暗纹东方鲀饲料中豆粕替代鱼粉的营养生理效应及其与大豆抗原蛋白的相关性

选择体质量为(39.84±3.09)g暗纹东方鲀,分为8组,分别饲喂等氮等能的高鱼粉组、低鱼粉组、低鱼粉发酵豆粕组、低鱼粉豆粕组4组实用饲料和添加大豆抗原蛋白的半纯化饲料(大豆抗原蛋白含量分别为0%、5%、8%和12.5%),进行为期两个月的生长实验,探讨大豆抗原蛋白对暗纹东方鲀生长和生理生化的影响。结果显示,用发酵豆粕替代部分鱼粉的低鱼粉发酵豆粕组生长性能显著优于低鱼粉组,用豆粕替代部分鱼粉的低鱼粉豆粕组与低鱼粉组无显著差异。半纯化饲料中随着大豆抗原蛋白含量增加,生长率呈现先增后降趋势;实用饲料和半纯化饲料对肌肉组成有不同程度的影响;在肝脏丙二醛、总抗氧化能力和血清丙二醛指标中,低鱼粉豆粕组显著高于低鱼粉组,低鱼粉发酵豆粕组则与低鱼粉组无显著性差异,半纯化饲料系列在8%组出现峰值,显著高于其他组。低鱼粉豆粕组血清谷草转氨酶活性显著高于低鱼粉组,低鱼粉发酵豆粕组与低鱼粉组相比无显著性差异,半纯化饲料组谷草转氨酶和谷丙转氨酶呈现先增后减趋势。研究表明,与豆粕替代鱼粉相比,用发酵豆粕替代鱼粉更能促进鱼体生长;大豆抗原蛋白是影响豆粕替代鱼粉效果的重要因素,但对生长、抗氧化性能和生理生化指标的影响则因大豆抗原蛋白的含量与单独存在与否而异。     

大黄蒽醌提取物对罗氏沼虾抗鳗弧菌感染的研究

将罗氏沼虾随机分成5组,每组三个平行,每个平行约1000尾(个体均重1g左右),第1组为对照组,投喂基础日粮,另外4组为试验组,在基础日粮中分别添加0.05%、0.1%、0.2%、0.4%大黄蒽醌提取物,饲养6周后对罗氏沼虾进行鳗弧菌(Vibrio anguillarum)感染.测定生长以及0、12、24、48h血清和肝胰腺溶菌酶、丙二醛(MDA)、总抗氧化能(T-AOC)以及超氧化物歧化酶(SOD)等指标.生长试验表明,与对照组相比,0.1%组、0.4%组罗氏沼虾的增重率、特定生长率显著提高,饵料系数显著降低.攻毒试验Ⅰ表明,各组48h内罗氏沼虾血清溶菌酶活性、肝胰腺溶菌酶含量、血清T-AOC均呈先升高后降低趋势,其中它们的最大值分别出现于0.4%组的12h、0.2%组24h、0.1%组12h;肝胰腺SOD活力呈上升趋势,而血清MDA则一直下降.攻毒试验Ⅱ表明,大黄蒽醌提取物能有效地降低试验组罗氏沼虾的死亡率,提高免疫保护率,其中0.4%组的保护效果为最佳.因此,在饲料中添加大黄蒽醌提取物降低罗氏沼虾对病原的敏感性,增强机体抗病力,促进生长.     

三丁酸甘油酯、α-酮戊二酸和丙氨酰–谷氨酰胺对罗氏沼虾生长性能、消化酶活性和免疫基因表达的影响

本研究旨在探讨三丁酸甘油酯(tributyrin, TB)、α-酮戊二酸(α-ketoglutarate, AKG)和丙氨酰-谷氨酰胺 (alanyl-glutamine, Ala-Gln)对罗氏沼虾(Macrobrachium rosenbergii)生长性能、消化酶活性和免疫相关基因表达的影响。以添加 40.00%豆粕和 33.70%花生粕两种饲料为对照组(命名为 SM 组和 PM 组), 分别在豆粕饲料中添加 0.10%、 0.20%的 TB (TB1 和 TB2 组), 1.00%、2.00%的 AKG (AKG1 和 AKG2 组), 1.00%、2.00%的 Ala-Gln (AGn1 和 AGn2 组), 配制 8 种等氮等能饲料。选取初始体重为(0.10±0.02) g 的罗氏沼虾 640 尾, 随机分为 8 组, 每组 4 个重复, 每个重复 20 尾, 实验期为 8 周。结果表明, 与 SM 组相比, TB、AKG 和 AGn 组对罗氏沼虾生长性能、血清超氧化物歧化酶活性和丙二醛含量、TOR 和 caspase-3 基因表达无显著影响(P＞0.05), TB、AKG 和 AGn 组的消化酶活性显著提高(P＜0.05), 且 AGn2 组显著高于其他试验组(P＜0.05)。此外, AKG1 组 caspase-8 相对表达量显著高于其他饲料组(P＜0.05), PM 组和 TB 组的 TNF-α 相对表达量显著降低(P＜0.05)。结果可知, 饲料中添加 TB、AKG 和 Ala-Gln 对罗氏沼虾生长性能和抗氧化功能没有显著影响; 添加 TB、AKG 和 Ala-Gln 对罗氏沼虾消化酶活性均具有明显的改善作用, 其中添加 2% Ala-Gln 改善作用最佳; 豆粕与花生粕相比可上调罗氏沼虾 TNF-α 的表达, 添加 TB 可以抑制这种基因表达。     

大黄蒽醌提取物对罗氏沼虾高温下抗氧化能力与热应激蛋白70基因表达的影响

将罗氏沼虾随机分成5组,每组3个平行,每个平行1 000尾,第1组为对照组,投喂基础日粮;另外4组为试验组,在基础日粮中分别添加0.05%、0.1%、0.2%、0.4%大黄蒽醌提取物。饲养10周后,对罗氏沼虾进行连续35 ℃高温应激48 h,测定肝胰腺总抗氧化能力、过氧化氢酶、超氧化物歧化酶、丙二醛、一氧化氮以及应激蛋白70的mRNA相对含量变化。结果表明:应激前,0.05%组显著提高了肝胰腺过氧化氢酶活性、超氧化物歧化酶活性,显著降低了肝胰腺丙二醛含量;0.2%试验组显著增加了肝胰腺总抗氧化能力、一氧化氮浓度,显著降低了肝胰腺丙二醛含量;0.10%、0.2%试验组显著增加HSP70 mRNA的相对含量;高温应激后,各组肝胰腺总抗氧化能力、过氧化氢酶活性、超氧化物歧化酶活性、一氧化氮浓度呈现降低趋势,其中0.1%和0.2%大黄蒽醌提取物相对较高,对照组较低;肝胰腺丙二醛含量呈现增加趋势,其中加0.1%和0.2%大黄蒽醌提取物比对照组低。应激6 h后0.1%和0.2%大黄蒽醌提取物组的HSP70 mRNA的相对含量仍比对照组高。因此添加0.1%和0.2%大黄蒽醌提取物提高了虾的抗氧能力,促进HSP70 mRNA的相对含量,对高温应激有一定的保护作用。     

水解鸡血珠蛋白部分替代鱼粉对罗氏沼虾生长、体组成和消化酶活性的影响

为探讨水解鸡血珠蛋白部分替代鱼粉对罗氏沼虾(Macrobrachium rosenbergii)幼虾(初重2.10±0.06 g)生长、体组成和消化酶活性的影响,试验用水解鸡血珠蛋白分别替代鱼粉0%(BC0,对照组)、10%(BC10)、30%(BC30)和50%(BC50)制成4种等氮(粗蛋白37.86%)等脂(粗脂肪8.77%)的试验饲料,开展9周的养殖试验。结果显示:利用水解鸡血珠蛋白替代鱼粉对罗氏沼虾存活率无显著性影响。当替代量为10%时,生长性能和饲料效率未受显著性影响,但肌肉中粗蛋白含量显著高于对照组。当替代量为30%和50%时,生长性能和饲料效率显著低于对照组,肌肉中的粗蛋白含量与对照组无显著差异。所有替代组肌肉中必需氨基酸和总氨基酸的含量均显著高于对照组,且肝胰腺胰蛋白酶的活力显著高于对照组。此外,所有替代组肌肉中粗脂肪含量均显著高于对照组,且BC10和BC30组肝胰腺脂肪酶活力亦显著高于对照组。以上结果表明,利用水解鸡血珠蛋白替代10%的鱼粉不影响罗氏沼虾生长和饲料效率,有利于增加肌肉中蛋白质和氨基酸的含量。     

饲料中n-3 PUFA/n-6 PUFA比值对罗氏沼虾幼虾生长性能和抗氧化能力的影响

为探讨饲料多不饱和脂肪酸n-3 PUFA/n-6 PUFA比值对罗氏沼虾幼虾生长性能、虾体肌肉组成、抗氧化能力、血清生理指标以及消化能力的影响，实验设计了n-3 PUFA/n-6 PUFA比值分别为0.37 (D1)、0.59 (D2)、0.93 (D3)、1.51 (D4)和4.38 (D5)的5种等氮等脂饲料饲喂罗氏沼虾幼虾8周，每组设4重复，每个重复40尾虾 。结果显示，饲料n-3 PUFA/n-6 PUFA比值对罗氏沼虾幼虾存活率 (SR)无显著影响；实验虾终末体重 (FW)、增重率 (WGR)和特定生长率 (SGR)随饲料n-3 PUFA/n-6 PUFA比值增加先升后降，均在D3组最高；且D3组虾有最大的肝胰腺蛋白酶活性及脂肪酸合成酶活性。虾体肌肉粗蛋白质、水分和灰分含量不受饲料n-3 PUFA/n-6 PUFA比值影响，但总脂肪含量在D3组显著高于其他组；各组虾体肌肉的n-3 PUFA/n-6 PUFA比值的变化趋势与饲料的n-3 PUFA/n-6 PUFA比值变化趋势呈正相关。随饲料n-3 PUFA/n-6 PUFA比值增加，实验虾血清和肝胰腺中超氧化物歧化酶 (SOD)活性、总抗氧化能力 (T-AOC)和血清铜蓝蛋白 (CP)含量均呈现先升后降趋势，并在n-3 PUFA/n-6 PUFA比值为0.93~1.51时达到最大，但丙二醛 (MDA)含量持续上升；D1组血清总胆固醇 (T-CHO)和甘油三酯 (TG)含量显著高于其他组；血清谷草转氨酶 (AST)和谷丙转氨酶 (ALT)活性先降后升，且D3组最低。研究表明，饲料适宜的n-3 PUFA/n-6 PUFA可显著提升罗氏沼虾生长性能和抗氧化能力，对增重率和特定生长率进行折线回归，建议罗氏沼虾幼虾饲料中最适n-3 PUFA/n-6 PUFA比值为0.86~0.94。     

泼洒糖蜜对池塘养殖罗氏沼虾生长和水质的影响

将单口面积1.33~2.33hm~2、环境相似的6口罗氏沼虾养殖池塘分为2组,3口池塘投喂蛋白质水平为35.4%的饲料,且每日适量泼洒糖蜜(试验组),3口池塘投喂蛋白质水平为41.9%的饲料,不泼洒糖蜜(对照组),常规管理。养殖期间,每隔15d取水样检测氨氮和亚硝态氮含量。156d的饲养结果表明,对照组和试验组罗氏沼虾的产量分别为6600kg/hm~2和6427.5kg/hm~2,降低饲料中的蛋白水平结合泼洒糖蜜不影响罗氏沼虾的生长(P0.05),养殖效益亦无显著差异(P0.05)。但试验组池塘水中氨氮较对照组低54.0%,亚硝态氮低21.0%,泼洒糖蜜显著降低了池塘氨氮和亚硝态氮含量(P0.05)。     

罗氏沼虾饲料中蛋白质的适宜含量及对豆粕作为饲料蛋白源的初步评价

试验采用以酪蛋白和鱼粉为蛋白源、有４个蛋白梯度的饲料以及以豆粕为唯一蛋白源的饲料，在流水孵化桶内饲养３．６克左右的罗氏沼虾，４９天后以增重率、饲料系数和蛋白质效率作饲料蛋白源的评价指标。结果表明：含５０％粗蛋白的饲料，其各项评价指标明显优于含４０％、３０％和２０／粗蛋白的饲料，组间差别十分显著（Ｐ＜０．０１）；４０％与２０％两组之间亦存在明显差异，但４０％与３０％以及３０％与２０％蛋白组的组间差别不明显。说明罗氏沼虾饲料中蛋白质的适宜含量与海水养殖虾类的相仿。以豆粕为蛋白源的两个组（粗蛋白含量均为３５％）也都取得理想的饲养效果，它们与５０％蛋白组无显著差异，表明豆粕可以用作罗氏沼虾饲料的蛋白源。考虑到实用性、经济效益和蛋白质利用率等诸种因素，将罗氏沼虾前中期饲料的蛋白含量定为４０％．后期饲料定为３５％是比较恰当的。     

不同脂肪源对红螯光壳螯虾幼虾生长、消化酶活性及其肌肉生化组成的影响

通过在人工配合饲料中分别添加5%的花生油、猪油、鱼油和豆油作为主要脂肪源,以商业饲料为对照,进行8周饲喂实验,研究不同脂肪源对红螯光壳螯虾(Cherax quadricarinatus)幼虾生长、消化酶活性及其肌肉生化组成的影响。结果显示,不同脂肪源对红螯光壳螯虾幼虾的体长增长率和特定增长率影响不显著(P0.05);但增重率各组间存在显著性差异(P0.05),以豆油组最高,达到2332.93%,花生油组最低,为1839.50%;豆油组肝胰腺指数显著高于其他各组(P0.05),为0.75%。幼虾存活率以豆油组最高(P0.05),达到83.3%,鱼油组较低,仅为56.7%。不同脂肪源饲喂组的肝胰腺胃蛋白酶活力无显著差异(P0.05);脂肪酶活力花生油组显著高于其他实验组(P0.05),为1177.23U/g(prot);淀粉酶活力各组间差异显著(P0.05),由高到低依次为鱼油组、对照组、豆油组、猪油组、花生油组;纤维素酶活力以花生油组较高,为61.14U/(gprot()P0.05)。幼虾腹部肌肉中各种脂肪酸的含量明显受到饲料中脂肪酸种类和含量的影响,饱和脂肪酸含量猪油组显著高于其他组(P0.05);单不饱和脂肪酸以花生油组含量最高,豆油组最低;多不饱和脂肪酸则以豆油组含量最高(P0.05)。在各实验组中,豆油组红螯光壳螯虾幼体具有最高的体质量增长率和存活率,较高的肝胰腺指数和肝胰腺消化酶活力,豆油组幼虾腹部肌肉中多不饱和脂肪酸尤其是亚油酸和亚麻酸含量也较高。因此,以豆油作为主要脂肪源能够满足红螯光壳螯虾幼体的生长需要,获得较好的饲养效果,并降低饲料成本。     

发酵豆粕替代鱼粉对凡纳滨对虾生长、免疫相关酶及免疫相关基因表达的影响

从免疫相关酶活及基因转录水平角度探讨发酵豆粕替代鱼粉对凡纳滨对虾健康生长及免疫机能机制的影响。实验设置5种实用饲料,以30%鱼粉组(FM)为对照组,分别用4%(FSM4)、8%(FSM8)、12%(FSM12)和16%(FSM16)的发酵豆粕,替代9.7%、19.4%、29.1%和38.8%鱼粉,分为4个处理组,饲养体质量为(7.62±0.23)g的凡纳滨对虾60 d后,统计生长性能,检测肌肉营养成分、血清及肝胰腺免疫相关酶活性,肝胰腺HSP70和鳃Toll受体、IMD、溶菌酶(LZM)免疫相关基因m RNA的表达水平。结果显示:(1)与对照组相比,发酵豆粕替代鱼粉对凡纳滨对虾成活率无显著影响;过低或过高水平的发酵豆粕替代鱼粉皆会影响凡纳滨对虾的特定生长率。(2)除FSM12组外,肌肉粗蛋白含量发酵豆粕替代组均低于对照组;粗脂肪含量随着发酵豆粕替代量的升高而降低,FSM16组最低。(3)血清谷丙转氨酶活FSM4和FSM16组显著高于对照组;谷草转氨酶活FSM4组最高,而FSM8组最低;除FSM12组外;碱性磷酸酶活性发酵豆粕替代组显著高于对照组;除FSM16组外,血清总蛋白与肝胰腺丙二醛含量发酵豆粕替代组与对照组无显著性差异。(4)随着发酵豆粕替代量增加,鳃Toll受体m RNA表达呈上升趋势,鳃IMD m RNA表达则呈先升后降趋势,发酵豆粕替代比例过高会降低鳃LZM m RNA表达水平,而肝胰腺HSP70 m RNA表达量则随着发酵豆粕替代比例增加呈上升趋势。综上所述,发酵豆粕适量替代鱼粉对凡纳滨对虾生长性能无显著影响,并可提高免疫相关酶活,改变免疫相关基因的表达。本实验条件下适宜发酵豆粕用量为8%~12%;替代量过高,会引起机体的过度应激。     

不同比例复合益生菌对凡纳滨对虾生长、免疫及抗氨氮能力的影响

对从凡纳滨对虾(Litopenaeus vannamei)肠道中分离出的鲍鱼希瓦氏菌(Shewanella haliotis)、蜡样芽孢杆菌(Bacillus cereus)和双壳气单胞菌(Aeromonas bivalvium)3株有益菌株,利用正交设计得到9种复合比例,通过饲料中添加上述9种比例混合的菌体(菌数总量为109 cfu/g)饲喂凡纳滨对虾,经过28 d养殖实验,评价其对凡纳滨对虾生长、免疫指标的影响。随后,利用氯化铵调节水体氨氮浓度至26.67 mg/L,经过16 d的氨氮毒性实验,研究不同比例复合益生菌对凡纳滨对虾抗氨氮能力的影响。研究结果表明,9个复合益生菌实验组的增重率和特定生长率均显著高于对照组(P0.05),并且以3株菌菌数6︰1︰3比例效果较好;不同配比的复合益生菌能够显著提高酸性磷酸酶(ACP)、碱性磷酸酶(ALP)、总超氧化物歧化酶(T-SOD)活力(P0.05),并表现出了不同的影响效果,其中,3株菌菌数(菌数总量为109 cfu/g,下同)2︰3︰3、4︰2︰3及6︰1︰3比例对ACP活力具有显著促进作用(P0.05),3株菌菌数4:2︰3和6︰1︰3比例对ALP活力具有显著促进作用(P0.05);3株菌菌数2︰1︰1比例对T-SOD活力具有显著促进作用(P0.05);各比例的复合菌对溶菌酶活力的影响不显著(P0.05);氨氮浓度26.67 mg/L条件下,不同比例复合菌组对虾累计存活率显著高于对照组(P0.05),其中以3株菌菌数4︰3︰1和6︰3︰2比例组累计存活率较高,即抗氨氮效果较好。     

Influence of the antibacterial herbs, Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia on the survival, growth and bacterial load of Penaeus monodon post larvae

The indiscriminate use of antibiotics and chemicals in shrimp hatcheries has led to biomagnification and that in turn could lead to rejection of a whole consignment. The application of the bioencapsulation technique as a tool for curative treatment in shrimp larvae was investigated. Herbs having antibacterial properties such as Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia (methanolic extracts) were bioencapsulated in Artemia and fed to Penaeus monodon post larvae PL 1–25. The post larvae were reared in a medium inoculated with pathogenic bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi and Vibrio sp. Post larvae reared in the non-inoculated water and fed with non-enriched Artemia exhibited 90% survival, highest specific growth rate (12.43%) and reduced bacterial load. P. monodon reared in the bacterial inoculated water and fed with the non-enriched Artemia exhibited the lowest survival (10–30%), specific growth rate (8.42–9.1%) and increased bacterial load (2.86 × 10³ to 3.76 × 10⁵ cfu/g). The methanolic extracts of the herbs helped to increase survival and specific growth rate and reduced bacterial load in the P. monodon culture system. Among the three herbal extracts, P. corylifolia enriched Artemia fed post larvae showed the tendency to higher survival (>50%), growth rate (11.5 averaged) and low bacterial load (1.12 × 10⁵ cfu/g). This revised version was published online in August 2006 with corrections to the Cover Date.     

Movement of the fluvial form of masu salmon, <Emphasis Type="Italic">Oncorhynchus masou masou</Emphasis>, in a mountain stream in Kyushu,Japan

Using mark-recapture methods, the movements of the fluvial form of masu salmon (Oncorhynchus masou masou) in a mountain stream on the island of Kyushu, Japan, were studied. Most (78%) of the masu salmon were recaptured in the pool in which they had been originally caught and tagged. Of those that moved between pools, the proportion of individuals that moved during the breeding period was not significantly higher than the proportion that moved during the non-breeding period. However, during the breeding period, a higher proportion of larger salmon moved than did smaller fish. The proportion of mobile large males during breeding period was higher than that for small males. Also, it was found that a few individuals showed long-range movement in the autumn. As a long-term movement, 78 individual fish (65%) that were recaptured more than three times showed high sedentary tendencies. Sixteen individual mobile fish (13%) moved and returned to the original pool. Fluvial form of masu salmon in Kyushu show a high sedentary nature; however, large mature males seem to actively move in search of female during breeding period.     

Cloning, expression, and characterization of a novel anti-HIV lectin from the cultured cyanobacterium, Oscillatoria agardhii

OAA, the potent anti-HIV protein from Oscillatoria agardhii NIES-204 belongs to a new lectin family, shows strict binding specificity for high-mannose N-glycans, and has an extremely high association constant in the picomolar range for recombinant gp120, an envelope protein of HIV. In this study we have cloned the gene encoding OAA from the genomic DNA of the cyanobacterium, and efficiently expressed the recombinant lectin (rOAA) in Escherichia coli. The rOAA expressed as a His-tagged fusion protein was recovered in a soluble form and purified in high yield (48 mg/1 l-culture) by metal chelate chromatography. The fusion protein was cleaved with factor Xa, and the resulting rOAA was isolated in a final yield of 14.8 mg/1 l-culture by reversed-phase HPLC. Both the N-terminal sequence and the molecular mass of rOAA were found to be identical with those of OAA. The rOAA was fully functional with the same properties as OAA, as evidenced by hemagglutination activity, hapten-inhibition test, and binding specificity for high-mannose-type N-glycans. This rOAA should be applicable as a specific probe for high-mannose N-glycans and should contribute to elucidation of the molecular basis of its strict carbohydrate-binding specificity and potent anti-HIV activity.     

Mortality of scallop spat in cultivation, infested with tube dwellingbristle worms, Polydora sp.

Between 1995 and 1997, a traditional Norwegian oyster poll with an attachednursery was used for the production of scallop (Pecten maximus) spat.During summer 1997, four batches of 2 mm scallop spat were placed in thenursery. In June, hydroids (Obelia) caused problems with fouling andaccumulation of sediment in the nursery. Thereafter, the scallop spat wereheavily infested with tube dwelling polychaets (Polydora sp.). Thepolychaets were both introduced with poll water and reproduced inside thenursery. Infested spat suffered high mortalities. Although the spat could have been affected by the hydroids, as well as shortage of food, Polydorainfestations were considered the main cause of the mortalities. Dead andinfested spat were continuously sorted out and discarded, but the infestationproblems persisted. As a result, the scallop spat did not represent anycommercial value for the company, and in September, the nursery wasemptied. In total, approximately one million spat – representing onethird of Norway's intensive scallop spat production in 1997, was lost.     

Parasites, pathological conditions and mortality in QX-resistant and wild-caught Sydney rock oysters, Saccostrea glomerata

Differences in the survival of QX-resistant fifth generation (QXR₅) and wild-caught (Wild-Caught) Sydney rock oysters were assessed over the QX-disease risk period in the Pimpama River, SE Queensland. Cumulative mortality of Wild-Caught oysters (31.7%) was significantly greater than QXR₅ oysters (0.0%) over the 118 days of the experiment. PCR and histological results showed that Wild-Caught oyster did not die from QX disease. Histology revealed oysters were infected with disseminating hemocytic neoplasia, a Steinhausia-like infection, a Rickettsia-like organism infecting epithelial cells of the gill, digenean flukes encysted in the gonadal tissue and a gill response to an unknown toxin. The cause of mortality is attributed to disseminating hemocytic neoplasia.     

Enrichment of Artemia nauplii in PUFA, phospholipids, and water-soluble nutrients using liposomes

Different liposome formulations, includingseveral combinations of membrane composition,type of vesicle (multilamellar and largeunilamellar vesicles), preparation method, andvehiculated nutrient, have been assayed asbioencapsulation products to enrich Artemia nauplii with nutrients for feeding fish larvae.The stability of the liposome preparationsunder conditions of use as enrichment producthas been tested using water soluble fluorescentmarkers as leakage indicators. The content ofthe fatty acids and lipid classesbioencapsulated in Artemia nauplii withliposomes has been analyzed by gas and thinlayer chromatography, respectively, andcompared with other enrichment products. Theeffect of the liposome enriched Artemianauplii used as food for fish larvae has beenevaluated in sea bass cultures. Liposomes withhigh content in polyunsaturated fatty acidsleak out more than 50% of their aqueous phasein less than 2 hours, unless they arestabilized with cholesterol and formed as largeunilamellar vesicles. Such vesicles hold70% of the encapsulated material for 8 hours.Liposome enriched nauplii in this study reflectthe influence of the enrichment products,however, they are far from the commercialemulsion (Super Selco) in terms ofdocosahexaenoic acid content, except for thenauplii enriched with liposomes made of purekrill phospholipid extract by the method ofdetergent solubilization. The liposome enrichednauplii show a higher amount of polar lipids incontrast to the feed enriched with emulsions.The larvae fed liposome enriched nauplii haveonly a slightly lower docosahexaenoic acidcontent than those fed emulsion enrichednauplii. The results obtained confirm thesuitable potential use of liposomes as foodsupplement in larviculture. Problems andadvantages are discussed.     

鳢流行性溃疡综合征病原分离鉴定与病理形态学观察

为寻找冬春季鳢(Channa maculata)烂身病的病原,应用组织压片、组织切片、扫描电镜技术、HE常规染色法和Grocott六胺银染色法、霉菌分离纯化及ITS的序列分析等对冬春季患疑似溃疡综合征的烂身病鳢进行了病原学与病理学研究。病变组织压片观察到大量直径10～20μm,分枝较少、纤细菌丝。扫描电镜观察到肌肉组织中延伸出大量的纤细的丝状真菌。患病鳢皮肤和肌肉表现为变性、坏死与炎性细胞浸润,溃疡灶肌肉内可见大量的慢性肉芽肿结节和炎性细胞浸润。结节基本结构由类上皮细胞和多核巨细胞、炎性细胞、霉菌菌丝(横断面呈圆形,斜断或纵断呈丝状)组成,霉菌位于结节中央。Grocott六胺银染色观察到结节中有大量棕色菌体。无菌分离培养可观察到典型丝状霉菌;霉菌在灭菌池塘水20℃过夜, 12 h后可观察原代孢子群形成,真菌ITS序列分析表明其与侵袭丝囊菌(Aphanomyces invadans)同源性为100%。侵袭丝囊霉菌(A. invadans)是杂交鳢溃疡综合症病的主要病原,为鱼类流行病学调查和疾病防治的深入研究奠定基础。     

Feeding of scleractinian coral, Galaxea fascicularis, on Artemia salina nauplii in captivity

Satisfying nutrient requirement of corals is still a major constraint for maintaining corals in marine aquariums. Corals are polytrophic in nature. Heterotrophic feeding on zooplankton is one of the corals’ strategies to overcome nutrient deficiency. Artemia salina nauplii are commonly used as biocarriers for many fish larvae in aquaculture and can also serve as a biocarrier for coral in aquariums, provided coral acceptability, optimal feeding rate, and digestibility of the nauplii are well understood. Feeding rate and digestibility of coral fed on A. salina nauplii at 100, 2,000, 4,000, 6,000, and 10,000 ind. l⁻¹ under light and dark conditions was assessed in this study. The maximum feeding rates of Galaxea fascicularis under light and dark conditions was 113.6 ind. polyp⁻¹ h⁻¹ and 76.9 ind. polyp⁻¹ h⁻¹, respectively. The daily feeding rates of G. fascicularis varies and depends on nauplii density. Light plays an important role in coral feeding. Nevertheless, the quantity of A. salina nauplii consumed by the coral under light and dark conditions was not significantly different (P > 0.05). A. salina nauplii are well accepted by G. fascicularis. Complete nauplii digestion was observed after 180 min. Digestibility of A. salina nauplii by G. fascicularis was positively correlated with digestion time.     

Comparison of age estimates from scale, opercular bone, otolith, vertebrae and dorsal fin ray in Labeo rohita (Hamilton), Catla catla (Hamilton) and Channa marulius (Hamilton)

The present study was undertaken with a view to compare the precision and reliability of the age readings obtained from different bony structures of some important freshwater teleosts viz., Labeo rohita (Hamilton), Catla catla (Hamilton) and Channa marulius (Hamilton). Standard procedures were followed to prepare and study the age structures. In L. rohita and C. marulius percent agreement between reader's age estimates was highest for scales, i.e. 96.3% and 90.5%, respectively and in C. catla percent agreement was highest (93.3%) for opercular bone. When scale ages were compared with other alternative structures viz., otoliths, opercular bone, vertebral centra and dorsal fin rays, percent agreement was found highest between scale and opercular bone age estimates (77.8%) in L. rohita and between scale and otoliths (94.8%) in C. marulius. In case of C. catla highest percent agreement was found between opercular bone and scale age estimates. In L. rohita each of the ageing structure showed significant (P < 0.05) underestimation of age in comparison to scales. In C. catla mean age estimates from opercular bone were comparable (P > 0.05) to the values obtained from all other structures except dorsal fin rays. In C. marulius mean age estimates from scales were comparable (P > 0.05) to those from all other structures except from dorsal fin rays. Results indicated scales to be the most suitable structure for ageing L. rohita and C. marulius and opercular bone for C. catla. However, in C. catla also scales may be used as a non-destructive method of age estimation with satisfactory results.