臭氧对冻虾仁微生物的控制及在生产应用的研究

采用臭氧消毒对冻虾仁中的微生物进行控制，冻虾仁总菌数大大减少，同时有效地抑制了冻虾仁中常见的致病菌的发生率，且感官特性无显著变化。     

熟制对虾虾仁超高压杀菌主要参数探讨

实验通过不同的压力和保压时间处理虾仁,以此考察超高压的杀菌效果以及对产品品质的影响。结果表明,压力是影响杀菌效果的主要因素,当压力为600MPa,保压时间为20min时,虾仁中接种的大肠杆菌、金黄色葡萄球菌、沙门氏菌和枯草芽孢杆菌总数分别下降7.1、7.0、7.2和4.3个log。枯草芽孢杆菌对高压最不敏感。超高压处理对产品的理化性质有一定影响,随着压力增大,水分含量有所减小,但幅度不大,色泽L值减小,红度a值无显著影响,硬度、弹性和咀嚼度都增大。在4℃低温保藏过程中,虾仁硬度有所增大,弹性无明显变化,而色泽红度呈现先缓慢增大后下降的趋势。感官评定结果表明,经600MPa保压15min的样品在4℃保藏60d后最被喜爱,120d后仍可被接受。     

菌氨清的杀菌效果及对鲫鱼的急性毒性研究

设置温度、时间、质量浓度等变量,探究菌氨清对大肠杆菌的杀灭效果和对鲫鱼的急性毒性。结果表明,对温度为5和25℃、质量浓度为1和10 mg/L的菌氨清分别处理1,10,20 min后,杀菌效率为100%;温度为5℃,质量浓度为0.1 mg/L的菌氨清处理1,10,20 min后,杀菌效率依次为97.5%,98.7%,98.9%;温度为25℃,质量浓度为0.1 mg/L的菌氨清处理1,10,20 min后,杀菌效率依次为99.2%,99.4%,99.6%。按照"静水式生物测试方法"在(13.0±1.5)℃,用不同剂量菌氨清对体长7.9～9.2 cm、体质量20～22.5 g的健康鲫鱼进行急性毒性试验,得到半致死浓度为1.39～4.10 mg/L,安全浓度为0.139 mg/L,根据化学药物对鱼类的毒性评价标准,菌氨清对鲫鱼为中毒药物。     

贮藏时间对“菌敌”抑、杀菌效果的影响

湖南五指峰生化有限公司以双链季铵盐为主要原料制备的“菌敌”,已经在水产养殖实际生产中被证明对水产动物细菌性疾病具有良好的防治与治疗作用,而且这种产品对水产动物机体的毒副作用比较小,因而被广大水产养殖业者认为是目前的渔药市场上一种良好的渔用药物。为了深入探讨这     

杀菌王对鱼类致病菌的杀灭效果

杀菌王系含氯消毒剂,为广谱高效杀菌药物,性能稳定,成产品在常温下贮藏两年,有效氯便下降2．7个百分点。杀菌王对嗜水气单胞菌,G4菌株,荧光机毛杆菌等鱼类病原菌有很强的杀灭作用,MIC为（3-5）×10-7,5×10-7杀菌王水溶液在1h内可杀灭受试病原菌的97％。     

不同泡沫清洁剂对畜禽运输设备的清洁杀菌效果研究

禽畜运输设备的清洁杀菌对动物的健康生长至关重要。针对多种泡沫清洁剂对禽畜运输车辆的清洁杀菌效果进行对比研究。结果表明,A、N、O泡沫清洁剂挂壁时间最长,但灭菌率和光洁度均不理想;从灭菌效果分析,灭菌率从高到低依次为B>Q>I>C>P,P、C泡沫清洁剂的挂壁时间一般。B、Q泡沫清洁剂的挂壁时间、灭菌率、光洁度等指标均是较优。研究为清洗禽畜运输设备时泡沫清洗剂的选择提供理论基础。     

一株海洋过氧化氢酶高产菌的鉴定及产酶条件优化

对来自青岛近海海域底泥的一株产过氧化氢酶菌株YS0810进行形态学观察、16S rDNA序列同源性分析及生理生化特性的鉴定,在250 ml摇瓶中进行发酵产酶条件优化。初步确定该菌属于不动杆菌属Acinetobacter。发酵培养的最佳碳、氮源分别为蔗糖20 g/L和蛋白胨15 g/L,无机盐MgSO4·7H2O、NaCl、KH2PO4最佳浓度分别为0.9、5.0和1.0 g/L;菌株在培养基起始pH=7.0、4%接种量、50 ml装液量和25℃的条件下发酵24 h获得较高的酶产量。在最佳培养条件下酶产量为2469 U/ml,是优化前的5倍。     

凡纳滨对虾熟虾仁的工艺研究及保藏特性分析

研究了凡纳滨对虾（Penaeus vannmei）虾仁在煮制过程中煮制时间及NaCl添加量对其感官品质的影响。通过测定失重率、感官评分等指标,得到凡纳滨对虾虾仁的优化煮制工艺为虾质量规格41／50,沸盐水煮制,NaCl添加量4％,煮制时间2min。测定真空包装后的虾仁在常温（25℃）下保藏过程中的细菌总数。结果显示其保藏期能达到7d。     

水分活度对干制虾仁产品的货架寿命和质构的影响

采用真空微波脱水的方法将虾仁干制成不同水分活度(Aw)的样品,测定样品在20℃时的水分吸附等温线,并通过保藏试验分析比较Aw对常温保藏后虾体内的细菌菌落总数以及对虾体的弹性、硬度等质构参数的影响。结果表明,当Aw控制在0.86~0.9(水分含量约25%(W/W))时,常温保藏的虾仁干制产品在口感及微生物指标等方面可取得平衡。     

溶藻细菌控藻作用及其在对虾养殖池塘中的应用前景

浮游微藻与养殖池塘的水质及对虾的健康状况密切相关,控制有害微藻的过度繁殖,维持优良的藻相对于养殖水环境的稳定、减少对虾疾病的发生具有重要意义。文章对浮游微藻与对虾养殖的关系及溶藻细菌的研究进展进行了概述,分析了溶藻细菌在对虾养殖中的应用前景,提出了利用溶藻细菌控制对虾养殖池塘有害微藻的研发思路。     

Molecular characterization of myostatin‐like genes expressed highly in the muscle tissue from Morotoge shrimp,Pandalopsis japonica

Myostatin is one of the transforming growth factor (TGF)‐β family members and plays inhibitory roles in the development and growth of muscle in mammals. Mammalian myostatins have been studied intensively, considering its medical and industrial potential use. Still, limited information is available about myostatin homologues in crustaceans. In the present study, we isolated for the first time cDNA that encodes for myostatin‐like protein (Pj‐MSTN) from Morotoge shrimp, Pandalopsis japonica. The putative mature peptide of Pj‐MSTN was composed of 109 amino acids, which contains an additional amino acid residue compared with mammalian myostatins. Pj‐MSTN exhibited 32% amino acid sequence identity and 52% similarity to human myostatin. Multiple sequence alignment analysis indicated that Pj‐MSTN shared the conserved proteolytic cleavage site (RXXR) for its maturation and nine cysteine residues for disulphide bridges. These results suggest that Pj‐MSTN has conserved the three‐dimensional structure of TGF‐β family members in vertebrates. Phylogenetic analysis suggests that Pj‐MSTN is a primitive form of vertebrate myostatin and GDF11. The expression of Pj‐MSTN was not just identified in muscular tissues, suggesting that Pj‐MSTN functions differently from mammalian myostatin. Ablation of the X‐organ/sinus gland complex significantly reduced the expression of Pj‐MSTN in most tissues, suggesting its potential association with moulting.     

虾类肌肉白浊病病原和病理的研究进展

本文针对虾类肌肉白浊病易感染的罗氏沼虾、凡纳滨对虾、中国对虾进行了分析。从病毒、细菌、寄生虫和环境因素方面,总结了近十几年来虾类肌肉白浊病的病原和病理特征。归纳了虾类肌肉白浊病的流行病学、检测方法及综合防治。     

有益微生物的应用对海水对虾养殖池塘中细菌数量动态变化的影响

2001年5~7月,在深圳东海岸水产公司南澳半封闭式斑节对虾Penaeus monodom精养基地,进行了有益微生物的应用对虾塘总异养细菌和弧菌数量影响的调查研究。结果表明,对虾养成过程中,施用有益微生物的实验组虾塘水体中总异养细菌和弧菌数量明显较未施用的对照组虾塘低,但各虾塘水体中总异养细菌和弧菌数量的变化特征基本相同,即在养殖前期,虾塘水体中总异养细菌和弧菌数量均较稳定,并处于相对较低的水平;而在养殖中、后期,总异养细菌和弧菌数量均急剧升高,尤以对照组虾塘的升幅最大,其弧菌数量甚至超过100×102CFU.mL-1的对虾发病之弧菌数量临界值。实验组与对照组虾塘中表层沉积物中,总异养细菌和弧菌数量差异不大,总异养细菌和弧菌数量变化特征也基本相同,但实验组与对照组之间有所差异,其中实验组表现为双峰型的变化特征,峰值出现在养殖前期或中期和养殖将结束时;对照组则呈单峰型变化,峰值均出现在养殖中期。有益微生物的应用对虾塘水体中总异养细菌和弧菌数量的抑制效果较对沉积环境中的效果明显。     

虾池有机污染物降解细菌的筛选

在实验室条件下对612株海洋细菌和10株海水驯化淡水菌进行筛选,检测其快速降解水体中富营养有机物的能力。利用对虾饵料培养基、BOD仪、胞外酶检测等方法进行筛选,最后筛选到10株对富营养有机物具有 较高降解性能的细菌。所有的细菌均能产生明胶酶和脂酶（Tween-80),其中9株细菌能产生淀粉酶,8株产生卵磷脂酶,2株产生酪蛋白酶,1株产生褐藻胶酶。通过测量BOD来衡量10株细菌利用对虾饵料的效果,2天时能消化46.6%-59.5%的对虾饵料,5天时能消化50.8%-70.2%的对虾饵料。用常规生理生化方法将细菌鉴定到属,其中3株为弧菌属细菌（Vibrio spp.),3株为假单胞菌属细菌（Pseudomonas spp.),2株为发光杆菌属细菌（Photobacterium spp.),1株为气单胞菌属细菌（Aeromonas spp.),1株为枯草杆菌（Bacillus subtilis)。     

Degradation and effect of hydrogen peroxide in small‐scale recirculation aquaculture system biofilters

From an environmental point of view, hydrogen peroxide (HP) has beneficial attributes compared with other disinfectants in terms of its ready degradation and neutral by‐products. The rapid degradation of HP can, however, cause difficulties with regard to safe and efficient water treatment when applied in different systems. In this study, we investigated the degradation kinetics of HP in biofilters from water recirculating aquaculture systems (RAS). The potential effect of HP on the nitrification process in the biofilters was also examined. Biofilter elements from two different pilot‐scale RAS were exposed to various HP treatments in batch experiments, and the HP concentration was found to follow an exponential decay. The biofilter ammonia and nitrite oxidation processes showed quick recuperation after exposure to a single dose of HP up to 30 mg L^?1. An average HP concentration of 10–13 mg L^?1 maintained over 3 h had a moderate inhibitory effect on the biofilter elements from one of the RAS with relatively high organic loading, while the nitrification was severely inhibited in the pilot‐scale biofilters from the other RAS with a relatively low organic loading. A pilot‐scale RAS, equipped with two biofilter units, both a moving‐bed (Biomedia) and a fixed‐bed (BIO‐BLOK^®) biofilter, was subjected to an average HP concentration of ～12 mg L^?1 for 3 h. The ammonium‐ and nitrite‐degrading efficiencies of both the Biomedia and the BIO‐BLOK^® filters were drastically reduced. The filters had not reverted to pre‐HP exposure efficiency after 24 h, suggesting a possible long‐term impact on the biofilters.     

不同饵料搭配对中国明对虾生长和饵料转化效率的影响

采用沙丁鱼肌肉(FF)、鹰爪虾肌肉(SF)、菲律宾蛤仔足肌(CF)、沙蚕(PW)和配合饲料(FD)5种饵料,设计了CF PW、CF FD、PW FD、CF FD PW、FF FD PW FD、FF SF CF PW FD共6种饵料搭配投喂模式,研究了不同饵料搭配对中国明对虾的生长和饵料转化效率的影响。中国明对虾摄食混合饵料后的生长都比除PW处理外的4种单种饵料投喂处理快,CF PW处理的对虾在实验结束时的体重、增重率最大。混合投喂处理的饵料转化效率均高于除PW外的所有单种饵料投喂处理,所有混合投喂处理的实际饵料转化效率都比预测值高,并且除了PW FD和CF FD PW两个处理的实际值与预测值差异不显著外,其它混合处理的饵料转化效率实际值都显著高于预测值。文中还对不同饵料搭配的优势对对虾饵料选择性的影响及产生这些优势的原因进行了探讨。     

Selection of probiotic bacteria for use in shrimp larviculture

Three candidate probiotics, Bacillus foraminis, Bacillus cereus biovar toyoi and Bacillus fusiformis , were isolated from hydrogen-producing fermented solution and identified using 16S rRNA sequence analysis. Bacillus foraminis and B. cereus biovar toyoi exhibited strong antagonism against Streptococcus iniae and Photobacterium damselae subsp. piscicida in in vitro co-culture for competitive exclusion assay and then were conducted in the larviculture system of Penaeus monodon reared from zoea 1 to postlarva 1. The daily addition of B. cereus biovar toyoi resulted in significantly deleterious effects on survival ( P <0.01) whereas the daily addition of B. fusiformis showed highest survival rate (88.7±0.7%) but no statistically significant difference from control (73.3±12.1%). Bacillus fusiformis was continuously applied in the larviculture system of Litopenaeus vannamei . Administration of B. fusiformis significantly increased survival ( P <0.01) in both treatments added daily (87.9±1.7%) and every other day (54.7±1.2%), respectively, at a concentration of 10⁵ CFU mL⁻¹ over control (41.2±1.3%).