冻融循环处理对皱纹盘鲍质地的影响

为探究冻藏温度的波动对鲍鱼质地的影响,选取商品速冻鲍鱼的贝柱部分作为研究对象,分析了5次冻融循环处理对肌肉的质构、保水性、场核磁共振T₂弛豫时间及蛋白氧化的影响。结果表明：鲍鱼肌肉质构的硬度、弹性和咀嚼性指标随冻融次数的增多而显著降低(P < 0.05),5次循环后分别降至原来的11.21、3.03和10.04%,而剪切力相反,发生显著升高;鲍鱼肌肉持水性的解冻损失、离心损失和蒸煮损失发生了显著升高(P < 0.05),分别从2.28、16.09和38.51%升高至10.50、28.53和43.67%;鲍鱼肌肉水分分布中结合水几乎不受影响,而不易流动水与自由水的弛豫时间T₂₂与T₂₃明显增大,其对应的峰面积比例P₂₂显著上升和P₂₃显著降低(P < 0.05);鲍鱼肌肉蛋白结构及功能的表面疏水性先上升后降低,羰基含量显著降低而活性巯基含量显著升高(P < 0.05)。这些研究表明,冻融循环会对鲍鱼的肌肉质地造成破坏,致使其质地品质劣变,商品价值降低,最终影响消费者的可接受性。     

环境因子与饲料对鲍生长影响的研究进展

主要综述了环境因子、饲料种类和营养成分对鲍生长发育的影响,详细叙述了鲍的最适生长盐度、温度,介绍了投喂鲍喜食的饵料和必要的营养元素对鲍生长起着至关重要的作用,分析了环境因子及饵料对鲍能量代谢的影响,以期为鲍养殖业的发展提供参考。     

赤潮对筏式吊笼养鲍的影响及应对措施

赤潮是海洋养殖主要灾害之一,频发于网箱等渔排养殖集中区,易造成鲍等养殖动物的大量死亡。该文总结近几年渔排式养鲍集中区赤潮发生情况,分析了赤潮引发鲍死亡的主要原因,并提出赤潮防范与应对措施。     

福建大连1号杂交鲍肠道及养殖水体中细菌产酶能力的分析

从大连1号杂交鲍养殖水体及肠道中分离出18株弧菌和32株异养型细菌,对其进行革兰氏染色及产胞外酶能力的分析。结果表明,养殖水体中分离出的14株弧菌和22株异养细菌,共有22株(61.1%)具有分泌脂肪酶、卵磷脂酶、明胶酶、蛋白酶、淀粉酶或溶血毒素的能力;鲍肠道分离出的4株弧菌和10株异养细菌,共有9株(64.3%)具有此产酶能力。但总体上,从水体中分离出的菌株的产酶能力要强于从鲍肠道中分离出的菌株,且数量更多,尤其是水体中异养细菌。在所有的50株菌株中,有2株(4%)具有产3种酶(脂肪酶、卵磷脂酶和溶血素)的能力;有9(18%)株具有产2种酶的能力。产酶菌株大部分为革兰氏阴性。本次试验对鲍肠道及养殖水体中菌株产酶能力进行了分析,为大连1号杂交鲍在南方的健康养殖提供科学依据。     

Growth and reproductive performance of triploid and diploid blacklip abalone, Haliotis rubra (Leach, 1814)

Growth and reproduction of triploid and diploid blacklip abalone Haliotis rubra (Leach, 1814) were compared in a 30-month study. Triploidy was induced by inhibition of the second polar body formation using 6-dimethylaminopurine (6-DMAP) or cytochalasin B (CB). There were no significant differences in growth and survivorship between triploid and diploid abalone. However, triploid abalone had a more elongated shell and greater foot muscles than diploid abalone. A slightly curvilinear growth in shell length was conformed to all treatments. While diploid abalone had reached sexual maturity and spawned during the study, gonadal development and gamete maturation were abnormal in triploids. Female triploids lacked an apparent gonad at the macroscopic level but microscopic examination revealed that they had a thin layer of oogonia development. In contrast, male triploids were able to form similar-sized gonads to diploids during most of the reproductive period, but with brown-yellow discolouration and stalled gametogenesis at spermatocyte formation. Sex ratio of triploid abalone did not deviate from 1:1. With the onset of sexual maturation, growth and gonadal maturation occurred concurrently in diploid abalone, and there was no indication that growth of (diploid) abalone was reduced.     

Variability and relationships between flow preference,aggregation size and forage frequency,duration and trajectories of juvenile Haliotis discus hannai Ino

The behaviour of individual abalone in a population is known to vary, and higher levels of activity are linked to better survival rate and faster growth. Considering that continuous illumination at night may cause stress to the abalone which would affect their behaviour over time, in this study observations were made under brief and minimal illumination. The observation lasted for 30 days. The relationships between activity traits were analysed in juvenile Haliotis discus hannai Ino, such as forage frequency, duration and trajectories; flow preference; and aggregation size. The aim was to identify an indicator of the abalone activity status, with the ultimate objective being to provide activity‐related data that might be useful in farm rearing. Ten traits related to locomotion behaviour of 47 juvenile abalone were recorded under laboratory conditions. The results showed that the exploratory level varied between individuals. More exploratory individuals foraged more frequently, spent more time outside hides, started foraging earlier and preferred higher water flow rate than less exploratory individuals. More exploratory and less exploratory individuals also differed in their extensive movements, hide‐shift frequency and aggregation size.     

引起九孔鲍大量死亡的一种球状病毒

鲍是重要的海水养殖经济贝类之一。近年来,受夏季高温胁迫,养殖鲍时常发生大规模死亡,给养殖业者带来了巨大的经济损失。本文回顾了近年来发生的养殖鲍大规模死亡事件,并从鲍的生长、繁育、存活、代谢和酶的活性等生理生化指标,细胞免疫、抗氧化系统、热休克蛋白、调控细胞凋亡、NF-κB信号通路、PI3K-AKT信号通路等相关基因的表达,及DNA甲基化和遗传多样性等方面总结了鲍高温胁迫响应机制的研究进展。现有研究表明,高温胁迫会引起鲍的摄食、新陈代谢等生理生化的异常,破坏其机体内环境的稳态,降低其抵抗病原入侵的能力和应对外部环境刺激的能力,从而对其生长、免疫等产生不良的影响,最终降低其生长速率、繁殖效率,甚至导致鲍的死亡。在此基础上,本文提出了鲍养殖生产中高温胁迫的预防调控措施,以期为了解鲍对高温胁迫的响应机制、开展鲍的耐高温品种选育研究、预防鲍夏季高温大规模死亡的发生等提供参考。     

我国鲍鱼养殖产业现状与展望

鲍养殖业已成为我国海洋经济发展中的重要组成部分。近年来,因低氧胁迫,特别是高温低氧联合胁迫而导致的养殖鲍大规模死亡的现象时常发生,给鲍养殖业带来了严重的经济损失,已成为阻碍鲍养殖业健康可持续发展的重要环境因素。本文从鲍的生长、存活、生理生化指标 (包括心率、代谢、酶的活性、pH等)、免疫机能、胁迫响应基因及其表达调控等方面综述了鲍低氧胁迫响应机制的研究进展,以期为进一步研究鲍的低氧胁迫响应机制、开展鲍耐低氧新品种的选育等提供参考。此外,本文还提出了鲍低氧胁迫的预防调控措施,希望对养殖业者减少因夏季低氧胁迫诱发的养殖鲍大规模死亡而造成的损失有所帮助。

     

Evaluation of Antiviral Effect against SARS-CoV-2 Propagation by Crude Polysaccharides from Seaweed and Abalone Viscera In Vitro

Crude polysaccharides, extracted from two seaweed species (Hizikia fusiforme and Sargassum horneri) and Haliotis discus hannai (abalone) viscera, were evaluated for their inhibitory effect against SARS-CoV-2 propagation. Plaque titration revealed that these crude polysaccharides efficiently inhibited SARS-CoV-2 propagation with IC₅₀ values ranging from 0.35 to 4.37 μg/mL. The crude polysaccharide of H. fusiforme showed the strongest antiviral effect, with IC₅₀ of 0.35 μg/mL, followed by S. horneri and abalone viscera with IC₅₀ of 0.56 and 4.37 μg/mL, respectively. In addition, immunofluorescence assay, western blot, and quantitative RT-PCR analysis verified that these polysaccharides could inhibit SARS-CoV-2 replication. In Vero E6 cells, treatment with these crude polysaccharides before or after viral infection strongly inhibited the expression level of SARS-CoV-2 spikes, nucleocapsid proteins, and RNA copies of RNA-dependent RNA-polymerase and nucleocapsid. These results show that these crude marine polysaccharides effectively inhibit SARS-CoV-2 propagation by interference with viral entry.     

Growth and feeding in juvenile triploid and diploid blacklip abalone, Haliotis rubra (Leach, 1814), at two temperatures

Growth and feeding of juvenile triploid and diploid blacklip abalone Haliotis rubra (Leach, 1814) were investigated at two temperatures of 17 and 21 °C over a 50‐day period. There were no differences in growth between triploid and diploid abalone as measured by shell length and body weight. Both triploid and diploid abalone increased in length but not in weight at 21 °C. Condition indices were similar for triploid abalone maintained at both temperatures; however, those for diploid abalone were significantly higher at 17 °C than at 21 °C. Food intake was significantly greater yet feed conversion efficiency was significantly lower in triploid than in diploid abalone. Both the feeding variables were independent of temperature. On average, diploid abalone were able to convert 1 g of dry food ingested to 0.58 g of body weight, but triploid abalone only 0.44 g.