis adeliae） and Antarctic fur seal （Arctocephalus gazella）. These studies indicate that the dietary changes of penguins correspond quite well with fluctuations in climate and sea ice extent during the Holocene. The depleted δ15N ratios found in modern Adelie penguins support the ＂krill surplus hypothesis＂ in relation to historic human depletion of krilleating fish, seals and whales.     

Mortality of sea lions along the central California coast linked to a toxic diatom bloom

Over 400 California sea lions (Zalophus californianus) died and many others displayed signs of neurological dysfunction along the central California coast during May and June 1998. A bloom of Pseudo-nitzschia australis (diatom) was observed in the Monterey Bay region during the same period. This bloom was associated with production of domoic acid (DA), a neurotoxin that was also detected in planktivorous fish, including the northern anchovy (Engraulis mordax), and in sea lion body fluids. These and other concurrent observations demonstrate the trophic transfer of DA resulting in marine mammal mortality. In contrast to fish, blue mussels (Mytilus edulus) collected during the DA outbreak contained no DA or only trace amounts. Such findings reveal that monitoring of mussel toxicity alone does not necessarily provide adequate warning of DA entering the food web at levels sufficient to harm marine wildlife and perhaps humans.     

Effects of Eriobotrya japonica (Lindl.) flower extracts on mercuric chloride-induced hepatotoxicity in rats

Mercury(II) is an important factor in hepatotoxicity that can enter the body through marine diets and amalgams.In the present study,the protective effect of the Eriobotrya japonica flower extract(EJFE) on HgCl 2-induced hepatotoxicity was investigated.Five mg/kg of mercuric chloride in drinking water was given to rats either with saline or EJFE(100 and 200 mg/kg as intraperitoneal(IP)) for 30 d.The mercury levels in different groups of liver tissues of the rats were measured with flameless atomic absorption spectroscopy(F-AAS).Also,mercury accumulation in the liver of the rats was modeled by using a parallel chemical kinetic model.The results showed that HgCl 2-induced oxidative damage led to a significant decrease in glutathione(GSH) and the total antioxidant capacity(TAC) levels,and to a significant increase in lipid peroxidation level.Accumulated mercury was 14.47% more in the livers of the stress groups than in those of the control groups(P<0.001),whereas the amount of Hg was adjusted to 13.49% and 13.93% in groups treated with 100 and 200 mg/kg of EJFE respectively,as compared with stress groups(P<0.001).HPLC analysis of EJFE revealed that hesperetin and gallic acid are the major antioxidants in EJFE.Results demonstrate that flowers of the Eriobotrya japonica cause a significant protection against HgCl 2 induced hepatotoxicity in all diagnostic parameters by strengthening the antioxidant defense mechanisms and they may have a therapeutic function in free radical mediated diseases.     

Effects of fish protein hydrolysate on growth performance and humoral immune response in large yellow croaker (Pseudosciaena crocea R.)

We investigated the effects of fish protein hydrolysate (FPH) on growth performance and humoral immune response of the large yellow croaker (Pseudosciaena crocea R.). One thousand and two hundred large yellow croakers [initial average weight: (162.75±23.85) g] were divided into four groups and reared in floating sea cages (3 m×3 m×3 m). The animals were fed with 4 diets: basal diet only (control) or diets supplemented with 5%, 10% and 15% (w/w) FPH. The results show that dietary FPH levels significantly influenced the growth and immunity of the large yellow croaker. Compared with the control group, total weight gain (TWG) in all treatment groups, relative weight gain (RWG) and specific growth rate (SGR) in fish fed with diets supplemented with 10% and 15% FPH were significantly increased (P<0.05). Similar results were observed in immune parameters [lysozyme activity, serum complements, immunoglobulin M (IgM)]. Lysozyme activity, complement C4 and IgM were also significantly increased (P<0.05) in fish fed with diets supplemented with 10% and 15% FPH, while complement C3 level was significantly increased (P<0.05) in all treatment groups. In general, with the supplementation of FPH, particularly at dose of 10%, the growth performance and immunity of the large yellow croaker can be improved effectively.     

Enhanced antioxidant capacities <Emphasis Type="Italic">in vivo</Emphasis> caused by the change in key constituent of <Emphasis Type="Italic">Terminalia chebula</Emphasis> Retz. treated with Tibet traditional process

In order to investigate the chemical-biological relationship caused by the special processing technology, the constituent’s content and antioxidant capacity in vivo of Euphorbia fischeriana Steud processing Terminalia chebula Retz. have been tested. Taking T. chebula Retz. as control, the content of gallic acid is analyzed with high performance liquid chromatography (HPLC) method. The results show that the increase of gallic acid concentration from 4.54% to 7.46% leads to enhancement of the antioxidant capacities in vivo of the E. fischeriana Steud processing T. chebula Retz. The significant antioxidant capacity in vivo (p<0.05) of the processed product possesses is better than the unprocessed herb. Its superoxide dismutase (SOD) and malondia-ldehyde (MDA) contents in serum, the MDA content in liver can match the effects of vitamine E when administered at high dosage.     

脱酚棉籽粕替代鱼粉对卵形鲳鲹肌肉品质的影响

为探讨脱酚棉籽粕(LCSM)替代鱼粉对卵形鲳鲹(Trachinotus ovatus)的肌肉品质、抗氧化能力及相关基因表达的影响,本研究选择体质量为28.42±0.02 g的卵形鲳鲹,分别利用LCSM替代0%、20%、40%、60%的鱼粉蛋白,配制了4组饲料(分别记为LCSM0、LCSM20、LCSM40、LCSM60组),饲养卵形鲳鲹6周。结果显示:(1)LCSM20组的肌肉硬度、弹性、内聚性、胶粘性、回复性与LCSM0组的差异无统计学意义(P>0.05),胶着性和咀嚼性显著下降(P < 0.05);LCSM40组和LCSM60组的内聚性显著提高(P < 0.05),其余质构指标显著下降(P < 0.05)。(2)LCSM20、LCSM40、LCSM60组的pH和蒸煮损失率与LCSM0组相比差异有统计学意义(P < 0.05),肌肉滴水损失率的差异无统计学意义(P>0.05)。(3)LCSM20组和LCSM40组的肌肉胶原蛋白(Collagen)的质量分数与LCSM0组相比差异无统计学意义(P>0.05),LCSM60组的显著下降(P < 0.05)。(4)LCSM20组的丙二醛(MDA)含量、谷胱甘肽过氧化物酶(GSH-Px)含量与LCSM0组相比差异无统计学意义(P>0.05),超氧化物歧化酶(SOD)含量显著下降(P < 0.05);LCSM40组和LCSM60组的MDA含量与LCSM0组相比差异无统计学意义(P>0.05),SOD含量和GSH-Px含量显著下降(P < 0.05)。(5)LCSM20组肌肉品质相关基因(Decorin、MSTN、MyoG和CatL)的转录水平与LCSM0组相比差异无统计学意义(P>0.05),COL1α1、CatB基因的转录水平显著上调(P < 0.05);LCSM40组和LCSM60组的MSTN、COL1α1基因的转录水平与LCSM0组相比显著上调(P < 0.05),LCSM40组的Decorin、MyoG、CatB和CatL基因的转录水平与LCSM0组相比差异无统计学意义(P>0.05),LCSM60组的Decorin基因的转录水平与LCSM0组相比显著下调(P < 0.05),MyoG基因的转录水平与LCSM0组相比差异无统计学意义(P>0.05),CatB、CatL基因的转录水平与LCSM0组相比显著上调(P < 0.05)。综上所述,以对肌肉品质、抗氧化能力及相关基因表达的影响为评价指标,利用脱酚棉籽粕替代卵形鲳鲹饲料鱼粉的最适比例为20%。     

Seasonal variation of gut Cyanophyta contents and liver GST expression of mud carp （Cirrhina molitorella） and Nile tilapia （Oreochromis niloticus） in the tropical Xiangang Reservoir （Huizhou, China）

Liver glutathione S-transferase(GST) plays a major role in the detoxification of microcystins(MCs) via conjugation to glutathione(GSH).We evaluated the relationship between seasonal variation in fish gut contents and the expression of GST isoforms in mud carp(Cirrhina molitorella) and Nile tilapia(Oreochromis niloticus).We quantified the abundance and diversity of plankton in the water column and foregut of mud carp and Nile tilapia in the tropical Xiangang Reservoir between October 2007 and July 2008.The mRNA expression of 7 liver GST isoforms was determined by real-time RT-PCR.The gut contents of both species were dependent on the amount and type of phytoplankton and zooplankton in the water.The expression of liver GST genes in Nile tilapia and mud carp was positively and negatively correlated,respectively,with the abundance of toxic cyanobacteria in the fore-gut.The expression of liver GST mRNA was correlated to the abundance of toxic cyanobacteria in the gut contents of both species,suggesting that mRNA expression of GST isoforms could be used as a biomarker in Nile tilapia and mud carp to monitor cyanobacteria blooms in reservoirs.     

微囊藻毒素对小鼠肝脏抗氧化系统的影响

通过灌胃染毒的方法研究了微囊藻毒素对小鼠抗氧化系统的毒性.结果显示,超氧化物歧化酶活性在第4周升高,过氧化氢酶活性在第3周和第4周下降,表明微囊藻毒素处理后导致H2O2积累,使得氧化损伤加强.谷胱甘肽含量从第2周开始出现明显下降.谷胱甘肽-S-转移酶活性在第4周时发生显著性升高,提示微囊藻毒素和谷胱甘肽结合的速率增高,从而加快了肝组织对微囊藻毒素的清除.本实验结果说明抗氧化系统在微囊藻毒素的解毒方面起到了十分重要的作用.     

黄鲷的生物学特性及人工繁殖技术

综述了黄鲷的形态、生态、生长及繁殖等生物学特征,报道了黄鲷亲鱼选择培养及人工促熟催产技术,胚胎发育、仔鱼的生长发育情况和苗种培育等有关技术.研究结果表明:注射LHRH-A,和LHRH-A2+DOM催产后,经营养强化培育的野生黄鲷可有规律地连续产卵.产卵一般在10:00～16:00时进行,产卵期长达45～57 d.在培育水温20～22 ℃、盐度28～30时,受精卵经35～37 h完成胚胎发育,孵出仔鱼,孵化率为89%,孵出的仔鱼活泼健壮.     

饲料能量和维生素B6对乌鳢生长和蛋白质代谢酶活性的影响

 选择体质量（10.92±0.42）g 的健康乌鳢Channa argus为试验鱼。试验一设计3 个蛋白质水平和三个能量水平的9种试验饲料;试验二设计3个蛋白质水平和3个维生素B6水平的9种试验饲料,探讨饲料能量和维生素B6分别与蛋白质的交互作用对乌鳢生长和蛋白质代谢酶活性的影响。结果表明：试验1：在相同饲料能量水平下,鱼体增重随能量水平升高而升高,各器官蛋白酶比活力亦显著提高(P<0.05)。在相同饲料蛋白质水平下,鱼体增重先随饲料能量水平从14.5 MJ/kg上升到16 MJ/kg而升高,随能量水平再升高而降低。饲料蛋白质水平和能量水平都极显著地影响肝脏中GPT的活力(P<0.01),饲料能量水平显著影响肝脏中LDH的活力以及肌肉中LDH和GPT的活力(P<0.05)。蛋能比极显著影响肝脏中GPT的活力(P<0.01)。试验2：乌鳢的生长随着饲料蛋白质水平的增加呈先升高后稳定的趋势,胃、肠和肝脏蛋白酶比活力和肝脏和肌肉中GPT的活力都受到显著地影响(P<0.05),肝脏和肌肉中LDH的活力受到极显著地影响(P<0.01)。随着维生素B6的添加,生长显著增加(P<0.05),胃和肝脏蛋白酶比活力极显著增加(P<0.01)。在同一维生素B6水平下,各器官蛋白酶比活力随着饲料蛋白质水平的升高而显著提高(P<0.05),肝脏和肌肉中GPT和肌肉中LDH的活力亦受到极显著地影响 (P<0.01),肝脏LDH的活力亦受到显著地影响 (P<0.05)。在该试验条件下,适宜蛋能比（23.3 g/MJ）能够提高乌鳢对蛋白代谢酶活力,促进蛋白质代谢,进而促进生长;随着饲料蛋白质含量的增加,适量添加维生素B6（18~30 mg/kg）可促进乌鳢对饲料的利用率,增强蛋白代谢酶的活力,促进蛋白质代谢,进而促进生长。     

裙带菜中不同分子质量岩藻多糖的理化成分和抗氧化性比较

从中国山东威海海域采收裙带菜(Undaria Pinnatifida)样品,利用乙醇浸提法对样品中的岩藻多糖粗品进行提取。采用透析的方法,制备分子质量小于1×10⁴u的低分子质量岩藻多糖分离物。测定了不同分子质量岩藻多糖分离物的硫酸盐、糖醛酸及其对1.1-二苯基-2-三硝基苯肼(DPPH)自由基、羟基自由基的清除能力。分析和比较了岩藻多糖粗提取物和分子质量小于1×10⁴u的岩藻多糖的理化成分和抗氧化活性。分析结果表明:粗提物的硫酸盐和糖醛酸含量略高于低分子质量岩藻多糖,其中粗提物中硫酸盐质量分数高达36.50%。与岩藻多糖粗提物相比,低分子质量岩藻多糖具有更高的一级和二级抗氧化能力。     

Preliminary studies on the chemical characterization and antioxidant properties of acidic polysaccharides from Sargassum fusiforme

In order to investigate the antioxidant properties of the polysaccharides from the brown alga Sargassum fusiforme, the crude polysaccharides from S. fusiforme (SFPS) were extracted in hot water, and the lipid peroxidation inhibition assay exhibited that SFPS possessed a potential antioxidant activity. Hence, two purely polymeric fractions, SFPS-1 and SFPS-2 were isolated by the column of DEAE (2-diethylaminoethanol)-Sepharose Fast Flow, with their molecular weights of 51.4 and 30.3 kDa determined by high performance gel permeation chromatography (HPGPC). They were preliminarily characterized using chemical analysis in combination of infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies and found to contain large amounts of uronic acids and β-glycosidical linkages. The antioxidant activities of these two SFPS fractions were evaluated using superoxide and hydroxyl radical-scavenging assays. The results show that the antioxidant ability of SFPS-2 was higher than that of SFPS-1, probably correlating with the molecular weight and uronic acid content.     

Using quantile regression to analyze the stressor–response relationships between nutrient levels and algal biomass in three shallow lakes of the Lake Taihu Basin,China

Understanding the stressor–response relationship between nutrient levels and algal biomass is a prerequisite for the management of eutrophication in lakes. In this study, a quantile regression(QR) approach was used to interpret the stressor–response relationships between nutrient(e.g., phosphorus, nitrogen) concentrations and algal biomass as measured by chlorophyll-a(Chl-a) levels. QR results indicated that Lake Dianshan and Lake Changdang,which are both heavily eutrophicated, were P-limited only.In contrast, Lake Kuilei, which has significantly lower nutrient levels and algal biomass than the other two lakes,was P- and N-limited. Moreover, in Lake Kuilei, N and P levels had significant interaction effects on the algal biomass at the upper quantiles(s [ 0.68). The degree to which the lakes were P-limited increased with rises in the mean total P concentration in the lakes. QR has many advantages over ordinary least squares regression for discriminating limiting factors and, in particular, allows us to estimate changes near the upper extremes of distributions associated with limiting factors. QR is adapted to more specialized risk management problems, such as early warnings of the risk of algal blooms.The probable value-at-risk of harmful algal blooms for Lake Kuilei, Lake Dianshan and Lake Changdang is s = 0.76(Chl-a = 9 mg/m3), s = 0.87(Chl-a = 24 mg/m3) and s = 0.72(Chl-a = 35 mg/m3), respectively. Given the results of the stressor–response relationship analysis, we conclude that reductions in P input represent the most feasible and least costly approach for managing eutrophication in the shallow lakes of the Lake Taihu Basin. To control the magnitude and duration of algal blooms in shallow lakes,reductions in P and N inputs are required. The 95 % CI bounds of slopes indicated that the interactions of nonnutrient factors with nutrients had strong impacts on the algal biomass in lightly eutrophicated Lake Kuilei. It is suggested that, in addition to reductions in nutrient loads,several ecological measures, such as an increase in the biomass of submerged macrophytes and the reduction of hydraulic retention time by flushing, could represent important components of an integrated approach to eutrophication management in the Lake Taihu Basin.     

广西沿海赤潮多发区高浓度氮磷营养元素来源探讨

【目的】探讨广西沿海赤潮多发区氮磷营养元素的来源,分析广西沿海赤潮发生的影响因素,为预防或减少赤潮灾害发生、保护海洋生态环境提供科学依据。【方法】现场调查以钦州湾海域为研究对象,测定表层海水的溶解态氮(DN)、溶解态磷(DP)含量并分析其分布特征,结合历史资料追溯高浓度DN、DP来源及污染物输运过程。【结果】钦州湾内高浓度DN、DP分布区与入海陆源工业污染排放区不一致,离工业污染区近的地方DN、DP浓度偏低,而离工业污染区远的地方DN、DP浓度反而偏高。【结论】广西主要入海河流各类污染物的增加以及不同的海域通过动力途径输送而来的海水可能是广西沿海赤潮多发区的高浓度氮磷营养元素的主要来源。     

鲨鱼肝蛋白粗提物对大鼠肝线粒体抗氧化功能的影响

摘以400mg／kg2次腹腔注射硫代乙酰胺（TAA）建立大鼠急性肝损伤模型,并在注射TAA前1h以80mg／kg2次腹腔注射鲨鱼肝蛋白粗提物进行预防,研究了鲨鱼肝蛋白粗提物对大鼠肝线粒体抗氧化功能的影响。注射TAA后,大鼠肝脏线粒体腺苷二磷酸（ADP）诱导的氧消耗、呼吸控制率（RCR）、磷／氧比（P／O）、氧化磷酸化率均低于对照组,而预防组线粒体ADP诱导的氧消耗、呼吸控制率、P／O和氧化磷酸化效率均高于模型组;TAA降低了线粒体中谷胱甘肽、谷胱甘肽还原酶、谷胱甘肽过氧化物酶的水平,而鲨鱼肝蛋白粗提物则使线粒体中谷胱甘肽过氧化物酶和超氧化物歧化酶的水平明显升高,说明鲨鱼肝蛋白粗提物能部分修复线粒体受损的呼吸功能,增强线粒体抗氧化能力。     

饲料中锰对日本沼虾抗氧化酶活性的影响

研究了日本沼虾(Macrobrachium nipponense)饲料中不同含量的Mn对虾体抗氧化酶活性的影响,以及在低氧胁迫下Mn对抗氧化酶的激活效果.结果表明,在投喂Mn的质量分数为150 ?g/g的饲料后,日本沼虾的超氧阴离子(O2·-)值降低,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GPX)活性升高.Mn对虾体内SOD,CAT和GPX的激活作用表现出明显的剂量效应,饲料中Mn的缺乏或过量都使它们的活性受到影响.在低氧胁迫下,饲料中适量的Mn在一定程度上可提高虾体对低氧环境的耐受力.