紫花苜蓿浓缩叶蛋白替代鱼粉对星斑川鲽幼鱼生长、体组成及血液生化指标的影响

研究了紫花苜蓿浓缩叶蛋白替代0%(S0)、10%(S10)、20%(S20)、30%(S30)、40%(S40)、50%(S50)的鱼粉蛋白对星斑川鲽(Platichthys stellatus)幼鱼生长、体组成及血液生化指标的影响。实验幼鱼体质量(83.0±0.20)g。结果显示:1)当替代比例≤20%时,各组间星斑川鲽幼鱼特定生长率(SGR)、日摄食率(DFI)、饲料效率(FE)和蛋白质效率(PER)均无显著变化,高于此值时呈显著下降(P<0.05)。随饲料中紫花苜蓿浓缩叶蛋白替代鱼粉比例的升高,鱼体肥满度(CF)呈显著下降趋势(P<0.05),而消化道指数(DTI)则呈显著上升趋势(P<0.05);各实验组干物质、蛋白质及脂肪表观消化率均呈直线下降趋势(P<0.05)。以星斑川鲽幼鱼特定生长率(SGR)为参考指标,采用折线回归分析得出,在本实验条件下,星斑川鲽幼鱼获得最佳生长时紫花苜蓿浓缩叶蛋白替代鱼粉蛋白的适宜比例为19.0%。2)紫花苜蓿浓缩叶蛋白替代鱼粉对星斑川鲽幼鱼肌肉水分、蛋白及粗灰分含量未产生显著性影响,肌肉脂肪含量仅S40组显著低于S0和S20组,其他各组间无显著差异;当替代比例小于20%时,肝脏水分呈显著上升趋势(P<0.05),之后趋于平稳(P>0.05)。肝脏粗脂肪变化趋势与此相反。肝脏粗蛋白含量仅表现为S30、S50组显著高于S0组(P<0.05),其他各组无显著差异(P>0.05)。肝脏粗灰分含量不受饲料鱼粉替代比例的影响(P>0.05);全鱼水分呈显著上升趋势(P<0.05),而粗脂肪含量呈显著下降(P<0.05)。S30组全鱼粗蛋白最高,S40组最低(P>0.05),除S30组外,其他各组均与S0组间无显著性差异(P>0.05)。各组间全鱼粗灰分含量变化不显著(P>0.05)。3)当替代比例>20%时,星斑川鲽幼鱼血浆甘油三酯(TG)含量呈显著降低。各组间胆固醇(CHO)含量随紫花苜蓿浓缩叶蛋白的添加呈直线下降趋势(P<0.05)。当替代比例≥20%时,碱性磷酸酶(ALP)活性有下降趋势(P<0.05)。当替代比例分别大于20%和40%时,谷草转氨酶(AST)和谷丙转氨酶(ALT)活性显著升高但各组间差异不显著(P>0.05)。实验鱼血浆溶菌酶(LSZ)活力随鱼粉替代比例的升高呈显著上升(P<0.05)。各实验组间血浆丙二醛(MDA)含量无显著差异,但均低于S0组(P<0.05),超氧化物歧化酶(SOD)活性不受紫花苜蓿浓缩叶蛋白替代鱼粉比例的影响(P>0.05)。结论认为,在本实验条件下,星斑川鲽幼鱼获得最佳生长时紫花苜蓿浓缩叶蛋白替代鱼粉蛋白的适宜比例为19.0%。     

大豆浓缩蛋白替代鱼粉对大黄鱼幼鱼生长、体成分、血清生化指标及肝组织学的影响

为探索大豆浓缩蛋白(SPC)替代鱼粉水平对大黄鱼(Larimichthys crocea)幼鱼生长、体成分和血清生化指标以及肝组织学的影响。以初始体重为(10.50±0.04)g的大黄鱼幼鱼为研究对象,用SPC替代基础饲料(含40%鱼粉)0%(FM)、25%(R25)、50%(R50)、75%(R75)、100%(R100)的鱼粉制作成5种等氮(粗蛋白水平为45%)等脂(粗脂肪水平为10%)的实验饲料。各实验组以对照组(FM)饲料蛋氨酸、赖氨酸含量为基准,分别添加适量的晶体赖氨酸和蛋氨酸。养殖实验在浙江省象山县西沪港区进行,每个处理随机分配3个网箱(1.5 m×1.5 m×2 m),每个网箱放养60尾,养殖周期为56 d。结果表明,与对照组相比(FM),SPC替代鱼粉水平对大黄鱼幼鱼的增重率(WGR)、特定生长率(SGR)、存活率(SR)以及饲料系数(FCR)没有显著影响(P0.05);肌肉粗蛋白和全鱼粗蛋白无显著差异(P0.05),肌肉粗脂肪和全鱼粗脂肪含量随替代比例的增加有下降的趋势,均以R100组含量最低,肌肉水分含量和全鱼水分有上升的趋势;血清各项指标没有显著性差异,但血清总蛋白(TP)、白蛋白(ALB)含量有下降趋势,以R100组含量最低;血清胆固醇(CHOL)、甘油三酯(TG)的含量呈现出先升高后下降的趋势。从肝组织学观察中发现,SPC替代水平超过75%会对肝细胞产生损伤,引起肝细胞空泡化,脂肪堆积加重,肝细胞核逐渐溶解或缺失。综上所述,在本研究条件下,SPC替代饲料75%的鱼粉,不会对大黄鱼幼鱼的生长造成负面影响。     

饲料中糖/脂肪比对暗纹东方鲀幼鱼生长、血液指标、肝代谢酶活性及PEPCK基因表达的影响

配制6种不同糖/脂肪比例（CHO∶L分别为4.29、2.79、1.86、1.19、0.73和0.41）的等氮等能饲料,饲养暗纹东方鲀幼鱼[初始体重为(11.2 ± 0.5) g] 60 d,探讨饲料中糖与脂肪比例对其生长、饲料利用、生理生化指标和PEPCK基因表达的影响。试验结果表明：随饲料中CHO∶L降低,暗纹东方鲀特定生长率（SGR）、蛋白质效率（PER）和饲料效率（FE）先升高后降低,且均在CHO∶L为1.86时达最大,显著高于CHO∶L为0.41、0.73和4.29时的值(P<0.05)。血浆甘油三酯和肝脏脂肪含量随CHO∶L降低而显著增加(P<0.05),而血糖和肝糖原含量随CHO∶L降低而显著降低(P<0.05)。随饲料中CHO∶L降低,肝脏脂肪酶和脂肪合成酶活性先增加后降低,分别在CHO∶L为1.19和1.86时活性最高。CHO∶L为1.86-4.29时PK活性显著高于其他饲料组(P<0.05)。CHO：L为0.41和0.73时,AMS活性显著低于其他饲料组(P<0.05),而PEPCK活性和mRNA相对表达量显著高于其他饲料组(P<0.05)。饲料中CHO∶L对暗纹东方鲀存活率和血浆总胆固醇含量无显著影响(P>0.05)。分别用二次多项回归模型拟合SGR、PER、FE和CHO∶L的关系,得到暗纹东方鲀幼鱼饲料中CHO∶L的适宜范围为2.01~2.16,且其对碳水化合物的利用能力要高于脂肪。     

三种肉骨粉替代鱼粉对乌鳢幼鱼生长的影响

用澳大利亚、乌拉圭和国产肉骨粉替代30%的鱼粉蛋白,配制成4种等氮(粗蛋白质含量45%)、等能(16.5 kJ/g)的饲料(D1—D4,其中,D1不含肉骨粉为对照组),在池塘网箱中饲养体质量(13.31±0.11)g的乌鳢(Ophiocephalus argus)幼鱼8周,研究了不同来源肉骨粉对乌鳢幼鱼生长的影响。结果表明,D1组乌鳢的特定生长率(SGR)显著高于D3和D4组(P<0.05),但与D2组差异不显著(P>0.05),D4组的SGR最低。D3与D4组饲料系数(FCR)差异不显著(P>0.05),但两者显著高于D1与D2组(P<0.05)。蛋白质效率(PER)的变化趋势与FCR相反。各组乌鳢的肥满度、脏体比和肝体比差异不显著(P>0.05)。在本实验条件下,澳大利亚肉骨粉对乌鳢幼鱼的饲喂效果优于乌拉圭和国产肉骨粉。     

蛹肽蛋白替代鱼粉对大菱鲆(Scophthalmus maximus L.)幼鱼生长、饲料利用、消化代谢酶及免疫性能的影响

选取蛹肽蛋白分别替代大菱鲆幼鱼配合饲料中0、15%、30%、45%、60%、75%的鱼粉,配制成6种等氮等能的饲料饲喂大菱鲆幼鱼(19.84±0.04 g)56 d,以研究蛹肽蛋白替代鱼粉的效果。结果显示,大菱鲆幼鱼的特定生长率、饲料效率随替代水平的升高而降低,30%及以上替代组显著低于对照组(P<0.05);鱼体粗蛋白、粗脂肪水平随替代水平的升高而降低,分别在75%和30%及以上替代组显著降低,鱼体水分和灰分含量随替代的升高而升高,分别在75%和30%及以上替代组显著升高(P<0.05)。摄食率随替代水平升高呈先上升后下降的趋势,在30%替代组呈现出最高的摄食率,且显著高于对照组(P<0.05)。饲料干物质的表观消化率在42.53%-54.36%之间,且当替代水平达到75%时显著低于对照组(P<0.05);而蛋白质表观消化率在71.67%-86.89%之间,仅45%和75%替代组显著低于对照组(P<0.05)。各替代组肝脏超氧化物歧化酶活性均高于对照组,在45%和60%替代组出现显著性差异(P<0.05)。综上所述,蛹肽蛋白可以替代大菱鲆幼鱼饲料中15%的鱼粉而不影响其生长摄食、饲料利用以及与消化、代谢、免疫相关的酶的活性。     

核糖蛋白替代鱼粉对大菱鲆幼鱼生长性能、肠道消化酶活性、免疫能力及血清生化指标影响

本研究旨在评价核糖蛋白替代大菱鲆(Scophthalmus maximus)饲料中鱼粉的潜力。采用单因素实验设计,设6个鱼粉替代水平。对照饲料(D1)中鱼粉含量为45%,通过添加核糖蛋白替代D1组饲料中鱼粉的0.5%(D2)、1%(D3)、2%(D4)、3%(D5)和4%(D6)。实验期间,每天分2次按饱食量投喂初始体重为(24.00±0.30)g大菱鲆幼鱼56 d。结果显示,幼鱼增重率、特定生长率、蛋白质效率随着核糖蛋白替代水平的变化呈先上升后下降趋势,均在D3组达到最高值,显著高于D5和D6组(P<0.05);饲料系数则呈相反趋势,在D3组达到最低值,显著低于D6组(P<0.05)。各替代组幼鱼血清胰岛素生长因子(IGF-1)和生长激素(GH)含量均显著低于对照组(P<0.05);核糖蛋白替代1%~3%的鱼粉后,显著提高了幼鱼肠道胰蛋白酶活性(P<0.05);幼鱼肠道α-淀粉酶活性在D4和D5组显著高于对照组(P<0.05);饲料中添加核糖蛋白替代鱼粉显著降低了幼鱼肠道脂肪酶活性(P<0.05)。各替代组幼鱼血清总蛋白、球蛋白含量和碱性磷酸酶活性均显著高于对照组(P<0.05);D3组溶菌酶活性显著高于D6组(P<0.05);各组间幼鱼血清白蛋白含量和超氧化物歧化酶活性无显著差异(P>0.05),但各替代组均显著提高了幼鱼血清白介素β1(IL-1β)和肿瘤坏死因子(TNF-α)含量(P<0.05);与对照组相比,D4~D6组血清总胆固醇和甘油三酯含量显著降低(P<0.05),低密度脂蛋白在D5和D6组显著降低(P<0.05);高密度脂蛋白在D4组显著升高(P<0.05)。血糖浓度呈先升高后降低的趋势,D3组显著高于对照组(P<0.05)。攻毒实验结果显示,D2组大菱鲆幼鱼48 h累积死亡率最低为56.45%。研究表明,饲料中添加核糖蛋白替代1%鱼粉时,大菱鲆幼鱼生长、消化酶活力及鱼体的免疫能力和抗细菌感染能力均达到最高。     

小麦蛋白替代鱼粉及大豆蛋白对日本黄姑鱼(Nibea japonica)和黑鲷(Sparus macrocephalus)血清生化指标及肝脏抗氧化指标的影响

本研究通过在低鱼粉型膨化饲料中添加不同比例的混合型小麦蛋白(GWT,由小麦蛋白、低筋面粉和牛磺酸分别以77.5%、20.5%和2.0%的比例混合而成),逐步替代饲料中低温干燥鱼粉(LT-FM)或大豆浓缩蛋白(SPC),饲喂日本黄姑鱼(Nibea japonica)[初始体重为(12.83±0.91)g]和黑鲷(Sparus macrocephalus)幼鱼[初始体重为(15.40±0.02)g]59 d,研究其对2种鱼类血清生化指标和肝脏抗氧化指标的影响。本研究配制8种等氮、等能饲料(粗蛋白:44.1%–45.6%、总能:21.5–22.0 MJ/kg),其中,对照组饲料以LT-FM(20.0%)和SPC(21.4%)为主蛋白源,6种实验饲料以GWT分别替代对照组饲料中33.3%、66.7%和100%的LT-FM或SPC蛋白,另配制1种实验饲料(联合替代组),用GWT替代对照组饲料中50%的LT-FM和SPC蛋白。结果显示,用GWT替代对照组饲料中的LT-FM对日本黄姑鱼血清总蛋白(TP)、甘油三酯(TG)和肝脏丙二醛(MDA)含量以及肝脏超氧化物歧化酶(SOD)活性均无显著影响(P0.05),但显著降低了血清总胆固醇(TC)、葡萄糖(GLU)含量(P0.05)。相较对照组,GWT高比例(66.7%和100%)替代LT-FM引起日本黄姑鱼血清SOD活性的显著升高(P0.05)。GWT替代对照组饲料中LT-FM或(和)SPC均未对黑鲷幼鱼血清中的TP、TG、TC、GLU含量、肝脏MDA含量和血清SOD活性产生显著影响(P0.05),而GWT完全替代LT-FM组、GWT替代33.3%和66.7%SPC组以及GWT联合替代组的黑鲷幼鱼肝脏SOD活性均显著上升(P0.05)。总之,在本研究中,日本黄姑鱼相较黑鲷对低鱼粉饲料中鱼粉用量的进一步下降更为敏感,GWT高比例甚至完全替代LT-FM和SPC,未对黑鲷血清生化指标和肝脏抗氧化指标造成显著影响。本研究首次以小麦蛋白作为饲用蛋白源替代LT-FM和SPC在日本黄姑鱼和黑鲷中开展研究;实验采用低鱼粉型(20%)膨化实用饲料作为对照组。     

饲料中豆粕替代鱼粉比例对牙鲆生长性能及生化指标的影响

以鱼粉和豆粕分别为主要动物性和植物性蛋白源,研究饲料中不同豆粕替代鱼粉比例对牙鲆幼鱼生长性能和生化指标的影响。设计4∶1、3∶1、2∶1和1∶1四种不同动植物蛋白比的等氮等脂饲料配方,按配方制备试验饲料,分别表示为D1、D2、D3和D4。牙鲆幼鱼随机分配到12个设有循环水系统的玻璃钢桶内(900L),每3桶鱼饲喂一种饲料,每天投喂饲料2次,每次达到表观饱食,饲喂期为56d。以增重率(WGR)、饵料系数(FCR)、特定生长率(SGR)、蛋白质效率(PER)、肝体指数(HSI)、肥满度(CF)、鱼体成分和饲料成本为依据,综合评价饲料中不同比例的豆粕替代鱼粉比例对牙鲆的饲养效果。通过测定尿素氮(BUN)、谷丙转氨酶(GPT)、谷草转氨酶(GOT)、游离脂肪酸(FFA)、总蛋白(TP)、甘油三酯(TG)、胆固醇(CHO)、高密度脂蛋白胆固醇(HDL-C)及低密度脂蛋白胆固醇(LDL-C)等生化指标,研究饲料中不同豆粕替代鱼粉比例对牙鲆蛋白质代谢和脂肪代谢的影响。随豆粕比例的增加,WGR、PER和SGR逐渐降低,FCR逐渐增加,当饲料中豆粕比例在24%以上时差异显著(P<0.05);HSI逐渐增加,且D1组显著低于其他...     

小麦蛋白替代鱼粉及大豆蛋白对日本黄姑鱼(Nibea japonica)和黑鲷(Sparus macrocephalus)血清生化指标及肝脏抗氧化指标的影响

本研究通过在低鱼粉型膨化饲料中添加不同比例的混合型小麦蛋白(GWT,由小麦蛋白、低筋面粉和牛磺酸分别以77.5％、20.5％和2.0％的比例混合而成),逐步替代饲料中低温干燥鱼粉(LT-FM)或大豆浓缩蛋白(SPC),饲喂日本黄姑鱼(Nibea japonica)[初始体重为(12.83±0.91)g]和黑鲷(Sparus macrocephalus)幼鱼[初始体重为(15.40±0.02)g]59 d,研究其对2种鱼类血清生化指标和肝脏抗氧化指标的影响.本研究配制8种等氮、等能饲料(粗蛋白:44.1％-45.6％、总能:21.5-22.0 MJ/kg),其中,对照组饲料以LT-FM(20.0％)和SPC(21.4％)为主蛋白源,6种实验饲料以GWT分别替代对照组饲料中33.3％、66.7％和100％的LT-FM或SPC蛋白,另配制1种实验饲料(联合替代组),用GWT替代对照组饲料中50％的LT-FM和SPC蛋白.结果显示,用GWT替代对照组饲料中的LT-FM对日本黄姑鱼血清总蛋白(TP)、甘油三酯(TG)和肝脏丙二醛(MDA)含量以及肝脏超氧化物歧化酶(SOD)活性均无显著影响(P＞0.05),但显著降低了血清总胆固醇(TC)、葡萄糖(GLU)含量(P＜0.05).相较对照组,GWT高比例(66.7％和100％)替代LT-FM引起日本黄姑鱼血清SOD活性的显著升高(P＜0.05).GWT替代对照组饲料中LT-FM或(和)SpC均未对黑鲷幼鱼血清中的TP、TG、TC、GLU含量、肝脏MDA含量和血清SOD活性产生显著影响(P＞0.05),而GWT完全替代LT-FM组、GWT替代33.3％和66.7％SPC组以及GWT联合替代组的黑鲷幼鱼肝脏SOD活性均显著上升(P＜0.05).总之,在本研究中,日本黄姑鱼相较黑鲷对低鱼粉饲料中鱼粉用量的进一步下降更为敏感,GWT高比例甚至完全替代LT-FM和SPC,未对黑鲷血清生化指标和肝脏抗氧化指标造成显著影响.本研究首次以小麦蛋白作为饲用蛋白源替代LT-FM和SPC在日本黄姑鱼和黑鲷中开展研究;实验采用低鱼粉型(20％)膨化实用饲料作为对照组.     

大豆浓缩蛋白对大黄鱼生长和肠道微生物菌群的影响

用大豆浓缩蛋白(SPC)替代鱼粉饲喂大黄鱼(Larimichthys crocea), 以探究其对幼鱼生长、肠道结构及肠道微生物菌群的影响。选取初始体重为(10.50±0.04) g的大黄鱼幼鱼, SPC替代鱼粉的比例分别为0% (SPC0, 对照组)、25% (SPC25)、50% (SPC50)、75% (SPC75)和100% (SPC100), 制作成5种等氮(粗蛋白水平为45%)等脂(粗脂肪水平为10%)的实验饲料, 进行为期56 d的饲养实验。结果表明, 与SPC0(对照组)相比, 幼鱼的存活率、增重率、特定生长率以及饲料系数受各SPC替代鱼粉水平的影响不显著(P>0.05)。肠道组织学显示, 各处理组幼鱼肠道的后肠黏膜厚度、皱襞高度、固有层宽度和杯状细胞个数差异性不显著(P>0.05)。Illumina HiSeq 高通量测序技术分析发现, SPC0 (TC: 对照组)、SPC25 (TB: 生长相对最佳组) 和SPC100 (TW: 生长相对最差组)的Chao1、香农指数(Shannon)、辛普森指数(Simpson)和覆盖率(good coverage)差异不显著(P>0.05); TC、TB和TW组幼鱼肠道细菌在门水平的优势菌群为厚壁菌门(Firmicutes), 类芽孢杆菌(Paenibacillus)在属水平占绝对优势。根据属水平的菌属差异结果发现幼鱼的生长受细菌微生物的组成的影响: 与TC组相比, TB组微小杆菌属(Exiguobacterium)、红杆菌属(Rhodobacter)和伦黑墨氏菌属(Rheinheimera)的物种丰度显著降低(P<0.05); 与TC组相比较, TW组红杆菌属(Rhodobacter)的物种丰度显著降低(P<0.05), 乳杆菌属(Lactobacillus)的物种丰度显著增加(P<0.05)。综上所述, 大黄鱼幼鱼的生长、肠道结构及肠道优势菌群不会因为鱼粉完全被大豆浓缩蛋白替代而产生负面的影响。     

黄鳍鲷幼鱼对几种不同糖源的利用

本研究用来评价黄鳍鲷幼鱼对饲料中葡萄糖、麦芽糖、糊精、玉米淀粉和预糊化玉米淀粉的利用。本试验饲料为6种等氮(粗蛋白:45%,干重)等脂(粗脂肪:9%,干重)的半纯化饲料,其中对照组糖源为纤维素。每种饲料设3个平行。试验鱼初始体重为(3.57±0.13)g(平均值±均差)。试验鱼饲养在含18个水族箱的循环系统中。水温保持在(27±1)℃。试验周期为8周。本试验用来评价黄鳍鲷幼鱼对饲料中不同糖源利用的指标为生长指标、饲料效率、蛋白质效率和肝脏的6-磷酸葡萄糖脱氢酶、苹果酸脱氢酶、异柠檬酸脱氢酶和葡萄糖-6-磷酸脱氢酶。试验结果表明,黄鳍鲷幼鱼体增重、特定生长率、肝体比、肠系膜脂肪体比、饲料效率、蛋白质效率、肝脂肪合成有关酶活性和全鱼、肌肉、肝脏组成均受到饲料中不同糖源的显著影响。预糊化玉米淀粉和麦芽糖组比其它糖源组显著具有更好的体增重和特定生长率,但与对照组没有显著性差异。黄鳍鲷幼鱼生长和体增重与饲料中糖源的复杂性没有相关性。饲喂预糊化淀粉和对照饲料鱼的饲料效率和蛋白质效率显著比其它组高。饲料中糖的添加增加了黄鳍鲷幼鱼的肝体比,但对照组肝体比与糊精组,玉米淀粉组没有显著性差异。预糊化玉米淀粉组肠系膜脂肪体比比其它饲料组要高。结论:基于体增重和特定生长率为指标,饲料中添加25%预糊化玉米淀粉和麦芽糖可以提高黄鳍鲷幼鱼的生长。另外,玉米淀粉预糊化显著提高了黄鳍鲷对玉米淀粉的利用。     

Dietary niacin levels in practical diets for Litopenaeus vannamei to support maximum growth

This study investigated the effects of dietary niacin on growth performance, feed utilization and non‐specific immune response in juvenile Pacific white shrimp. Six isonitrogenous and isolipidic practical diets were formulated with graded niacin levels of 10.9, 65.8, 121.2, 203.4, 387.5 and 769.3 mg kg^?1 of dry diet, respectively. Results indicated that per cent weight gain (WG), specific growth rate (SGR), feed efficiency (FE), protein efficiency ratio (PER) and protein productive value (PPV) were significantly influenced by the dietary niacin levels. The maximum WG and SGR occurred at 121.2 mg kg^?1 niacin diet. However, survival and proximate composition of whole body were not significantly affected by the dietary niacin levels. Dietary niacin levels had no significant effects on the total protein, glucose, triacylglycerol and cholesterol contents in the haemolymph. The activity of catalase and lysozyme in the haemolymph was significantly affected by dietary niacin levels. Based on a two‐slope regression analysis of SGR against dietary niacin level, the dietary niacin requirement of juvenile Pacific white shrimp was 109.6 mg kg^?1.     

Evaluation of pea protein isolate as alternative protein source in diets for juvenile tilapia (Oreochromis niloticus)

To evaluate isolated pea protein as feed ingredient for tilapia (Oreochromis niloticus) juveniles, triplicate groups were fed with four isonitrogenous [crude protein: 421.1–427.5 g kg⁻¹ in dry matter (d.m.)] and isoenergetic (gross energy: 20.46–21.06 MJ kg⁻¹ d.m.) diets with varying protein sources for 8 weeks. Fish meal-based protein content of diets was substituted with 0% (diet 100/0=control group), 30% (diet 70/30), 45% (diet 55/45) and 60% (diet 40/60) isolated pea protein. Tilapia juveniles with an initial body weight of 2.23–2.27 g were fed in average at a level of 5% of their body weight per day. Highest individual weight gain (WG: 21.39 g) and specific growth rate (SGR: 4.21% day⁻¹) and best feed conversion ratio (FCR: 0.90) were observed in tilapia fed diet 100/0, followed by fish-fed diet 70/30 (WG: 19.09 g; SGR: 4.03% day⁻¹; FCR: 0.98), diet 55/45 (WG: 16.69 g; SGR: 3.80% day⁻¹; FCR: 1.06) and diet 40/60 (WG: 16.18 g; SGR: 3.74% day⁻¹; FCR: 1.06). Although fish fed diet 100/0 showed the best performance, inclusion of 30% protein derived from pea protein isolate resulted in a growth performance (in terms of WG and SGR) that did not differ significantly from diet 100/0 in contrast to fish fed diet 55/45 and 40/60. Crude ash content in the final body composition of the experimental fish decreased with increasing dietary pea protein content, while crude protein and lipid content remained equal between the groups. Significant decreasing growth performance and body ash incorporation of tilapia at higher inclusion levels seem to be mainly related to the dietary amino acid profile and phytic acid contents.     

Protein requirement of jundia fingerlings, Rhamdia quelen, at two dietary energy concentrations

A feeding trial was carried out where five protein concentrations [26%, 29%, 33%, 37%, and 41% crude protein (CP)] were fed to jundia fingerlings at two dietary energy concentrations [3200 and 3650 kcal metabolizable energy (ME)/kg diet] to establish the protein requirement for this species. Triplicate groups of 23 fish (average weight 1.52±0.34 g) were each stocked in 120-l aquaria and fed semipurified diets twice a day to apparent satiation. After 90 days, fish weight gain (WG), specific growth rate (SGR), feed efficiency (FE), protein efficiency ratio (PER), energy retention (ER), apparent net protein utilization (ANPU), feed consumption (% body weight) and body composition (crude protein, fat, and ash) were affected by diet composition. Weight gain, SGR, FE, ANPU and ER increased (P<0.05) as the dietary protein concentration increased up to 33% and 37%, for fish fed diets containing 3650 and 3200 kcal, respectively. A significant interaction between dietary protein and energy was observed for WG, SGR, and PER. Feed consumption was not affected by dietary energy concentration, but decreased with increasing dietary protein concentration (P<0.05). Body fat decreased as dietary protein increased at both energy concentrations, but was higher in fish fed the 3650 kcal diet. The opposite was observed for body protein, ER, and ANPU (P<0.05). Our findings demonstrate that jundia presents dietary protein sparing effect when the energy concentration increases from 3200 to 3650 kcal/kg. Jundia protein requirement, determined by the broken line method, is between 32.6% and 37.3% CP, depending on dietary energy concentration.     

日粮铁对草鱼生长、营养成分和部分血液指标的影响

选用(7.12±0.22)g的草鱼(Cenopharyngodon idellus)鱼种,分别在纯化日粮中添加铁0,100,200,300,400,500 mg/kg,进行为期78 d的生长试验以考察铁对草鱼生长性能、营养成分和部分血液指标的影响。试验结果显示,日粮中添加铁对草鱼的生长、体成分和血红蛋白和红血细胞数目等都有显著影响。日粮中添加铁300 mg/kg时,草鱼增重率、特定生长率、饲料效率、蛋白质效率比、蛋白沉积效率达最大值;体蛋白和肌肉蛋白含量高,脂肪含量低,灰分含量高;血红蛋白和红血细胞均达最高水平。结果说明:草鱼纯化日粮中铁的适宜添加量为300 mg/kg。     

Optimum dietary phosphorus level of juvenile Japanese flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis> reared in the recirculating system

ABSTRACT:   An 8-week feeding trial was conducted to determine the optimum dietary phosphorus level of juvenile Japanese flounder Paralichthys olivaceus reared in the recirculating system. The basal diet containing 0.33% total phosphorus (TP) was supplemented with NaH₂PO₄·H₂O to provide 0.33, 0.51, 0.71, 0.94, 1.10 and 2.12% TP for the experimental diets. Fish averaging 2.0 ± 0.04 g (mean ± SD) were fed in triplicate groups with the experimental diets for 8 weeks. After 8 weeks, fish fed the 0.51% TP diet showed significantly higher weight gain (WG), feed efficiency (FE), specific growth rate (SGR), and protein efficiency ratio (PER) than those fed the 0.33% and 2.12% TP diets ( P  < 0.05). Meanwhile, no difference was observed in WG, FE, SGR and PER of fish fed the 0.51, 0.71, 0.94 and 1.10% TP diets. Fish fed the 0.33% TP diet showed phosphorus deficiency symptoms such as poor growth and a deformed head by the end of 8 weeks. Ash and phosphorus contents of bone increased with the increase of dietary phosphorus concentrations. anova test, the quadratic regression analysis, and the broken line analysis suggested that the optimum dietary phosphorus level could be between 0.45 and 0.51% TP for maximum WG in juvenile Japanese flounder.     

Reevaluation of the Dietary Protein Requirements and Optimum Dietary Protein to Energy Ratios in Japanese Eel, Anguilla japonica

A 2 × 3 factorial design was used to reevaluate the dietary protein requirements and to determine the optimum dietary protein to energy (P/E) ratios in Japanese eel, Anguilla japonica, reared in the recirculating system. For each of two experiments, six experimental diets (₄₅P₁₆, ₄₅P₁₇, ₄₅P₁₉, ₅₀P₁₆, ₅₀P₁₇, and ₅₀P₁₉) were formulated and prepared to contain two protein levels (45 and 50%) and three energy levels (16, 17, and 19 kJ/g diet) at each protein level. In the first experiment, glass eel of initial weight 0.1 ± 0.02 g (mean ± SD) were used, while the second experiment was conducted with juvenile eel of initial weight 15.0 ± 3 g (mean ± SD). The first and second experimental periods were 6 and 16 wk for the glass and juvenile eel, respectively. At the end of the first experiment, there were no protein, energy, and their interaction effects. Also, there were no significant differences in weight gain (WG), specific growth rate (SGR), feed efficiency (FE), and protein efficiency ratio (PER) for glass Japanese eel fed all diets. Although there were no significant differences in growth parameters of glass eel fed all experimental diets, these parameters were higher for fish fed ₅₀P₁₆ than for fish fed the other diets. For the second experiment, there were significant protein effects on WG, SGR, and PER (P < 0.05). However, there were neither significant energy effects nor protein and energy interaction effects on WG, SGR, FE, and PER. Fish fed ₄₅P₁₉ had a higher WG, SGR, and PER than did fish fed ₄₅P₁₆, ₅₀P₁₆, and ₅₀P₁₉ (P < 0.05). However, there were no significant differences in growth parameters among fish fed ₄₅P₁₆, ₄₅P₁₇, ₅₀P₁₆, ₅₀P₁₇, and ₅₀P₁₉ and among those fed ₄₅P₁₇, ₄₅P₁₉, and ₅₀P₁₇. These results may indicate that the optimum dietary protein requirement and the P/E ratio could be 44.3% and 24.1 mg protein/kJ (₄₅P₁₉), respectively, in juvenile Japanese eel, based on WG, SGR, and PER.     

Growth,feed utilization and body composition of African bonytongue,Heterotis niloticus,fingerlings fed diets containing various protein and lipid levels

In order to evaluate the effects of dietary protein and lipid levels on the growth, feed utilization and body composition of Heterotis niloticus fingerlings, a factorial experiment with three replicates was conducted. Six experimental diets containing three crude protein levels (28%, 32% and 36%) and two crude lipid levels (6% and 13%) were tested. Heterotis niloticus (2.34 g) were fed with the diets to apparent satiation, twice a day. For 56 days, weight gain (WG), specific growth rate (SGR), feed efficiency (FE) and protein retention (PR) were significantly affected by dietary protein and dietary lipid levels respectively (P<0.01). The highest WG, SGR and FE were observed for fingerlings fed the diet containing 36% protein and 6% lipid, but no significance difference was found between groups fed with the following diets: P28L13 (28% protein and 13% lipid), P32L6, P32L13 and P36L13. A significant interaction between dietary protein and lipid was observed for WG, SGR, FE and PR. The whole‐body protein, lipid, moisture and ash content were not significantly affected by dietary lipid levels, but body protein and lipid content were significantly affected by dietary protein. The dietary protein‐sparing effect was clearly demonstrated when the dietary energy of lipid increased from 17 to 19.6 kJ g^?1 at 28% crude protein on H. niloticus.     

美洲鲥幼鱼饲料中蛋白质的适宜含量

为研究饲料中不同蛋白质含量对美洲鲥幼鱼生长的影响,设置了蛋白质含量分别为35%、40%和45%的3组实验,经过41d的试验得出:蛋白质含量为40%的饲料组,幼鱼的增重率、特定生长率最高(P<0.05);蛋白质含量为40%组和45%组的蛋白质效率和饲料转化率无显著差异(P>0.05),但均高于35%组(P<0.05)。     

Effect of dietary protein levels on growth,feed utilization and carcass composition of endangered bagrid catfish Horabagrus brachysoma (Gunther 1864) fingerlings

An 84‐day feeding trial was conducted to study the effect of different levels of dietary protein, 250 (P25), 300 (P30), 350 (P35), 400 (P40) and 450 g (P45) kg^?1 dry matter (DM) on growth, feed intake, feed utilization and carcass composition of bagrid catfish Horabagrus brachysoma fingerlings. Triplicate groups of fingerlings with mean initial body weight of 2.2 g were fed the experimental diets twice daily, till satiation, in 150‐L tanks supplied with flow‐through freshwater. Daily dry matter intake by the fingerlings decreased significantly (P < 0.05) when fed P25 diet, containing 250 g protein kg^?1. The highest body weight gain, specific growth rate (SGR) and protein efficiency ratio (PER), and the lowest feed conversion ratio (FCR) were observed in fish fed 350 g protein kg^?1 diet. The fish fed with P45 diet had the lowest (P < 0.05) carcass lipid content. The polynomial regression analysis indicates that H. brachysoma fingerlings require 391 g dietary crude protein kg^?1 diet.