Abstract:鱼肠道弧菌(Vibrio ichthyoenteri)可引起多种养殖鱼类发病死亡, 给鱼类养殖业带来严重经济损失。为解决养殖过程中鱼肠道弧菌的现场快速检测问题, 本研究研制了鱼肠道弧菌胶体金快速检测试纸。通过制备兔抗鱼肠道弧菌多克隆抗体, 间接ELISA分析发现其与鱼肠道弧菌的外膜蛋白、鞭毛蛋白、胞外产物及全菌破碎蛋白发生阳性免疫反应, 与副溶血弧菌(Vibrio parahaemolyticus)、鳗弧菌(Vibrio anguillarum)、溶藻弧菌(Vibrio alginolyticus)、哈维氏弧菌(Vibrio harveyi)的4种抗原蛋白发生程度不等的免疫交叉反应。制备胶体金标记鱼肠道弧菌抗体, 确定了鱼肠道弧菌4种抗原蛋白的划线浓度, 以4种抗原蛋白作为4条检测线, 羊抗兔IgG作为质控线, 基于竞争法免疫层析技术研制出鱼肠道弧菌快速检测试纸。对鱼肠道弧菌、副溶血弧菌、鳗弧菌、溶藻弧菌和哈维氏弧菌的检测结果显示, 该试纸可以准确鉴别出鱼肠道弧菌, 并能判别其他病原菌的交叉反应。该试纸对鱼肠道弧菌的最低检测限为5×10⁵ CFU/mL, 检测耗时为10 min。对患病牙鲆组织的检测结果显示, 该试纸与ELISA结果一致, 表明具有较好的检测准确性。本研究为水产养殖现场的鱼肠道弧菌快速、准确检测提供了有力工具。

Abstract:This study aimed to evaluate the effect of genetic variation on expression of the calcineurin B gene (FcCN-B) in a breeding population of Fenneropenaeus chinensis. Thirty-two full-sib families of the G13 generation were randomly selected in 2018, and one individual from each family was randomly selected and rehomed to new cages (each cage contained 32 shrimps). The amount of feed was limited, and real-time PCR was used to detect the expression of the FcCN-B gene in the ganglion tissue of each shrimp. The results showed that the expression of the FcCN-B gene at the individual level had a positive skew distribution. The higher value of the mean (8.25) compared to the median (6.95) indicates the presence of individuals with extremely high expression. The maximum expression of individuals was 44.48 times the minimum expression of individuals, and the range was 43.48. The variation coefficient of FcCN-B expression at the individual level was 66.55%, whereas it was relatively small (19.31%) at the family level. The maximum expression was only 2.20 times the minimum expression at the family level. One-way analysis of variance showed that there were significant differences in the expression level of the FcCN-B gene between families (P<0.05). Heritability for FcCN-B gene expression, estimated using the animal models and their pedigrees, was 0.60±0.13. This indicates that there was a high level of genetic variation in the nuclear breeding population, and great genetic gain may be obtained. The results provide reference data to investigate the molecular mechanism of the competitive behavior and improve competitive ability in F. chinensis.

Abstract:为了解恒定高温对赤点石斑鱼(Epinephelus akaara)生长和繁殖的影响, 以孵化后120~420 日龄的幼鱼为研究对象, 对性腺发育以及与繁殖相关的基因gnrh、fshβ和lhβ表达进行了研究。对照组为自然水温(13.2~27.1 ℃)饲养, 实验组为26 ℃恒温饲养。每隔30 d或40 d采样1次, 比较两组中鱼的体长、体重、性腺指数(GSI)、性腺发育情况以及gnrh、fshβ和lhβ基因表达的差异。结果表明, 从240日龄开始, 实验组鱼的体长和体重均显著高于对照组(P<0.05)。实验结束时, 实验组体长约为对照组的1.3倍, 体重约为对照组的2倍。对照组GSI一直维持在0.25%以下的低值, 实验组GSI在330日龄前处于0.4%以下, 但在360日龄时出现GSI 1%以上的个体。在360、390和420日龄的个体中, 实验组GSI显著高于对照组(P<0.05)。实验结束时, 对照组中未检测到具有卵黄形成期卵母细胞的个体, 但实验组在330、360和390日龄出现了具有卵黄成熟期卵母细胞的个体。对照组和实验组间幼鱼脑中gnrh基因表达在各年龄段均无显著性差异(P>0.05), 但脑垂体中fshβ表达在360、390和420日龄, lhβ在390和420日龄时, 实验组均显著高于对照组(P<0.05)。研究表明, 26 ℃恒温调节不仅能促进赤点石斑鱼幼鱼体长、体重和GSI的增加, 同时也能显著提高脑垂体中fshβ和lhβ基因含量, 从而加速性腺发育成熟。

Abstract:为比较不同温度下长牡蛎(Crassostrea gigas)和葡萄牙牡蛎(C. angulata)杂交稚贝的生长与存活差异, 以正交组GA(长牡蛎♀×葡萄牙牡蛎♂)、反交组AG(葡萄牙牡蛎♀×长牡蛎♂)、自交组GG(长牡蛎♀×长牡蛎♂)和AA(葡萄牙牡蛎♀×葡萄牙牡蛎♂)的稚贝为材料, 开展了温度适应性研究。结果表明, GA和AG的亚致死温度为37.50 ℃, GG和AA的亚致死温度为37.00 ℃; GA致死温度为44.00 ℃, AG、GG和AA的致死温度为43.50 ℃; LT₅₀由高到低依次为GA (42.47 ℃)、AG (41.94 ℃)、AA (41.63 ℃)、GG (41.55 ℃)。多重比较表明, GA和AG的最适生存温度为16~28 ℃, GG为20~28 ℃, AA为24~28 ℃; GA、AG和GG的最适生长温度为20~28 ℃, AA为24~28 ℃。所有温度下杂交稚贝均表现出生长与存活优势。其中, 生长中亲杂种优势H和单亲优势H_AG在20 ℃时最高, 分别为35.1和38.8, 单亲优势H_GA在32 ℃最高, 为43.4; 16 ℃时存活中亲杂种优势H为28.4, 单亲优势H_GA和H_AG分别为21.5和36.4。32 ℃时中亲杂种优势H为42.2, 单亲优势H_GA和H_AG分别为72.7和20.0。研究表明, 杂交稚贝耐热性大于双亲, 具有显著的生长和存活优势, GA的优势更加明显。

Abstract:用大豆浓缩蛋白(SPC)替代鱼粉饲喂大黄鱼(Larimichthys crocea), 以探究其对幼鱼生长、肠道结构及肠道微生物菌群的影响。选取初始体重为(10.50±0.04) g的大黄鱼幼鱼, SPC替代鱼粉的比例分别为0% (SPC0, 对照组)、25% (SPC25)、50% (SPC50)、75% (SPC75)和100% (SPC100), 制作成5种等氮(粗蛋白水平为45%)等脂(粗脂肪水平为10%)的实验饲料, 进行为期56 d的饲养实验。结果表明, 与SPC0(对照组)相比, 幼鱼的存活率、增重率、特定生长率以及饲料系数受各SPC替代鱼粉水平的影响不显著(P>0.05)。肠道组织学显示, 各处理组幼鱼肠道的后肠黏膜厚度、皱襞高度、固有层宽度和杯状细胞个数差异性不显著(P>0.05)。Illumina HiSeq 高通量测序技术分析发现, SPC0 (TC: 对照组)、SPC25 (TB: 生长相对最佳组) 和SPC100 (TW: 生长相对最差组)的Chao1、香农指数(Shannon)、辛普森指数(Simpson)和覆盖率(good coverage)差异不显著(P>0.05); TC、TB和TW组幼鱼肠道细菌在门水平的优势菌群为厚壁菌门(Firmicutes), 类芽孢杆菌(Paenibacillus)在属水平占绝对优势。根据属水平的菌属差异结果发现幼鱼的生长受细菌微生物的组成的影响: 与TC组相比, TB组微小杆菌属(Exiguobacterium)、红杆菌属(Rhodobacter)和伦黑墨氏菌属(Rheinheimera)的物种丰度显著降低(P<0.05); 与TC组相比较, TW组红杆菌属(Rhodobacter)的物种丰度显著降低(P<0.05), 乳杆菌属(Lactobacillus)的物种丰度显著增加(P<0.05)。综上所述, 大黄鱼幼鱼的生长、肠道结构及肠道优势菌群不会因为鱼粉完全被大豆浓缩蛋白替代而产生负面的影响。

Abstract:为了综合评价稻田和池塘两种养殖模式下建鲤(Cyprinus carpio var. jian)的肠道健康及肌肉风味, 在夏秋两季对这两种养殖模式下建鲤的肠道菌群、肠道免疫酶活性及肌肉氨基酸含量进行比较分析。结果显示, 与养殖模式相比较，建鲤肠道菌群受季节的影响更显著。夏秋两季两种模式下建鲤肠道的优势菌群为厚壁菌门(Firmicutes)、梭杆菌门(Fusobacteria)、变形菌门(Proteobacteria), 且池塘模式下秋季肠道菌群多样性显著高于夏季(P<0.05)。建鲤肠道免疫酶活性夏季比秋季显著降低(P<0.05), 其中夏季和秋季池塘的碱性磷酸酶(AKP)活性显著高于稻田模式(P<0.05)。建鲤肌肉中共检测出18种游离氨基酸, 其中肌肉中天冬氨酸、谷氨酸、丙氨酸、甘氨酸、苏氨酸、精氨酸、组氨酸及苯丙氨酸的含量在稻田模式显著高于池塘模式(P<0.05), 且鲜、甜及苦3种呈味氨基酸总体含量均高于池塘模式(P<0.05)。综上所述, 与池塘养殖建鲤相比, 稻田养殖的建鲤肠道菌群更稳定, 肌肉具有更强烈的呈味特性。

Abstract:虹鳟(Oncorhynchus mykiss)与硬头鳟(O. mykiss)为同一种的不同生态型, 都属冷水性鱼类。为探讨急性高温胁迫对虹鳟和硬头鳟抗氧化酶活性的影响, 选取虹鳟[体重(22.76±2.89) g]和硬头鳟[体重(23.2±1.22) g]幼鱼, 分别在不同温度梯度(16 ℃、20 ℃、22 ℃和24 ℃; 16 ℃、19 ℃、21 ℃和23 ℃)进行热应激实验, 在达到设定温度后的0 h、1 h、6 h、12 h和24 h分别取样, 测定受试鱼心脏、肝、鳃、肾、脑和肌肉中超氧化物歧化酶(superoxide dismutase, SOD)、过氧化氢酶(catalase, CAT)和谷胱甘肽过氧化物酶(glutathione peroxidase, GPx)活性。结果表明, 虹鳟和硬头鳟幼鱼具有极为相似的抗氧化酶分布模式。两类幼鱼肝脏、鳃和肌肉SOD含量较高; 肝脏、肾脏和鳃CAT含量较高; 在心脏、肝脏、肾脏和鳃GPx分布较多。总体而言, 两类鱼肝脏中抗氧化酶分布最多。急性高温应激对两类鱼的抗氧化防御系统均可产生影响, 引起3种抗氧化酶活性的变化。虹鳟和硬头鳟在24 ℃和23 ℃组应激强烈, 两类鱼在应激24 h时SOD活性均大幅降低。虹鳟20 ℃组24 h内SOD活性与对照组无显著差异(P>0.05), 硬头鳟19 ℃组12 h内SOD与CAT活性与对照组无显著差异(P>0.05)。在高温胁迫恢复实验中, 虹鳟22 ℃组经过24 h, SOD和GPx明显下降, CAT也逐渐恢复, 而硬头鳟21 ℃组24 h SOD仍处于较高水平, 这表明此温度下虹鳟幼鱼抗高温胁迫能力强于硬头鳟。结果表明, 硬头鳟幼鱼抗氧化酶活性对温度升高的反应比虹鳟幼鱼敏感。

Abstract:基于2018年春季和秋季在海州湾及邻近海域开展的渔业资源底拖网调查数据, 构建了海州湾及其邻近海域的LIM-MCMC (linear inverse models using a Monte Carlo method coupled with Markov Chain)模型, 对其生态系统能量流动和生态系统特征进行了研究, 旨在为深入研究海州湾生态系统以及实施基于生态系统的渔业管理提供理论依据。研究表明, 在包含18个功能群的海州湾生态系统中, 共形成196条能量流动路径, 可将其划分为4个能量等级, 即0.00~1.00 t/(km²·a), 1.00~10.00 t/(km²·a), 10.00~100.00 t/(km²·a)和>100.00 t/(km²·a)。在0.00~1.00 t/(km²·a)区间内主要为高营养层次功能群, 共包括155条能量流动路径, 表明食物网中弱能量流动路径占总路径数的绝大部分比例, 在维持生态系统稳定性方面具有重要作用。1.00~10.00 t/(km²·a)区间内包含21条能量流动路径, 在将能量由低营养级传递到高营养级过程中起到重要枢纽作用。在10.00~100.00 t/(km²·a)和>100.00 t/(km²·a)区间内分别包括12条和8条能量流动路径, 均为低营养层次功能群, 为生态系统提供基本的营养来源。在海州湾生态系统中, 低营养层次功能群的呼吸消耗量与流入碎屑量远高于高营养级。整体能流分布为低营养级值大, 越往顶级越小, 呈典型的金字塔型能量流动。根据生态系统成熟度理论, 海州湾生态系统属于成熟的生态系统, 能够在较大程度上抵御外界扰动带来的影响。本研究可为海州湾食物网营养动力学的深入研究以及海州湾渔业资源的科学管理提供科学依据。

Abstract:We investigated the distribution and the in-situ target strength (TS, dB) of the skipjack tuna Katsuwonus pelamis associated with light falling-nets in the South China Sea using the Simrad EY60 scientific echosounder. The volume backscattering strength (Sv, dB), TS, and mean number of fish per sampled volume (N_V) were studied. The average fork length of skipjack tuna in the S13, S14, and A12 stations were (362.20±35.73) mm, (357.66± 36.61) mm, and (366.70±36.43) mm, respectively. There was no significant difference in the average fork length among the three stations (P>0.05). Within the depth range of 10–50 m, the mean S_V change pattern of the three stations at different time phases was similar. Before the fishing lights were turned on (18:00–19:00), the K. pelamis was mainly distributed at a water depth of 40–50 m; after the lights turned on, the K. pelamis was gradually attracted and floated, and thus the depth corresponding to the peak of the S_V distribution curve became shallower. With the increase of lighting time (20:00–21:00), the K. pelamis was stably distributed at a depth range of 10–30 m. In the depth range of 10–50 m, the number of individual signals at the three stations in different time phases was also similar to the mean depth change pattern. Before the fishing lights were turned on (18:00–19:00), the signals were mainly distributed at a depth of 35 m, and few signals were detected. After the lights were turned on, K. pelamis were gradually attracted and floated, resulting in a shallower mean depth of the signals, and the number of signals increased significantly. There were no N_V limit values at the three stations in this study, and all cells can be used for the in-situ TS calculation. The mean in-situ TS was (–51.84±3.84) dB at the S13 station, (–49.87±3.72) dB at the S14 station, and (–49.68±2.96) dB at the A12 station. The in-situ TS of K. pelamis at the three stations were non-normally distributed (P<0.05). These results help us better understand the fish behavior and acoustic characteristics under the conditions of light trapping and also set up a technical foundation for future acoustic evaluation.

Abstract:With the collapse of inshore fishery resources, small economic fishes have become the major fish resource in the coastal waters of China. As one of the most important fish resources, big head croaker (Collichthys lucidus) has a wide distribution and high production in Chinese estuaries and is included on the List of China State Key Protected Commercial Sources of Aquatic Animals and Plants. However, the population structure of C. lucidus is still unclear, and knowledge of this is essential for decision-makers to sustainably develop the fishery industry. In the present study, the population genetic structure of C. lucidus in the coastal waters of China was examined based on mitochondrial cytochrome b gene sequences. A total of 342 individuals were sampled from nine localities from September to November 2019, and 174 haplotypes were subsequently identified. The median-joining network and neighbor-joining tree of haplotypes show two significantly divergent clades, Clade N and Clade S, which correspond to the geographical North group and South group, respectively. Analyses of molecular variance (AMOVA) also revealed significant genetic differentiation between the North and South groups (P<0.01). The genetic diversity results indicated that the haplotype diversity of the South group was higher than that of the North group (0.9418 vs. 0.8758); however, the results of nucleotide diversity showed the opposite outcome (0.0036 vs. 0.0041). Analyses of pairwise F_ST and N_m revealed significant genetic differentiation between the North and South group populations (P<0.05), with little gene exchange (N_m=0.06). The results of mismatch distribution and neutrality tests show that population expansion occurred for big head croaker along the coast of China in the Pleistocene era, and the expansion times of the North and South groups were estimated to be 7990–19900 and 26310–65770 years ago, respectively. The divergence time of big head croaker between the North and South groups was estimated at 345000–862500 years ago based on genetic distances. Historical events, biological characteristics, and other extrinsic forces (i.e., coastal currents) may all be associated with the current phylogeographic pattern of big head croaker in the coastal areas of China. In conclusion, the population structure of big head croaker along the coastal waters of China consist of the North group and the South group, which should be exploited and managed individually in fisheries.

Abstract:根据2018年4月(春季)、10月(秋季)在舟山群岛东侧海域进行的渔业资源调查数据, 利用相对重要性指数确定调查海域各种鱼类的重要性程度, 应用平均拥挤度、Shannon指数及Pianka指数, 分析了该海域主要鱼类的生态位宽度及生态位重叠。结果表明, 春季与秋季主要鱼类分别有10种与12种。春、秋两季主要鱼类生态位宽度值范围分别为0.06~2.01、0.34~2.19, 两季生态位宽度值差异较大, 其中广生态位种(B_i≥2.0)春季仅小黄鱼(Larimichthys polyactis) 1种, 而秋季为叫姑鱼(Johnius grypotus)、鮸(Miichthys miiuy)、小黄鱼和六丝钝尾虾虎鱼(Amblychaeturichthys hexanema) 4种, 春、秋两季中生态位种(2.0>B_i≥1.0)均为6种, 窄生态位种(1.0>B_i>0)春季3种, 秋季为2种。两季生态位重叠程度差异较大, 春季生态位重叠显著的种对有20对, 占总种对数的44.44%, 重叠程度相对较高; 而秋季主要鱼类重叠程度较低, 种对间重叠显著的只有16对, 占总种对数的24.24%。冗余分析(RDA)显示温度、盐度变化是影响春秋季主要鱼类生态位分化的直接因素, 水深则为重要因素, 主要鱼类受这些环境因子的影响表现出较为明显的生态位分化现象。

Abstract:软骨鱼类(鲨、鳐和银鲛类)多位居海洋食物网的顶端或近顶端, 通过下行效应调控海洋生态系统结构和功能, 多为生态系统中的关键性物种。脊椎骨是软骨鱼类支撑身体的重要硬组织, 其生长贯穿整个生活史, 主要应用于鉴定年龄。随着微化学技术的兴起, 并结合脊椎骨轮纹的特殊结构, 可进而掌握鱼类整个生活史中摄食及洄游信息。目前, 国内外基于脊椎骨的微化学研究主要集中在稳定同位素和微量元素分析, 并已取得一定的进展。本文在归纳国内外应用脊椎骨在软骨鱼类生长、摄食及洄游中的应用案例基础上, 着重分析了脊椎骨应用于年龄鉴定及校正、摄食及洄游等核心问题上的研究现状和发展前景, 以期为今后学者展开基于软骨鱼类脊椎骨的相关研究提供参考。