嗜水气单胞菌ompA、flaA基因重组干酪乳杆菌对鲤生长及免疫效果分析

为构建嗜水气单胞菌ompA和flaA基因重组干酪乳杆菌并分别检测其表达产物对鲤生长及免疫效果的影响,实验将目的基因克隆至乳酸菌穿梭表达质粒pPG612中,并电转至干酪乳杆菌中,经诱导后包被饲料对鲤进行饲养56 d,称重并采集血清及组织,分析生长指标及免疫指标变化。在56 d饲养免疫结束后结果显示,生长指标显示重组干酪乳杆菌组与对照组无显著差异,表明重组干酪乳杆菌对生长无影响;免疫效果分析显示,血清中IgM表达水平显著上升。血清中AKP、LZM、SOD、CAT、C3和C4也均显著升高。荧光定量PCR检测发现,免疫后肝脏、脾脏、头肾及肠组织中的细胞免疫因子基因IL-1β、IL-8、TNF-α、 NF-κB、 TLR5及MYD88的表达水平有不同程度的显著提升;其中TLR5及MYD88表达量在Lc-mcs-flaA组高于Lc-mcs-ompA组。攻毒后Lc-mcs-ompA与Lc-mcs-flaA组免疫保护率分别为59%与54%,显著高于对照组。研究表明,本实验构建的重组干酪乳杆菌Lc-mcs-ompA与Lc-mcs-flaA免疫鲤能刺激机体产生免疫应答反应,进而提高自身存活率,为预防鱼类嗜...     

2020年湘江长沙段仔稚鱼资源现状及其对水文环境的响应

为了解湘江下游长沙段仔稚鱼资源现状,2020年5-6月,在湘江下游长沙香炉洲江段(28°20′17″N ,112°53′5″E)进行为期57天的仔稚鱼资源调查。结果显示：(1)采集点共出现鱼苗汛7次,第一次为5月22日,最后一次为6月29日,7次鱼汛平均水温为26.5±0.57 ℃,网口平均流速为0.237±0.095m/s;(2)共采集仔稚鱼54.8万尾,分别隶属5目、8科、41种,其中,鲤科鱼类30种、占比73.2%,分析鱼卵类型和生态习性发现,主要以产沉性卵鱼类(23种)和广适性鱼类(24种)为主,分别占56.1%、58.5%,分析相对重要性指数发现,优势种为9种：子陵吻鰕鯱(Rhinogobius giurinus,2416.9)、飘(Pseudolaubuca sinensis,1507.0)、大鳍鱊(Acheilognathus macropterus,451.5)、银鲴(Xenocypris argentea,321.9)、鲤(Cyprinus carpio,314.6)、?(Hemiculter leucisculus,219.1)、黄尾密鲴(Xenocypris davidi,206.2)、鲫(Carassius auratus,179.9)和麦穗(Pseudorabora parva,158.7);(3)白天时段鱼苗总密度(0.093 ind/m_³)远低于夜间,约为夜间(0.567 ind/m_³)1/6,鲴类的昼夜差异更加明显,夜晚占比为白天的25倍,经Spearman检验,优势种及家鱼种类中,大鳍鱊、子陵吻鰕鯱、银鲴及草鱼(Ctenopharyngodon diellus)昼夜分布存在显著差异(P＜0.05);(4)分析发现,表层鱼苗密度(0.548 ind/m_³)为中下层(1.048 ind/m_³)的1/2,且子陵吻鰕鯱、银鲴、鲤鱼(Cyprinus carpio)及草鱼垂直分布存在显著差异(P＜0.05);(5)冗余分析(RDA)发现,流速对方差的贡献率为90.8%,与鱼苗总密度变化呈显著性相关(P=0.042),但与优势种及家鱼种类未表现出显著关系性,水温为9.2%,未表现出显著相关性。综上,湘江长沙段仔稚鱼资源丰富,且存在一定的昼夜垂直分布规律,应进一步完善湘江长沙段仔稚鱼资源的时空分布规律及其对水文环境的响应的调查研究,为长江十年禁渔效果评估提供理论依据和数据参考。     

The effects of variation in feed protein level on the culture of white shrimp, Litopenaeus vannamei (Boone) in low-water exchange experimental ponds

The present study was conducted to evaluate the effect of varying dietary protein level on pond water quality and production parameters of white shrimp Litopenaeus vannamei (Boone). Experimental units consisted of nine 400‐m² earthen ponds with a low water exchange. Two treatments were tested: treatment HP consisted of shrimp fed a high‐protein diet (40%) during the whole grow‐out, and treatment LP consisted of the use of a low‐protein diet for the complete farming period. No differences on any of the water quality parameters were observed among treatments. Excellent survival (over 85%) and feed conversion ratios (around 1.6), and acceptable growth (over 12 g) and biomass (from 1721 to 1793 kg ha^?1) were recorded in all experimental ponds. No significant differences in any of the production parameters were found among treatment groups.     

日粮赖氨酸水平对皖西白鹅繁殖力的影响

在日粮主要营养成份达标的基础上,通过调节赖氨酸水平0.49%、0.64%、0.79%,探讨其对皖西白鹅繁殖力的影响,结果表明:1赖氨酸水平影响产蛋量P<0.05,而不影响其它的繁殖力指标P>0.05;20.64%的赖氨酸水平最能体现皖西白鹅的繁殖性能。     

Production of polyclonal antiserum against recombinant VP28 protein and its application for the detection of white spot syndrome virus in crustaceans

The VP28 gene of white spot syndrome virus (WSSV) was cloned into pRSET B expression vector. The VP28 protein was expressed as a protein with a 6-histidine taq in Escherichia coli GJ1158 with NaCl induction. Antiserum was raised against this recombinant-VP28 protein in rabbits and it recognized VP28 protein in naturally and experimentally WSSV-infected shrimp, marine crabs, freshwater prawns and freshwater crabs. The antiserum did not recognize any of the other known WSSV structural proteins. Various organs such as eyestalks, head muscle, gill tissue, heart tissue, haemolymph, tail tissue and appendages were found to be good materials for detection of WSSV using the antiserum and detection of WSSV was successful in experimentally infected Penaeus monodon and P. indicus at 12 and 24 h post-infection (p.i.), respectively. The antiserum was capable of detecting WSSV in 5 ng of total haemolymph protein from WSSV-infected shrimp.     

Furunculosis in Atlantic salmon (Salmo salar L.) is not readily controllable by bacteriophage therapy

The potential of bacteriophage therapy to control bacterial disease in farmed fish was tested using, as an example, furunculosis of Atlantic salmon, caused by Aeromonas salmonicida subsp. salmonicida.

In vivo testing with Atlantic salmon and rainbow trout (Oncorhynchus mykiss Walbaum) showed no adverse effects, with bacteriophage generally cleared within 96 h of administration by either intraperitoneal (i.p.) injection or oral in-feed.

Juvenile Atlantic salmon were administered a combination of bacteriophage O, R and B (1.9 × 10⁸ pfu fish^− 1) by i.p. injection, after they had been challenged with A. salmonicida subsp. salmonicida 78027, also by i.p. injection. The fish that were injected with bacteriophage immediately after challenge died at a significantly slower rate then those that were either not treated with bacteriophage, or treated 24 h post-challenge. However, the end result (100% mortality) was not affected.

In further experiments the effects of oral (1.88 × 10⁵ pfu g^− 1 fish^− 1 daily for 30 days), bath (1.04 × 10⁵ ml^− 1 daily for 30 days) and i.p. (6.25 × 10⁷ pfu fish^− 1) phage treatment to control furunculosis in experimentally infected Atlantic salmon were compared with antibiotherapy (treatment with 10 mg kg^− 1 bw^− 1 day^− 1 oxolinic acid for 10 days), using an indirect cohabitation challenge. No protection was offered by any of the bacteriophage treatments, compared to the positive challenge group, although significant protection was offered by the oxolinic acid treatment. Analysis of samples taken from the trials demonstrated that bacteriophage were correctly administered to the fish and, on occasion, were isolated from fish that had succumbed to furunculosis. It was also shown that bacteriophage resistant A. salmonicida subsp. salmonicida isolates could be recovered from mortalities in all the treatment groups.

The results suggest that, although there were no safety problems associated with the approach, furunculosis in Atlantic salmon is not readily controllable by application of bacteriophage.     

黄海北部发现的中华白海豚Ⅰ.外形和内脏器官的测定结果

中华白海豚(SousaChinensis)属于国家Ⅰ级重点保护野生动物,在中国主要分布于广西、海南、广东、香港、澳门、台湾、福建、浙江沿岸,向北可达长江口。2003年5月9日在黄海北部(北纬39°35′01″,东经122°51′50″),由于渔业生产误捕的中华白海豚,是迄今为止该种发现的最北记录,笔者报告了对该海豚的外形和内脏器官测定结果。     

水温 饵料 投饵率对河蟹生长和饵料转化率的影响

在实验室条件下研究了水温、饵料和投饵率对河蟹生长的影响。结果表明,在10～26℃水温范围内,河蟹对不同饵料的摄饵率和特定生长率均与水温呈正相关关系;相比之下,用配饵投喂,河蟹对温度的变化较为敏感,但配饵的饲养效果明显次于螺蛳。随着水温的升高,当螺蛳的投饵率由半饱增至全饱时,河蟹的湿重生长率增长不明显,而体蛋白量则增加了13%～28%。在适温范围内,适当降低投饵率可提高饵料转化率和蛋白质利用率,可是蟹体蛋白量的增加则明显下降。     

磁珠富集法制备大口鲶的微卫星分子标记

2004年3月16日-6月8日，在广东广远渔业集团有限公司玻璃钢大滚筒冷海水金枪鱼延绳钓渔船“华远渔19”号，对印度洋马尔代夫海域进行金枪鱼渔业调查。所获数据资料包括：①CTD测定的温度、盐度和深度数据，TDR测定的实际钩深；②作业参数，包括每次作业的钩数、投绳位置、投绳时间、航向、航速、出绳速度、两浮子间的钩数、起绳位置、起绳时间等；③渔场环境数据，包括风速、风向、钓具对地漂移速度和方向；④渔获统计，包括大眼金枪鱼的渔获尾数以及部分大眼金枪鱼的钓获钩号；⑤生物学数据，包括起捕时已死的大眼金枪鱼的体温。分析计算的方法和步骤为：①由理论公式推算出每次作业时各钩号的理论深度；②应用逐步回归的方法，建立理论钩深与实测的平均钩深之间的数学关系模型；③根据实际平均钩深模型计算出每个钓钩的平均作业深度；④根据CTD测得的作业地点的温度、盐度的垂直分布（41次），获得分布曲线。由此，以计算的钩深，从曲线上查出该尾鱼捕获水深处的温、盐数据；⑤根据121尾大眼金枪鱼的取样数据，推算出各水层、水温段、盐度段的渔获率；⑥根据起捕时已死的34尾大眼金枪鱼（鱼体发硬）的体温、以死鱼体温为引数，在曲线上查出该尾鱼捕获水深和盐度；最后，对钓获的大眼金枪鱼的钓获水层、水温和盐度进行了总体分析。分析结果表明：在马尔代夫海域，捕获大眼金枪鱼的水层为50～210m、水温范围为13．0～29．9℃、盐度范围为35．00～35．79；渔获率最高的水层为70～90m、水温范围为27．0～27．9oC、盐度范围为35．70～35．79；捕获时已死鱼的捕获水层、水温和盐度推算数据为63～203m、14．0～27．0℃和34．94～35．42，主要集中在63～134m、16．0～27．0℃和35．30～35．42。