Artificial burrow preference by the Japanese crayfish Cambaroides japonicus

SUMMARY: Preference for artificial burrows by the endangered Japanese crayfish species Cambaroides japonicus was studied to improve its cultivation. The occupation of artificial burrows, which were made from straight polyvinyl chloride pipes of different internal diameters ( Y , mm), by crayfishes of different total lengths ( X , mm) was significantly ( P < 0.001, n = 56) described by a linear regression: Y = 0.49 X + 3.42 (19.0 ≤ X ≤ 70.2). Among burrows of different lengths [crayfish total length (TL) × 1, × 2, × 3, and × 4], crayfishes significantly preferred burrows that were greater than TL × 3 ( P < 0.001, n = 588).     

Effects of different bronopol treatments on final survival rates in the artificial incubation of crayfish eggs (Pacifastacus leniusculus,Astacidae)

Two experiments were conducted on the effects of bronopol in the artificial incubation of crayfish eggs (Pacifastacus leniusculus) with the aim to search an alternative to formaldehyde. In the first experiment, 50, 250, 500 and 1000 ppm bronopol and 3000 ppm formaldehyde (control) in periodical administrations were tested on a density of 6.6 eggs cm^?2. After 44 days of incubation, the highest survival was obtained with 1000 ppm bronopol (81.9% to stage 2 juvenile, with no significant difference from formaldehyde), whereas lower bronopol concentrations resulted in significantly lower survival. In the second experiment, 1000, 3000 and 5000 ppm bronopol and 3000 ppm formaldehyde (control) administered for 15 min every second day were tested on eggs at a density of 20 eggs cm^?2. After 78 days of incubation, bronopol at 3000 ppm allowed for a stage 2 juvenile survival rate of 65.0% (with no significant difference from formaldehyde), whereas significantly lower survival was obtained with 1000 ppm or 5000 ppm. This study shows that bronopol may constitute an alternative to formaldehyde in the artificial incubation of crayfish eggs. A concentration of 3000 ppm administered for 15 min every second day may be adequate even on long incubations at high densities (at least 20 eggs cm^?2, one complete layer).     

海水养殖花鲈对几种饲料蛋白原料的表观消化率

测定了在室内海水流水系统中养殖的花鲈对7种常用饲料原料,宠物级鸡肉粉(P-PBM)、饲料级鸡肉粉(F-PBM)、血粉(BM)、羽毛粉(FEM)、蚕蛹粉(SWP)、豆粕(SBM)和菜粕(RSM)以及1种混合动物蛋白粉(MM=50%P-PBM+20%F-PBM+20%BM+10%FEM)的干物质、蛋白质和能量表观消化率(ADC)。实验饲料由70%基础饲料(蛋白质含量为42.0%,能量含量为18.9MJ/kg)和30%的待测原料组成。基础饲料和实验饲料中均添加1%(质量分数)的Cr2O3作为外源标记物。饲养实验共进行4周。实验期间每天投饵两次,采用虹吸方法收集粪便。实验结果显示:花鲈对P-PBM、F-PBM、BM、FEM、MM、SWP、SBM和RSM干物质ADC分别为61%～87%,蛋白质ADC为80%～96%,能量ADC为75%～93%。其中,花鲈对SBM的蛋白质ADC最高,对MM的蛋白质ADC最低,对BM的干物质和能量ADC最高,对RSM的干物质和能量ADC最低。     

Effects of six alternative lipid sources on growth and tissue fatty acid composition in Japanese sea bass (Lateolabrax japonicus)

Ten-week experiment was carried out on Japanese sea bass (5.87 ± 0.02 g) to study the effects of replacement of fish oil with six alternative lipid sources: pork lard, PL; beef tallow, BT; poultry fat, PF; soybean oil, SO; corn oil, CO; and a mixed-fat (MF: tallow, 60%; soy oil, 20%; fish oil, 20%) on growth performance and fatty acid (FA) composition in fillet and liver. Seven isoenergetic and isonitrogenous experimental diets were formulated, containing 10% of added lipid. Fish oil was used in control diet, which was substituted by 50% with the alternative lipid sources in the other six diets.

Weight gain (WG), specific growth rate (SGR), Feed conversion ratio (FCR) feed intake and hepatosomatic index (HSI) of fish fed the experimental diets were not significantly different (P > 0.05). Protein efficiency ratio (PER) in fish fed the PF diet were significantly lower than those of fish fed SO and CO diets. Significant differences in carcass moisture and lipid contents of carcass and liver were observed among fish fed the dietary treatments. Generally, the fatty acid composition of fish fillets and livers reflected the dietary FA composition.     

鲈幼鱼对饲料中苏氨酸的需要量

以初始体质量(8.00±0.20)g的鲈为实验对象,在海水网箱(1.5 m×1.5 m×2.0 m)中进行为期8周的摄食生长实验,研究鲈对饲料中苏氨酸的需要量。通过在半精制基础饲料中添加晶体L-苏氨酸使饲料中苏氨酸含量分别达到0.75%、1.03%、1.36%、1.67%、2.04%和2.31%,配制成6水平等氮等能饲料(41.83%粗蛋白质,19.68 kJ/g总能)。每种饲料设3个重复,每个重复随机放养30尾鲈。实验采用表观饱食投喂方式,每天投喂2次(06:00和17:30),实验期间水温为26～32℃,盐度为22～28,溶解氧含量在7 mg/L左右。实验结果表明,各饲料处理组成活率(94.4%～98.9%)无显著差异。随着饲料中苏氨酸含量的增加,鲈的增重率显著升高(150.3%～256.9%)(P<0.05),且在1.67%苏氨酸饲料组达到最大值(256.9%),然而,随着饲料中苏氨酸含量的进一步增加,增重率有下降的趋势。鲈的氮累积率随着饲料中苏氨酸含量的增加而显著升高(13.18%～26.36%)(P<0.05),且在1.67%苏氨酸饲料组达到最大值(26.36%),随着饲料中苏氨酸含量的进一步增加,氮累积率有下降的趋势。饲料苏氨酸含量对鲈鱼体粗蛋白、粗脂肪和灰分含量无显著影响。以增重率和氮累积率为评价指标经二次回归分析得出,鲈对饲料中苏氨酸的需要量分别为1.77%和1.88%,占饲料蛋白质的4.21%和4.47%。     

饥饿及恢复投饵过程中花鲈肌肉组成及非特异免疫水平的变化

探讨了饥饿及恢复投饵过程中花鲈（Lateolabrax japonicus）（196±38g）肌肉组成分及鱼体非特异免疫水平的变化。实验设S0组（对照组,持续正常投喂）,S5组（饥饿5d后恢复正常投喂）,S10组（饥饿10d后恢复正常投喂）,S15组（饥饿15d后恢复正常投喂）。S0组每隔5d取样,S5,S10和S15组分别在结束饥饿及恢复投饵后每隔5d取样测定。结果显示：饥饿程度对花鲈肌肉组成有显著影响。与对照组相比,S10组饥饿结束时肌肉的总脂含量显著降低;S15组饥饿结束时肌肉的总脂含量和粗蛋白含量都显著降,同时显著增加了肌肉的水分含量。表明饥饿过程中花鲈先动用肌肉脂肪,后动用肌肉蛋白。在恢复投饵过程中,S10和S15组总脂含量表现出先降后升的规律,而S15组蛋白表现为逐步回升的趋势。表明花鲈在饥饿后恢复投饵的过程中,先恢复肌肉蛋白含量,后恢复肌肉脂肪含量。饥饿15d时花鲈血清蛋白浓度显著降低。与对照组相比,S5组血清、脾脏和头肾溶菌酶活性均无显著变化;S10组头肾溶菌酶活性在恢复投饵10d时补偿性升高。S15组在饥饿结束时显著降低了花鲈头肾溶菌酶活性,但在恢复投饵5d时恢复到对照组水平。花鲈白细胞的吞噬活性也受饥饿程度及恢复投饵的影响。饥饿会降低花鲈血液白细胞的吞噬活性。在恢复投饵过程中,饥饿（5d）后恢复投饵会引起白细胞吞噬百分率和吞噬指数的补偿性升高。表明饥饿及恢复投饵也影响花鲈的非特异免疫水平。     

Effects of dietary protein to energy ratios on growth and body composition of juvenile Japanese seabass, Lateolabrax japonicus

A growth experiment was conducted to determine the optimal dietary protein to energy (P/E) ratio for juvenile Japanese seabass (initial average weight 6.26±0.10 g). Nine practical diets were formulated to contain three protein levels (36%, 41% and 46%), each with three lipid levels (8%, 12% and 16%), in order to produce a range of P/E ratios (from 19.8 to 28.6 mg protein kJ⁻¹). Each diet was randomly assigned to triplicate groups of 60 fish in sea floating cages (1.5×1.5×2.0 m). Fish were fed twice daily (06:30 and 16:30) to apparent satiation for 8 weeks. The water temperature fluctuated from 26.5 to 32.5 °C, the salinity from 32‰ to 36‰ and dissolved oxygen content was approximately 7 mg l⁻¹ during the experimental period. The results showed that the growth was significantly affected by dietary P/E ratio (P<0.05). Fish fed the diets with 46% protein (12% and 16% lipid, P/E ratio of 26.7 and 25.7 mg protein kJ⁻¹) had the highest specific growth rates (SGR) (4.26 and 4.24% day⁻¹). However, fish fed the diet with 41% protein and 12% lipid showed comparable growth (4.20% day⁻¹), and had higher protein efficiency ratio (PER), protein productive value (PPV) and energy retention than other groups (P<0.05). No significant differences in survival were found among dietary treatments. Carcass lipid content positively correlated with dietary lipid level irrespective of protein level and inversely correlated with carcass moisture content. Carcass protein and ash contents increased with increasing dietary lipid at each protein level. These results suggest that the diet containing 41% protein and 12% lipid with P/E of 25.9 mg protein kJ⁻¹ is optimal for Japanese seabass.     

Artificial incubation of noble crayfish (Astacus astacus) eggs in a partially recirculating system using formaldehyde as an antifungal treatment

There is little information on the long‐term artificial incubation of noble crayfish eggs. The present study evaluated artificial incubation in a partially recirculating system using formaldehyde baths as antifungal prophylaxis. Crayfish eggs were treated three times a week in a formaldehyde bath of 3000 ppm for 15 and 20 min and in 2500 ppm for 15, 20 and 25 min. In all treated groups, high final survival rates (87.8–92.0%) to stage 2 juveniles were obtained after 83 days. Significantly lower survival was observed in the control group (45.4%). It was concluded that recirculating systems can be used successfully for artificial incubation of crayfish eggs in order to conserve water. Formalin was found as an effective fungicide but its use should be carefully considered because of its safety issues for farm staff and environmental pollution.     

晶体氨基酸提高混合动物蛋白替代花鲈饲料中鱼粉的潜力

实验以鸡肉粉∶牛肉骨粉∶喷雾血球干燥粉∶水解羽毛粉=40∶35∶20∶5的比例组成的混合动物蛋白(animal protein blend,APB)分别直接替代或在补充赖氨酸、蛋氨酸、苏氨酸后替代花鲈饲料中50%、75%、100%的低温干燥鱼粉,研究其对花鲈生长及生理功能的影响。经过8周的饲养后发现,花鲈的生长性能随替代比例的提高而降低;摄食含APB饲料的花鲈,其成活率,摄食率和生长性能均显著低于对照组(P<0.05)。与APB直接替代鱼粉的处理组相比,添加3种必需晶体氨基酸极显著提高了花鲈的生长性能及全鱼蛋白、脂肪、能量含量(P<0.01),显著降低了花鲈的全鱼水分、灰分,肝指数及脏体比(P<0.05)。晶体氨基酸与APB的替代水平对花鲈的生长性能、形体指标及体组成成分存在显著的交互作用(P<0.05)。实验结果表明,(1)混合动物蛋白替代初始体重为13.2 g的花鲈饲料中白鱼粉的比例应小于50%;(2)添加必需晶体氨基酸能显著提高APB在花鲈饲料中的应用潜力;(3)花鲈具备一定的利用晶体氨基酸的能力。     

铜绿微囊藻对克氏原螯虾幼虾存活及成虾几种酶类的影响

为研究铜绿微囊藻对克氏原螯虾的影响,将克氏原螯虾幼虾及成虾暴露在不同浓度的铜绿微囊藻溶液中,研究了铜绿微囊藻对幼虾存活率、外部形态及肝胰腺超微结构的变化和成虾总血细胞密度(THCs)、血清中血蓝蛋白含量、总超氧化物歧化酶(T-SOD)、过氧化物酶(POD)、酚氧化物酶(PO)以及鳃丝Na⁺/K⁺-ATP酶活性的影响。结果表明,(1) 高浓度的铜绿微囊藻能显著降低幼虾的存活率。(2) 显微观察表明,1.0×10⁷/mL及以上浓度的铜绿微囊藻液中培养7 d后,幼虾肝胰腺呈现暗红色,并伴有一定的肿大现象,透射电镜显示其肝胰腺细胞受到损伤。(3) 高浓度的铜绿微囊藻能造成应激反应,THCs在暴露1 d后显著升高并稳定在较高水平;血蓝蛋白含量变化不明显,只在5 d时显著低于对照组(P<0.05),PO活性都表现出先显著性增强(P<0.01),回落后又有所增加的波动趋势;血清中的T-SOD活力在1 d后受到抑制,5 d时被激活至较高水平;POD活性都表现出先显著性增强(P<0.01),回落后又有所增加的波动趋势;鳃丝中Na⁺/K⁺-ATP酶活性在暴露1 d后显著降低(P<0.01)后回升,并最终维持在较高水平。研究结果表明,高浓度的铜绿微囊藻能造成克氏原螯虾幼虾存活率显著降低并影响其肝胰腺超微结构;而克氏原螯虾成虾对铜绿微囊藻有相对较强的耐受力,血淋巴的酶学变化表明,暴露在铜绿微囊藻水体的成虾经历过应激反应并有逐步适应的过程。     

外源激素对花鲈(Lateolabrax japonicus)血清IGF-1含量及肝脏IGF-1和IGFBP-1 mRNA表达的影响

对花鲈(Lateolabrax japonicas)成鱼腹腔注射促黄体激素释放激素类似物(LHRH-A3)和人体绒毛膜促性腺激素(HCG),利用放射性免疫激素测定方法(RIA)检测了花鲈血清中类胰岛素生长因子(Insulin-like growth factor 1,IGF-1)在注射后6、12、24、48 h内的变化情况,同时还利用荧光实时定量PCR技术检测了花鲈肝脏中IGF-1和类胰岛素生长因子结合蛋白1(Insulin-like growth factor-binding protein 1,IGFBP-1)mRNA的相对表达量的变化情况。结果表明,注射LHRH-A3的花鲈血清中IGF-1的含量在24 h后出现了明显的降低(P0.05),而花鲈肝脏中IGF-1 mRNA的相对表达量在注射6 h后较对照组明显升高(P0.05),而肝脏中IGFBP-1 mRNA的相对表达量则呈现下降趋势。注射HCG的花鲈血清中IGF-1的含量在注射后12 h出现了明显降低(P0.05),24 h后血清中IGF-1含量持续降低。肝脏中IGF-1 mRNA的相对表达量在注射后的24 h内均保持稳定,而在处理后的48 h出现了显著上升(P0.05)。肝脏中IGFBP-1 mRNA的相对表达量在注射后12h检测到显著升高(P0.05)。研究结果表明,LHRH-A3和HCG均可以通过直接或间接的刺激作用来触发花鲈IGF系统的应答反应,但是其中具体机制尚不明了。     

刺参(Apostichopus japonicus)重要经济性状相关SNP标记的验证分析

本研究在前期构建的刺参(Apostichopus japonicus)高密度遗传连锁图谱和QTL分析的基础上,筛选出26个与体长、体重、体宽、棘刺总数、抗病力相关的SNP位点,设计出可用于HRM检测的SNP扩增引物13对。在扩大群体中利用HRM小片段法对这13个刺参重要经济性状相关的候选SNP位点进行分型和多态性检测,并结合扩大群体的相关性状数据进行了QTL位点验证。多态性结果显示,13个位点中有3个单态性位点,其余10个多态性位点中有3个位点为低等位多态性,7个位点为中等位多态性。10个多态性位点的最小等位基因频率(MAF)介于0.016(SNP113)~ 0.332(SNP160)之间,平均值为0.173;各位点的观测杂合度(Ho)介于0.031(SNP113)~0.818(SNP9)之间,平均值为0.433;期望杂合度(He)介于0.031(SNP113)~0.834(SNP9)之间,平均值为0.402;多态信息含量(PIC)介于0.030(SNP113)~0.393(SNP160)之间,平均为0.248,有6个位点偏离Hardy- Weinberg平衡。QTL验证结果表明,SNP40和SNP160位点为与生长(体长、体重、体宽)相关的位点,各位点的优势基因型分别为SNP40(CC)和SNP160(AA);SNP88、SNP112和SNP126这3个位点为与抗病力相关的位点,各位点的优势基因型为SNP88(CC)、SNP112(AA)和SNP126(TT)。基于这5个位点构建生长和抗病二倍型,发现二倍型K1(CC AA TT)抗病力最强,S1(CC AA)、S3(CC AC)在生长方面优势显著,相关研究结果可为分子标记辅助育种在生产中应用提供基础数据。     

棉子糖对刺参幼参生长、生理指标及糖代谢的影响

为研究饲料中添加棉子糖对刺参生长、消化与糖代谢的影响,实验以初始体质量为(11.46±0.06) g的刺参幼参为对象,在基础饲料中添加包膜棉子糖,配制成棉子糖含量分别为0.00%(D1)、0.02%(D2)、0.03%(D3)、0.06%(D4)、0.08%(D5)和0.11%(D6)的6组实验饲料,进行为期67 d的生长实验。结果显示：(1)随着棉子糖含量的增加,刺参的增重率及特定生长率均先升后降,D2～D5组显著高于D1组,D4组达最大值,体壁基本营养成分不受棉子糖含量的影响。(2)肠道蛋白酶、脂肪酶、淀粉酶和超氧化物歧化酶活性均先升后降,D3、D4组显著高于D1组;丙二醛含量先降后升,D4组达最低值;D3～D5组肠道皱襞高度显著高于D1组,D5、D6组出现炎症细胞浸润。(3)葡萄糖激酶、果糖磷酸激酶和丙酮酸激酶活性先升后降,葡萄糖激酶和果糖磷酸激酶活性在D4组达最大值,丙酮酸激酶活性在D3组达最大值;磷酸烯醇式丙酮酸羧激酶活性先上升后平稳,D4～D6组显著高于其他组。(4)葡萄糖激酶、果糖磷酸激酶和丙酮酸激酶基因表达量均先升后降,D2～D6组均显著高于D1组,葡萄糖激酶和果糖磷酸...     

基于线粒体Cytb基因探讨我国日本囊对虾4个地理群体的遗传结构及种群分化

为了分析日本囊对虾两种表型差异类型的系统发育关系,实验系统比较了两种类型线粒体全基因组的基因结构、遗传距离和密码子偏好性等特征。结果显示,两种类型线粒体基因组的基因重叠区、基因间隔和密码子等方面均存在差异。两种类型的线粒体蛋白编码基因核苷酸序列的相似度为91.10%~95.00%,氨基酸序列的相似度为96.15%~100%。两种类型的A+T富集区的同源性只有82.60%,分歧度为15.40%,呈现高度遗传分化。日本囊对虾两种类型蛋白编码基因的核苷酸序列分歧度大于明对虾属和叉肢螯虾属,但氨基酸序列的分歧度小于后者。研究发现,基于cytb基因的种间遗传距离大于种内遗传距离的10倍;基于cox1基因的种间遗传距离分别为类型Ⅰ和类型Ⅱ的种内遗传距离的14.6倍和5.2倍。两种类型的nd1、nd4和nd5基因的Ka/Ks值大于1,表明受到正向选择。基于20种隶属9属的对虾线粒体基因组蛋白编码序列构建系统发育树,结果显示能有效区分各属对虾,其中日本囊对虾的两种类型首先聚类,再与宽沟对虾聚类。研究表明,日本囊对虾的两种表型差异类型基本达到物种水平,有必要进一步评估更多的性状差异,以提高两种囊对虾的特异性养殖技术。     

HMG(High-Mobility Group Box Protein)在刺参(Apostichopus japonicus)肠道再生期间的表达情况分析

运用实时荧光定量PCR (qRT-PCR)技术,测定了一种核酸内非组蛋白类蛋白HMG(High-mobility group box protein)在刺参肠道再生第30分钟、1、2、6小时、1、3、7天的mRNA表达情况,结果显示,再生第6小时之前,表达量与正常刺参肠道相比无显著变化,再生第1–7天,其表达量显著高于对照组,并于第7天达到最大值。采用免疫荧光技术,分析测定了HMG在刺参肠道再生各时期的蛋白表达情况,结果显示,再生第2、6小时,HMG蛋白荧光信号弱,仅在浆膜层和黏膜层有少量分布;再生第1–7天,HMG蛋白荧光信号逐渐增强,再生第1天的HMG荧光主要分布在浆膜层和肌肉层,再生第3天和第7天的荧光信号最强,各层均有分布。结合HMG在其他物种组织修复再生中的作用,推测HMG可使免疫系统识别损伤信号,启动修复再生功能,调控细胞外基质(ECM)成分的降解与生成,诱导干细胞迁移、分化,并可能在伤口愈合阶段过后参与细胞免疫。     

Metabolic scope, swimming performance and the effects of hypoxia in the mulloway, Argyrosomus japonicus (Pisces: Sciaenidae)

The culture of the mulloway (Argyrosomus japonicus), like many other Sciaenidae fishes, is rapidly growing. However there is no information on their metabolic physiology. In this study, the effects of various hypoxia levels on the swimming performance and metabolic scope of juvenile mulloway (0.34 ± 0.01 kg, mean ± SE, n = 30) was investigated (water temperature = 22 °C). In normoxic conditions (dissolved oxygen = 6.85 mg l^− 1), mulloway oxygen consumption rate (M·o₂) increased exponentially with swimming speed to a maximum velocity (U_crit) of 1.7 ± < 0.1 body lengths s^− 1 (BL s^− 1) (n = 6). Mulloway standard metabolic rate (SMR) was typical for non-tuna fishes (73 ± 8 mg kg^− 1 h^− 1) and they had a moderate scope for aerobic metabolism (5 times the SMR). Mulloway minimum gross cost of transport (GCOT_min, 0.14 ± 0.01 mg kg^− 1 m^− 1) and optimum swimming velocity (U_opt, 1.3 ± 0.2 BL s^− 1) were comparable to many other body and caudal fin swimming fish species. Energy expenditure was minimum when swimming between 0.3 and 0.5 BL s^− 1. The critical dissolved oxygen level was 1.80 mg l^− 1 for mulloway swimming at 0.9 BL s^− 1. This reveals that mulloway are well adapted to hypoxia, which is probably adaptive from their natural early life history within estuaries. In all levels of hypoxia (75% saturation = 5.23, 50% = 3.64, and 25% = 1 .86 mg l^− 1), M·o₂ increased linearly with swimming speed and active metabolic rate (AMR) was reduced (218 ± 17, 202 ± 14 and 175 ± 10 mg kg^− 1 h^− 1 for 75%, 50% and 25% saturation respectively). However, U_crit was only reduced at 50% and 25% saturation (1.4 ± < 0.1 and 1.4 ± < 0.1 BL s^− 1 respectively). This demonstrates that although the metabolic capacity of mulloway is reduced in mild hypoxia (75% saturation) they are able to compensate to maintain swimming performance. GCOT_min (0.09 ± 0.01 mg kg^− 1 m^− 1) and U_opt (0.8 ± 0.1 BL s^− 1) were significantly reduced at 25% dissolved oxygen saturation. As mulloway metabolic scope was significantly reduced at all hypoxia levels, it suggests that even mild hypoxia may reduce growth productivity.     

穗花狐尾藻(Myriophyllum spicatum L.)饲喂对刺参(Apostichopus japonicus)幼参生长、体成分及消化酶的影响

为了探究穗花狐尾藻(Myriophyllum spicatum L.)替代鼠尾藻(Sargassum thunbergii)饲喂刺参(Apostichopus japonicus)幼参的效果,探讨了穗花狐尾藻添加量依次为0(对照)、15%(A1)、30%(A2)、45%(A3)和60%(A4)的5种饲料对刺参幼参[(1.66±0.61) g]生长、体成分和消化酶活性的影响。结果显示,A4组刺参的增重率(GR)显著高于其他4个组(P<0.05),刺参成活率最高,达到了97.78%;A4组刺参的粗蛋白含量最高(50.92%),显著高于A0、A1和A2组(P<0.05);A3组刺参的淀粉酶活力最高(0.83 U/g prot),显著高于A0、A1与A2组(P<0.05);A4组刺参的蛋白酶活力最高(1.62 U/g prot),显著高于其他4个组(P<0.05)。结果显示,穗花狐尾藻能够促进刺参生长。因此在刺参饲料中添加穗花狐尾藻,以替代资源日益匮乏的鼠尾藻是经济可行的。     

养殖克氏原螯虾体内白斑综合征病毒的绝对定量分析

近年来克氏原螯虾的养殖受到WSSV的威胁,病毒在宿主组织中的绝对定量对于了解病毒的致病性具有重要意义,但克氏原螯虾组织中WSSV的绝对定量分布还有待研究。实验调查了湖北省5个主养区克氏原螯虾WSSV的感染率,结果表明80%以上克氏原螯虾都携带有WSSV。采用WSSV-VP28蛋白特异性抗体对克氏原螯虾提取蛋白进行Western Blot检测,在WSSV-PCR阳性样品中可检测到VP28特异性条带,在WSSV-PCR阴性样品中没有检测到相应条带。采用实验室建立的WSSV绝对定量PCR方法,对携带病毒的克氏原螯虾6个组织(鳃、胃、肠、血淋巴细胞、肝胰腺和心脏)进行检测。结果表明,在鳃、胃和肠可检测到较多病毒量(约108拷贝/mg),其次是血淋巴细胞(107拷贝/mg)、肝胰腺(106拷贝/mg),在心脏中病毒的含量最低(103拷贝/mg),表明病毒的复制存在组织特异性。结果显示WSSV主要存在于消化系统中,预示着克氏原螯虾可能主要在摄食过程中感染WSSV;不同地区克氏原螯虾组织病毒携带量表现出一定差异,预示着WSSV感染可能受到环境因素的影响。     

6-姜酚协同超高压处理对花鲈挥发性成分的影响

为揭示6-姜酚浸泡协同超高压处理对花鲈挥发性成分的影响,及时掌握鱼肉品质变化情况。采用电子鼻和顶空固相微萃取-气相色谱质谱联用CHS-SPME-GC-MS技术研究了浓度为8μg/m L的6-姜酚浸泡协同超高压处理(200 MPa)的花鲈和对照组(空白、8μg/m L 6-姜酚浸泡、200 MPa处理)品质及挥发性成分的变化。分析了处理组和对照组花鲈样品的色泽、质构特性及挥发性成分的变化。结果表明,6-姜酚浸泡协同超高压处理比6-姜酚浸泡、200 MPa处理及未处理的效果显著,有效改善了花鲈色泽及质构特性。电子鼻能够较好区分不同处理方式下花鲈的风味;主成分分析显示各个样品间差异明显,电子鼻区分度良好。采用气-质联用技术分析表明,花鲈在不同处理方式下的挥发性成分发生明显变化。主要挥发性物质有醇、醛、酮、酸、酯、烃、芳香族和含氮化合物等。在空白组、6-姜酚浸泡、200 MPa处理和6-姜酚浸泡+200 MPa处理的鱼肉中分别检测出43、40、49及30种主要的挥发性物质,这些挥发性物质的结合,形成了各自的风味特征,决定了不同处理方式下花鲈肉风味的差异。