维生素C对胡子鲶生长、免疫与抗病作用的影响

在胡子鲶基础料中分别添加 0、5 0 0、10 0 0、15 0 0、2 0 0 0mg/kg的维生素C(VC) ,分别在饲喂不同实验料后的第 12、2 4、36和 5 2天 ,测定各组的生长指标、血清的溶血活力和杀菌活力 ;并在饲喂后的第 4 0天 ,用鲁氏不动杆菌进行攻毒实验 ,观察胡子鲶死亡情况。结果表明 ,添加VC对胡子鲶体重、特定生长率和体长增长率有提高作用 ,但无规律性 ;在添加后的第 12、2 4、36天对血清溶血活力有明显的提高作用 ;对血清杀菌活力没有增强作用。攻毒结果表明 ,VC能明显提高胡子鲶对鲁氏不动杆菌的抵抗力     

维生素C对胡子鲶生长、免疫与抗病作用的影响

在胡子鲶基础料中分别添加0、500、1000、1500、2000mg／kg的维生素C(VC)，分别在饲喂不同实验料后的第12、24、36和52天，测定各组的生长指标、血清的溶血活力和杀菌活力；并在饲喂后的第40天，用鲁氏不动杆菌进行攻毒实验，观察胡子鲶死亡情况。结果表明，添加VC对胡子鲶体重、特定生长率和体长增长率有提高作用，但无规律性；在添加后的第12、24、36天对血清溶血活力有明显的提高作用；对血清杀菌活力没有增强作用。攻毒结果表明，VC能明显提高胡子鲶对鲁氏不动杆菌的抵抗力。     

溶藻弧菌对凡纳滨对虾血清中一氧化氮及氧自由基的影响

对凡纳滨对虾注射浓度为1×105、1×106、1×107mL-1的溶藻弧菌悬液,在注射后4、12、24、48、72和120 h于腹血窦取血,测定其血清中一氧化氮(NO)、丙二醛(MDA)含量,以及一氧化氮合酶(NOS)、超氧化物岐化酶(SOD)活力。结果表明,注射溶藻弧菌后,凡纳滨对虾血清中NO含量及NOS活力显著高于对照组,且NOS活力最大值出现时间较NO早;而SOD活力先升高后下降,MDA含量在SOD活力开始下降后逐渐升高,说明一氧化氮系统对凡纳滨对虾感染的溶藻弧菌有清除作用,并能在一定程度上对损伤过程中生成的氧自由基产生作用。     

双棘黄姑鱼血清性类固醇激素的周年变化

采用放射免疫法(RIA)测定双棘黄姑鱼(Nibea diacanthus)血清性类固醇激素的周年变化。结果表明:雌鱼血清雌二醇(Estadiol-17β)浓度一年出现两次峰值,均在成熟产卵前一个月,即4月[(338±59)pg/mL]和9月[(296±48)pg/mL];血清睾酮(T)浓度在卵黄发生期急剧上升,并在卵巢成熟期达到最高值,分别是5月(2.506±0.262 ng/mL)和10月份(2.268±0.243 ng/mL),分别在血清雌二醇浓度两次峰值出现1个月之后,因此,雌鱼的血清雌二醇浓度和血清睾酮浓度均与性腺发育相关。雄鱼血清睾酮浓度的两次峰值均出现在性腺已发育成熟的5月份(2.307±0.792 ng/mL)和10月份(2.286±0.607 ng/mL),与性腺发育有明显的相关性;而血清雌二醇浓度全年维持在一个相对稳定的水平,与雄性性腺发育相关性不明显。     

3种免疫途径对嗜水气单胞菌灭活疫苗保护作用的影响

应用间接ELISA方法,研究经嗜水气单胞菌疫苗浸泡、口服、注射免疫后鳜皮肤、肠道黏液和血清中抗体的变化关系,揭示鳜对3种免疫途径的免疫应答效果。结果显示:黏液抗体产生快(7 d达到峰值),但持续时间短,抗体水平低(213);血清抗体产生慢(28 d方达峰值),但持续时间长,抗体水平高(225)。不同方式免疫鳜后均产生远高于对照组的抗体滴度(P<0.05)。注射组产生的抗体水平高(225),免疫保护率最理想(70.6%);口服组相对另两个实验组,其抗体峰值(215)和免疫保护率(41.2%)均较低;浸泡组在皮肤黏液产生水平和溶菌酶含量方面,产生较好的免疫效应,分别为213和178μg/mL,但相对保护率仅为47.1%,低于注射组的70.6%。浸泡和口服组可诱发局部黏膜免疫,在抗体动态变化方面表现出相似的规律且峰值时间早于注射组。初步推断浸泡和口服可以直接刺激鱼体黏膜组织产生局部的特异性抗体。     

15种植物提取液对丁鱼岁幼鱼引诱作用的初步研究

鱼类对植物提取液产生趋向行动(taxis或chemotaxis)属于生态生物化学的范围,这类研究具有广泛的科学和实践意义[1].国内用动植物提取液或提取物研究过南方鲶幼鱼、鲤鲫鱼、草鱼鱼种、罗非鱼的摄食行为[2～5],国外用氨基酸作为诱食剂[6].     

腹腔注射恩诺沙星和氟苯尼考对红笛鲷血清IgM含量的影响

以20mg·kg-1恩诺沙星和氟苯尼考分别腹腔注射红笛鲷,通过间接酶联免疫吸附实验法(ELISA)测定红笛鲷血清IgM的含量,研究恩诺沙星与氟苯尼考对红笛鲷血清IgM含量的影响。结果显示:健康红笛鲷血清中IgM抗体的含量为3.591±0.314mg·mL-1,注射后,恩诺沙星组增加至4.234±0.013mg·mL-1,第3周后恢复至初始水平,而氟苯尼考组则降低至2.538±0.214mg·mL-1,第5周仍未恢复至初始水平。可见,恩诺沙星可提高红笛鲷血清中抗体IgM的含量,而氟苯尼考则降低鱼体血清中抗体IgM的含量,且影响时间也较长。     

10种CpG-ODNs对罗非鱼抗海豚链球菌感染的作用

采用人工合成的10种未甲基化CpG-ODNs序列分别注射健康的吉富罗非鱼Oreochromis niloticus,48 h后注射海豚链球菌(Streptococcus iniae)进行人工感染,分别于感染24 h和48 h后检测鱼体血清溶菌酶(Lysozyme,LSZ)、超氧化物歧化酶(Superoxide dismutase,SOD)和碱性磷酸酶(Alkaline phosphatase,AKP)的活性,并记录死亡率。结果显示:注射ODN-205的罗非鱼LSZ、AKP和SOD活性变化均不显著(P>0.05),推测注射ODN-205后罗非鱼能较好的维持机体的平衡,增强机体的抗菌能力;注射ODN-1681、1670、2133和2006的罗非鱼LSZ活性逐渐降低,而注射ODN-1826、2143、1668、2102、1669的罗非鱼LSZ活性呈现先升高后降低的趋势。AKP活性的变化趋势同LSZ活性变化大体相似,而SOD活性前后变化不显著(p值>0.05)。注射CpG-ODNs的实验组抑制海豚链球菌感染的作用差异显著(p值<0.05),其中以注射ODN-205组的死亡率最低(18%),其次为注射ODN-1670、1681、2006和2133组,死亡率均低于30%,而ODN-1669组和生理盐水组的死亡率均超过90%。实验表明,注射一定量的ODN-205、1670、1681、2006和2133能明显提高吉富罗非鱼抗海豚链球菌感染能力。     

盐度对尼罗罗非鱼血清甲状腺素浓度和成活率的影响

在尼罗罗非鱼(Oreochromis niloticus)由淡水逐渐向不同盐度海水(5,10,15,20,25)适应过程中,运用放射免疫测定法研究血清中三碘甲腺原氨酸(T3)浓度的变化,并分析盐度变化对尼罗罗非鱼成活率的影响。结果表明,盐度对尼罗罗非鱼血清中T3水平和成活率有着显著的影响。在盐度5~20的范围内变化后,血清T3的浓度在6 d内随着盐度上升而增大,第7天达到高峰;随后,逐渐降低并趋于稳定,在第14天时,各盐度组尼罗罗非鱼血清中T3开始处于稳定状态;稳定后,各实验组血清中T3的浓度均比对照组升高,并表现出随盐度的升高而升高的趋势。在盐度20时,实验第17天,尼罗罗非鱼的成活率为80%。而在盐度为25时,实验第11天,尼罗罗非鱼的成活率仅为54%。对不同盐度下尼罗罗非鱼死亡原因及血清甲状腺激素在盐度变化下的生理意义和对死亡率的影响作了讨论。     

非诺贝特对卵形鲳鲹PPAR α及CPTI基因表达的影响

对卵形鲳鲹(Trachinotus ovatus)腹腔注射20、50、100 mg/kg的激动剂非诺贝特,用RT-PCR检测肝脏、肌肉中PPARα和CPTI基因表达的变化趋势,研究激动剂对卵形鲳鲹PPARα和CPTI基因表达的影响。结果表明,PPARα基因表达量50 mg/kg非诺贝特组高于其他组,差异有统计学意义(P0.05),而CPTI表达量在20 mg/kg组有较高的表达水平(P0.05);50 mg/kg非诺贝特组中PPARα基因表达量随着时间的变化呈现先降低后恢复至初始水平的趋势,CPTI表达量随时间变化先升高后降低,随后又升高的变化趋势,肝脏组织中,CPTI表达量在注射后30 h达到最高(P0.05),而在肌肉组织中18 h时达到最高值(P0.05);非诺贝特组PPARα和CPTI基因的表达量均高于PBS对照组(P0.05)。非诺贝特可诱导PPARα基因的表达,但CPTI与PPARα基因表达无较明显的相关性。     

哈维氏弧菌GST核酸疫苗制备及其对斜带石斑鱼的免疫保护作用

通过同源引物从致病性哈维氏弧菌(Vibrio harveyi)ZJ0603基因组中克隆GST的开放阅读框(ORF),构建真核表达质粒pcDNA-GST。大量抽提重组质粒后,于背鳍基部肌肉注射重组质粒免疫斜带石斑鱼(Epinephelus coioides),分析重组质粒的免疫效果。通过核酸水平检测重组质粒在鱼体肝、肌肉、头肾和脾脏组织的分布;用ELISA法检测鱼体血清的抗体水平,用Western-blot检测目的蛋白的表达情况。结果表明:该序列全长615 bp;免疫7 d后,鱼体中均有质粒分布;斜带石斑鱼血清中产生抗GST的高效抗体(1∶4 096);相应的目的蛋白也在鱼体中成功表达。攻毒后,疫苗免疫保护率达80%,表明GST可作为防治哈维氏弧菌病有效候选抗原。     

Induction of ovulation in female mud skipper (Boleophthalmus pectinirest ris) by HCG,analogue of LHRH and pimozide

The effects of two intraperitoneal injections of human chorionic gonadotropin (HCG) or [D-ALA⁶, pro⁹-N-ethylamide]-luteinizing hormone releasing hormone analogue (LHRH-A), respectively, and the combined effect of LHRH-A with pimozide (PIM), a dopamine antagonist, on ovulation in female mud skipper were investigated. A high rate of ovulation (83.3%) was observed after injection with HCG(30 I. U./g). Injection of LHRH-A at a total dosage of 2 μg/g was 100% effective in inducing ovulation. No ovulations occurred in the group receiving a low dosage of LHRH-A (0.02 μg/g). Injection of LHRH-A (0.2 μg/g) with PIM (10 or 20 μg/g) induced greater ovulatory response than injection with LHRH-A (0.2 μg/g) alone. PIM at total dosages of 0.2 μg/g or 2 μg/g did not enhance the potency of LHRH-A to stimulate ovulation.     

Spatio-Temporal Variations in Co-Occurrence Patterns of Fish Communities in Haizhou Bay,China: Null Model Analysis

Co-occurrence pattern of fish species plays an important role in understanding the spatio-temporal structure and the stability of fish community. Species coexistence may vary with time and space. The co-occurrence patterns of fish species were examined using the C-score under fixed-fixed null model for fish communities in spring and autumn over different years in the Haizhou Bay, China. The results showed that fish assemblages in the whole bay had non-random patterns in spring and autumn over different years. However, the fish co-occurrence patterns were different for the northern and southern fish assemblages in spring and autumn. The northern fish assemblage showed structured pattern, whereas the southern assemblage were randomly assembled in spring. The co-occurrence patterns of fish communities were relatively stable over different years, and the number of significant species pairs in northern assemblage was more than that in the southern assemblage. Environmental heterogeneity played an important role in determining the distributions of fish species that formed significant species pairs, which might affect the co-occurrence patterns of northern and southern assemblages further in the Haizhou Bay.     

Impacts of mariculture practices on the temporal distribution of macrobenthos in Sandu Bay,South China

Sandu Bay is located in the East China Sea and is characterized by high-density fish farming and kelp culture. Despite this, little is known about the impacts of these different mariculture practices on the local environment. We investigated the temporal variation in macrobenthos and environmental conditions at three sites in the bay (fish farming site, kelp culture site, and a control site). We collected water and sediment samples during nine cruises between May 2009 and February 2010. The density of macrobenthos peaked at the fish farming site in July (655 ind./m2) whereas density did not fluctuate as widely at the other two sites. Biomass varied significantly at both the control and kelp culture sites, but had only a single peak at the fish farming site in June (21.90 g/m2). The dominant species varied throughout the study period at the control and kelp culture sites, whereas a single terebellid species (Lysilla pacifica) dominated the macrobenthos at the fish farming site. The diversity index H’ increased at the control site beginning in February then decreased after May, whereas H’ was low at the other sites in December. The mean dissolved oxygen level was highest at the control site (6.59 mg/L) and lowest at the fish farming site (5.54 mg/L). DO levels were lowest at all sites in summer (July and August). The sediment acid volatile sulfide content was higher at the fish farming site (1.46 mg/g dry weight) than those at the kelp culture and control sites (1.22 and 0.14 mg/g, respectively). Our results suggest that mariculture practices have a clear impact on the benthic environment/ community in Sandu Bay.     

Trophic interactions, ecosystem structure and function in the southern Yellow Sea

The southern Yellow Sea is an important fishing ground, providing abundant fishery resources. However, overfishing and climate change have caused a decline in the resource and damaged the ecosystem. We developed an ecosystem model to analyze the trophic interactions and ecosystem structure and function to guide sustainable development of the ecosystem. A trophic mass-balance model of the southern Yellow Sea during 2000–2001 was constructed using Ecopath with Ecosim software. We defined 22 important functional groups and studied their diet composition. The trophic levels of fish, shrimp, crabs, and cephalopods were between 2.78 and 4.39, and the mean trophic level of the fisheries was 3.24. The trophic flows within the food web occurred primarily in the lower trophic levels. The mean trophic transfer efficiency was 8.1%, of which 7.1% was from primary producers and 9.3% was from detritus within the ecosystem. The transfer efficiency between trophic levels II to III to IV to V to >V was 5.0%, 5.7%, 18.5%, and 19.7%–20.4%, respectively. Of the total flow, phytoplankton contributed 61% and detritus contributed 39%. Fishing is defined as a top predator within the ecosystem, and has a negative impact on most commercial species. Moreover, the ecosystem had a high gross efficiency of the fishery and a high value of primary production required to sustain the fishery. Together, our data suggest there is high fishing pressure in the southern Yellow Sea. Based on analysis of Odum’s ecological parameters, this ecosystem was at an immature stage. Our results provide some insights into the structure and development of this ecosystem.     

Vaccination in three different ways against vibriosis of Seriola dumerili caused by Vibrio hollisae

Bacterin was prepared by formalin-inactivating the virulent strain of Vibrio hollisae isolated from diseased Seriola dumerili (amberjack) suffering from vibriosis. Healthy S. dumerili were vaccinated by respective procedures of intramuscular injection, immersion, and orally administration. Results of the three different vaccinations were compared. Blood was drawn from the vaccinated fish every 7 days, and the antibody titers and lysozyme activities of the sera were determined. The antibody titer of injected fish was 1:40 at 7 d, and reached its peak of 1:320 at 28 d, while the fish vaccinated by immersion and orally administration exhibited weak antibody responses, the antibody titres of <1:10, 1:20, 1:160 were observed at 7 d, 14 d, 35 d respectively. Compared with the control, the vaccinated fish exhibited significantly higher lysozyme activities (P<0.05). Upon challenge with virulent strain, the relative percent survival (RPS) of injected, immersed and oral administrated fish were 75%, 45%, and 40% respectively, and the injected fish showed significantly higher RPS than immersed and oral administrated fish. The results suggested that vaccination of S. dumerili by the injection would be the best strategy to prevent the vibriosis in S. dumerili farm.