脂质对中华花龟不同组织脂肪酸组成的影响

将体质量(1828±468)g的4龄雌性成体中华花龟随机分成4组,常温饲养在150cm×50cm×50cm的水池中,每组6只,分别投喂饲料中鱼油为豆油替代0%、33.3%、66.7%和100%的饲料,每周投喂2次。饲养1年后,从每组中随机取6只中华花龟,检测肝脏、肌肉、卵巢中脂肪酸的组成。试验结果表明,饲料中鱼油比例较高(豆油替代0%和33.3%鱼油组)能促进肝脏和肌肉中二十碳五烯酸和二十二碳六烯酸的积累,但豆油替代率对卵巢二十碳五烯酸和二十二碳六烯酸的积累影响不显著。饲料中花生四烯酸在肌肉和卵巢中大量累积,豆油替代33.3%鱼油组肌肉和豆油替代0%鱼油组卵巢中花生四烯酸占总脂肪酸的含量[(5.26±0.94)%、(1.31±0.04%)]最高,肝脏中花生四烯酸积累较少。豆油替代66.7%和100%鱼油组肝脏中亚油酸含量显著高于其他两组(P0.05),豆油替代100%鱼油组卵巢中亚麻酸含量最高(P0.05)。饲料中豆油替代鱼油比例升高促进了中华花龟组织中亚油酸和亚麻酸的积累,抑制了二十碳五烯酸、二十二碳六烯酸和花生四烯酸等的积累;当豆油替代33.3%鱼油时,中华花龟肝脏、肌肉、卵巢中脂肪酸组成及含量与全鱼油组差异不显著。     

豆油替代鱼油对圆斑星鲽幼鱼生长和肌肉脂肪酸的影响

本实验旨在研究饲料中豆油替代鱼油对圆斑星鲽(Verasper variegatus)幼鱼生长和肌肉脂肪酸组成的影响。用豆油分别替代0、25%、50%和75%的鱼油,配制4组等氮、等脂肪的饲料。选择初始体重为(65.47±1.57)g的圆斑星鲽幼鱼360尾,随机分为4组,每组3个重复,每个重复30尾鱼,养殖56 d。结果显示,(1)随着豆油替代水平的升高,增重率(WGR)呈现降低的趋势(P0.05),饲料系数(FCR)呈现升高的趋势(P0.05),25%替代组的WGR高于鱼油组(P0.05)。(2)豆油替代鱼油对圆斑星鲽肌肉的粗蛋白、粗脂肪、灰分和水分含量无显著性影响(P0.05),对肝体比(HSI)、脏体比(VSI)和肥满度(CF)无显著性影响(P0.05),豆油替代组肝脏的脂肪含量显著高于鱼油组(P0.05)。(3)随着饲料中豆油水平的增加,圆斑星鲽幼鱼肌肉亚油酸(C18:2n-6)和亚麻酸(C18:3n-3)显著升高(P0.05),而二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)则显著降低(P0.05)。研究结果表明,在该实验条件下,饲料中高比例的豆油替代鱼油会降低鱼体的生长性能和肌肉脂肪酸营养品质。     

饲料中不同种类的碳水化合物对大菱鲆生长性能和代谢反应的影响

为探讨在低蛋白水平(40%)下,饲料中不同种类的碳水化合物(葡萄糖、蔗糖和糊精)对大菱鲆幼鱼[(8.12±0.04)g]生长、成活、饲料利用、体组成和血液生理生化指标等的影响,实验在对照组饲料中未添加可消化碳水化合物,含40%的蛋白质和18%的脂肪,然后在对照组饲料的基础上,调节脂肪水平为12%,分别添加15%的葡萄糖、蔗糖和糊精配制3组实验饲料。在流水式养殖系统中进行9周的大菱鲆生长实验。结果显示,各处理组大菱鲆成活率均高于95.24%,并且各组间无显著差异;对照组和糊精组大菱鲆的增重率(WGR)和特定生长率(SGR)均显著高于葡萄糖组和蔗糖组。各组间的日摄食率(DFI)没有显著差异。对照组和糊精组饲料效率(FE)显著高于蔗糖组,但葡萄糖组FE与其它各组无显著差异;各处理组间蛋白质和脂肪表观消化率(ADC)未受碳水化合物种类的显著影响,而可消化碳水化合物的ADC依次为:葡萄糖组>糊精组>蔗糖组(。葡萄糖组的能量ADC最高,蔗糖组的最低;除对照组肌肉脂肪含量显著高于其它各组外,碳水化合物的种类对大菱鲆肌肉常规组成及糖原含量无显著影响,但显著影响了肝脏的脂肪和糖原含量。大菱鲆肝脏脂肪含量依次为对照组>糊精组>蔗糖组>葡萄糖组,肝脏糖原含量依次为葡萄糖组>蔗糖组>糊精组>对照组;不同碳水化合物种类对大菱鲆幼鱼血浆葡萄糖含量没有显著影响,但显著影响血浆总氨基酸、胰岛素、总胆固醇(CHO)和甘油三酯(TAGs)的含量。结果表明,本实验条件下,大菱鲆对糊精的利用效率优于葡萄糖和蔗糖,并且不同种类的碳水化合物通过糖脂关联代谢等途径对大菱鲆幼鱼的体组成和血液生理生化指标造成一定的影响。     

饲料中添加氧化鱼油对黑鲷幼鱼生长的影响

研究了饲料中添加氧化鱼油对黑鲷(Acanthopagrus schlegeli)生长性能、脂质过氧化及肝组织结构的影响.分别以新鲜鱼油(过氧化物值 POV,1.27 meq O2·kg-1油)与氧化酸败鱼油(POV,45 meq O2·kg-1油)为脂肪源配制等蛋等能的两种配合饲料,投喂平均体重18.9 g的黑鲷幼鱼9周.结果显示,氧化鱼油显著降低了黑鲷幼鱼的增重率(WG)、饲料效率(FE)及蛋白质效率(PER)(P＜0.05).饲料中添加氧化鱼油导致鱼体蛋白质含量极显著降低(P＜0.01)、肝脏与肌肉中脂肪含量显著升高(P＜0.05),而对鱼体、肝脏及肌肉中的水分及灰分含量无显著影响(P＞0.05).氧化鱼油组肝脏中脂质过氧化产物丙二醛(MDA)含量显著高于对照组,而维生素E含量则显著低于对照组(P＜0.05). 饲料中添加氧化鱼油显著影响黑鲷肝脏内主要抗氧化酶活性,氧化鱼油组肝脏中超氧化物歧化酶(SOD)与过氧化氢酶(CAT)活性显著高于对照组(P＜0.05);组织学结果显示氧化鱼油组肝脏出现明显病变,细胞核多集中在肝细胞边缘,肝细胞变大. 统计分析表明,氧化酸败油脂显著降低了黑鲷的生长性能,加重了组织中脂质过氧化的程度,并导致肝脏组织发生病变.     

饲料脂肪水平对俄罗斯鲟幼鱼生长、血液生化指标及抗氧化性能的影响

以鱼油、豆油、亚麻籽油等比例混合,配成脂肪含量分别为5.45%(L1)、7.00%(L2)、10.44%(L3)、14.37%(L4)、16.34%(L5)、18.91%(L6)及20.15%(L7)的等氮饲料,饲喂俄罗斯鲟(Acipenser gueldenstaedtii)幼鱼[(6.20±0.02)g]8周。实验结果表明,L3组的终末体质量、增重率最大,但与L2组间无显著差异(P0.05),L3组的蛋白质效率显著高于其它组(P0.05),且饲料系数最低。L6和L7组终末体质量、增重率和蛋白质效率显著低于L2和L3组(P0.05)。将幼鱼的增重率与饲料脂肪水平进行回归分析,得出俄罗斯鲟幼鱼在饲料脂肪水平为10.69%时生长最佳。随着饲料脂肪水平的升高,各组鱼的肝体比和体粗脂肪有上升趋势,其中肝体比在饲料脂肪含量大于14.37%时显著增大(P0.05)。血清中的甘油三酯、胆固醇含量也随脂肪水平升高而显著提高(P0.05),提示脂肪过高会影响俄罗斯鲟幼鱼的生长,降低蛋白质效率,导致脂肪在体内的过量积蓄。L7组鱼血清中高密度脂蛋白胆固醇含量最高,而L1组鱼的低密度脂蛋白胆固醇含量最高。肝脏脂蛋白酯酶活性随饲料脂肪水平的提高而升高,脂肪酸合成酶活性则随脂肪水平升高而降低,提示饲料脂肪水平的提高会促进鱼体脂肪的分解代谢。肝脏丙二醛含量和超氧化物歧化酶活性均随着饲料脂肪水平的提高显著升高(P0.05),表明脂肪含量过高会导致脂质过氧化,引发机体抗氧化酶活性的升高。综合俄罗斯鲟幼鱼的生长、血液指标及抗氧化性能,建议生产中将幼鱼的饲料脂肪水平控制在7.00%~10.69%。     

茶多酚对大菱鲆生长、抗氧化能力及脂肪代谢相关基因表达的影响

为了研究饲料中添加茶多酚对大菱鲆生长、抗氧化能力及脂肪代谢相关基因表达的影响,以初始体质量为(13.51+0.31) g的大菱鲆幼鱼为实验对象,设计4组添加不同梯度茶多酚(0%、0.01%、0.02%和0.05%,干重添加量分别为0、100、200和500 mg/kg)的等氮等脂实验饲料,进行为期70 d的摄食生长实验。结果显示:①与对照组相比,饲料中添加0.01%～0.02%茶多酚显著提高了大菱鲆幼鱼增重率(WGR);饲料效率(FE)随饲料中茶多酚添加水平升高而升高,但各组间差异不显著;随饲料中茶多酚添加水平升高,大菱鲆肝体比(HSI)呈降低趋势,且显著低于对照组;②鱼体组成分析表明,投喂添加茶多酚饲料组大菱鲆鱼体和肝脏粗脂肪含量呈下降趋势,且在茶多酚添加水平为0.02%～0.05%时达到最低值,显著低于对照组;③与对照组相比,投喂添加茶多酚饲料组大菱鲆血清总抗氧化能力(T-AOC)及谷胱甘肽过氧化物酶(GSH-Px)活性显著升高,且各添加组间差异不显著;超氧化物歧化酶(SOD)活性随茶多酚的添加水平升高呈先升高后降低趋势,且在添加水平为0.02%时显著高于对照组;血清丙二醛(MDA)含量随茶多酚添加水平升高而降低,且在添加水平为0.02%～0.05%时显著低于对照组;④大菱鲆肝脏固醇调节元件结合蛋白1(SREBP-1)表达量随着饲料中茶多酚添加水平升高而降低,且在添加水平为0.02%～0.05%时达到最低值,显著低于对照组;脂肪酸合成酶(FAS)表达量随茶多酚添加水平的升高呈先降低后升高趋势,且在添加水平为0.02%时显著低于对照组;过氧化物酶体增殖物激活受体α(PPARα)表达量变化趋势与FAS相反,且在添加水平为0.02%时达到最高值。肉毒碱棕榈酰转移酶1(CPT1)表达量随饲料中茶多酚添加水平升高而升高,显著高于对照组,且各添加组间差异不显著。研究表明,高脂饲料中添加茶多酚能促进大菱鲆生长、降低肝脏脂肪过度沉积并提高血清抗氧化能力,高脂饲料中添加0.02%茶多酚是大菱鲆幼鱼生长的最适添加量。     

植物油替代鱼油对虹鳟、花鲈和大黄鱼组织结构的影响

以初始体重分别为(11.24±0.07 g)、(18.60±0.36 g)和(8.93±0.21 g)的虹鳟、鲈鱼和大黄鱼幼鱼为研究对象,用植物油(亚麻籽油:豆油=1:1)分别替代0%(FO,对照组)、50%(FV)和100%(VO)的鱼油来配制三种等氮(粗蛋白含量为41%)等脂(粗脂肪含量为12%)的实验饲料。通过投喂实验探讨不同植物油替代鱼油水平对虹鳟(淡水鱼)、鲈鱼(广盐性鱼类)和大黄鱼(海水鱼)肝脏和肠道组织结构的影响差异。70 d投喂实验后发现,随着替代水平增加虹鳟、鲈鱼和大黄鱼的肝细胞中脂肪滴累积程度逐渐增高,相同替代水平下肝细胞中脂肪滴累积程度为大黄鱼>鲈鱼>虹鳟;肠道组织中杯状细胞随植物油替代水平升高而增多,而在大黄鱼全植物油组出现脂肪滴累积和上皮细胞死亡现象。以上结果表明植物油替代鱼油对虹鳟组织结构影响最小对大黄鱼影响最大。     

小麦胚芽油替代鱼油对半滑舌鳎幼鱼生长、体成分、血清生化指标及脂肪代谢酶的影响

以初始体重为(3.70±0.01)g的半滑舌鳎(Cynolossus semilaevis Günter)幼鱼为实验对象,研究小麦胚芽油替代鱼油对其生长、体成分、血清生化指标及脂肪代谢酶的影响。以添加7.5%的鱼油组为对照组,用小麦胚芽油分别替代0、20%、40%、60%、80%、100%的鱼油配制成6组等氮等能饲料,在海水循环养殖系统中进行68 d的养殖实验。结果显示:饲料中小麦胚芽油替代鱼油对半滑舌鳎幼鱼存活率无显著影响;随着替代水平的升高,特定生长率和蛋白质效率降低,饲料系数升高。各组间脏体比、肝体比和肥满度均无显著性差异。肝脂肪含量随替代水平的升高而升高,而全鱼脂肪含量降低;80%和100%替代组全鱼水分含量显著高于对照组(P0.05)。随着饲料中小麦胚芽油水平的升高,鱼体组织中亚油酸和亚麻酸含量显著升高(P0.05),EPA和DHA含量显著降低(P0.05)。各组间血清谷丙转氨酶、谷草转氨酶、碱性磷酸酶和溶菌酶活性均无显著性差异(P0.05);80%和100%替代组甘油三酯和总胆固醇含量显著高于对照组(P0.05);血清丙二醛含量呈降低趋势。随着替代水平的升高,肝脂蛋白酯酶、肝酯酶、总酯酶、脂肪酸合成酶以及肠道脂肪酶活性升高。研究表明,在本实验条件下,小麦胚芽油可替代60%的饲料鱼油而不影响半滑舌鳎幼鱼的生长;小麦胚芽油的添加,促进了鱼体脂肪代谢,抑制脂质过氧化作用,但显著改变了鱼体脂肪酸组成。     

混合微藻替代鱼油对大菱鲆幼鱼生长性能、体组成及肠道部分生化指标的影响

本实验以大菱鲆(Scophthalmus maximus)幼鱼[(39.69±0.25) g]为研究对象,探究由裂壶藻(Schizochytrium sp.)和拟微绿球藻(Nannochloropsis sp.)组成的混合微藻替代鱼油对幼鱼生长性能、体组成、肠道消化水平及抗氧化能力的影响,以确定混合微藻替代鱼油的适宜比例。通过在基础饲料中添加不同比例的混合微藻,分别替代0、25%、50%和100%的鱼油,制成4组等氮等脂的实验饲料(分别命名为D1、D2、D3和D4),每组饲料设3个重复,实验周期为12周。结果显示,随替代比例的提高,大菱鲆幼鱼的增重率(WGR)和饲料效率(FE)呈下降趋势,D1、D2和D3组的特定生长率(SGR)和FE无显著性差异,但均显著高于D4组(P<0.05);肝体比(HSI)在D1组达到最大值,且显著高于其他各组(P<0.05);存活率(SR)和肥满度(CF)在各组之间无显著差异(P>0.05)。随着混合微藻替代鱼油比例的升高,全鱼和肌肉粗脂肪含量呈先升高后降低的变化趋势,且D4组显著低于D1组(P<0.05);大菱鲆幼鱼鱼体中C20:4n-6和n-6 PUFA含量显著升高,在D4组均达到最大值,且显著高于对照组(P<0.05)。而EPA、DHA和n-3 PUFA含量随之显著下降,对照组(D1)含量显著高于其他各组(P<0.05);肌肉中C20:4n-6和DHA含量在不同实验组间无显著性差异(P>0.05),EPA和n-3 PUFA含量呈显著降低趋势(P<0.05)。肠道脂肪酶活力在D3组达到最大值,显著高于对照组(P<0.05),肠道胰蛋白酶活力也是在D3组最高,但与对照组无显著性差异(P>0.05)。与D1组相比,D3组肠道中酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、溶菌酶(LZM)活力和补体C3含量均显著升高(P<0.05)。肠道中超氧化物歧化酶(SOD)、总抗氧化能力(T-AOC)和过氧化氢酶(CAT)活力随替代比例的提高呈先升高后降低的趋势,均在D3组达到最大值,显著高于D1组(P<0.05),而肠道中丙二醛(MDA)含量在不同实验组间并未表现出显著性差异(P>0.05)。综上所述,混合微藻替代50%的鱼油并不会对大菱鲆幼鱼的生长性能产生负面影响,同时可以提高肠道的消化性能、抗氧化能力和非特异性免疫能力。     

饲料中添加氧化鱼油对黑鲷幼鱼生长的影响

研究了饲料中添加氧化鱼油对黑鲷（Acanthopagrus schlegeli）生长性能、脂质过氧化及肝组织结构的影响。分别以新鲜鱼油（过氧化物值POV，1．27meq O2·kg^-1油）与氧化酸败鱼油（POV，45meq O2·kg^-油）为脂肪源配制等蛋等能的两种配合饲料，投喂平均体重18．9g的黑鲷幼鱼9周。结果显示，氧化鱼油显著降低了黑鲷幼鱼的增重率（WG）、饲料效率（FE）及蛋白质效率（PER）（P〈0．05）。饲料中添加氧化鱼油导致鱼体蛋白质含量极显著降低（P〈0．01）、肝脏与肌肉中脂肪含量显著升高（P〈0．05），而对鱼体、肝脏及肌肉中的水分及灰分含量无显著影响（P〉0．05）。氧化鱼油组肝脏中脂质过氧化产物丙二醛（MDA）含量显著高于对照组，而维生素E含量则显著低于对照组（P〈0．05）。饲料中添加氧化鱼油显著影响黑鲷肝脏内主要抗氧化酶活性，氧化鱼油组肝脏中超氧化物歧化酶（SOD）与过氧化氢酶（CAT）活性显著高于对照组（P〈0．05）；组织学结果显示氧化鱼油组肝脏出现明显病变，细胞核多集中在肝细胞边缘，肝细胞变大。统计分析表明，氧化酸败油脂显著降低了黑鲷的生长性能，加重了组织中脂质过氧化的程度，并导致肝脏组织发生病变。     

Effect of variation in the dietary ratio of linseed oil to fish oil on growth,body composition,tissues fatty acid composition,flesh nutritional value and immune indices in Manchurian trout,Brachymystax lenok

In order to study the effects of linseed oil substitution on the growth, body composition, tissue fatty acid composition, flesh nutritional value and immune indices of juvenile Manchurian trout, five feed types containing different levels of linseed oil (LO) mixed with fish oil (FO) were prepared: 0 (0 LO); 250 g/kg (25 LO); 500 g/kg (50 LO); 750 g/kg (75 LO); and 1000 g/kg (100 LO); and fed to juvenile Manchurian trout (initial weight 6.43 ± 0.02 g) for 9 weeks. The results showed that substitution of FO with 750 g/kg LO did not affect the growth of juvenile trout, with protein content in the dorsal muscle, and lipid content in the liver not showing any significant difference (p > 0.05). The highest lipid content found in muscle samples occurred for the 25 LO diet. The fatty acid composition found in the dorsal muscle and the liver of the Manchurian trout reflects the fatty acid composition in the diet, where the relative amount of linolenic acid (ALA), linoleic acid (LA) and docosahexaenoic acid (DHA) found in these organs has a positive linear correlation with their relative composition in the diet (p < 0.05). As the amount of LO in the diet was increased, the composition of ALA found in the sampled organs increased, while the composition of DHA and eicosapentaenoic acid (EPA) decreased. At the same time, the index of atherogenicity (IA) and thrombogenicity (IT) of the muscle samples from the 75 LO and 100 LO diets was significantly lower than for the 0 LO and 25 LO diets (p < 0.05), while the flesh lipid quality (FLQ) in the 100 LO diet was significantly lower than for the other diets (p < 0.05). The aspartate transaminase (AST) activity decreased initially, and then increased, as the level of LO replacement for FO was increased, with the 25 LO diet being significantly lower than for other groups (p < 0.05). The alanine aminotransferase (ALT) activity in serum samples from the 100 LO diet was higher than that from other diets. The lysozyme (LZM) activity in both serum and liver tissue first increased to a peak for the 25 LO and 50 LO diets, respectively, and then decreased as the level of LO was further increased. There was no significant change in the alkaline phosphatase (AKP) activity in the liver samples; however, the acid phosphatase (ACP) activity decreased significantly from the highest value for 0 LO feed group. In conclusion, the composition of fatty acids in the dorsal muscle and the liver was found to be modified by the diets, and with the diet containing less than 750 g/kg LO, being both beneficial for growth, and improved immunity, while maintaining the nutritional value of the lipid content in the dorsal muscle during the 9‐week period.     

Replacement of fish oil with soybean oil in diets for juvenile Chinese sucker (<Emphasis Type="Italic">Myxocyprinus asiaticus</Emphasis>): effects on liver lipid peroxidation and biochemical composition

This study was designed to evaluate the effect of the replacement of fish oil (FO) by soybean oil (SO) on growth performance, liver lipid peroxidation, and biochemical composition in juvenile Chinese sucker, Myxocyprinus asiaticus. Fish (13.7 ± 0.2 g) in triplicate were fed five experimental diets in which 0% (FO as control), 40% (SO40), 60% (SO60), 80% (SO40), and 100% (SO100) FO were replaced by SO. The body weight gain of fish fed SO40, SO60, or SO80 diet was similar to FO group, but diets that have 100% soybean oil as dietary lipid significantly reduced fish growth (P < 0.05). Although the level of SO resulted in increasing crude lipid content of the liver, the level of SO did not significantly alter the hepatosomatic index (HSI). Indicators of peroxidation, such as vitamin E (V_E) and thiobarbituric acid-reactive substance (TBARS) contents, were changed as increasing dietary SO. It was shown that the inclusion of SO in the diets increased V_E concentrations, but reduced TBARS in the liver and total cholesterol (T-CHO) in the plasma. Linoleic acid (LA) and linolenic acid (LNA) significantly increased in fish liver fed diets that contained SO, but eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and the ratio n-3/n-6 were significantly reduced by the inclusion of dietary SO (P < 0.05). Our results indicated that the inclusion of SO increased the hepatic V_E content and reduced lipid peroxidation in fish. However, diet containing 100% SO as dietary lipid could reduce growth performance. Thus, we recommended that 40–80% SO can be used as dietary lipid to replace FO for juvenile Chinese sucker.     

Effects of Different Dietary Lipid Sources on Growth Performance,Fatty Acid Composition,and Antioxidant Enzyme Activity of Juvenile Rockfish,Sebastes schlegeli

This study was carried out to investigate and compare the effects of various dietary lipid sources on growth performance, body composition, fatty acid profiles, and hepatic and plasma antioxidant enzyme activities of juvenile rockfish, Sebastes schlegeli. Three replicate groups of fish (initial mean weight, 1.7 ± 0.04 g) were fed four isonitrogenous and isolipidic diets containing either fish oil (FO), soybean oil (SO), linseed oil (LO), or a mixture of SO and LO (SO + LO) for 8 wk. There were no significant differences in survival, weight gain, feed efficiency, and protein efficiency ratios of fish fed the diets containing different lipid sources (P > 0.05). The fatty acids compositions of the liver and muscle tissues reflected the dietary fatty acid compositions. Liver and muscle of fish fed the SO diet had high concentration of linoleic acid, whereas those of fish fed the LO diet were rich in linolenic acid. Liver and muscle of fish fed the FO diet had significantly (P < 0.05) higher levels of eicosapentaenoic acid and docosahexaenoic acid than those of fish fed the SO and LO diets. Dietary lipid source had no significant effect on the hepatic and plasma enzyme activities of superoxide dismutase and glutathione peroxidase. The results of this study suggest that SO and LO can be used as a replacement for FO in the diets of juvenile rockfish without incurring any negative effects on growth, feed utilization, and antioxidant enzyme activity, when the dietary essential fatty acid requirements are satisfied for rockfish.     

大菱鲆幼鱼对饲料中泛酸最适需求量的研究

为研究大菱鲆(Scophthalmus maximus)幼鱼对泛酸的最适需求量,在基础配方中添加不同梯度的泛酸钙,制成6组泛酸含量分别为6.24、10.64、15.02、23.81、41.40和76.57 mg/kg等氮等能实验饲料,投喂初始体重为(24.73±0.10) g的大菱鲆幼鱼80 d。结果显示：1)泛酸对幼鱼成活率(SR)无显著影响(P>0.05),10.64~76.57 mg/kg饲料组增重率(WGR)和特定生长率(SGR)显著提高(P< 0.05);泛酸含量超过23.81 mg/kg时,肝体比(HSI)显著降低(P<0.05);2)随着饲料中泛酸含量的提高,全鱼粗蛋白、粗脂肪和肌肉粗蛋白均呈先升后降趋势,肝脏脂肪含量显著下降(P<0.05);3)肠道消化酶、Na+, K+-ATPase和肝脏胆碱酯酶(ChE)活力随泛酸添加量的增加呈先上升后下降趋势,10.64~76.57 mg/kg饲料组肠道肌酸激酶(CK)活力显著提高(P<0.05);4)血清、肝脏中过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活力均呈先升后降趋势;6.24 mg/kg饲料组血清丙二醛(MDA)含量显著高于其他5组(P<0.05);5)随泛酸含量的增加,肝脏脂肪合成酶(FAS)基因表达量先升后降,脂蛋白酯酶(LPL)基因表达量显著上升(P<0.05)。研究表明,饲料中添加适宜的泛酸能显著增强大菱鲆幼鱼肠道消化、吸收能力和机体抗氧化能力,并可提高脂肪代谢相关基因的表达水平,从而提高其生长性能。以增重率为判据,经折线模型拟合得出,初体重为24.73 g的大菱鲆幼鱼对泛酸的需求量为16.08 mg/kg饲料。     

Effects of replacing dietary fish oil and squid liver oil with vegetable oils on the growth,tissue fatty acid profile and total carotenoids of the giant freshwater prawn, Macrobrachium rosenbergii

A feeding trial was conducted to investigate the complete substitution of either fish oil (FO) or squid liver oil (SLO) with crude palm oil (CPO), canola oil (CO) sunflower oil (SFO) or linseed oil (LO), as the sole added lipid source in diets fed to triplicate groups of giant freshwater prawn, Macrobrachium rosenbergii (initial weight = 0.42 ± 0.01 g) for 6 weeks. Prawns fed the CO or SLO diets showed significantly higher (P < 0.05) specific growth rate than those fed the FO or CPO diets. The feed conversion ratio of the prawns was significantly better when fed the CO diet, compared with the FO, CPO, SFO and LO diets. The muscle eicosapentaenoic acid content of prawns fed the vegetable oil (VO) diets were not significantly different (P > 0.05) from those fed the FO diet, although all VO‐based diets led to a significantly lower docosahexaenoic acid content compared with prawns fed the FO or SLO diet. The whole‐body total carotenoid content was significantly lower for prawns fed the SLO diet compared with prawns on the CO or CPO diets. The successful use of VO instead of marine‐based oils in prawn diets will likely reduce feeding costs associated with M. rosenbergii aquaculture.     

Effects of dietary fish oil substitution with linseed oil on growth,muscle fatty acid and metabolism of tilapia (Oreochromis niloticus)

This study was conducted to evaluate the effect of linseed oil (LO) replacing different levels of fish oil (FO) on growth, muscle fatty acid composition and metabolism of gift tilapia (Oreochromis niloticus) (mean initial weight 22 ± 0.5 g) in indoor recycle aquarium tanks for 8 weeks. Fish fed the diet with 50% of the oil as LO had higher final body weight (FWG), specific growth rate (SGR) and protein efficiency ratio (PER) than the other groups (P < 0.05). Hepatopancreas lipid content of fish fed 50% LO was lower than the other groups. Total n‐3 and n‐6 PUFA contents in the dorsal muscle and superoxide dismutase (SOD) activity in serum increased with increasing dietary LO level. Fish fed 50% LO had higher alanine transaminase (ALT), aspartate transaminase (AST) and lipoprotein lipase (LPL) activities in hepatopancreas and total antioxidant capacity (T‐AOC) and alkaline phosphatase (AKP) activities in serum than the other groups (P < 0.05). However, malate dehydrogenase (MDH) activities and malondialdehyde (MDA) contents in hepatopancreas were lower than other groups (P < 0.05) with a 50% substitution level. Results of this study indicated that LO could substitute <50% FO without influencing the growth of tilapia. The higher substitution levels of LO induced negative influences on growth, feed utilization and antioxidant ability of tilapia, but could promote DHA synthesis in tilapia muscle.     

Effects of dietary fish oil replacements with three vegetable oils on growth,fatty acid composition,antioxidant capacity,serum parameters and expression of lipid metabolism related genes in juvenile Onychostoma macrolepis

Five isonitrogenous and isoenergetic diets with soybean oil (SO), linseed oil (LO), algae oil from Schizochytrium sp. (AO), mixed oil (MO, SO:LO:AO = 1:1:1) and fish oil (FO; control group) were selected to feed juvenile Onychostoma macrolepis (initial weight 1.86 ± 0.07 g) for eight weeks. The results showed that in the LO and FO groups fish grew best. There was no significant difference in specific growth rate (SGR) and feed efficiency (FE) between the MO and FO groups (p > .05). The highest contents of 18:2n‐6, 18:3n‐3 and 22:6n‐3 in liver and muscle were found with the SO, LO and AO groups, respectively (p < .05). There appeared the highest malondialdehyde (MDA) content and the lowest superoxide dismutase (SOD) activity in the fish liver of the AO group. There appeared the highest concentrations of serum glucose (GLU), cholesterol (CHOL) and triglycerides (TG) in the SO group. The expressions of lipid anabolism genes were significantly up‐regulated by dietary SO and LO (p < .05). The expressions of lipid catabolism genes were significantly higher with the AO, MO and FO groups (p < .05). This study recommended that LO or MO as a better vegetable oil source for juvenile O. macrolepis.     

Effects of diets rich in linoleic (18:2n - 6) and α-linolenic (18:3n - 3) acids on the growth,lipid class and fatty acid compositions and eicosanoid production in juvenile turbot (Scophthalmus maximus L.)

Three practical-type diets utilizing fishmeal and casein as the protein sources and containing fish oil (FO), safflower oil (SO) or linseed oil (LO) were fed to duplicate groups of juvenile turbot (Scophthalmus maximus) of initial weight 1.2 g for a period of 12 weeks. No differences in final weight, mortality or development of pathological lesions were evident either between duplicate tanks or between dietary treatments over this period. Fish fed diets containing SO and LO contained significantly greater amounts of liver triacylglycerol compared to fish fed FO. The major C₁₈ polyunsaturated fatty acids (PUFA) in SO and LO diets, 18:2(n-6) and 18:3(n-3) respectively, were readily incorporated into both total lipid and individual phospholipids of turbot tissues. There was no accumulation of the Δ6-desaturation products of these fatty acids, namely 18:3(n-6) and 18:4(n-3), in any of the tissues examined. The products of elongation of 18:2(n-6) and and 18:3(n-3), 20:2(n-6) and 20:3(n-3) respectively, accumulated in both total lipid and phospholipids with the highest levels of 20:2(n-6) in liver PC and 20:3(n-3) in liver PE. Eicosapentaenoic acid [EPA, 20:5(n-3)] levels exceeded those of arachidonic acid [AA, 20:4(n-6)] in phosphatidylinositol (PI) from liver and gill of fish fed LO. EPA levels in liver PI from fish fed LO were 3-fold and 2-fold greater than SO-fed and FO-fed fish, respectively. Fish fed diets containing SO and LO had significantly reduced levels of AA in liver and muscle total lipid and lower AA in individual phospholipid classes of liver and gill compared to FO-fed fish. The concentration of thromboxane B₂ was significantly reduced in plasma and isolated gill cells stimulated with calcium ionophore A23187 of fish fed SO and LO compared to those fed FO. Prostaglandin E produced by isolated gill cells stimulated with A23187 was significantly reduced in fish fed both SO and LO compared to fish fed FO.     

高植物蛋白饲料中不同水平低分子水解鱼蛋白对大菱鲆(Scophthalmus maximus L.)幼鱼生长及肝脏IGF-I受体表达的影响

本研究利用低分子水解鱼蛋白设计了4组等氮等能的高植物蛋白饲料,研究不同水平低分子水解鱼蛋白对大菱鲆(Scophthalmus maximus L.)幼鱼[(4.16±0.01)g]生长性能、鱼体组成及肝脏中类胰岛素生长因子Ⅰ受体(Insulin-like growth factor receptor,IGF-IR)表达的影响.水解鱼蛋白分别替代总蛋白的5％(UF-5)、10％(UF-10)、20％(UF-20)的鱼粉,无添加FPH组为对照组(UF-0),用这4种饲料饲喂大菱鲆幼鱼84 d,结果显示,UF-0、UF-5和UF-10组的增重率、特定生长率无显著差异(P＞0.05),但显著高于UF-20组(P＜0.05);UF-0、UF-5组的饲料效率、蛋白质效率和蛋白质沉积率无显著差异(P＞0.05),而显著高于UF-10、UF-20组(P＜0.05);UF-0、UF-5和UF-10三组鱼体粗蛋白、粗脂肪含量无显著差异(P＞0.05),但显著高于UF-20组(P＜0.05);UF-5组必需氨基酸含量及必需氨基酸与非必需氨基酸比值显著高于其他3组(P＜0.05),其他3组间无显著差异(P＞0.05);肝脏中IGF-IR mRNA的表达随着水解鱼蛋白替代水平的增加而升高,且UF-20组与其他3组差异显著(P＜0.05).结果表明,适当添加低水平水解鱼蛋白(UF-5)可促进大菱鲆幼鱼的生长、提高饲料效率及促进肌肉必需氨基酸的积累;高水平添加低分子水解鱼蛋白(UF-20)会抑制其生长及饲料利用等;低分子水解鱼蛋白可提高大菱鲆肝脏中IGF-IR基因的表达量.