精氨酸和赖氨酸对瓦氏黄颡鱼幼鱼生长和非特异性免疫力的影响

以初始体质量(2.12±0.01) g的瓦氏黄颡鱼为研究对象,在室内流水系统中进行为期56 d的摄食生长实验,探讨饲料中精氨酸、赖氨酸水平及其交互作用对瓦氏黄颡鱼幼鱼生长和非特异性免疫力的影响。采用3×3双因子实验设计,制作9种Arg和 Lys不同配比的饲料(粗蛋白42%、粗脂肪10%),其中Arg水平为2.41%、4.86%和6.81%(饲料蛋白),在每个Arg水平分别设1.95%、5.84%和8.27%(饲料蛋白)3个Lys水平。每种饲料随机投喂3桶(养殖桶规格:40 L),每桶30尾实验鱼。实验结果表明,饲料中Arg、Lys水平对瓦氏黄颡鱼生长和头肾巨噬细胞呼吸爆发活性均有显著影响(P<0.05),当Arg/Lys为6.81/5.84(饲料蛋白)时,实验鱼生长最佳,而头肾巨噬细胞活性最高值出现在 Arg/Lys 为4.86/8.27(饲料蛋白)水平。饲料中Arg水平对瓦氏黄颡鱼血清一氧化氮合酶(NOS)活性有显著影响(P<0.05),且在适中和高Arg水平时,血清NOS活性均高于低水平Arg组。饲料中Arg、Lys水平对血清精氨酸酶(ARG)活性和过氧化氢酶(CAT)活性无显著影响(P>0.05)。饲料中Arg和Lys对瓦氏黄颡鱼的生长存在交互作用,而对体组成、肝指数、头肾巨噬细胞呼吸爆发活性、血清中NOS、ARG和CAT活性均无交互作用。     

中华绒螯蟹对赖氨酸、蛋氨酸和精氨酸的需要量

试验以酪蛋白、白鱼粉、豆粕和晶体氨基酸为蛋白源,配制了15组试验饲料,分别测定了中华绒螯蟹幼蟹对赖氨酸(Lys)、蛋氨酸(Met)和精氨酸(Arg)的需要量。养殖试验在室内玻璃纤维水族缸中进行,试验水温为(28±3.0)℃,pH为7.4左右,试验周期为56 d。试验组1～试验组5为Lys试验,试验组6～试验组10为Met试验,试验组11～试验组15为Arg试验,试验用蟹平均初重分别为:Lys试验(2.050±0.027)g,Met试验(2.027±0.033)g,Arg试验(2.05±0.032)g。每个试验设5个氨基酸梯度,其中Lys梯度为:1.58%、1.98%、2.38%、2.78%和3.18%;Met梯度为:0.50%、0.75%、1.00%、1.25%和1.50%;Arg梯度为:1.39、2.09、2.79、3.49和4.19%。每个梯度设3重复。试验结果表明,Lys试验中,试验组3(含2.38% Lys)获得最大的增重率和特定生长率,但与试验组2(1.98%Lys)和试验组4(2.78%Lys)之间没有显著性差异;且试验组3的全蟹水分含量显著较低,而蛋白质含量显著较高(P<0.05)。Met试验中,试验组8(含1.00% Met)的增重率和特定生长率显著较高(P<0.05),而其它试验组的增重率和特定生长率差异不显著(P>0.05);试验组10 全蟹水分含量显著较高,而粗蛋白含量显著较低(P<0.05)。Arg试验中,试验组14(日粮含3.49% Arg)的增重率和特定生长率显著高于其它试验组(P<0.05);而各试验组间全蟹营养组成均没有显著性差异。根据试验的生长反应和二次曲线回归分析,确定了中华绒螯蟹幼蟹饲料中最适赖氨酸、蛋氨酸和精氨酸的需要量分别为2.34%,1.12% 和 3.62%。     

不同蛋白质和小麦淀粉水平对大黄鱼生长性能、糖酵解和糖异生关键酶活性的影响

本实验旨在研究不同蛋白质和小麦淀粉水平对大黄鱼生长性能、肝脏糖酵解和糖异生关键酶活性、血清指标、糖原含量及消化酶活性的影响。采用2×3双因素实验设计,共配制6组饲料,包含2个蛋白质水平(41%、46%)和3个小麦淀粉水平(10%、20%、30%),选取初重约为(14.84±0.16) g的大黄鱼900尾,随机分为6组(每组3个重复,每个重复50尾),进行8周的养殖实验。实验结果表明:饲料蛋白质和小麦淀粉水平的交互作用对大黄鱼增重率和特定生长率无显著影响(P>0.05),且在相同的饲料蛋白质水平下,饲料小麦淀粉水平对大黄鱼增重率和特定生长率无显著影响(P>0.05)。饲料蛋白质和小麦淀粉的交互作用对大黄鱼肝脏6-磷酸果糖激酶(phosphofructokinase,PFK)、丙酮酸激酶(pyruvate kinase,PK)、果糖-1,6-二磷酸酶(fructose-1,6-bisphosphatase,FBPase)活性有显著影响(P<0.05),但对葡萄糖激酶(glucokinase,GK)、葡萄糖-6-磷酸酶(glucose-6-phosphatase,G6Pase)、磷酸烯醇式丙酮酸羧激酶(phosphoenolpyruvate,PEPCK)活性无显著影响(P>0.05)。当饲料蛋白质水平为41%时,饲料小麦淀粉水平对葡萄糖激酶、6-磷酸果糖激酶和果糖-1,6-二磷酸酶活性有显著影响(P<0.05),且果糖-1,6-二磷酸酶活性随着饲料小麦淀粉水平的升高呈下降趋势,但对丙酮酸激酶、葡萄糖-6-磷酸酶、磷酸烯醇式丙酮酸羧激酶活性无显著影响(P>0.05);当饲料蛋白质水平为46%时,饲料小麦淀粉水平对葡萄糖激酶、6-磷酸果糖激酶、丙酮酸激酶、果糖-1,6-二磷酸酶活性有显著影响(P<0.05),且葡萄糖激酶、6-磷酸果糖激酶、丙酮酸激酶均随饲料小麦淀粉水平的升高呈上升趋势,但对葡萄糖-6-磷酸酶和磷酸烯醇式丙酮酸羧激酶活性无显著影响(P>0.05)。实验表明,大黄鱼在高蛋白质水平下能够有效调节糖酵解和糖异生关键酶活性,降低血糖含量及丙氨酸转氨酶、天冬氨酸转氨酶活性,并且未显著影响增重率;在低蛋白质水平,血糖含量和肝糖原含量随小麦淀粉水平的升高呈上升趋势,但增重率随着饲料小麦淀粉水平的升高呈上升趋势,表明在低蛋白质水平下高小麦淀粉水平对大黄鱼的生长有一定的改善作用。     

盐度对大菱鲆幼鱼生长和肌肉营养成分的影响

将平均体质量为(7.16±0.07)g的大菱鲆幼鱼分别饲养在不同盐度(12、18、24、30和36)的水体中60 d,以探讨盐度对幼鱼特定生长率、生长激素、成活率、摄食率、饲料效率和肌肉营养成分的影响。结果表明:大菱鲆幼鱼在盐度分别为18、24、30和36的水体中均生长良好,成活率为100%,特定生长率分别为1.97、1.87、1.87和2.00 %/d;在盐度为12的水体中,幼鱼的成活率和特定生长率均显著低于盐度30组(对照组)(P<0.05),分别为80.77%和1.45 %/d。生长激素为0.41～1.66 ng/mL时,盐度18和36组均显著高于盐度30组(P<0.05),而盐度12组显著低于盐度30组(P<0.05)。饲料效率为1.12%～1.38%时,盐度18、24和36组均显著高于盐度30组(P<0.05),而盐度12组显著低于盐度30组(P<0.05)。摄食率为1.19～1.28 %/d时,盐度12和24组均显著低于盐度30组(P<0.05),其它盐度组之间均无显著差异(P>0.05)。幼鱼特定生长率随血清生长激素和饲料效率的升高而增大,与盐度的相关性不显著。幼鱼肌肉中的粗蛋白质含量随水体盐度的升高而降低,除盐度12和18组之间无显著性差异外(P>0.05),其余各盐度组之间均存在显著性差异(P<0.05);盐度12组幼鱼肌肉中的粗脂肪低于其它盐度组,灰分显著高于其它盐度组(P<0.05),其余各盐度组之间粗脂肪和灰分均无显著性差异(P>0.05);各盐度组之间幼鱼肌肉中的水分均无显著性差异(P>0.05)。综上所述,适当降低盐度可改善大菱鲆幼鱼生长和肌肉品质,其适宜盐度为18。     

日粮中添加鱼溶浆粉和鱼油对草鱼生长、肝脏脂肪含量和血清理化指标的影响

本实验探讨以猪肉粉为动物蛋白源的草鱼日粮中添加鱼溶浆粉和鱼油以补充鱼类所需的部分生长因子,对草鱼生长、肝脏脂肪含量和血清理化指标的影响,以期达到节约鱼粉的目的。在实用配方模式下,设计6种等氮等能饲料,分别是添加6%猪肉粉(6P)、3%猪肉粉+3%鱼溶浆粉(3P3SW)、6%鱼溶浆粉(6SW)、3%猪肉粉+3%鱼溶浆粉+2%鱼油(3P3SW2O)、6%鱼溶浆粉+2%鱼油(6SW2O)和6%鱼粉(6F,对照)。在池塘网箱中饲喂(80.0±2.0)g的草鱼72 d。结果表明,6P和6F在SGR、FCR、PRR、ERR和HSI方面均无显著差异(P>0.05)。添加鱼溶浆粉后,3P3SW、6SW与6F相比,SGR提高了9.1%～9.6%,FCR下降了8.5%～11.2%,差异显著(P<0.05),但3P3SW和6SW无显著差异(P>0.05),同时,在PRR、FRR和ERR方面,3P3SW、6SW均有一定程度提高。添加鱼油后,3P3SW2O、6SW2O和3P3SW、6SW比,SGR分别下降了9.7%、15.4%,FCR分别上升了6.9%、31.1%,除3P3SW2O和3P3SW的FCR之外,其余差异显著(P<0.05);在PRR和ERR方面,3P3SW2O、6SW2O均有一定程度下降;同时,3P3SW2O、6SW2O的FRR和肝脏粗脂肪含量都出现不同程度增高,HSI增大,血清TBA、CHOL、HDL和LDL与肝脏粗脂肪呈现出相同趋势,且上述指标均是6SW2O组最高,与其余各组均存在显著差异(P<0.05)。此外,在对饲料中游离氨基酸和生物胺与FCR和SGR的相关性分析中,发现游离Lys、Tau和Put与FCR和SGR的Pearsion相关系数都大于0.8,且符合二次函数关系。因此,鱼溶浆粉对草鱼的促生长作用优于鱼粉,在无鱼粉日粮中添加少量的鱼溶浆粉能满足草鱼需求,节约鱼粉用量,这种促生长作用与饲料中游离Lys、Tau和Put的关系密切;由于鱼油促使脂肪在体内和肝脏沉积,加重肝脏脂质代谢负担,加上其易氧化变质特性,限制了它在水产饲料中的使用。     

玉米蛋白粉替代鱼粉对大菱鲆摄食、生长及体组成的影响

以鱼粉和玉米蛋白粉作蛋白源,配制6种等氮等能的饲料。其中5种饲料(C0、C12、C25、C38和C50.5)分别含有0%、12%、25%、38%和50.5%的玉米蛋白粉以替代相应的鱼粉蛋白。其余1种饲料(C50.5CAA)是在饲料C50.5基础上补充1.8%晶体氨基酸混合物(L-lysine:1.2%,L-arg:0.6%)。经7周的生长试验,结果表明随着饲料中玉米蛋白粉替代水平的升高,大菱鲆(12.51±0.02)g的摄食率、特定生长率、饲料效率和蛋白质效率均显著下降。饲料中玉米蛋白粉含量为50.5%时,大菱鲆摄食率显著低于其他处理组(P<0.05)。当饲料中玉米蛋白粉含量超过25%时,大菱鲆特定生长率显著低于对照组(C0)(P<0.05)。当饲料中玉米蛋白粉含量超过38%时,饲料效率和蛋白质效率与对照组(C0)相比显著下降(P<0.05)。C50.5CAA组的摄食率、特定生长率和蛋白质效率与C50.5组相比都有升高的趋势,但差异不显著。而饲料中添加晶体氨基酸显著提高了大菱鲆的饲料效率(P<0.05)。饲料中玉米蛋白粉替代鱼粉对大菱鲆鱼体水分、粗蛋白、粗脂肪及灰分含量均无显著影响。饲料中玉米蛋白粉替代鱼粉对大菱鲆血清甘油三酯和尿素氮含量也不产生显著影响,然而,随着饲料中玉米蛋白粉含量升高,血清总胆固醇含量显著下降(P<0.05)。     

饲料中有效磷对吉富罗非鱼生长、体组成及生化指标的影响

为探讨饲料中不同有效磷水平对吉富罗非鱼幼鱼生长、体组成及生化指标的影响,以磷酸二氢钙(MCP)为磷源,配制含有效磷(AP)水平分别为0.52%(对照组)、0.61%、0.70%、0.78%、0.87%、0.96%和1.05%的7种等氮等能实用饲料,饲喂初始均重为(29.40±0.15)g的实验鱼。每种饲料设置3个重复,每个重复放25尾鱼,进行56 d的养殖实验。结果表明:饲料AP水平对罗非鱼的增重率(WGR)、特定生长率(SGR)、饲料系数(FCR)和脏体比(VSI)均有显著影响(P<0.05)。以WGR为评价指标,通过二次回归分析得出,罗非鱼饲料的适宜AP水平为0.80%。随饲料AP水平的增加,罗非鱼全鱼总磷和灰分含量显著增加并达到稳定(P<0.05),而全鱼水分含量差异不显著(P>0.05),全鱼和肠系膜、肝脏组织脂肪含量均显著下降(P<0.05)。用折线模型分析全鱼磷和灰分含量,得出罗非鱼幼鱼对饲料AP的需求量分别为0.81%和0.80%。随饲料AP水平的增加,肝脏苹果酸脱氢酶(MDH)、丙酮酸激酶(PK)、脂蛋白脂酶(LPL)和肝酯酶(HL)活性均显著增加(P<0.05)。血清谷丙转氨酶(GPT)活性显著下降(P<0.05),而碱性磷酸酶(AKP)活性显著上升(P<0.05),血清超氧化物歧化酶(SOD)活性呈先升后降趋势,在0.78%水平组达到最大值,而肝脏丙二醛(MDA)含量正好相反,在0.78%水平组最低。综上所述,研究结果表明:吉富罗非鱼(30~150 g)实用饲料的最适有效磷水平为0.80%。     

饲料中添加核苷酸对凡纳滨对虾幼虾生长、组织生化组成及非特异性免疫功能的影响

选用960尾初始体重为(0.43?0.01) g 的凡纳滨对虾,随机分为8组,分别投喂基础饲料和7种添加核苷酸混合物(mix-NT)的试验饲料,5种核苷酸(5′-腺苷酸∶5′-胞苷酸∶5′-尿苷酸二钠∶5′-肌苷酸二钠∶5′-鸟苷酸二钠)按照质量比为1∶1∶1∶1∶1(W/W)混合,添加量分别为0.1、0.2、0.4、0.6、0.8、1.0和1.2 g/kg 饲料,试验周期为5周。结果显示,当mixNT添加量为0.4 g/kg饲料时,凡纳滨对虾的增重率(WGR)、特定生长率(SGR)和摄食量(FI)显著高于对照组(P<0.05),饲料系数(FCR)比对照组降低5.5%(P>0.05)。0.6和1.0 g/kg mix-NT添加组的蛋白质沉积率(PDR)显著高于对照组(P<0.05)。试验组对虾存活率(SR)和肝胰指数(HSI)均不同程度的高于对照组,但差异不显著(P>0.05)。饲料中添加mix-NT对全虾粗脂肪、灰分含量的影响显著(P<0.05),各mix-NT添加组的全虾干物质和粗蛋白含量均高于对照组,但差异未达到显著水平(P>0.05)。肝胰腺RNA含量和总蛋白(TP)含量均随饲料中mix-NT添加量的增加而升高,其中0.2~1.0 g/kg组的肝胰腺RNA含量显著高于对照组(P<0.05),TP含量差异未达到显著水平(P>0.05);各mixNT添加组的肠道TP含量均显著高于对照组(P<0.05),0.4和0.6 g/kg组的肠道RNA量极显著高于对照组(P<0.01)。外源mix-NT显著降低血清尿酸(UA)含量(P<0.05),但对TP、谷丙转氨酶(GPT)、高密度脂蛋白(HDL)含量无显著影响(P>0.05)。当mix-NT添加量为1.2 g/kg 饲料时,血清中谷草转氨酶(GOt)活性显著性升高(P<0.05)。鳃和肌肉酚氧化酶(PO)活性均在0.4 g/kg组达到最大,其中0.1～0.6 g/kg 组的鳃PO活性显著高于对照组(P<0.05),而各组肌肉PO活性无显著差异(P>0.05)。凡纳滨对虾肝胰腺和血清中溶菌酶(LZM)活性随饲料中mix-NT添加量的增加而显著升高(P<0.05)。结果表明,饲料中添加一定量的5种核苷酸混合物能显著提高凡纳滨对虾幼虾的增重率、特定生长率、摄食量、蛋白质沉积率、全虾粗脂肪和灰分含量,一定程度提高全虾粗蛋白和肝胰腺总蛋白含量,显著增加肝胰腺RNA、肠道总蛋白和RNA含量,提高对虾的非特异性免疫功能。     

凡纳滨对虾对饲料中钙、磷的营养需求

水温28~31℃,盐度21~24,养殖凡纳滨对虾幼虾,投喂以乳酸钙为钙源、磷酸二氢钠为磷源,在钙添加水平为0%、0.5%、1.0%的条件下,分别添加0%、0.4%、0.8%、1.2%、1.6%的磷配制的15种饲料,探讨凡纳滨对虾饲料中钙、磷的适宜添加量。8周的养殖试验结果显示,饲料钙、磷水平及钙、磷水平的交互作用极显著影响对虾质量增加率、特定生长率、蛋白质效率、饲料系数和存活率(P<0.01)。饲料钙、磷水平极显著影响对虾肌肉粗蛋白、粗脂肪和全虾粗蛋白的含量(P<0.01)。饲料钙、磷水平的交互作用极显著影响全虾粗蛋白和肌肉粗蛋白、粗脂肪的含量(P<0.01)。饲料钙水平极显著影响全虾和虾壳的钙、磷含量及肌肉磷含量(P<0.01),显著影响对虾肌肉钙含量(P<0.05)。饲料磷水平及钙、磷水平的交互作用极显著影响全虾、肌肉、虾壳的钙、磷含量(P<0.01)。饲料钙、磷水平及钙、磷水平的交互作用均不显著影响血清钙离子含量(P>0.05)。在本试验条件下,以特定生长率为判断依据,通过折线模型分析得出,饲料中添加0.5%的钙和0.88%的磷时凡纳滨对虾的特定生长率最高。     

蜡样芽孢杆菌YB1对大菱鲆幼鱼生长性能、肠道消化酶、肝脏抗氧化酶及肠道组织结构的影响

为探究在饲料中添加蜡样芽胞杆菌(Bacillus cereus) YB1对大菱鲆(Scophthalmus maximus)幼鱼生长性能、肠道消化酶活力和肝脏抗氧化酶活力以及肠道组织结构的影响,本研究选取720尾初始体质量为(3.6±0.7) g的大菱鲆幼鱼,随机分为4组,每组3个平行,每个平行60尾。4组大菱鲆幼鱼在投喂的饲料中分别添加活菌量为0 (对照)、105、106和107 CFU/g的YB1,养殖期为50 d。结果显示,YB1添加量为107 CFU/g时,大菱鲆幼鱼的增重率(WGR)和特定生长率(SGR)显著高于对照组(P<0.05)。YB1添加量为106 CFU/g组的大菱鲆幼鱼肠道蛋白酶和淀粉酶活力分别提高了57.86%和82.37%,显著高于对照组(P<0.05);YB1添加量提高到107 CFU/g时,脂肪酶的含量显著高于对照组(P<0.05)。饲料中添加YB1对大菱鲆幼鱼肝脏过氧化氢酶活力无显著性影响(P>0.05);YB1添加量为106 CFU/g组的幼鱼肝脏丙二醛含量下降了42.03%,显著低于对照组(P<0.05);实验组大菱鲆幼鱼肝脏超氧化物歧化酶活力相较于对照组有上升的趋势,差异不显著(P>0.05)。YB1添加量为106 CFU/g组的大菱鲆幼鱼肠道肌层厚度增加最为显著(P<0.05),与对照组相比在实验末期提高了68.91%。研究表明,饲料中添加适量蜡样芽胞杆菌YB1具有促进大菱鲆幼鱼生长、提高幼鱼肠道消化酶和肝脏抗氧化酶活力以及改善幼鱼肠道组织结构的作用,推荐添加量为106 CFU/g。     

大豆浓缩蛋白替代鱼粉对大菱鲆摄食、生长及体组成的影响

研究了大豆浓缩蛋白(SPC)替代鱼粉对大菱鲆生长及生理生化指标的影响。5种饲料分别含有0、12.0%、25.0%、37.0%和49.5%的SPC以替代相应的鱼粉,并分别添加0、0.83%、1.65%、2.48%和3.30%的必需氨基酸混合物(L-lysine∶DL-methionine∶L-leucine∶Lvaline∶L-threonine=18∶6∶3∶2.5∶2)以平衡各组饲料的氨基酸组成。每种饲料投喂3个水族箱(300 L),每个水族箱放养实验鱼16尾,实验鱼初始体质量为(31.1±0.1)g。经过9周生长实验,结果显示随着饲料中SPC替代水平的升高,大菱鲆摄食率、特定生长率均显著下降(P0.001)。然而,当使用0~37.0%的SPC替代鱼粉时,各处理组饲料效率和蛋白质效率未出现显著差异(P0.05)。饲料中SPC替代鱼粉对大菱鲆鱼体水分、粗蛋白、粗脂肪及灰分含量均无显著影响(P0.05)。各处理组干物质和粗蛋白的表观消化率之间也未出现显著差异(P0.05)。研究表明,在本实验条件下SPC不能作为大菱鲆饲料中替代鱼粉的有效蛋白源,造成SPC替代效果较差的主要原因是其对大菱鲆饲料适口性的显著影响。     

Effects of Dietary Lysine Levels on Growth,Intestinal Digestive Enzymes,and Coelomic Fluid Nonspecific Immune Enzymes of Sea Cucumber,Apostichopus japonicus,Juveniles

A 56‐d feeding trial was conducted to evaluate the effects of dietary lysine levels on growth performance, intestinal digestive enzymes, and nonspecific immune response of Apostichopus japonicus juveniles. Five semipurified diets were formulated to contain graded levels of lysine (from 0.28 to 2.32% of dry matter). Although no significant differences (P > 0.05) were observed in survival rate, final weight (FW), and body weight gain (BWG), the FW and BWG increased from 0.28 to 1.19% with increasing dietary lysine levels, then showed a declining tendency. Broken‐line regression analysis of BWG indicated sea cucumber requires lysine at 0.76% of dry diet. Proximate composition, lysine content of the body wall, and total amino acid profiles were not affected by dietary treatments. Intestinal protease level increased with increasing dietary lysine level from 0.28 to 1.19%, then decreased. Acid phosphatase and superoxide dismutase activities of the sea cucumbers were not affected by various dietary lysine levels; however, significantly (P < 0.05) higher alkaline phosphatase activity was observed in sea cucumbers fed 2.32% lysine diet than those fed diets having 0.28 and 1.89% lysine. Overall, sea cucumber juveniles fed with diets containing between 0.76 and 1.19% lysine showed better growth performance, digestive enzymes, and nonspecific immune enzyme activities.     

Interactions among dietary minerals,arginine and lysine in rainbow trout (Salmo gairdneri)

Studies were conducted to determine whether interactions occur among dietary lysine, arginine and monovalent minerals in rainbow trout. In one experiment, rainbow trout fingerlings were fed diets containing three levels of lysine (2.4, 3.1 and 3.8 g per 100 g diet), two levels of arginine (1.7 and 2.5 g per 100 g diet) and two mixtures of Na⁺ K⁺ and Cl in a 3×2×2 factorial design. The mixtures varied in the proportions of cations to anions such that Cl equalled the sum of Na⁺ and K⁺ (cations – anions = 0 mEq/kg diet) in one mixture and exceeded the sum of Na⁺ and K⁺ (cations – anions = –200 mEq/kg diet) in the second mixture. Growth and efficiency of feed conversion were not affected by dietary lysine and arginine in fish fed diets containing – 200 mEq/kg balance, but when fish were fed diets containing a 0 mEq/kg balance, 3.8% lysine and a combination of 3.1% lysine and 2.5% arginine depressed both measures of response. Trout receiving the 0 mEq/kg cation-anion balance had significantly higher free histidine concentrations and lower free lysine concentrations in muscle and higher hepatic arginase activity (P0.01) than those receiving –200 mEq/kg. In another experiment, trout were fed diets containing three levels of K⁺ (21, 191 and 360 mEq/kg), two levels of Na⁺ (21 and 191 mEq/kg) and two levels of Cl^– (179 and 347 mEq/kg) in a 3×2×2 factorial design. Growth and efficiency of feed conversion were depressed and hepatosomatic index increased with higher levels of dietary K⁺ (P0.01), Na⁺ (P0.05) and Cl (P0.01), with significant K⁺ x Cl⁺ (P0.01) and K⁺ x Na⁺ x Cl (P0.05) interactions. Increasing dietary K⁺ resulted in increased levels of muscle free histidine and decreased levels of muscle free lysine and arginine (P0.01), while increasing dietary Cl increased muscle free lysine, the effect of which was dependent on dietary potassium (K⁺ x Cl^–, P0.01). It is concluded that dietary levels of K⁺, Na⁺ and Cl^–, irrespective of overall cation-anion balance of these minerals, affects growth rate, efficiency of feed utilization and the metabolism of basic amino acids in tissues of trout. Excess lysine causes depressed growth and efficiency of feed utilization. These effects were due to a lysine toxicity rather than a lysine-arginine antagonism, as they were not prevented by supplemental dietary arginine.     

Effect of dietary lysine on growth,intestinal enzymes activities and antioxidant status of sub-adult grass carp (Ctenopharyngodon idella)

The dietary lysine requirement of sub-adult grass carp (460 ± 1.5 g) was assessed by feeding diets supplemented with grade levels of lysine (6.6, 8.5, 10.8, 12.9, 15.0 and 16.7 g kg^?1 diet) for 56 days. The test diets (28 % CP) contained fish meal, casein and gelatin as sources of intact protein, supplemented with crystalline amino acids. Weight gain (WG), feed intake and feed efficiency were significantly improved with increasing levels of lysine up to 12.9 g kg^?1 diet and thereafter declined (P < 0.05). Quadratic regression analysis of WG at 95 % maximum response indicated lysine requirement was 10.9 g kg^?1 diet. Activities of trypsin, chymotrypsin, lipase, Na⁺, K⁺-ATPase and alkaline phosphatase in intestine, creatine kinase activity in proximal and mid-intestine responded similar to WG (P < 0.05). In addition, lipid and protein oxidation decreased with increasing levels of lysine up to certain values and increased thereafter (P < 0.05); the anti-hydroxyl radical capacity, dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase (GST) activities and glutathione content were increased with increasing dietary lysine levels up to certain values in the detected tissues, except for hepatopancreatic GST. Requirement estimated on the basis of malondialdehyde content in intestine and hepatopancreas was 10.6 and 9.53 g lysine kg^?1 diet, respectively.     

Effect of dietary protein and lipid levels on growth and body composition of juvenile turbot (Scophthalmus maximus L) reared under optimum salinity and temperature conditions

Effect of dietary protein and lipid levels on growth and body composition of juvenile turbot was determined at optimum salinity and temperature conditions of 17 g L^?1 and 19.2 °C, respectively, by using 3 × 2 (protein levels: 550, 600 and 650 g kg^?1; lipid levels: 69 and 168 g kg^?1) factorial design with three replications of each. Fish were hand‐fed to satiety twice daily throughout the feeding trial. Weight gain and specific growth rate of fish were significantly (P < 0.05) increased with increased dietary lipid level, but not by dietary protein level. Daily feed intake was significantly (P < 0.05) affected by both dietary protein and lipid levels. Feed efficiency ratio and protein efficiency ratio were significantly (P < 0.05) affected by dietary lipid level, but not by dietary protein level. Moisture content of whole body was significantly (P < 0.05) affected by dietary lipid level, but not by dietary protein level. Crude lipid content of whole body was significantly (P < 0.05) affected by dietary lipid level, but not by dietary protein level. Significantly higher 20:5n?3, 22:6n?3 and n?3 highly unsaturated fatty acids were observed in turbot fed the low lipid diet than fish fed the high lipid diet in all protein levels, but significantly lower 18:2n?6 was observed in fish fed the former compared with the latter. In considering results of growth, specific growth rate and efficiency of feed, optimum dietary protein and lipid levels for juvenile turbot seemed to be 550 and 168 g kg^?1 of the diet, respectively, under optimum salinity and temperature conditions.     

饲料中添加精氨酸对仿刺参幼参生长、免疫能力及消化酶活力的影响

为研究精氨酸对仿刺参幼参生长、免疫能力及消化酶活力的影响,在基础饲料中添加0、1.00%、2.00%、3.00%和4.00%的包膜精氨酸(精氨酸含量为40%),配制精氨酸含量为0.32%、0.73%、1.16%、1.61%和1.99%的5种实验饲料(命名为D1,D2,D3,D4和D5),饲喂初始体质量9.10 g的仿刺参幼参60 d。结果表明,精氨酸显著提高了仿刺参的增重率、特定生长率和蛋白质效率,且在D4组达到最高;D3、D4和D5组仿刺参的脏壁比、肠壁比及肠长比显著低于D1和D2组,但3组之间差异不显著;精氨酸显著提高了体壁粗蛋白的沉积,但对水分及粗脂肪含量影响不显著;精氨酸显著提高了体壁谷氨酸、精氨酸、亮氨酸、组氨酸、羟脯氨酸、必需氨基酸及总氨基酸的含量,降低了赖氨酸含量;体腔液中总超氧化物歧化酶(T-SOD)、总抗氧化能力(T-AOC)、一氧化氮(NO)、一氧化氮合成酶(NOS)、碱性磷酸酶(AKP)、谷丙转氨酶(ALT)及谷草转氨酶(AST)活力随着精氨酸含量的增加而显著提高;肠道蛋白酶活力与饲料精氨酸含量呈二次负相关关系(Y酶活=-3.228X2精氨酸+2.865X精氨酸+26.24,R2=0.934),D3、D4和D5组纤维素酶活力显著高于D1和D2组,淀粉酶及脂肪酶活力不受精氨酸含量的影响。以增重率为评价指标,一元二次回归分析表明,体质量9.10 g的仿刺参饲料中精氨酸适宜含量为1.55%(7.10%饲料粗蛋白)。     

亚麻籽油替代鱼油对大菱鲆幼鱼生长、脂肪酸组成及脂肪沉积的影响

为研究亚麻籽油替代不同鱼油水平对大菱鲆幼鱼[初始体质量为(5.89±0.02)g]生长、脂肪酸组成以及肝脏和肌肉脂肪沉积的影响,以亚麻籽油分别替代0、33.3%、66.7%和100%鱼油,配制4种等氮等脂饲料。每组饲料随机投喂3组实验鱼,饱食投喂,养殖周期为92 d。结果发现,饲料亚麻籽油水平并未显著影响大菱鲆幼鱼存活率(SR)和特定生长率(SGR),但显著影响其摄食率(FI)、饲料效率(FE)和表观净蛋白利用率(ANPU)。随饲料亚麻籽油水平升高,FI显著升高,而FE和ANPU显著下降,且其均在100%亚麻籽油组分别达到最大值或最小值。饲料亚麻籽油水平并未显著影响大菱鲆饲料脂肪表观消化率、肝体比和肌肉脂肪含量。当饲料中亚麻籽油替代100%鱼油,鱼体肝脏脂肪含量显著高于全鱼油组。肝脏和肌肉脂肪酸组成与饲料脂肪酸组成相似。相对于全鱼油组,亚麻籽油替代组肌肉和肝脏中亚油酸和亚麻酸显著升高,而EPA和DHA含量显著下降。研究表明,大菱鲆饲料中亚麻籽油替代水平应低于66.7%,且大菱鲆饲料中n-3长链多不饱和脂肪酸含量需大于0.8%。     

Comparison of the bioavailability of lysine in blood meals of various origins to that of l-lysine HCL for rainbow trout (Oncorhynchus mykiss)

The bioavailability of lysine in blood meals from various origins was examined in rainbow trout. Bioavailability of lysine of the blood meals was assessed in comparison to that of l-lysine HCL using a slope ratio assay experimental design. A corn gluten meal-based diet, deficient in lysine (1.5% diet), was used as the basal diet. Two levels of spray-dried poultry blood meal (SDBM), flash-dried bovine blood meal (FDBM), disc-dried poultry blood meal (DDBM), and lysine-HCL substituted corn gluten meal in the basal diet to produce experimental diets containing 1.8 or 2.2% lysine. These diets were pair-fed to rainbow trout (initial body weight = 25 g/fish) reared at 15 °C for 12 weeks. Weight gain, feed efficiency ratio (FER, gain: feed), retained nitrogen (RN), and recovered energy (RE) increased significantly (P < 0.05) with increasing lysine levels. Diets containing SDBM and FDBM recorded significantly greater weight gain, FER, RN and RE compared to DDBM (P < 0.05). At the 1.8% lysine level, the diet containing FDBM recorded significantly greater weight gain, and RN than the diet supplemented with l-lysine HCl. The weight gain, FER and RN of the fish fed diets containing SDBM was not significantly different from that of the fish fed the diets with l-lysine HCl, at both lysine levels. At the 2.2% lysine level, feeding diets containing FDBM and DDBM resulted in significantly lower weight gain than diet supplemented with l-lysine HCl, suggesting that other nutrients may have become more limiting than lysine at high levels (20%) of blood meal. Results suggest that the bioavailability of lysine in SDBM or FDBM is slightly greater than that of l-lysine HCL. Bioavailability of lysine in the DDBM used in this study appeared to be significantly lower than that of spray-dried or flash-dried blood meals.     

Dietary Arginine Requirement of Fingerling Indian Major Carp,Catla catla (Hamilton)

Dietary arginine requirement of fingerling Catla catla (3.55 ± 0.05 cm; 0.61 ± 0.02 g) was determined by feeding casein–gelatin‐based isonitrogenous (33% crude protein) and isocaloric (3.40 kcal/g digestible energy) amino acid test diets containing six graded levels of l ‐arginine (1, 1.25, 1.5, 1.75, 2, and 2.25% dry diet) for 12 wk. Maximum absolute weight gain (6.93 g/fish), protein efficiency ratio (2.13), protein deposition (0.36), arginine retention efficiency (78%), and best feed conversion ratio (1.42) were recorded in fish fed 1.75% arginine of the dry diet. Maximum carcass protein (15.57%) and RNA/DNA ratio (4.79) were also recorded for the group fed 1.75% arginine of the dry diet. Quadratic regression analysis at 95% maximum or minimum response of above growth parameters yielded optimum arginine requirement of fingerling C. catla at 1.67% of the dry diet. On the basis of the above analysis of the growth parameters, it is recommended that the inclusion of dietary arginine at 1.67% of the dry diet is optimum for formulating arginine‐balanced, cost‐effective quality feeds for the mass culture of fingerling C. catla .     

Effects of dietary arginine and lysine levels on growth performance and biochemical parameters of juvenile Japanese flounder Paralichthys olivaceus

ABSTRACT: To investigate the effects of disproportionate levels of dietary arginine and lysine on juvenile Japanese flounder Paralichthys olivaceus , growth performance and biochemical parameters were evaluated by feeding five test diets, comprising different levels of arginine and lysine, to triplicate groups of juveniles (initial bodyweight 1.85 g) for 40 days. Crystalline amino acids were supplemented to test diets to correspond to the amino acid pattern found in the whole body protein of the Japanese flounder, except for arginine and lysine. After the feeding trials, plasma arginine, lysine and urea levels, excreted ammonia-N, and liver arginase activity were analysed. Survival, specific growth rate, feed conversion efficiency, and apparent protein retention were adversely affected ( P  <   0.05) by the deficiency in dietary arginine or lysine concentrations. An excess of either lysine or arginine in the diet did not depress growth when the diets contained adequate levels of either arginine or lysine, proving that there is no evidence for an arginine–lysine antagonism. Results for plasma arginine, lysine and urea levels, excreted ammonia, and liver arginase activity also demonstrated that Japanese flounder juveniles are not sensitive to excess dietary levels of lysine and arginine.