罗非鱼的微冻保鲜

本文以养殖的罗非鱼为对象,在-3℃±0.5℃空气微冻条件下,通过对鱼肉鲜度指标K值、细菌数及pH值的测定,探讨微冻鱼的质量的变化情况,并与冰藏鱼作比较。同时还对微冻鱼肌肉作组织切片,观察其冰结晶,并与-18℃冻结鱼及新鲜鱼作对照。实验结果表明,-3℃微冻法比冰藏法温度仅低3℃,但鱼肉鲜度指标K值上升缓慢,细菌繁殖受到抑制,大大延长了罗非鱼的保藏时间,贮藏期可达一个月左右。鱼肉pH值与鱼的鲜度之间无明确的相关关系。-3℃微冻鱼肌肉中的冰结晶是慢冻型的,对肌肉组织有损伤,但其冻结率比-18℃冻鱼低,未冻结部分的肌肉组织与新鲜鱼的肌肉组织相接近。     

凡纳滨对虾虾仁在冻藏过程中品质变化研究

以凡纳滨对虾（Penaeus vannamei）为研究对象,经过去头和去壳处理后,于-35℃冷冻过夜,然后置于-18℃条件下进行保藏试验。通过测定解冻损失率和肉色变化,明确冻藏期间虾肉的质量变化规律,结合腺苷三磷酸（ATP）及其降解产物、总挥发性盐基氮（TVB-N）和酸碱度（pH）等鲜度指标的测定结果,分析对虾在冻藏条件下鲜度的变化规律,旨在为其生产加工提供理论依据。研究结果表明,冷冻保藏至第18天时解冻损失率达到最大,同时表面色差（L^＊）也达到最大值41.56。而虾肌肉中的ATP质量摩尔浓度冻藏第1天就降低了71.78%,次黄嘌呤（Hx）和次黄嘌呤核苷（HxR）则一直维持在较低水平。第10天鲜度指标（K值）达到最大值7.18%,并能比较稳定地保持这一水平,结合TVB-N测定结果,发现冻藏至第30天时,虾肌肉中的TVB-N仍未超过腐败临界值。因此,冻藏处理可以保持凡纳滨对虾的鲜度,使各项理化指标维持在较低水平,但会加重解冻损失现象。     

若干水产品鲜度变化规律的研究

前言水产品,特别是动物性水产品,由于肌肉组织较脆弱、蛋白质含量丰富及含水量高,一旦被捕获而离开水体死亡之后,由于肌肉组织细胞中固有的复杂酶系作用和外界细菌的侵蚀,蛋白质乃至其它有机成份(例如糖类、脂类等)都可能发生变化,诸如蛋白质的分解、糖元的酵解以及脂肪的氧化,从而导致鲜度的变化,影响食用品质。过去许多研究者以挥发性盐基氮(TVB-N)等理化指标研究中后期水产品的鲜度,近年来在国外曾提出K值(=H_xR+H_x/(ATP+ADP+AMP+IMP+H_xR+H_x)以及pH值等理化指标来表征水产品的早期鲜度变化。本文试图通过TVB-N,三甲胺一氮(TMA-N)、pH值及粗氨等项指标的测定,以研究当前在市场上销售的若干水产品在早中期(销售过程中)鲜度的变化规律;比较不同温度(反映不同季节)条件下早、中期鲜度变化;探索不同类水产品变化规律的异同点;对TMA-N与TVB-N的关系也作了初步的探讨;对销售过程中不同类水产品pH值及粗氨的变化也作了一番研究。其研究结果对水产品的经营者和消费者都有重要的参考意义,对深入研究水产食品的营养与卫生质量有重要的理论意义。     

鳙在不同保藏温度下的鲜度变化

为了阐明不同保藏温度对淡水鱼类鲜度变化的影响,采用K值、TVB-N、细菌总数和感官检定等 4种鲜度指标,对鳙在 20℃～-3℃范围的 5种不同温度贮藏中的鲜度变化进行比较系统的测定和考察。结果表明:(1)鳙的鲜度变化。在20℃和10℃常温下速度很快,保鲜期从数小时到4天;在 0℃前后的3种低温下速度变慢,保鲜期最长的可达 11天。(2)4种鲜度指标中,以感官的一、二、三级为基准,K 值的一、二级鲜度大体高于或等于感官的一、二级;而 TVB-N 一、二级鲜度(也包括细菌总数)则大体相当于或低于感官二、三级,显示了K值作为代表鱼体死后早期高鲜度等级的特征。(3)计算K 值变化速度常数 k_f 值表明 20℃的 K值变化速度较 10℃高6.3倍,而10℃较0℃仅高3.9倍,显示保持接近 0℃的低温,能明显抑制K值的变化,保持较好的鲜度。文中并指出了在5℃以下的低温范围,由于TVB-N 的数量水平偏低,似不适于作为鳙一类淡水鱼鳞度指标,认为在我国采用 K 值鲜度指标更适合淡水鱼高鲜度质量标准的要求。     

咸鱼品质的质构与感官相关性分析

为了探讨咸鱼品质的质构与感官评定的相关性,对其品质的感官评定结果与质构仪器分析结果进行了研究.以3种咸鱼,11个样品为研究对象,对其质构进行人工感官评价与质构仪(TPA模式)测定,对测定结果进行方差分析,结果显示11个样品的感官评价具有显著性差异(P＜0.05),TPA各个参数之间也存在一定的差异性.对仪器质构测定结果与感官评定结果进行相关性分析,结果表明仪器质构测定结果与感官评定结果之间有密切的相关性.其中,仪器测定的弹性参数与感官评价指标均具有显著(P＜0.05)或极显著(P＜0.01)相关性,相关系数为0.398 ～0.859;而咀嚼性只与硬度具有显著相关,相关系数为0.650;其他参数均存在不同的相关性(r=-0.355 ～0.829).对感官评价总分与仪器分析结果进行相关性分析,得出硬度、咀嚼性与感官评价总分呈显著正相关关系(P ＜0.05,R=0.974 ～0.994),内聚性、弹性、黏着性与感官评价总分呈显著负相关关系(P ＜0.05,R=0.937～0.998).3种咸鱼品质的质构仪器分析值与感官评价值具有很好的相关性,为质构仪在咸鱼品质评价上的应用提供了理论依据.     

不同光照、温度及不同规格海蜇耗氧率和排氨率的测定

试验在密闭(盐度25.1,pH 7.9~8.1)条件下进行,溶氧量和氨氮量分别采用Winkler法和纳氏试剂法测定。分析不同规格海蜇耗氧率和排氨率时,得出体质量(m)与伞径(D)的关系式为:m=0.0003D2-0.0007D+0.0427,r2=0.9913。幼蜇伞径从7 mm到35 mm,其耗氧率(OCR)和排氨率(AER)均随着伞径的增大而不断降低,分别经回归分析得到曲线:OCR=0.0063D2-0.3531D+6.1533,r2=0.9751和AER=0.4221D2-26.585D+518.83,r2=0.9587。光照影响试验结果表明:各组别光照下的耗氧率、排氨率均显著大于黑暗条件(P<0.01)。分析结果表明,只有20℃和25℃耗氧率差异不显著(P>0.05),而其余各温度间的耗氧率差异均显著(P<0.05);15℃与25℃,20℃与25℃之间排氨率差异不显著(P>0.05),而升温至30℃时,幼蜇代谢明显加快,尤其是排氨率上升较快,与其余各温度间的排氨率差异均极显著(P<0.01)。对幼蜇在光照和黑暗条件下的窒息点进行了测定,发现溶氧小于0.45 mg/L时,试验所采用的伞径为15 mm的幼...     

温度和规格对波纹巴非蛤耗氧率和排氨率的影响

本研究以波纹巴非蛤为实验材料，比较了温度和规格对其耗氧率和排氨率的影响。实验温度设为15、20、25和30℃，设立了大（A）和小（B）两种规格，其壳长分别为4.35 ± 0.19 cm 和3.53 ± 0.15 cm。结果表明温度对耗氧率和排氨率存在显著影响（P < 0.05）。规格对耗氧率存在显著影响（P > 0.05），而对排氨率影响不显著（P > 0.05）。在温度15 - 30℃之间，波纹巴非蛤的耗氧率随温度升高而增大。在15和20℃条件下，B组的耗氧率显著大于A组（P < 0.05）；在25和30℃条件下，B组的耗氧率大于A组，但差异不显著（P > 0.05）。在温度15 - 30℃之间，波纹巴非蛤的排氨率随温度升高而增大。在各温度条件下，两组排氨率没有显著差异（P > 0.05）。     

冷藏草鱼片新鲜度分级方法的建立

现有淡水鱼片评价方法存在评价体系单一、不稳定的问题,为提供一种冷藏草鱼片新鲜度分级方法,实验以生鲜鱼片的色泽、气味、组织形态、肌肉弹性和熟鱼片的气味、滋味、汤汁形态各细分感官描述为指标,依据主成分分析(PCA)和系统聚类分析(HCA)划分鲜度区间;将K值等理化指标和肌间线蛋白、肌钙蛋白T等生化指标与细分感官描述指标比较;最后依据感官、理化、生化指标的PCA和HCA结果,评价以上冷藏草鱼片新鲜度。结果显示,根据感官描述分析PCA和HCA,冷藏草鱼片可分为3个鲜度等级:0～1 d (一级鲜度),2～7 d (二级鲜度),8～10 d (三级鲜度)。一级鲜度终点肌间线蛋白和肌钙蛋白T相对灰度值下降至95.68%和96.75%;二级鲜度终点肌间线蛋白和肌钙蛋白T分别下降至56.4%和69.6%;三级鲜度终点肌间线蛋白和肌钙蛋白T相对灰度值分别下降至56.36%和52.85%。研究表明,HCA鲜度划分区间与细分感官描述分析鲜度划分区间一致,细分感官描述分析可较全面反映冷藏草鱼新鲜度变化情况;肌钙蛋白T与细分感官描述变化规律一致,可以根据其变化判定冷藏草鱼片的新鲜度。本研究依据细分感官评价指标划分了鲜度区间并评价了该方法;在此基础上,研究了肌间线蛋白和肌钙蛋白T变化规律与感官评价HCA的关系,得出肌钙蛋白T反映冷藏草鱼片鲜度效果好,为后续根据新鲜度指示蛋白的变化规律开发鱼肉新鲜度检测试纸奠定基础。     

温度变化对虾夷扇贝耗氧率和排氨率的影响

为探索虾夷扇贝(Datinopecten yessoensis)夏季大量死亡的生理原因,模拟虾夷扇贝筏式养殖区夏季水温变化情况,采用室内控温实验,研究了温度剧烈和缓慢变化对虾夷扇贝耗氧率和排氨率的影响及其影响的差异性。实验设置10℃、15℃、20℃、25℃4个温度梯度,设计温度骤变(每小时升温5℃)和温度缓变(每天升温1℃)2种温度处理方式,测定升温前后耗氧率和排氨率。结果显示,温度变化对虾夷扇贝耗氧率和排氨率影响显著(P0.05)。温度缓变组耗氧率变化范围为1.910～2.722mg(/g·h),排氨率变化范围为1.499～5.003μm/(g·h),耗氧率(OR)和排氨率(NR)与温度(T)之间的相关方程为OR=2.303+0.425T-0.133T(2R2=0.941)和NR=-1.536+4.384T-0.893T(2R2=0.435)。温度骤变组耗氧率和排氨率大于温度缓变组,且温度骤变组耗氧率在15℃、20℃和25℃,排氨率在20℃和25℃与温度缓变组差异显著(P0.05)。     

鳙在冷藏和微冻贮藏下品质变化规律的研究

文章研究了鳙（Aristichthys nobilis）在不同贮藏温度下的品质变化规律。将经过前处理的鳙分别贮藏在4℃和-3℃中，通过测定其感官和理化指标，即总挥发性盐基氮（TVB—N）、硫代巴比妥酸（TBA）、鲜度K值、pH、汁液流失率和蒸煮损失率，评价不同温度对鳙品质的影响。结果显示，鳙分别在4℃贮藏至第10天和-3℃贮藏至第30天时失去感官食用品质。但K值在4℃贮藏至第6天和-3℃贮藏至第20天超过临界值。4℃下鳙的TVB—N显著高于-3℃。在整个贮藏过程中TBA均未超过2．00mg·kg-1。的限量值，说明TBA不适合单独用于评价鳙的品质变化。pH分别在4℃贮藏至第4天和-3℃贮藏至第10天达到最低值，分别为6．81和6．76。与4℃相比，-3℃下鳙的汁液流失率和蒸煮损失率较高，这可能与-3℃微冻条件下鳙肉组织冰晶生成导致持水力下降有关。综合K值和感官指标的变化，4℃和-3℃下鳙的货架期分别为6d和20d，且-3℃贮藏能明显延长鳙的货架期。     

马苏大麻哈鱼生物学及其增殖

马苏大麻哈鱼生物学及其增殖董崇智，赵春刚（中国水产科学研究所黑龙江水产研究所，哈尔滨１５００７０）马苏大麻哈鱼Ｏｎｃｏｒｈｙｎｃｈｕｓｍａｓｏｕ（Ｂｒｅｒａｒｔ），奇孟鱼（东宁之地方名）。属鲑形目Ｓａｌｍｏｎｉｔｏｒｍｅｓ、鲑亚目Ｓａｌｍｏｎｉａ、鲑...     

Ammonia nitrogen excretion in Mandarin Fish (Siniperca chuatsi) and Grass Carp (Ctenopharyngodon idellus) fed practical diets: the effects of water temperature

To understand the actual production of fish culture about the utilization of dietary protein and excreta impact on the environment between mandarin fish (Siniperca chuatsi) and grass carp (Ctenopharyngodon idellus), the study to investigate the effect of temperatures (19 ± 0.5°C, 24 ± 0.5°C and 29 ± 0.5°C) on ammonia‐N excretion in mandarin fish and grass carp under fed and fasted states was conducted. These two species were fed a practical diet containing 325.2 g kg^?1 crude protein at 3% body weight per day. The ammonia‐N excretion rate was significantly increased when temperature increased from 19 to 29°C, and a linear relationship between ammonia‐N excretion rate and temperature. The maximum ammonia‐N excretion levels of mandarin fish and grass carp were observed at 4–8 h and 2–4 h after feeding, respectively, and the minimum values for both species were observed at 24 h after feeding. Under the feeding condition, mandarin fish had a lower ammonia‐N excretion level compared to grass carp at 24°C and 29°C. The average amount of ammonia‐N excreted by mandarin fish at 24 h is significantly higher than grass carp under fasting conditions, except 19 ± 0.5°C. These results indicated that mandarin fish might make better use of protein at higher temperature than grass carp when fed practical diets in commercial production. These results of this study suggested that mandarin fish had a lower ammonia‐N excretion level compared with grass carp, making a less contribution to environmental loading in an intensive fish culture.     

Enhancing Growth of Common Carp, Rohu and Mozambique Tilapia through Plant Substrate: The Role of Bacterial Biofilm

Experiments were conducted to enhance the growth of common carp (Cyprinus carpio), rohu (Labeo rohita) and Mozambique tilapia (Oreochromis mossambicus) through use of sugarcane bagasse as substrate. Bagasse was suspended in water with or without supplementation with fertilizers. Bagasse supplemented with cattle dung and urea favoured higher zooplankton production and significantly (p < 0.05) increased fish growth by over 50% compared to bagasse or fertilizers on their own. This higher production of fish is attributed to bacterial biofilm promoted on the substrate which, apart from forming food for zooplankton and fish, contributed to improved water quality by lowering ammonia.     

Vaccination of rainbow trout, Oncorhynchus mykiss (Walbaum), against cryptobiosis: efficacy of the vaccine in fresh and sea water

Adult rainbow trout, Oncorhynchus mykiss (Walbaum), maintained in either fresh or sea water were vaccinated with a live Cryptobia salmositica vaccine. All vaccinated fish were protected 4 weeks later against the cryptobiosis, while unvaccinated rainbow trout developed the disease (e.g. high parasitaemia and severe anaemia) after challenge with virulent C. salmositica . There was also no disease in vaccinated fish when they were transferred from fresh to sea water immediately after vaccination. Complement fixing antibodies (CFAbs) were detected in vaccinated fish and the CFAbs lysed parasites under in vitro conditions. The antibody titres increased rapidly at one week post-challenge in vaccinated fish in fresh water and vaccinated fish transferred from fresh water to sea water after vaccination. However, the production of CFAbs was delayed by one week in vaccinated fish in sea water and the antibody titre was significantly lower than that in fish maintained in fresh water.     

Reduced total hardness of fresh water enhances the efficacy of bathing as a treatment for amoebic gill disease in Atlantic salmon, Salmo salar L

The current treatment for amoebic gill disease (AGD)-affected Atlantic salmon involves bathing sea-caged fish in fresh water, often sourced from local dams, for 3-4 h. In both a small-scale laboratory and an on-farm field experiment, the effects of water hardness on the efficacy of freshwater bathing were assessed. Results showed that soft fresh water (19.3-37.4 mg L(-1) CaCO3), whether it be naturally soft city mains water or artificially softened dam water, was more efficacious at alleviating AGD in affected fish than hard fresh water (173-236.3 mg L(-1) CaCO3). Soft freshwater bathing significantly reduced viable gill amoebae numbers (from 73.9 to 40.9% of total count) and significantly alleviated gill pathology, both gross and histological. Following bathing, gross gill pathological scores of soft freshwater bathed fish lagged 2 weeks behind hard freshwater bathed fish. Significant gill lesion fragmentation, and shedding of lesion-associated hyperplastic tissue, was accompanied by a significant reduction in AGD-affected gill filaments in soft freshwater bathed fish. Furthermore, soft freshwater bathing alleviated the blood plasma electrolyte imbalance seen in control (sea water) and hard freshwater bathed fish. This study showed that the use of soft fresh water for bathing AGD-affected Atlantic salmon could be an improvement to the current method of treatment. Not only does it reduce gill amoeba numbers, but also, it is of a therapeutic advantage with the potential to reduce bathing frequency.     

Effects of linalool on physiological responses of Cyprinus carpio (Linnaeus, 1758) and water physico‐chemical parameters during transportation

This study investigated the potential of linalool as an anaesthetic during transportation of common carp, Cyprinus carpio. The fish were transported at a loading density of ~103 g/L for 3 hr in 12 plastic bags (3 L water and 6 L pure oxygen) divided into four triplicated treatments: control (without linalool), L50 (50 mg linalool/L), L100 (100 mg linalool/L) and L200 (200 mg linalool/L). After 3‐hr transportation, serum physiological responses and water physico‐chemical parameters were compared among the treatments. Results showed that water total and un‐ionized ammonia increased and dissolved oxygen decreased in all treatments after transportation. Water total ammonia and dissolved oxygen levels in the linalool‐treated bags were significantly lower than the control. After transportation, the control fish showed significant elevation in serum cortisol and glucose levels; however, the levels were significantly lower than the linalool‐treated fish. All fish showed similar serum lactate levels, significantly lower than the value obtained before transportation. The control fish showed serum urea levels similar to the level obtained before transportation; however, the linalool‐treated fish had significantly higher serum urea levels compared to the control and before transportation levels. After transportation, all fish had decreased serum chloride and sodium levels compared to the before transport level. Overall, the present results showed that linalool is not beneficial for carp transportation in plastic bags, because it reacts with water oxygen, increases stress in fish, interferes with ammonia excretion and has no benefits in preventing ion loss.     

海中鱼类集群地点与海水中氨量分布的关系

鱼类栖息水中随着时间的增加,排泄物不断增多,特别是鱼类密集成群时,排泄物显著增加,从而影响到水质的变化;在较浅的水域里,往往凭感官即能察觉出来。例如有经验的渔民认为冬季带鱼汛期,渔场海水常有一种特殊的“香味”,并以嗅此种“香味”作为寻找鱼群的指标。     

不规则盐度脉冲对许氏平鲉氨氮、磷排泄的影响

在静水系统中,骤然改变水体盐度,形成盐度脉冲;研究许氏平鲉Sebastodes fuscescens(Houttuyn)经历该脉冲后其氨氮、活性磷酸盐排泄的情况。结果表明,盐度改变后,许氏平鲉的氨氮排泄率比正常盐度(30)下呈现出不同程度的升高趋势;当盐度由30降为25和20时,随着体重增加,氨氮排泄率先增大,后又减小;当盐度由30上升为35时,氨氮排泄率随体重增加而呈下降趋势。盐度改变后,许氏平鲉的活性磷酸盐排泄率随体重增大呈先增大后减小的趋势。在同一体重下,盐度由30降至20时,活性磷酸盐的排泄率最大;盐度由30升至35时,磷的排泄率最小。方差分析表明,盐度脉冲对许氏平鲉氨氮排泄率有显著的影响(P<0.05),对活性磷酸盐排泄率的影响不显著(P>0.05)。该研究对于鱼类养殖的水质管理、养殖场的布设等有重要的指导意义。     

一种自行研制的养殖水原位净化装置的应用效果试验

基于硝化细菌、聚磷菌等微生物种群分布于自然水体中,且喜欢吸附在固体表面形成生物膜,吸收水中氨氮、亚硝酸盐氮、磷等营养成分进行繁殖和生长的生物学原理,研制了一个由支架浮力系统、微生物附着基、上升流系统、锁磷区和光伏发电系统5部分组成的圆柱形(半径75 cm、高100 cm)养殖水原位净化装置。试验结果显示:生物膜建成后,装置在1 mg/L、3 mg/L和5 mg/L氨氮质量浓度组的淡水(水温22~25℃)和海水(水温27~31℃)中,日消减氨氮量分别为304.587 g、283.748 g、314.753 g和247.274 g、261.756 g、282.721 g,日消减淡水和海水中总磷量分别为0.485 g、0.427 g、0.462 g和0.566 g、0.595 g、0.493 g,显示出较强的氨氮和总磷的消减能力。日氨氮消减量差异性,淡水3个质量浓度组间不显著(P>0.05),海水3个质量浓度组间显著(P<0.05)。日总磷消减量差异性,淡水3个质量浓度组间、海水3个质量浓度组间均不显著(P>0.05)。该装置具有较强的氨氮和磷的消减能力和使用方法简单、运行成本低等特点,可在水产养殖尾水净化处理中推广使用。     

Evaluating the Rearing condition of Rainbow Trout (Oncorhynchus Mykiss) Using Fuzzy Inference System

Rainbow trout (Oncorhynchus mykiss) is one of the most popular aquacultured species in the world. Sustainable production of this fish at commercial scale is very important but requires maintaining good water quality throughout the total rearing period. The present study aimed to develop a rainbow trout production index in order to raise awareness about the conditions of the rearing environment, enhance production, and reduce losses. For this purpose, an intensive rainbow trout production system was selected as the study system. In this system, there were seven stations including (a) 3000 5-g fish, (b) 3000 25-g fish, (c) 3000 50-g fish, (d) 3000 100-g fish, (e) 3000 220-g fish, (f) 2000 350-g fish, and (g) 2000 830-g fish. The fuzzy inference system was used to develop the target rearing index. Water quality parameters involved in the variation in the rainbow trout rearing conditions were classified into three groups including un-ionized ammonia, nitrite, and nitrate, Alkalinity and phosphate, along with dissolved oxygen and linear velocity. For each group and condition of rearing, a separate fuzzy inference system was defined and the output of each fuzzy system was named I₁, I₂, I₃. Finally, I₁, I₂, and I₃ were considered as the inputs to a fuzzy system in order to evaluate their effects on the index of general rearing conditions (I). The results indicated that un-ionized ammonia, nitrite, nitrate, and phosphate had negative effects while dissolved oxygen, linear velocity, and alkalinity positively affected water quality and rearing index. Most of the decline in the rainbow trout rearing index was related to the effect of un-ionized ammonia, nitrite, and nitrate due to food decomposition. Therefore, intelligence feeding based on fish appetite through reducing food conversion rate and water pollution can improve rainbow trout production in this system. The index of rainbow trout production conditions reflects the type, amount, and effect of water quality pollutants on rearing conditions. Producers can use this information to reduce the negative environmental effects and improve the product quality.