池塘循环水养殖对混养草鱼食用品质的影响

为探究养殖模式对草鱼(Ctenopharyngodon idellus)鱼肉品质的影响,实验对两种养殖模式下(传统池塘养殖和池塘循环水养殖)草鱼的食用品质进行了差异比较。结果表明,循环水养殖草鱼肌肉白度和弹性高于传统池塘养殖的草鱼,且其不饱和脂肪酸和必需氨基酸含量均显著高于传统池塘养殖;其中, n-3和n-6系列不饱和脂肪酸含量显著高于传统池塘养殖草鱼,是其1.2倍,使得草鱼的肌肉品质和营养品质更佳。此外,循环水养殖可降低草鱼中带有土腥味和青草味的己醛、庚醛和1-辛烯-3-醇等物质的含量,且鲜味核苷酸(IMP)含量高于传统池塘养殖草鱼,使得草鱼的风味更鲜美、浓厚。研究表明,循环水养殖草鱼的肌肉品质和营养特性均优于传统池塘养殖。     

不同养殖模式对亚东鲑幼鱼生长性能、血清生化指标和肌肉营养成分的影响

为了探索亚东鲑(Salmon trutta)多元化养殖模式,以初始体质量(100.05±1.12) g幼鱼作为研究对象,开展循环水和开放流水模式养殖比较,试验周期180d,分析比较其生长性能、血清生化指标和肌肉营养成分差异。结果表明:在开放流水模式下增重率、肥满度、肝体指数、特定生长率和饲料转化率均显著高于循环水模式(P<0.05),存活率二者差异不显著(P>0.05);在循环水模式下补体C₄、总蛋白和生长激素均显著低于开放流水模式(P<0.05),但溶菌酶、谷丙转氨酶和谷草转氨酶相反(P<0.05),补体C₃、碱性磷酸酶、酸性磷酸酶和球蛋白在两种模式之间差异均不显著(P>0.05);肌肉主要营养成分粗蛋白、粗脂肪含量开放流水模式高于循环水模式,氨基酸组成二者差异不显著(P>0.05),脂肪酸中油酸、α-亚麻酸、C20:1、C20:2和MUFA含量均显著低于开放流水(P<0.05),而EPA+DHA、SAFA和PUFA含量相反,二者之间差异性显著(P<0.05),矿物质镁含量循环水模式显著高于开...     

野生与池塘、工厂化养殖牙鲆肌肉理化品质及质构特性比较研究

实验以牙鲆为研究对象, 测定野生与池塘、工厂化养殖牙鲆肌肉的持水性、胶原蛋白含量、肌纤维直径和质构特性, 以了解3种生长方式下牙鲆肌肉理化品质及质构特性的差异。结果表明: (1) 3种生长方式牙鲆有眼侧及无眼侧肌肉的滴水损失均呈野生组池塘组工厂化组(P0.01); 工厂化组失水率显著小于野生组及池塘组(P0.01), 而野生组与池塘组无显著差异(P0.05)。(2) 3种生长方式牙鲆有眼侧及无眼侧肌肉胶原蛋白含量和纤维直径差异均不显著 (P0.05)。(3)通过主成分分析, 发现黏附性和胶黏性是反映牙鲆肌肉质构特性的主要因素。工厂化养殖牙鲆肌肉具有较好的持水能力, 池塘养殖牙鲆肌肉的理化品质和质构特性与野生牙鲆相近。野生牙鲆并没有在理化特性上表现出明显优势。       

短时微流水处理对池塘养殖鳙鱼肌肉滋味品质的影响

为探究短时微流水处理对池塘养殖鳙鱼(Aristichthys nobilis)肌肉滋味品质的影响, 采用微流水装置对池塘养殖鳙鱼进行处理, 研究处理时间(0、2d、4d、6d、8d和10d)对池塘养殖鳙鱼肌肉中基本营养成分、游离氨基酸、脂肪酸、核苷酸及其降解产物、甜菜碱含量和感官评分的影响, 以期为提升鳙鱼滋味品质提供新方法。结果表明: 随着微流水处理时间的延长, 鳙鱼肌肉中总游离氨基酸含量、甜味氨基酸含量、腺苷酸(Adenosine monophosphate, AMP)含量和甜菜碱含量呈现先增加后降低的趋势, 均在处理6d时含量最高, 较未处理组分别增加了17.74%、39.45%、28.00%和50.16%; 灰分和鲜味氨基酸含量呈现增加的趋势; 粗脂肪、总脂肪酸含量、饱和脂肪酸含量、单不饱和脂肪酸含量、多不饱和脂肪酸含量、苦味氨基酸含量、酸味氨基酸含量、次黄嘌呤核苷(Hypoxanthine riboside, HxR)和次黄嘌呤(Hypoxanthine, Hx)含量则逐渐降低; 粗蛋白含量在处理过程中无显著变化。滋味分析仪(电子舌)和感官评分结果表明, 微流水处理显著提高了鳙鱼肌肉鲜味和甜味, 降低了其咸味、苦味和腥味, 且处理6d时鳙鱼肌肉的滋味、气味、质地和色泽感官评分最高。故短时微流水处理可显著提高鳙鱼的肌肉滋味品质, 不降低营养品质, 适宜的处理时间为6d。     

工程化循环水养殖池塘的氮磷收支研究

为了探寻更清洁高效的养殖模式,研究将淡水池塘循环水养殖系统进行了改良,对5个月试验周期内池塘水体理化指标和氮磷收支情况进行了分析。结果显示,池塘水体的理化指标呈波动性变化,试验结束时总氮、总磷浓度分别为4.85和1.04 mg/L,总氮浓度符合淡水养殖尾水排放二级标准。饲料和底泥是池塘氮磷输入的主要来源,分别占池塘氮元素输入量的50.6%和43.7%,磷元素输入量的49.4%和46.9%;底泥积累是池塘氮磷输出的主要途径,分别占池塘氮磷元素输出量的53.3%和78.7%。试验池塘对氮磷的利用率分别为65.2%和16.6%,其中鲤对氮磷的利用率显著高于其他鱼类(P<0.05),鲢、鳙对磷的利用率无显著差异(P>0.05)。研究表明,改良后的池塘循环水养殖系统有效降低了营养负荷,提高了养殖生物的氮磷利用率,减轻了养殖尾水对周边环境的影响,兼顾生态与经济效益,是一种成本较低且可持续发展的池塘养殖模式。     

净化时间对微流水系统中鳙品质影响的研究

以商品规格的鳙为研究对象, 利用湖泊建立为流水系统, 研究净化时间对系统中鳙肌肉的营养成分、质构和持水特性及肌肉中滋味成分与挥发性气味物质的影响。结果表明, 在整个净化过程, 鳙肌肉中蛋白、脂肪含量呈显著下降, 灰分含量处理前后无显著差异; 鳙肌肉中挥发性盐基氮含量、羰基含量随净化时间延长而显著下降; 肌肉质构的硬度随净化时间延长而显著上升, 黏着性和咀嚼性优于净化初期, 弹性和回复性与初期显示差异不显著; 水溶性蛋白含量和游离氨基酸含量呈先上升后下降的趋势。综上所述, 微流水净化处理能够显著提升鳙肌肉品质, 改善鳙肌肉口感和风味。     

象山港南沙岛不同养殖类型沉积物酸可挥发性硫化物的时空分布

2007年分4个航次测定了象山港南沙岛不同养殖类型(贝类养殖、藻类养殖和网箱养殖)沉积物酸可挥发性硫化物(AVS)含量的时空变化规律.研究结果表明,南沙岛养殖区沉积物AVS变化范围为0.01-30.03μmoL/g,平均3.75μmol/g,其中贝类养殖区、藻类养殖区、网箱养殖区和对照区AVS年平均含量分别为1.03、0.64、5.06和0.70 μmol/g.网箱养殖中心区(S10)AVS的含量分别是贝类养殖区、藻类养殖区和对照区的8.5倍、13.6倍和12.6倍.ANOVA分析表明,表层沉积物(0-3cm) AVS含量的季节变化差异不显著,但柱状样(0-15 cm)平均含量差异显著,夏秋季明显高于冬春季.AVS含量总体上随着沉积物深度的增加而增加,6-9 cm达到最大值,夏秋季尤为明显.聚类分析表明,南沙岛养殖区调查站位分为3类,网箱养殖中心区(S10)和距离较近的S13和S12为一个类群,贝类养殖区、藻类养殖区和对照区为一个类群,其余站位为一个类群.总体上,养殖中心区AVS含量最高,随着与养殖中心区距离的增加含量逐渐降低,网箱养殖对底质AVS的影响主要集中在200 m以内,500 m以外则影响较小.     

不同温度竹荪品种挥发性成分及风味特性分析

[目的]分析研究不同温度竹荪品种挥发性成分及风味特性。[方法]选生长温度、子实体形态有明显差异的两个代表性竹荪品种:红托竹荪、棘托竹荪,采用顶空固相微萃取(HS-SPME)和气相色谱-质谱联用(GC-MS)技术,分析其挥发性成分。[结果]两种竹荪挥发性成分涵盖醛、醇、酯、酮、烃、杂环等类,两个品种所含化合物种类、含量有差异。中温品种挥发性成分72种,含量95. 279%,气味表现成分36种,含量27. 713%,占其挥发性成分的29. 086%。中高温品种挥发性成分55种,含量94. 392%,气味表现成分29种,含量15. 916%,占其挥发性成分的16. 862%。[结论]不同温度竹荪品种,其所含挥发性成分不同,气味表现物质不同,其风味特征不同。     

低鱼粉饲料中添加苏氨酸对三倍体虹鳟抗氧化能力、消化生理及肠道炎症因子基因表达的影响

研究低鱼粉饲料中不同水平苏氨酸对三倍体虹鳟(Oncorhynchus mykiss)生长、抗氧化能力、消化生理及肠道炎症因子基因表达的影响, 以初始体质量(18.42±0.20) g的三倍体虹鳟为研究对象, 在室内200 L流水水族箱中进行摄食生长试验56d。在基础饲料中添加L-苏氨酸, 配制苏氨酸水平分别为0.45%(对照)、0.76%、1.09%、1.29%和1.64%的5种等氮等能饲料。将450尾三倍体虹鳟随机分为5组, 每组处理3个重复, 每个重复30尾鱼。结果表明, 当添加量为1.09%、1.29%和1.64%时, 血清超氧化物歧化酶(SOD)活力显著提高, 同时显著降低了丙二醛(MDA)的含量(P<0.05), 过氧化氢酶(CAT)在1.29%组含量最高, 相比对照组差异显著(P<0.05)。在饲料中添加苏氨酸(0.76%—1.64%)时, 肠道脂肪酶(LPS)和胰蛋白酶的消化酶活性显著高于对照组(P<0.05), 但随着饲料苏氨酸水平达到1.64%时, 消化酶活性有所降低。1.09%和1.65%组的肠道组织形态最佳, 绒毛发达, 排列整齐, 无融合和脱落现象。苏氨酸水平对肠道炎症因子IL-2、IL-8、IL-10、IgM、TNF-α和PepT1都有显著影响(P<0.05), 随着苏氨酸水平的增加, IL-2、IgM和PepT1呈现先升高后降低的变化趋势, 在1.29%和1.09%组的表达量达到最高; IL-8呈逐渐升高趋势; 而IL-10和TNF-α呈下降的变化趋势。研究结果表明, 在低鱼粉饲料(15%)中添加适量水平的苏氨酸, 对提高三倍体虹鳟幼鱼生长、消化酶活性、促进肠道形态结构发育和增强免疫具有积极的作用。     

两种对虾养殖模式下池塘底泥耗氧速率的研究

通过采集试验前后池塘不同位点的底泥沉积物,就对虾单养和虾蛤混养两种模式下底泥耗氧速率(SOD)做初步研究,探讨不同水温和有机质含量对不同养殖模式池塘底泥SOD 的影响。结果表明,在对虾单养和虾贝混养两种模式下池塘底泥SOD都随着水温的升高而升高,且呈良好的幂指数相关,相关系数R2分别为0.979 9、0.990 5;SOD与有机质含量相关性显著(P<0.05)。对不同养殖模式下虾池底泥SOD 分析表明,虾蛤混养池与对虾单养池的SOD 差异极显著 (P<0.01);在相同养殖模式下,SOD试验初期小于试验后期(P<0.05)。在相同时期,单养虾池底泥的SOD 高于虾蛤混养池(P<0.05)。     

Impact of black soldier fly larvae meal on the chemical and nutritional characteristics of rainbow trout fillets

The present research studied the effect of a dietary inclusion with Hermetia illucens larvae meal (Hi) on rainbow trout’s fillets chemical composition. The effect of Hi inclusion in diets on rainbow trout chemical characteristics was evaluated. Trout were fed three different diets: control (C, no Hi inclusion), 25% and 50% of substitution of fish meal with Hi (Hi25 and Hi50, respectively). Fillets were analysed to quantify proximate composition, carbohydrates percentage, colour parameters, nucleotides concentration, fatty acids profile, volatile organic compounds (VOCs) and myofibrillar and sarcoplasmic concentrations. Diets did not affect proximate composition. Contrariwise, Hi50 diet decreased fillet yellowness and both substitution percentages affected negatively adenosine monophosphate concentration. Saturated fatty acids, mostly C12 : 0, increased their contents in relation with Hi inclusion at the expense of monounsaturated and polyunsaturated (both n-3 and n-6) fatty acids. Less modifications were reported in VOCs as only heptanal and octanal concentrations were affected, no new compounds appeared in relation with Hi inclusion. No modifications in proteins patterns were shown even if myofibrillar content decreased in trout fed Hi50. The results highlighted that chemical modifications occurred in fillets were related to the chemical composition of the H. illucens meal and to the percentage of inclusion in the diet. Substitution of fish meal with a precisely percentage of H. illucens meal could be a potential future solution in order to decrease the quantity of fish meal used in aquafeeds.     

Flesh qualities and muscle fiber characteristics in triploid and diploid rainbow trout

Analyzed with regard to their slaughter weights and flesh quality 78‐month‐old diploid and triploid rainbow trout (full sibs) were reared together in a pond after tagging at an age of 12 months. Triploids had higher body weights and carcass percentages than diploids (6 kg vs 4 kg and 66% vs 52%). Triploid fish also displayed lower electrical conductivity values and darker (L* value) and redder (a* value) flesh color. The fillets of the triploid trout contained more crude fat and less moisture than the diploids (6% vs 3% and 68% vs 74%, respectively). No effect of ploidy was found with regard to the protein contents. Triploid rainbow trout had larger mean white and intermediate muscle fiber areas than diploid fish in the dorsal and pelvic fin regions. In the pelvic fin part, the white muscle fiber areas were larger than in the dorsal fin part. In conclusion, adult triploid rainbow trout grow faster especially by fiber hypertrophy and have better flesh quality parameters than diploid fish.     

Comparison of nutritional quality and volatile flavor compounds among bighead carp from three aquaculture systems

To explore the differences in the nutritional quality of the muscles of bighead carp from different environments and aquaculture systems, we investigated three types of water bodies typically used for aquaculture: A common culture pond (NC), a natural lake (PY), and a cold water reservoir (XHK). Parameters affecting quality were evaluated, including muscle microstructure, fatty acid profiles, amino acid profiles, and volatile compounds. Fish from the XHK reservoir had the smallest muscle fiber diameter and the highest muscle fiber density (25.3 fibers/0.01 mm²), while muscle fiber density was lowest in fish from the NC pond (9.7 fibers/0.01 mm²). The bighead carp from the XHK reservoir had a much wider variety of unsaturated fatty acids, as well as higher levels of total polyunsaturated fatty acids. Eicosapentaenoic acid (EPA), docosahexenoic acid (DHA), and arachidonic acid (AA) were all significantly more abundant in the XHK group, increases of 7.48%, 12.12%, and 17.49%, respectively (P < 0.05). The bighead carp from NC contained more “fishy” volatile flavor substances, as well as hydrocarbons with higher threshold values. Fish from XHK and NC had a greater umami intensity due to the presence of abundant volatiles with special aromas, including 1-Octene-3ol, DL-Menthol, and 2-ethyl-.     

虹鳟spindlin基因克隆及不同倍性的表达分析

spindlin基因是减数分裂纺锤体相关因子, 为了研究spindlin基因在二倍体和三倍体雌性虹鳟减数分裂过程中出现的差异, 通过cDNA末端快速扩增(RACE)技术获得spindlin基因cDNA 4529 bp(GenBank登录号: MN378564), 其中3′非编码区(UTR)和5′非编码区(UTR)分别长3662 bp和141 bp, 开放阅读框(ORF)长726 bp, 编码241个氨基酸, 该蛋白质序列的相对分子量为28.3 kD, 理论等电点值为5.94, 无跨膜结构。同源性分析表明, 虹鳟(Oncorhynchus mykiss)与银大马哈鱼(Oncorhynchus kisutch)同源最高, 高达99.59%。系统发育进化树显示, 虹鳟与大鳞大马哈鱼(Oncorhynchus tshawytscha)和红点鲑(Salvelinus alpinus), 聚为一支。实时荧光定量(RT-PCR)结果显示, spindlin基因在二倍体雌性虹鳟卵巢、肾、肝、脾、肌、鳃、心、眼、肠和鳍组织中均有表达, 其中, 在卵巢中的表达量极显著高于其他组织(P<0.01)。对于二倍体雌性虹鳟, 在受精后240—300d (days post fertilization, dpf)发育阶段, spindlin基因在卵巢组织中的相对表达量显著下降。对于三倍体雌性虹鳟, 该基因在240—330 dpf阶段的表达量显著上升。在同一发育阶段中, spindlin基因在二倍体雌性虹鳟卵巢中的表达量较三倍体雌性虹鳟相对较高, 且均存在极显著差异(P<0.01)。通过免疫组化结果发现, 二倍体雌性虹鳟在240 dpf阶段, Spin蛋白在初级卵母细胞核内信号最强, 在270—330 dpf阶段逐渐减弱; 三倍体虹鳟卵巢在240—330 dpf发育阶段, 在卵原细胞中信号逐渐增强。减数分裂异常是性腺败育的关键原因, 研究结果表明三倍体虹鳟在减数分裂过程中出现异常与spindlin基因的低表达有关, 这可能是卵巢发育阻滞的原因之一。     

Effects of dietary lipid sources on flavour volatile compounds of brown trout (Salmo trutta L.) fillet

The high cost and unpredictable availability of fish meal and fish oil (FO) forced feed mill companies to look for alternative ingredients for aquafeeds. In this study, the effects of alternative dietary lipid sources [FO as control, canola oil (CO), oleine oil (OO), poultry fat (PF) and pork lard (PL)] in trout feed on flavour volatile compounds occurring in brown trout (Salmo trutta L.) fillet were evaluated after 70 days of feeding (rearing temperature 14.6°C). Total amounts of volatile compounds identified were higher for fillets of fish fed diets containing only FO as lipid sources. Total amount of alcohols and aldehydes of the fillets were linearly directly related to the percentage content of polyunsaturated fatty acids (PUFA) n‐3 of brown trout flesh. The use of alternative dietary lipid sources, modifying the fillet fatty acids composition, affect the total amount of volatile compounds and, changing the relative amount of each volatile compound, affect the flavour of the fish flesh.     

Evaluation of different commercial feeds on grow-out silver black porgy,Sparidentex hasta (Valenciennes), for optimum growth performance,fillet quality,and cost of production

The objective of the study was to find a cost-effective feed from three commercial feeds, namely, Arasco (Saudi Arabia), Skretting (Turkey), and Biomar (Greece) for commercially producing silver black porgy (sobaity bream), Sparidentex hasta in Kuwait. For confidentiality, these feeds were randomly given code names, diets 1, 2, and 3, which were known only to the investigating staffs. The trash fish (diet 4) was used as the control. The experiment was conducted for 28 wk with grow-out sobaity bream (210.0 ± 0.51 g) using a flow-through system consisting of twelve 1-m³ tanks. There were three replicates for each treatment. Fish were fed two times daily at satiation level. The results showed that fish fed diet 2 resulted in significantly (P > 0.05) better growth performance, feed utilization, and higher fillet eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content compared to other diets. A comparison of fillet quality of cultured and wild sobaity bream showed no significant (P > 0.05) difference between sensory attributes, except that of ‘flavor’ in cooked fillets of wild sobaity bream. A simple economic analysis showed that the cost per kilogram of fish production was significantly (P > 0.05) the lowest in diet 2 (USD4.13), followed by diet 1 (USD5.70), diet 4 (USD6.33), and diet 3 (USD6.92). Thus, based on growth performance, feed utilization, cost of production, and nutritional quality of fillet, it is concluded that diet 2 may be recommended for commercial culture of sobaity bream in Kuwait. However, future research should focus on how to improve fillet quality of the cultured fish at par with wild fish by manipulating the feed formulation.     

Biochemical and morphological correlates of growth in diploid and triploid rainbow trout

Diploid and triploid rainbow trout contained the same amount of RNA per unit weight of white muscle tissue at a given growth rate. This finding, along with a previous finding that the protein content of triploid muscle tissues is not different from that of the diploids, indicates that triploid nuclei produce more RNA than their diploid counterparts. This increased production of RNA is probably due to the expression of the extra set of chromosomes in triploid nuclei. RNA-based growth correlates and liver somatic index ( I _H) were valid predictors of growth for both triploid and diploid fish. RNA concentration appeared to be better than RNA/DNA and RNA/protein in predicting growth.     

Fatty acid composition of wild and cultured northern pike (Esox lucius)

The aim of the study was to determine the effect of diet on the fatty acids composition of cultured northern pike (Esox lucius) fillet (mean body weight, 620 g; age, 2.5 years; commercial feed) profiles when compared with wild pike caught in Lake Dga? Wielki in northern Poland (mean body weight, 570 g; age 3.5 years). Cultured pike fillets contained several times more fat (2.40%) compared with wild fish (0.19%, P < 0.01). The total relative quantity of saturated fatty acids (SFA; % of total fatty acids) and unsaturated fatty acids (USFA) in cultured and wild pike were similar. Monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) content differed in wild and cultured fish. Cultured pike contained nearly two times more MUFA (30.90% compared with 15.97%; P < 0.01) but less PUFA (42.04% compared with 58.33%; P < 0.01), n‐3 PUFA (32.42% compared with 41.26%; P < 0.01), and n‐6 PUFA (6.47% compared with 15.79%; P < 0.01). The largest differences were noted with regard to docosahexaenoic acid (DHA) and arachidonic acid (AA), the levels of which in cultured and wild pike were 18.93% vs 27.96% and 0.73% vs 8.60%, respectively (P < 0.01). Quality compositions of the commercial feed and the cultured pike fillets were identical.     

不同年龄段养殖宽体沙鳅肌肉营养成分分析与评价

采用国家标准方法对1、2、3龄宽体沙鳅养殖群体的肌肉营养成分及品质进行了分析比较。结果显示: (1)各年龄组宽体沙鳅肌肉粗蛋白质和粗脂肪含量较高且随着年龄的增长呈增长趋势。其中, 粗蛋白在2龄和3龄组增长不显著(P>0.05), 粗脂肪增长显著(P<0.05)。(2)各年龄组肌肉氨基酸组成相同, 均以鲜味特征氨基酸谷氨酸含量最高, 其次为天门冬氨酸; 第一限制性氨基酸均为缬氨酸; 支链氨基酸与芳香族氨基酸的比值(F值)分别为2.22、2.08和2.12。(3)各年龄组宽体沙鳅脂肪酸在组成和含量上略有差异, 表现为不饱和脂肪酸含量高于饱和脂肪酸含量(P<0.05); 不饱和脂肪酸中单不饱和脂肪酸含量较高(P<0.05); 多不饱和脂肪酸(PUFA)在2龄组最高(P<0.05)且EPA+DHA含量随年龄的增长递增(P<0.05)。综上, 各年龄段宽体沙鳅肌肉营养丰富, 味道鲜美, 以2龄鱼体营养质量最优。