低盐度和不同硫酸铜浓度对银鲳鳃离子调节酶和肝抗氧化功能的影响

开展银鲳(Pampus argenteus)试养海域的盐度易随气候降低, 且受到一定程度Cu等重金属污染, 研究低盐条件下硫酸铜对银鲳的影响十分必要。本实验首先进行银鲳幼鱼低盐度适应, 将盐度以4的幅度从24逐步降低至12。稳定后进行硫酸铜胁迫, 在盐度12下CuSO₄·5H₂O浓度梯度设为0、0.1、0.3、0.5 mg·L^–1, 盐度24下CuSO₄·5H₂O浓度梯度设为0、0.5 mg·L^–1, 胁迫持续144 h。通过检测两种鳃离子调节酶: Na⁺/K⁺-ATP酶(NKA)和V-H⁺-ATP酶(VHA), 以及3种肝抗氧化活性物质－还原型谷胱甘肽(GSH)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT), 探究低盐条件下铜离子对银鲳幼鱼上述指标的影响。结果显示, 盐度逐步降低后, NKA与VHA活力呈上升后下降的变化, 之后NKA活力随硫酸铜浓度增加而减弱; VHA活力加入硫酸铜后都出现显著下降, 其中CuSO₄·5H₂O 0.3 mg·L^–1与0.5 mg·L^–1组在72 h时下降更为明显; 盐度24硫酸铜组NKA和VHA活力都在24 h时增强而后减弱。GSH含量和SOD活力在盐度降低时出现跃升, CAT活力则呈波动变化, 加入硫酸铜后, 0.3 mg·L^–1与0.5 mg·L^–1组GSH含量持续下降后显著上升而后回落; 各硫酸铜组SOD活力都出现增强后回落的变化; 0.3 mg·L^–1与0.5 mg·L^–1组CAT活力在72 h有显著增强。本实验表明, 铜离子对NKA与VHA有抑制作用, 盐度降低时其作用更强; GSH、SOD和CAT的变化能反映低盐度和铜离子对银鲳的伤害程度。银鲳对水体铜离子有一定的抗性, 但在盐度降低等环境变化时, 应当密切注意水体中铜等重金属浓度。

     

嗜水气单胞菌灭活疫苗免疫后大鲵外周血免疫指标的变化

以福尔马林灭活的嗜水气单胞菌(Aeromonas hydrophila)作为免疫原(F-AH), 通过腹腔注射免疫健康大鲵(Andrias davidianus), 分别于免疫后的第1、4、7、14、21、28天采集血液样品, 进行大鲵外周血液的血细胞计数与白细胞组成分析, 测定吞噬细胞的吞噬活性以及血清中和抗体效价, 于免疫28 d后进行攻毒感染试验。结果表明, 与对照组相比, 在免疫后第4、7、14和第21天, 免疫大鲵外周血中血细胞数量显著增加, 其中, 红细胞和白细胞数量均于第4天达峰值, 分别为7.83×10⁷个/mL和6.74×10⁶个/mL; 嗜中性粒细胞百分比也在第4天达峰值, 为28.60%, 单核细胞百分比在第7天达峰值, 为10.53%; 吞噬细胞活性显著提高, 且吞噬百分比和吞噬指数均在第4天达到最高值, 分别为34.09%和3.73。随后, 淋巴细胞百分比和中和抗体效价显著增加, 均在第21天达峰值, 分别为75.30%和1︰426.67。攻毒感染实验结果表明, 免疫组的相对免疫保护率为69.23%。由此可见, F-AH免疫原能够通过促进血细胞数量的增加、吞噬细胞吞噬活性增强以及特异性抗体的产生等方式提高大鲵的免疫保护力。

     

NaCl盐度和NaHCO3碱度对鲤、鲫和大鳞鲃的精子活力及其受精率的影响

研究了不同NaCl盐度(0、1、2、3、4、5、6、7、8、9、10、11、12)和NaHCO₃碱度(0 mmol/L、10.00 mmol/L、15.85 mmol/L、25.12 mmol/L、39.81 mmol/L、63.10 mmol/L)对松浦镜鲤(Cynipus carpio)、方正鲫(Carassius auratus gibelio)和大鳞鲃(Barbus capito)精子活力及其受精率的影响。结果表明: 1) 在盐度为4时, 方正鲫和大鳞鲃精子的激烈运动时间、快速运动时间和寿命最长, 方正鲫分别为(90.11±9.03) s、(126.34±13.90) s和(154.27±11.36) s; 大鳞鲃分别为(48.91±1.43) s、(62.19±4.28) s和(90.68±4.46) s。在盐度为5时松浦镜鲤精子的激烈运动时间、快速运动时间和寿命最长, 分别为(72.44±9.42) s、(102.16±8.82) s和(206.99±6.65) s。2) 当盐度达到8以上时, 3种鱼的精子激活将受到抑制; 盐度大于10时, 方正鲫和大鳞鲃精子死亡; 盐度大于11时, 松浦镜鲤精子死亡。3) 在碱度为15.83 mmol/L时, 3种鱼的精子激烈运动时间、快速运动时间和寿命均最长, 且显著高于其他碱度条件下的精子活力(P<0.05)。4) 在盐度为1时, 方正鲫和大鳞鲃受精率达到最高分别为63.0%和68.0%, 在盐度为3时, 松浦镜鲤受精率达到最高为72.3%, 当盐度大于3时, 受精率开始呈明显下降趋势。碱度为10.00 mmol/L时, 3种鱼的受精率均最高, 分别为75.4%、54.0%和66.0%。本实验旨在通过测定不同NaCl盐度、NaHCO₃碱度条件下3种鱼类精子的活力和受精率所受的影响, 为北方地区碳酸型盐碱水域的渔业开发利用提供基础资料。 

     

斜带石斑鱼(♀)×鞍带石斑鱼(♂)杂交子代仔、稚鱼的异速生长

应用实验生态学的方法研究斜带石斑鱼(Epinephelus coioides)(♀)×鞍带石斑鱼(E. lanceolatus)(♂)杂交子代(青龙斑)仔、稚鱼阶段的生长模式。利用Q-Capture Pro 6软件对仔、稚鱼(0~28日龄)的全长、肛前长、体高、头长、眼径、口径、第二背鳍棘、腹鳍棘、胸鳍、臀鳍和尾鳍等11个可量性状进行拍照和测量。研究表明青龙斑全长的生长可分为3个阶段, 不同阶段生长速率存在显著差异(P<0.05)。各功能器官均表现为异速生长。在11个可量性状中, 肛前长为等速生长, 头长和体高的生长由正异速生长分别转变为等速生长和负异速生长; 头部器官(口径和眼径)生长在20 ~22日龄时出现拐点, 拐点后分别转变为等速生长和负异速生长; 运动器官在拐点前均为正异速生长, 除臀鳍外, 其他各鳍的生长均存在不同的拐点。通过对青龙斑仔、稚鱼异速生长的研究, 发现在早期发育过程中, 有关摄食、感觉、运动等功能器官得到优先发育。在人工繁殖苗种的培育中, 可根据青龙斑重要器官发育的优先性, 创造有利的外部环境, 提高苗种的成活率。

     

肌醇对哲罗鲑生长性能、体成分及消化酶活性的影响

为了探讨肌醇对哲罗鲑(Hucho taimen)生长性能、体成分及消化酶活性的影响, 以鱼粉、明胶和酪蛋白为蛋白源配制肌醇含量为99.8(不添加肌醇)、199.8、299.8、499.8、699.8、899.8和5 099.8 mg/kg的7种饲料, 分别投喂7个处理组, 每组3个重复, 每重复30尾鱼, 进行为期56 d的饲养实验。结果表明, 投喂肌醇含量为499.8 mg/kg饲料组的增重率最大, 且与添加量低于299.8 mg/kg的3个饲料组差异显著(P<0.05)。饲料系数在499.8 mg/kg饲料组最低, 在5 099.8 mg/kg饲料组最高, 两组间差异显著(P<0.05)。肌醇含量为499.8~899.8 mg/kg饲料组的特定生长率显著高于99.8~299.8 mg/kg及5 099.8 mg/kg饲料组(P<0.05)。肌肉中水分、粗脂肪和粗蛋白各组间差异不显著(P>0.05), 肝淀粉酶、幽门盲囊脂肪酶活性各组间差异不显著(P>0.05)。肠道蛋白酶活性在肌醇含量为199.8~499.8 mg/kg饲料组较高, 显著高于其他组(P<0.05), 脂肪酶活性在299.8~899.8 mg/kg饲料组高于99.8 mg/kg饲料组(P<0.05)。由此得出, 饲料中适量添加肌醇可提高哲罗鲑的生长性能及消化酶活性; 肌醇含量过低时哲罗鲑增重率、消化酶活性均较低; 肌醇含量过高时哲罗鲑特定增长率、消化酶活性较低, 饲料系数较高; 以增重率为指标由折线回归模型分析得出, 肌醇的最适含量为536.6 mg/kg饲料。

     

烟台近海3种贝类中呈味核苷酸和氨基酸的测定及比较分析

对水产品中呈味核苷酸和氨基酸的高效液相色谱检测方法进行了优化, 并对烟台近海长牡蛎(Ostrea gigas)、栉孔扇贝(Chlamys farreri)和中国蛤蜊(Mactra chinensis)3种贝类中呈味核苷酸和氨基酸的含量进行了比较分析, 从而为开发贝类复合调味料提供科学依据。以纯水提取呈味物质, 采用DABS-Cl柱前衍生反相高效液相色谱法测定游离氨基酸, 流动相为17 mmoL/L柠檬酸溶液(pH 6.4, 含4%DMF)和乙腈溶液(含4%DMF), 梯度洗脱, 检测波长436 nm。反相离子对色谱法测定呈味核苷酸, pH 4.5的磷酸二氢钾溶液和乙腈溶液为流动相, 磷酸二氢钾溶液内含5 mmoL/L四甲基氢氧化氨(TMAOH), 梯度洗脱, 检测波长254 nm。方法加标回收率为90.2%~108%, 相对标准偏差(RSD)为0.7%~7.1%。准确度、精密度均满足分析要求。测定结果显示: 长牡蛎中牛磺酸、丙氨酸和谷氨酸含量较高, 栉孔扇贝中甘氨酸、牛磺酸和丙氨酸含量较高, 中国蛤蜊含有较多的甘氨酸、牛磺酸和丙氨酸; 3种贝类中, 丙氨酸、谷氨酸的TAV均大于1, 栉孔扇贝和中国蛤蜊中, 甘氨酸的TAV大于1, 对呈味具有显著贡献。呈味核苷酸中, 长牡蛎中IMP含量最高, 占总呈味核苷酸的80%, 其次是GMP。中国蛤蜊中AMP含量最高, 其次是IMP。而栉孔扇贝中仅检测到IMP。3种贝类中呈味核苷酸含量虽然都较低, TAV未超过1, 但核苷酸之间、核苷酸和氨基酸之间的协同增效作用, 会对贝类的呈味产生重要影响。本研究通过对烟台近海3种贝类中各类鲜味物质和多种辅助呈味物质的含量、比例关系及其相互作用规律进行探讨, 旨在为充分利用贝类营养氨基本作为复合调味料及其功能性开发和评价提供科学依据。

     

鲢小清蛋白的cDNA克隆及在大肠杆菌中的原核表达

以鲢(Hypophthalmichthys molitrix)肌肉cDNA为模板, 利用小清蛋白特异性引物进行PCR扩增, 克隆得到β小清蛋白两种不同亚型, 即Ⅰ型、Ⅱ型编码区基因。将目的基因片段连接到pET28a (+)表达载体, 并在大肠杆菌[E.coli BL21 (DE3)]中诱导表达。结果表明, 经诱导的小清蛋白重组质粒菌株有特异的蛋白表达。SDS-PAGE分析显示, 目的蛋白的分子量约为13 kD, 与预期大小一致。菌体超声破碎后发现2种亚型的小清蛋白均为可溶表达。利用Ni²⁺亲和层析柱对重组蛋白进行纯化, 得到高纯度的重组小清蛋白PVⅠ和PVⅡ。经Western Blot 鉴定, 重组小清蛋白PVⅠ和PVⅡ均能与抗鲢小清蛋白单克隆抗体反应。本研究为进一步分析小清蛋白的结构与致敏性的关系提供了重要的基础。

     

斑鳜精液超低温冷冻保存及其效果分析

实验所用翘嘴鳜(♀, Siniperca chuatsi) 2~3龄, 体质量1 000~1 500 g; 斑鳜(♂, Siniperca scherzeri Steindachner)1~2龄, 体质量300~500 g。于繁殖季节选取成熟度好的亲鱼以促黄体素释放激素类似物(LHRH-A2)、绒毛膜促性腺激素(HCG)和马来酸地欧酮(DOM)进行催产。通过筛选D-15、D-17、Ringer液 和 M-Hank’s液4种稀释液和二甲基亚砜 (DMSO)、 甘油(Gly)、乙二醇 (EG)、1,2-丙二醇 (PG)和二甲基甲酰胺 (DMF)5种抗冻剂, 发现DMSO和D-17分别是优选的抗冻剂和稀释液。以D-17作为斑鳜精子的稀释液, 按照1︰3(精液︰稀释液)体积比稀释, 添加10%体积的DMSO作为抗冻剂, 按照三步冷冻法超低温冷冻保存, 37℃水浴解冻的斑鳜精子, 经CASA分析精子活率为(83.26±18.20)%, SCGE检测表明70%以上的精子核DNA不会发生损伤; FCM分析表明26.74%的解冻精子有完整的细胞膜且线粒体功能正常; 用冷冻复苏斑鳜精子与翘嘴鳜精卵进行人工授精, 最高受精率(39.6±6.5)%, 温度24~28℃孵化时间38 h, 孵化后的鱼苗发育正常, 开口1周以后的鱼苗全长(1.346±0.255 ) cm, 体高(0.438±0.103) cm, 体质量(0.045±0.020) g。鲜精受精鱼苗和冻精受精鱼苗在开口后1周的生长没有显著差异。因此认为D-17+10% DMSO可用于斑鳜精液的超低温冷冻保存。本研究将有助于斑鳜种质资源的收集保存和冷冻保存的斑鳜精液在翘嘴鳜(♀)×斑鳜(♂)杂交中的应用。

     

臭氧对斜带石斑鱼胚胎发育和初孵仔鱼的毒性效应

为了评价臭氧消毒技术及其对石斑鱼(Epinephelus)潜在的毒性, 首先评价了两种质量浓度(0.05 mg/L和0.30 mg/L)臭氧对亚硝酸盐和弧菌的水处理效果, 并以斜带石斑鱼(E. coioide)受精卵为实验材料, 探讨臭氧对胚胎发育和初孵仔鱼的毒性作用。结果显示, 臭氧的水处理效果良好, 0.30 mg/L的臭氧在3 h内对水中亚硝酸盐的去除率可达72.29%; 0.05 mg/L的臭氧处理20 min后也能完全杀灭弧菌。但高浓度臭氧(0.30 mg/L)对胚胎发育具有一定的毒性, 会造成胚胎油球数目增多、萎缩、解体和死亡, 而低浓度组(0.05 mg/L)臭氧处理后22 h胚胎孵化率高达(87.14±7.20)%, 与对照组无显著差异。与胚胎相比, 初孵仔鱼对臭氧更加敏感, 0.05 mg/L的臭氧处理24 h也会导致初孵仔鱼的全部死亡。本研究结果旨在为石斑鱼育苗及养殖过程中正确使用臭氧消毒技术提供重要的数据参考和理论依据。

     

小肽对星斑川鲽幼鱼消化酶活性、抗氧化能力和生化组成的影响

选用初始体质量(15.30?.03) g的星斑川鲽(Platichthys stellatus)幼鱼, 在其基础饲料中添加不同梯度的小肽(鱼水解肽), 添加水平分别为0 (对照组)、0.25%、0.50%、0.75%、1.0%和1.5%, 每组设3个重复, 每个重复30尾鱼, 实验周期为56 d。结果表明: 1) 除肝胰脏淀粉酶外, 星斑川鲽幼鱼胃、肠和肝胰脏中消化酶活性在各组间均存在显著性差异(P<0.05), 且随着小肽添加水平的上升而呈现先上升后下降的趋势。2) 饲料中添加小肽显著降低了肝胰脏和血清中的丙二醛含量(P<0.05), 并显著提高了1.0%和1.5%小肽添加组血清的总抗氧化能力, 而对肝胰脏超氧化物歧化酶和谷胱甘肽还原酶均无显著影响(P>0.05), 同时, 1.0%和1.5%小肽添加组血清超氧化物歧化酶和谷胱甘肽氧化物酶活性以及0.75%和1.0%小肽添加组血清谷胱甘肽还原酶活性均显著高于对照组(P<0.05)。3)小肽添加组苯丙氨酸含量均显著高于对照组(P<0.05), 0.50%~1.5%小肽添加组亮氨酸含量也显著高于对照组(P<0.05), 而其他氨基酸在不同小肽添加组间均无显著性差异(P>0.05); 0.75%和1.0%小肽添加组多不饱和脂肪酸含量显著高于对照组(P<0.05), 0.5%~1.0 %小肽添加组DHA和EPA含量均显著高于对照组(P <0.05), 而ARA在不同添加组间无显著差异(P>0.05)。综上可知, 饲料中添加适量小肽可有效提高消化酶活性和抗氧化能力, 促进机体生长, 并在一定程度上提高鱼肉品质。

     

Food and feeding habits of Tilapia aurea (Steindachner) (Cichlidae) in Lake Kinneret (Israel)

An analysis of the food of 274 specimens of Tilapia aurea (Steindachner), which had been collected in Lake Kinneret, showed that this species is mainly a zooplankton consumer.A study of the quantitative dynamics of the food components in the course of a year has proved that the species in question feeds more intensely in spring, this being the time when zooplankton forms are more abundant in the water of the lake. Vegetable detritus, mixed with plankton and benthos forms, served as additional and alternative food.The lack of clearly positive degree of food component selectivity, as well as the low values of the intestine repletion index and of the condition coefficient, account for the slowness in growth of Tilapia aurea in Lake Kinneret.The low values of the growth and feeding indices are due, according to the authors, to the pressure brought to bear by the other local fish species, which are competitors for the same food.     

Food and feeding habits of Tilapia zillii (Gervais) (Cichlidae) in Lake Kinneret (Israel)

Analysis of the gut content of 329 specimens of T. zillii (Cichlidae) collected from Lake Kinneret, has shown great variation in the sorts of food.A study of seasonal dynamics has proved the prevalence in the food of Chironomida pupae (Diptera) in winter and spring and of zooplankton forms in summer and autumn. The additional food consisted of the various groups of algae, the most frequently found being Cyanophyta (100%) and Pyrrophyta (64.16%). An extremely voraceous species, it consumes — while searching for its preferred food — anything that comes its way in the water: algae, scraps of macrophytes, autochthonous and allochthonous insects, and forms of benthic origin, such as Nematoda, Ostracoda, Porifera and Chironomida (larvae).The satiation index is high (between 4.08 and 5.63), in contradiction to the low values of the coefficient of condition (between 3.05 and 3.51), and with the slow rate of growth in Lake Kinneret. The main food of Tilapia zillii, consists of arthropod species with a chitin content (which is eliminated unchanged) of more than 50% of the total weight, and this may account for the poor exploitation of the trophic base.This species of fish may be considered as being detrimental to others (i.e. commercially important species) because of its successful competition for food, and not, as is often incorrectly assumed, because it is an aggressive consumer of their spawn and fry.     

Incorporation and metabolism of (n-3) and (n-6) polyunsaturated fatty acids in phospholipid classes in cultured turbot (Scophthalmus maximus) cells

The incorporation and metabolism of various (n-3) and (n-6) polyunsaturated fatty acids (PUFA) supplemented to the culture medium was investigated in a turbot cell line (TF). The distribution, and the occurrence and extent of further metabolism of incorporated PUFA via desaturation/elongation mechanisms in specific phospholipid classes was determined from the different fatty acid compositions. The cells contained Δ6 and Δ4 desaturase activities but were generally deficient in C18–20 elongase activity. Δ5 Desaturase activity was generally masked by this deficiency but was present. The compositional data indicated that there was a high degree of specificity between individual phospholipid classes and particular fatty acids probably driven by the specificities of the acylating enzymes. The highest percentages of the supplemented acids were generally observed in the phosphatidic acid/cardiolipin fraction (PA/CL), suggesting a role for PA in the incorporation of the supplemented acids into the phospholipid pool. PI had a characteristic composition consistent with a putative role as a pool of precursor fatty acid for eicosanoid synthesis. Mechanisms were evident for generating and/or maintaining this composition.     

Incorporation and metabolism of (n-3) and (n-6) polyunsaturated fatty acids in phospholipid classes in cultured rainbow trout (Salmo gairdneri) cells

The incorporation and metabolism of various (n-3) and (n-6) polyunsaturated fatty acids supplemented to the culture medium was investigated in the rainbow trout cell line, RTG-2. The distribution, and the occurrence and relative extent of further desaturation and elongation of the incorporated acids was determined in individual phospholipid classes by analysis of the fatty acid compositions. RTG-2 cells exhibited Δ6 and Δ5 desaturase activities whereas Δ4 desaturase activity was almost totally absent. The percentage of precursor acids was greatest in the phosphatidic acid/cardiolipin fraction (PA/CL), suggesting a role for possibly PA in the initial incorporation of these acids into the phospholipid pool. The compositional data indicated that individual intermediates and products of the desaturation pathways were associated with specific phospholipid classes probably via mechanisms depending upon the specificities of the acylating enzymes. The composition of phosphatidylinositol (PI) and the tightly controlled mechanisms for generating/maintaining it are consistent with a role for this phospholipid in providing precursor fatty acid for eicosanoid synthesis.     

鱼体内环境激素ＤＭＰ和ＤＥＰ的检测方法

建立同时检测鲫(Carassuys auratus Linnaeus)血浆和肌肉中邻苯二甲酸二甲酯(DMP)和邻苯二甲酸二乙酯(DEP)的高效液相色谱方法,进行初步的代谢动力学研究.血浆样品经液-液萃取,肌肉样品经液-液萃取和固相小柱处理后,以乙腈:水= 40:60(V/V)为流动相,流速1.0 mL/min,采用SHIMADZU ODS柱(150 mm×4.6 mm; i.d., 5 μm)色谱柱分离.测定鲫经口染毒后血浆和肌肉中DMP和DEP的浓度.结果表明,标准曲线线性范围为0.05～10.0 μg/mL,线性关系良好(r>0.99),定量限为0.05 μg/mL,回收率95%以上,日内变异系数和日间变异系数均低于15%.经口染毒48 h内,鲫血浆和肌肉中均能检测到DMP和DEP的残留.该法操作简便、快速、灵敏、准确,已经初步用于鲫血浆和肌肉中DMP和DEP的代谢动力学和残留研究.     

鱼体内环境激素DMP和DEP的检测方法

建立同时检测鲫(Carassuys auratus Linnaeus)血浆和肌肉中邻苯二甲酸二甲酯(DMP)和邻苯二甲酸二乙酯(DEP)的高效液相色谱方法,进行初步的代谢动力学研究。血浆样品经液-液萃取,肌肉样品经液-液萃取和固相小柱处理后,以乙腈∶水=40∶60(V/V)为流动相,流速1.0mL/min,采用SHIMADZU ODS柱(150mm×4.6mm;i.d.,5μm)色谱柱分离。测定鲫经口染毒后血浆和肌肉中DMP和DEP的浓度。结果表明,标准曲线线性范围为0.05~10.0μg/mL,线性关系良好(r>0.99),定量限为0.05μg/mL,回收率95%以上,日内变异系数和日间变异系数均低于15%。经口染毒48h内,鲫血浆和肌肉中均能检测到DMP和DEP的残留。该法操作简便、快速、灵敏、准确,已经初步用于鲫血浆和肌肉中DMP和DEP的代谢动力学和残留研究。     

卵形鲳鲹碱性磷酸酶和酸性磷酸酶的分布及其低温保存

测定了卵形鲳鲹（Trachinotus ovatus）的碱性磷酸酶（AKP）和酸性磷酸酶（ACP）在不同器官和肌肉中的活性;将样品分别置于4℃、-20℃和-80℃下保存3 d、7 d、15 d和30 d,研究不同保存温度和保存时间对样品中AKP和ACP酶活性的影响。结果表明,在卵形鲳鲹胃中未检测到AKP活性,其他器官中均检测到AKP活性,AKP活性大小顺序依次为后肠〉幽门盲囊〉肾〉中肠〉肝〉前肠〉心〉肌肉;ACP在卵形鲳鲹体内分布较广,所测器官中均有ACP活性,其活性大小顺序为肝〉肌肉〉后肠〉中肠〉幽门盲囊〉肾〉心〉前肠〉胃。低温保存试验结果表明,AKP和ACP在4℃和-20℃下保存,时间越长,活力越低;在-80℃下保存,AKP和ACP活力在30 d内基本稳定,只有幽门盲囊的AKP和ACP在长时间保存后活力明显下降。     

Quality Indices of Squid (Photololigo duvaucelii) and Cuttlefish (Sepia aculeata) Stored in Ice

The objective quality indices of squid (Photololigo duvaucelii) and cuttlefish (Sepia aculeata) stored in ice were compared with the subjective counterparts. Sensory (overall quality rating, quality index method [QIM], and multisample difference test), microbiological (total viable count [TVC], psychrophilic count), chemical (trichloroacetic acid-soluble peptide [TCA-soluble peptide], trimethylamine nitrogen [TMA-N], total volatile bases nitrogen [TVB-N], ammonia content, and protein pattern), and physical analyses (expressible drip, color, and texture) were determined in both species during 16 days of iced storage. As storage time increased, TCA-soluble peptide, TVB, ammonia content, and expressible drip were increased (p < 0.05). TMA content was markedly increased after 10 and 8 days of storage in squid and cuttlefish, respectively. Both TVC and psychrophilic count increased as the storage time increased (p < 0.01). Myosin heavy chain was degraded with coincidental decrease in shear force and sensory texture during storage (p < 0.05). According to the overall rating score, shelf life of both species in ice was estimated to be 6 days. The increases in ammonia content and expressible drip were highly correlated with the decrease in overall quality rating and increase in quality index score of squid and cuttlefish (p < 0.01).     

虚拟现实(VR)和增强现实(AR)技术在渔业上的应用

随着计算机网络技术的发展,增强现实(VR)和虚拟现实(AR)技术逐渐进入人们的视野和现实生活中。作为新兴的产业之一,VR和AR技术在许多行业都具有广阔的应用前景。文章介绍了VR和AR技术的基本概念、技术特点,并着重探讨了这两项技术在渔业领域的应用现状和发展趋势,有助于加深渔业从业者对VR和AR技术的认识,拓宽这两项技术在渔业领域的应用场景。     

Tetraploid induction in tropical oysters,Crassostrea belcheri (Sowerby) and Crassostrea iredalei (Faustino)

Tetraploid induction has been conducted on temperate oysters but not on tropical oysters. In this study, different heat shocks (32, 35 and 38°C) and cold shocks (1, 4 and 7°C) were used to induce tetraploidy in two tropical oyster species, Crassostrea belcheri and Crassostrea iredalei, through meiosis I inhibition. Temperature shocks were applied on the newly fertilized eggs at 8–10 min post fertilization and terminated when second polar bodies began to form in the control eggs. The ploidy of the larvae and spat was determined via direct chromosome count. The percentage of larval survival until Day 20 was low (between 0.4% and 42.9%) for both temperature shocks and oyster species. No surviving larva was recorded for induction at 1, 4 and 38°C. Tetraploid spat was only recorded in C. iredalei but the percentage is low through heat shock induction of 32 and 35°C. This study shows that the tetraploid induction success rate was slightly higher in C. iredalei compared to C. belcheri. No surviving tetraploid spat were recorded for both oyster species through the cold shock method. This study shows that heat shock can be used to inhibit meiosis for the production of tetraploids but more experiments need to be conducted to determine the optimum temperature when dealing with tropical oysters.