饲喂不同水平虫草培养残基对中华绒螯蟹营养品质的影响

在基础饲料中分别添加0.25%、0.5%、1.0%、2.0%、4.0%、8.0%、16.0%的蛹虫草培养残基(简称虫草基),以基础饲料为对照,饲喂规格为(4.0±1.0)g的中华绒螯蟹75 d,测定中华绒螯蟹(Eriocheir sinensis)常规营养成分、肌肉与血清氨基酸及肝胰腺脂肪酸含量,研究虫草基对中华绒螯蟹营养品质的影响。结果显示:(1)虫草基对中华绒螯蟹水分和蛋白含量无影响(P>0.05),0.5%和1.0%添加组的全蟹、肌肉、肝胰腺粗脂肪含量显著高于对照组(P<0.05)。(2)适量添加虫草基可增加中华绒螯蟹肌肉游离氨基酸含量,0.5%～2.0%的添加组显著高于对照组(P<0.05),但对氨基酸组成及主要呈味氨基酸含量影响不显著(P>0.05);1.0%和16.0%添加组中华绒螯蟹血清氨基酸和主要呈味氨基酸含量明显提高(P<0.05)。(3)虫草基的添加可提高肝胰腺不饱和脂肪酸及必需脂肪酸含量,且1.0%添加组显著高于对照组(P<0.05)。饲料中添加适量的虫草基可提高中华绒螯蟹肌肉与血清的游离氨基酸、血清必需氨基酸、肝胰腺不饱和脂肪酸和必需脂肪酸含量,从而改善中华绒螯蟹营养品质。     

北方寒区2龄和3龄雄性中华绒螯蟹成蟹可食率、色泽及品质比较

为开发中华绒螯蟹(Eriocheir sinensis)新种质并阐述其品质特征, 本研究以北方寒区 2 龄雄性成熟中华绒螯蟹(简称 2 龄蟹)为对照, 探究 3 龄雄性成熟中华绒螯蟹(简称 3 龄蟹)的可食率、色泽、常规营养品质、脂肪酸、游离氨基酸和矿物质元素差异, 为 3 龄蟹新种质开发和利用提供重要的判断依据。结果表明; 9 月 15 日 2 龄蟹肝胰腺指数(HSI)极显著高于 3 龄蟹(P＜0.01), 而出肉率(MY)则显著低于 3 龄蟹(P＜0.05)。2 龄蟹与 3 龄蟹相比, 头胸甲和肝胰腺湿样 L* , 头胸甲和肝胰腺干样 a* 存在显著性差异(P＜0.05)。2 龄蟹肝胰腺中粗脂肪含量显著高于 3 龄蟹 (P＜0.05), 而性腺系统和肌肉中粗蛋白含量则高于 3 龄蟹。就脂肪酸而言, 2 龄蟹肝胰腺、性腺系统和肌肉中 DHA 和 DHA/EPA 含量均高于 3 龄蟹, 而 ARA 则低于 3 龄蟹。肌肉中脂肪酸显著性差异项(5 项)明显高于肝胰腺(1 项) 和性腺系统(1 项)。就游离氨基酸而言, 2 龄蟹肝胰腺、性腺系统和肌肉中总必需氨基酸(ΣEFAA)、总游离氨基酸 (ΣFAA)均高于 3 龄蟹。性腺系统中显著性差异项(6 项)明显高于肝胰腺(0 项)和肌肉(2 项)。2 龄蟹肝胰腺和性腺系统中谷氨酸(Glu)、总鲜味氨基酸(ΣTUV)高于 3 龄蟹, 而肌肉中则低于 3 龄蟹。就矿物质元素而言, 2 龄蟹 3 种可食组织中 Na、K、Ca、Mg 和 Cu 元素含量均低于 3 龄蟹。肝胰腺中矿物质元素显著性差异项(5 项)明显高于性腺系统 (1 项)和肌肉(2 项)。综上所述, 2 龄蟹大部分常规营养成分、脂肪酸、游离氨基酸指标均优于 3 龄蟹, 但可食率参数、大部分矿物质元素含量则明显低于 3 龄蟹。整体来看, 2 龄和 3 龄雄蟹各有优势, 均具有较高的营养价值。     

长江、黄河和辽河种群中华绒螯蟹雄体成蟹可食组织营养组成的比较

采用养殖实验和生化分析方法,在相似的池塘条件下将辽河、黄河和长江种群中华绒螯蟹(Eriocheir sinensis)扣蟹养殖至成蟹,比较了三群体雄体成蟹的性腺指数、肝胰腺指数、出肉率、总可食率和肥满度,进一步测定和比较了可食组织中的常规生化成分、脂肪酸及氨基酸,旨在评价三种群雄体成蟹的营养品质和可食率。研究结果显示:(1)黄河种群中华绒螯蟹的性腺指数略高于其他两种群蟹,长江种群中华绒螯蟹的肝胰腺指数、出肉率、总可食率和肥满度最高,但均无显著差异(P0.05)。(2)辽河种群性腺中蛋白质含量显著高于其他两种群(P0.05),三群体性腺中水分、脂肪和灰分含量差异不显著(P0.05);长江种群肝胰腺的水分含量最低,但其蛋白质、脂肪和灰分含量高于其他两种群;黄河种群肌肉中脂肪含量显著低于辽河种群的含量,而其灰分含量显著高于黄河种群(P0.05),水分和蛋白质含量无显著差异(P0.05)。(3)三种群性腺中主要多不饱和脂肪酸(PUFA)含量相近,长江种群性腺中∑PUFA、∑n6PUFA和总高度不饱和脂肪酸(∑HUFA)含量最高;三种群肝胰腺中各PUFA、∑PUFA和∑HUFA含量无显著差异(P0.05);三种群肌肉中C_(18:3n3)(LNA)和C_(20:5n3)(EPA)的含量存在显著差异,且黄河种群的这两种脂肪酸含量都显著高于辽河种群(P0.05)。(4)辽河种群性腺中的蛋氨酸和半胱氨酸含量显著高于其他两种群(P0.05),且辽河种群的总必需氨基酸(EAA)、总非必需氨基酸(NEAA)和总氨基酸(TAA)含量高于黄河和长江种群;长江种群雄体肌肉中的EAA、总EAA、总NEAA、TAA含量最高。(5)辽河种群性腺中存在3种限制性氨基酸(赖氨酸、缬氨酸和色氨酸),且其平均必需氨基酸分(EAAS)最低;三种群肌肉中均无限制性氨基酸,辽河水系EAAS仍然最低。综上,不同种群中华绒螯蟹性腺发育和营养成分具有一定的差异,这可能与其发育阶段和遗传因素有关。     

中华绒螯蟹抱卵前后脂肪酸和氨基酸组成的比较

为研究中华绒螯蟹抱卵前后体成分变动规律,测定分析了雌蟹抱卵前后不同组织(性腺、肝胰腺、肌肉)中的脂肪酸和氨基酸的变动。结果表明,抱卵前肝胰腺指数(7.31±0.73)显著高于抱卵后(5.59±0.82)(P 0.05)。在肌肉和肝胰腺中,抱卵前饱和脂肪酸(SFA)和单不饱和脂肪酸(MUFA)百分量均显著高于抱卵后(P 0.05),其中脂肪酸C16∶00和C18∶1n9百分量最高;抱卵前多不饱和脂肪酸(MUFA)中C18∶2n6和C18∶3n3百分量显著高于抱卵后(P 0.05),但EPA(C20∶5n3)和DHA(C22∶6n3)百分量低于抱卵后。与抱卵前相比,抱卵后雌蟹肝胰腺和肌肉中氨基酸含量均显著升高(P 0.05),其中谷氨酸含量最高、半胱氨酸含量最低。研究结果揭示,脂肪是中华绒螯蟹雌蟹繁殖前期的主要能源代谢底物,氨基酸在繁殖期逐渐积累。     

配合饲料替代杂鱼对中华绒螯蟹生长发育、体成分及脂肪酸组成的影响

通过分别投喂配合饲料和天然杂鱼,研究配合饲料替代杂鱼对中华绒螯蟹生长发育、体成分及脂肪酸组成的影响。试验池塘设在上海市崇明县水产技术推广站特色水产养殖基地,每种饵料设3个平行。试验时间为2010年4月至11月,养殖结束后统计各试验组的存活率、体质量、产量,并随机取样测定各试验组雌雄蟹的肝胰腺指数、性腺指数、出肉率,同时测定肝胰腺、性腺和肌肉中水分、总脂、粗蛋白含量及脂肪酸组成。结果显示,杂鱼组和配合饲料组蟹的存活率、体质量、肝胰腺指数、性腺指数、出肉率等指标均无显著差异(P>0.05);杂鱼组雌雄蟹肝胰腺及雄蟹肌肉中水分含量极显著高于配合饲料组(P<0.01);杂鱼组雌雄蟹肝胰腺、性腺及雌蟹肌肉中总脂含量均显著低于配合饲料组(P<0.05);杂鱼组雌雄蟹肝胰腺中粗蛋白含量均显著高于配合饲料组(P<0.05),但杂鱼组雌蟹卵巢中粗蛋白含量极显著低于配合饲料组(P<0.01)。配合饲料组雌蟹肝胰腺游离脂肪酸含量显著高于杂鱼组(P<0.05),磷脂含量杂鱼组显著高于配合饲料组(P<0.05);配合饲料组雌蟹卵巢和肌肉甘油三酯含量均显著高于杂鱼组(P<0.05或P<0.01),游离脂肪酸和磷脂含量则杂鱼组显著高于配合饲料组(P<0.05或P<0.01);雌蟹肌肉中胆固醇含量配合饲料组极显著高于杂鱼组(P<0.01)。两组饵料雄蟹肝胰腺各脂类组成无显著差异;精巢中甘油三酯及游离脂肪酸含量为杂鱼组显著高于配合饲料组(P<0.01),磷脂含量为杂鱼组显著低于配合饲料组(P<0.05);雄蟹肌肉胆固醇含量配合饲料组显著低于杂鱼组(P<0.05)。杂鱼组雄蟹肝胰腺和肌肉中LOA含量极显著或显著低于配合饲料组(P<0.01或P<0.05),而杂鱼组雄蟹肌肉中ARA含量显著高于配合饲料组(P<0.05);杂鱼组雌蟹卵巢中LNA、ARA和DHA的含量极显著或显著低于配合饲料组(P<0.01或P<0.05)。研究结果表明,适宜的配合饲料替代杂鱼全程养殖中华绒螯蟹成蟹对其生长发育无显著负面影响,而对其体成分组成及脂肪酸组成有一定影响。     

有机养殖模式下中华绒螯蟹抗氧化防护和溶菌酶的活性

比较了有机和常规养殖模式下,体质量165~175g中华绒螯蟹鳃、肝胰脏和肌肉中溶菌酶活性、超氧化物歧化酶、过氧化氢酶和谷胱甘肽过氧化物酶活性以及丙二醛含量。结果显示,有机养殖模式下,中华绒螯蟹肝胰脏和肌肉中超氧化物歧化酶和过氧化氢酶活性显著高于常规养殖模式(P0.05),但鳃中超氧化物歧化酶和过氧化氢酶活性与常规养殖组差异不显著(P0.05);鳃、肝胰脏和肌肉中谷胱甘肽过氧化物酶活性均显著高于常规养殖模式(P0.05);鳃、肝胰脏和肌肉中丙二醛含量显著低于常规养殖模式(P0.05)。有机养殖模式下中华绒螯蟹肝胰脏中的溶菌酶活性显著高于常规养殖组(P0.05)。试验结果表明,有机养殖模式下中华绒螯蟹具有较高的抗氧化防护能力和抗菌能力。     

池塘和稻田养殖模式下克氏原螯虾肌肉和肝脏营养成分比较

通过对池塘和稻田2种养殖模式下克氏原螯虾(Procambarus clarkii)的肌肉常规营养成分进行测定,同时,对肌肉和肝胰腺的氨基酸和脂肪酸组成进行测定,从而对其营养品质进行分析评价。结果显示,2种养殖模式下克氏原螯虾粗蛋白和粗脂肪无显著性差异(P>0.05),池塘养殖模式下水分显著高于稻田模式(P<0.05),而粗灰分显著低于稻田模式(P<0.05)。在2种模式下肌肉和肝胰腺中均检测出17种氨基酸,包括7种必需氨基酸和4种鲜味氨基酸。2种养殖模式下肌肉的必需氨基酸总含量占氨基酸总量(WEAA/WTAA)值无显著性差异(P>0.05),而肝胰腺中池塘养殖模式WEAA/WTAA值显著高于稻田模式(P<0.05)。根据氨基酸评分(AAS)和化学评分(CS),克氏原螯虾肌肉和肝胰腺中第一限制氨基酸均为甲硫氨酸＋胱氨酸,肌肉中第二限制氨基酸为缬氨酸,肝胰腺中第二限制氨基酸为亮氨酸。另外,在肌肉中检测出20种脂肪酸,而在肝胰腺中检测出24种脂肪酸,其中,肌肉和肝胰腺中饱和脂肪酸含量最高的是棕榈酸(C16:0);单不饱和脂肪酸含量最高的是油酸(C18:1n9c)。研究表明,池塘和稻田2种养殖模式下的克氏原螯虾,肌肉和肝胰腺均具有较高的食用价值和营养价值。     

中华绒螯蟹、日本绒螯蟹及其杂交种性腺发育和生化组成的比较

研究了中华绒螯蟹(Eriocheir sinensis)、日本绒螯蟹(E.japonica)及其杂交种成蟹性腺指数、肝胰腺指数、出肉率、总可食率及其常规生化成分,结果显示:(1)中华绒螯蟹的精巢指数显著高于其它两种群蟹,但其肝胰腺指数、出肉率和总可食率均无显著差异;中华绒螯蟹的卵巢指数也显著高于日本绒螯蟹和杂交蟹,而杂交蟹的肝胰腺指数显著高于其它两种群蟹。(2)中华绒螯蟹、日本绒螯蟹和杂交种精巢中水分、蛋白和脂肪含量分别最低,日本绒螯蟹精巢中碳水化合物含量最高;杂交种肝胰腺蛋白、脂肪和碳水化合物含量均最高,日本绒螯蟹肌肉中脂肪含量显著低于其它两种群。(3)日本绒螯蟹卵巢水分含量显著高于其它两种群蟹,蛋白、脂肪和碳水化合物含量显著低于其它两种群;日本绒螯蟹肝胰腺的水分和蛋白含量最高,但脂肪含量最低,杂交种肝胰腺中脂肪含量最高、水分含量最低;日本绒螯蟹肌肉中的水分含量最高,其它生化成分含量最低;中华绒螯蟹肌肉的水分含量最低,其它生化成分含量最高。整体上,中华绒螯蟹具有早熟特性,不同种群绒螯蟹性腺中的主要生化成分含量可能与其发育阶段有关,杂交蟹肝胰腺中脂肪含量较高,日本绒螯蟹肌肉中脂肪含量较低。     

配合饲料和冰鱼对单体养殖中华绒螯蟹生长、性腺发育及其肌肉品质的影响

为研究配合饲料和冰鱼对中华绒螯蟹的养殖性能和营养状况的影响,本实验通过连续采样分析了单体养殖中华绒螯蟹的生长性能、性腺发育和肌肉的营养成分,并进一步比较了终末体质量、增重率、特定增长率、成活率和蜕壳间隔。结果显示:(1)配合饲料组的成活率极显著高于冰鱼组,而终末体质量、增重率、特定增长率和蜕壳间隔二组无显著差异;在不同蜕壳阶段,在体质量指标上,配合饲料组小于冰鱼组,其中第3次蜕壳后二组间差异显著;增重率在雌、雄蟹体间存在差异,其中雌蟹在第2次蜕壳后配合饲料组的增重率极显著小于冰鱼组,而雄蟹在第1次和第4次蜕壳后2个阶段配合饲料组的增重率极显著大于冰鱼组。(2)在配合饲料和冰鱼2组投喂下肝胰腺指数分别为3.59%和4.45%,性腺指数二者分别为3.20%和2.25%,肝胰腺指数和性腺指数在二组投喂下无显著差异。(3)在肌肉氨基酸含量方面,氨基酸总量(∑TAA)、必需氨基酸总量(∑TEAA)和呈味氨基酸总量(∑FAA)配合饲料组显著小于冰鱼组;从单个氨基酸含量看,赖氨酸(Lys)和精氨酸(Arg)含量配合饲料组显著小于冰鱼组,而脯氨酸(Pro)含量则是配合饲料组显著大于冰鱼组。(4)在肌肉脂肪酸含量方面,高度不饱和脂肪酸(∑HUFA)和DHA+EPA含量配合饲料组显著高于冰鱼组;从单个脂肪酸看,单不饱和脂肪酸(∑MUFA)中C16:1和C18:1n-9含量配合饲料组显著小于冰鱼组,而多不饱和脂肪酸(∑PUFA)中的ARA和DHA配合饲料组却显著高于冰鱼组。研究表明,在该单体养殖条件下,配合饲料组在中华绒螯蟹生长性能和肌肉品质上接近冰鱼组,而在性腺发育和成活率上则优于冰鱼组,配合饲料对中华绒螯蟹养殖业更具有发展优势。     

池养中华绒螯蟹不同性别形态及质量差异分析

池塘养殖中华绒螯蟹(Eriocheir sinensis)是当前的主要生产方式,为了解池养中华绒螯蟹形态指标参数,分别测定了中华绒螯蟹幼体和成体的头胸甲长、头胸甲宽、体高、体质量和各部位的质量及含水率,计算了肝胰腺指数和肌肉指数,旨在了解池养中华绒螯蟹形态指标及质量参数的关系。结果显示,不同性别幼蟹头胸甲长、头胸甲宽、体高、肌肉指数无显著差异(P>0.05),而体质量差异显著(P<0.05);不同性别成蟹各形态指标差异极显著(P<0.01);幼蟹的肝胰腺、肌肉及其他部分含水率差异极显著,高于成蟹(P<0.01);成蟹的肌肉指数和肝胰腺指数差异极显著,高于幼蟹(P<0.01)。本研究分别建立了幼蟹体质量(Y1)与体高(X3)、成蟹体质量(Y2)与头胸甲宽(X2)的回归方程：Y1=?12.067+16.416X3,Y2=?268.423+62.078X2,幼蟹的决定系数高于成蟹。本研究可为中华绒螯蟹生态养殖中的产量估算和品质鉴定提供参考。     

Comparative study on the nutrition composition of adult male Chinese mitten crab (Eriocheir sinensis) with different coloured hepatopancreases

High lethality of white hepatopancreas syndrome has caused large economic loss of Chinese mitten crab (Eriocheir sinensis). Hepatopancreas colour of diseased crabs is gradually lighter, turning from golden yellow to yellow‐white to white. This study investigated composition of conventional nutrients in three edible parts of different coloured hepatopancreases of adult males, including normal yellow hepatopancreas group (Control), yellow‐white hepatopancreas group (YWH) and white hepatopancreas group (WH). No significant differences were observed in tissue indices and total edible yield among three crab types; however, condition factor level in crabs of YWH and WH was significantly lower. Dry matter content was significantly reduced in crabs of WH, especially crude fat level of hepatopancreas in WH males. Levels of all the amino acids of WH crabs in muscles and gonads were significantly lower than that of control. Proportion of saturated fatty acids and monounsaturated fatty acids were much lower in hepatopancreas of WH crabs than those of control, while proportion of polyunsaturated fatty acids and highly unsaturated fatty acids were significantly higher. Overall, YWH and WH do not affect growth. WH crabs showed poor nutritional quality, and nutritional value of YWH was in the middle as transition state between control and WH.     

中华绒螯蟹“蟹黄”与“蟹膏”的营养成分比较分析

本试验对中华绒螯蟹"蟹黄"与"蟹膏"的粗蛋白、氨基酸、粗脂肪、脂肪酸、卵磷脂和维生素等营养成分进行了测定分析。试验结果表明,蟹黄与蟹膏中的粗蛋白质含量为29.79%和9.64%,蟹黄显著高于蟹膏(P0.05);至少共含有17种氨基酸,蟹黄中的必需氨基酸显著高于蟹膏(P0.05),4种致鲜氨基酸比例明显高于蟹膏(P0.05);蟹黄、蟹膏中粗脂肪含量为44.3%和34.9%,差异不显著(P0.05),不饱和脂肪酸含量丰富,蟹黄高于蟹膏,差异不显著(P0.05);蟹黄中卵磷脂、维生素A、D、E的含量均显著高于蟹膏(P0.05)。试验表明,蟹黄比蟹膏具有更高的营养与食用价值。     

Effect of dietary lipids and vitamin E on growth performance,body composition,anti‐oxidative ability and resistance to Aeromonas hydrophila challenge of juvenile Chinese mitten crab Eriocheir sinensis

Vitamin E supplement is important in protecting lipid oxidation and enhancing immunity of aquatic animals. A 10‐week feeding trial was conducted to evaluate the effect of dietary lipid and vitamin E on juvenile Chinese mitten crab Eriocheir sinensis. The experimental diets included three levels of vitamin E (0, 100 and 300 mg kg^?1) and two levels of lipid (6% and 9%). The 9% lipid diet significantly enhanced the body lipid of crabs compared with the 6% lipid diet. The vitamin E concentration of hepatopancreas increased with the increase in vitamin E in the diets regardless of dietary lipid levels. The hepatopancreas fatty acids, especially polyunsaturated fatty acid and highly unsaturated fatty acid, were significantly enhanced by vitamin E supplement or 9% dietary lipid. Vitamin E supplement significantly increased the total antioxidant capacity, superoxide dismutase, lysozyme and phenoloxidase activities of crabs compared with those fed the diets without vitamin E supplement. The hepatopancreas malondialdehyde of crabs fed 100 mg vitamin E kg^?1 was significantly lower than those fed 0 or 300 mg vitamin E kg^?1. The phenoloxidase activity of crabs fed the 9% lipid diet was significantly higher than those fed 6% lipid, irrespective of vitamin E levels. Vitamin E supplementation increased the bacterial resistance of juvenile crab. This study indicates that dietary lipid and vitamin E supplement do not affect crab growth and survival, but vitatmin E supplement at 100 mg kg^?1 can enhance immunity and antioxidant capacity of crab fed 6% or 9% dietary lipids.     

中华绒螯蟹池塘套养与温室养殖的中华鳖雄体生物学指数和营养成分比较

分别取中华绒螯蟹(Eriocheir sinensis)池塘套养和温室养殖中华鳖(Trionyx sinensis)雄体(分别简称为"套养鳖"和"温室鳖")各5只,解剖取四肢肌肉、裙边和肝脏,分析和比较两种鳖的生物学指数,可食组织常规营养成分、氨基酸含量和脂肪酸组成的差异。结果显示:(1)温室鳖裙边指数(SI)和肝体比(HSI)均显著高于套养鳖(P0.05)。(2)套养鳖肌肉灰分和裙边水分含量均显著高于温室鳖,而裙边蛋白含量则以温室鳖较高(P0.01),套养鳖和温室鳖其余常规营养成分均无显著差异(P0.05)。(3)温室鳖肌肉和裙边中的大部分氨基酸、总必需氨基酸(∑EAA)和总氨基酸(TAA)含量显著高于套养鳖,半胱氨酸含量及EAA/TAA以套养鳖较高(P0.05);套养鳖和温室鳖肌肉和裙边中的必需氨基酸评分(EAAS)较为接近,而EAAS平均值以套养鳖较高。(4)温室鳖肌肉C18:1n9、C18:1n7及单不饱和脂肪酸(∑MUFA)总量显著高于套养鳖,而C22:6n3、总多不饱和脂肪酸(∑PUFA)、∑n-3PUFA、总高度不饱和脂肪酸(∑HUFA)含量及n-3/n-6以套养鳖较高(P0.05);就裙边而言,除温室鳖C17:0和C20:2n6含量显著高于套养鳖外(P0.05),其余脂肪酸含量均无显著差异(P0.05)。综上可见,中华鳖在两种养殖模式下均具有较高的营养价值。     

不同脂肪源饲料对中华绒螯蟹幼蟹生长、消化酶活力和脂肪酸组成的影响

选用初始体重为(2.15±0.10)g的中华绒螯蟹(Eriocheir sinensis)雄性幼蟹,随机分为5组(每组12只幼蟹),饲喂100%鱼油组(简称F1组)、100%豆油组(F2组)、100%亚麻油组(F3组)、50%鱼油+50%豆油组(F4组)、50%鱼油+50%亚麻油组(F5组)不同脂肪源配制的5种等氮等能饲料。实验蟹单个体养殖,实验周期为112 d。结果表明,F5组体重、增重率和特定生长率都显著高于其他饲料组(P0.05),各组的蜕壳间隔和肝胰腺指数没有显著差异(P0.05)。肝胰腺组织消化酶活力测定结果表明,F1组幼蟹肝胰腺的类胰蛋白酶活力显著高于其他各组(P0.05);F3组的胃蛋白酶活力显著高于其他各组(P0.05);F1组、F2组和F4组的脂肪酶活力显著高于其他两组(P0.05);各组的淀粉酶活力差异不显著(P0.05)。脂肪酸测定结果表明,肝胰腺和肌肉中的亚油酸(LOA)(C18:2n-6)、亚麻酸(LNA)(C18:3n-3)、EPA(C20:5n-3)和DHA(C22:6n-3)等主要脂肪酸含量与饲料脂肪酸组成呈正相关关系,F1组的高度不饱和脂肪酸(HUFA)含量显著高于其余各组(P0.05),F2组的LOA含量显著高于其余各组(P0.05),F3组的LNA含量显著高于其余各组(P0.05)。本研究结果表明,以50%的豆油或亚麻油替代鱼油能促进中华绒螯蟹幼蟹的生长,但可能使幼蟹的成活率降低。以豆油或亚麻油替代鱼油会影响幼蟹胰蛋白酶、胃蛋白酶和脂肪酶的活力和肝胰腺、肌肉脂肪酸组成。     

中华绒螯蟹肝胰腺白化症的病因研究

2002年10月以来,通过逐户访问及调查问卷的形式对2001～2002年东太湖中华绒螯蟹(Eriocheir sinensis)养殖区"白膏症"发病症状、扣蟹的来源、投饵模式、水草覆盖率、螺蛳投入量、底泥状况、回捕率、产量等进行较为系统的调查。同时对病蟹进行寄生虫检查、病原微生物分离、回接攻毒及病变组织的电镜观察等病原学研究,结果未发现致病性生物。调查结果表明,中华绒螯蟹"白膏症"的发病率雄蟹显著高于雌蟹,其症状为甲壳发黄,头胸甲腹面下肝区发白色或青黑色,肝胰腺由正常的橘黄色变成淡黄或白色;症状严重的病蟹胸腔积水,肌肉松驰萎缩,肝胰腺呈糜烂状,鳃丝发黑。调查结果显示,"白膏症"的发生与饵料的投喂量、动植物饵料之比及水环境有着密切的联系。根据该病的主要症状及发病原因,认为该病应命名为中华绒螯蟹肝胰腺白化症。     

Nutritional qualities of normal and precocious adult male Chinese mitten crabs (Eriocheir sinensis)

The nutritional values of edible gonad, hepatopancreas and muscle tissues from normal and precocious adult male Chinese mitten crabs (Eriocheir sinensis) were investigated herein. The results showed that the average weight and meat yield (MY) of normal crabs were significantly higher than those of precocious crabs, while the hepatopancreas indexes (HSI) and gonadosomatic indexes (GSI) had no significant differences. Precocious and normal crabs had greater protein and lipid contents, respectively, and the differences were mainly reflected in gonads and hepatopancreas. While assessing the amino acid profiles, both precocious and normal crabs could be high‐quality protein sources, particularly the precocious crabs which showed higher levels of essential amino acids. In fatty acid profiling experiments, precocious crabs revealed higher EPA, ∑n‐3 polyunsaturated fatty acids (PUFA) and ∑n‐3/∑n‐6 ratios than normal crabs; however, DHA and ∑n‐6 PUFA contents were considerably lower. Additionally, contents of nutritious minerals K and Ca in precocious crabs were significantly higher than those in normal crabs, while Zn and Fe were significantly lower. In short, our data indicated that precocious Chinese mitten crabs are also a nutritious food, and even in some respects their nutritional value is higher than normal crabs.     

Biochemical composition of pond-reared and lake-stocked Chinese mitten crab Eriocheir sinensis (H. Milne-Edwards) broodstock

The morphological characteristics, tissue indices, proximate and fatty acid compositions of hepatopancreas, gonad and muscle of pond‐reared (PR) and lake‐stocked (LS) Eriocheir sinensis broodstock were compared. Lake‐stocked crabs are characterized by a blue carapace, white abdomen, golden legs and yellow setae while PR crabs have a brown carapace, grey abdomen, black legs and similar yellow setae. The carapace length and width of PR crabs were significantly less than those of LS crabs of the same wet weight (WW). The results showed that the hepatosomatic index (HSI) of PR males was significantly higher, but the gonadosomatic index (GSI) was significantly lower for PR females when compared with LS individuals of the same sex. Regardless of their origin, the muscular index (MI) of males was higher than that of females. The hepatopancreas of LS crabs had higher protein levels and lower lipid levels compared with PR crabs. The results of proximate analysis of male gonads from two different sources were similar, while the protein level in the ovary of LS females was higher than that of PR females. The tissues of males had higher water content but lower lipid and protein levels compared with females regardless of their source. The LS crabs had higher highly unsaturated fatty acid (HUFA) levels than PR crabs in their gonad and hepatopancreas. In conclusion, our results suggest that the nutritional quality of LS crabs is better than that of PR crabs, the nutritional quality of males is poorer than that of females. The reproductive performance and larval quality of crabs from these two rearing systems should be further verified.     

A combination of vitamins C and E alleviates oxidized fish oil‐induced hepatopancreatic injury in juvenile Chinese mitten crab Eriocheir sinensis

Dietary lipid oxidation is a lasting concern to aquafeed manufacturers and aquaculture farmers. Here, we determined if there was an association between oxidized fish oil (OFO) and hepatopancreatic injury in Chinese mitten crab, and evaluated the alleviating effects of a combination of vitamins C and E on hepatopancreatic injury. There were significant reductions in the body weight gain, hepatopancreatic index, and feed efficiency in crabs that received OFO. Diets with OFO also resulted in reduced crude fat contents in the hepatopancreas and muscle tissues, and alternations in the hepatopancreatic fatty acid compositions, especially a reduction in polyunsaturated fatty acids. Moreover, dietary OFO exposure reduced the antioxidant defense and non‐specific immune response, caused hepatopancreatic injury, and even apparent whitening. An ultrastructural examination of the whitened hepatopancreas revealed that hepatopancreatic cells were injured at varying degrees following OFO exposure. The combination of vitamins C and E could efficiently maintain a constant fatty acid profile in the hepatopancreas exposed to OFO, thus alleviating OFO‐induced hepatopancreatic injury. In addition, a biochemical analysis indicated that a combination of vitamins C and E not only improved the antioxidant status by mitigating the harmful effects of oxidized oil, but also modulated non‐specific immune responses in the crab that received OFO. Overall, OFO‐induced hepatopancreatic injury may be alleviated by a dietary combination of vitamins C and E, and the feeding of rancid forage fish or diets that contain highly oxidized oil is likely a cause of hepatopancreatic necrosis that is frequently observed in farmed crabs.