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。     

脱脂磷虾粉对圆斑星鲽(Verasper variegatus)幼鱼生长、非特异性免疫力和血清生理代谢指标的影响

为研究脱脂磷虾粉替代鱼粉对圆斑星鲽(Verasper variegatus)幼鱼生长性能、非特异性免疫力和血清生理代谢指标的影响,实验以鱼粉和脱脂磷虾粉为蛋白源,鱼油为脂肪源,分别以脱脂磷虾粉蛋白替代基础饲料中0、10％、20％、30％、40％、50％和100％的鱼粉蛋白制成7种等氮、等脂的饲料(分别记为R0、R10、R20、R30、R40、R50、R100),投喂初始体重为(60.11±0.13)g、体长为(14.12±0.25) cm的圆斑星鲽幼鱼8周,每组设3个重复,每个重复20尾鱼.结果显示,R10-R50组的特定生长率(SGR)、存活率(SR)和饲料效率(FER)与R0组(对照组)没有显著性差异(P＞0.05),但从R30组开始有下降的趋势.R10-R50组的蛋白质效率(PER)和R0组无显著性差异(P＞0.05),但R100组的PER显著低于R0组(P＜0.05).R10-R20组血清中的酸性磷酸酶(ACP)显著高于R0组(P＜0.05),R30组血清中酸性磷酸酶(ACP)和R0组没有显著性差异(P＞0.05).R30-R100组血清中的碱性磷酸酶(AKP)显著高于R0组(P＜0.05).R10组血清中超氧化物歧化酶(SOD)和R0组差异不显著(P＞0.05).R10组肝脏中ACP显著高于R0组(P＜0.05),R40-R50组和R0组没有显著性差异(P＞0.05).R30-R40组肝脏中AKP和R0组差异不显著(P＞0.05).R10-R40组肝脏中SOD和R0组没有显著性差异(P＞0.05).R10-R50组血清的总蛋白(TP)显著高于R0组(P＜0.05).各处理组和R0组血清中的谷草转氨酶(GOT)和谷丙转氨酶(GPT)没有显著性差异(P＞0.05).综合来看,10％-30％的脱脂磷虾粉替代组和对照组R0组对圆斑星鲽幼鱼的生长、饲料利用、免疫力及蛋白利用有相同的效果.     

饲料中不同水解蛋白对鲈鱼(Lateolabrax japonicus)幼鱼鱼体及组织脂肪含量的影响

本研究通过8周的摄食生长实验来探讨高植物蛋白饲料中添加不同类型的水解蛋白对鲈鱼(Lateolabrax japonicus)幼鱼(初始平均体重为31.99 g)鱼体及组织脂肪含量的影响.实验设4个等氮等能的饲料处理组,对照组含有30％的鱼粉,通过在对照组饲料基础上分别添加水解猪血蛋白、水解豆粕蛋白和水解酵母蛋白替代10％的鱼粉来获得不同类型的实验组饲料,即水解猪血蛋白组、水解豆粕蛋白组和水解酵母蛋白组.养殖实验在近海浮式网箱中进行,每组饲料投喂3个重复的养殖网箱,每个网箱30尾鱼.实验结果显示,高植物蛋白饲料中水解猪血蛋白、水解豆粕蛋白及水解酵母蛋白并没有对鲈鱼幼鱼的鱼体、肝脏、肌肉和内脏的脂肪含量产生显著影响.但与对照组相比,添加水解酵母蛋白的处理组显著降低了鲈鱼幼鱼的血清甘油三酯、总胆固醇及低密度脂蛋白胆固醇含量(P＜0.05).水解酵母蛋白替代鱼粉显著提高了鲈鱼幼鱼肌肉中C20:1n-9的含量,而水解豆粕蛋白和水解酵母蛋白显著降低了肌肉中C22:5n-3的含量(P＜0.05).与对照组相比,水解酵母蛋白显著降低了血清中C20:5n-3的含量(P＜0.05).在腹部脂肪组织中,与对照组相比,猪血、豆粕及酵母蛋白水解物替代鱼粉极显著提高了饱和脂肪酸、十八碳及十六碳单不饱和脂肪酸、亚油酸及亚麻酸的含量,而极显著降低了C20:1n-9、C20:4n-6、C22:5n-3和C22:6n-3的含量(P＜0.01).本研究表明,高植物蛋白饲料中猪血、豆粕及酵母蛋白水解物替代10％的饲料鱼粉并未有效调节鲈鱼幼鱼鱼体、肝脏、肌肉及内脏的脂肪累积,但水解酵母蛋白在一定程度上改善了血清甘油三酯和胆固醇的代谢.水解蛋白对鲈鱼幼鱼脂肪酸组成的调节因水解蛋白的类型及鱼体组织类型而异.本研究是国内外首次系统研究不同类型水解蛋白对养殖鱼类脂肪累积的调节作用,对该领域相关研究具有重要借鉴和参考意义.     

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%。     

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。     

大豆浓缩蛋白对中华鲟幼鱼生长、血脂和体成分的影响研究

分别用大豆浓缩蛋白(SPC)替代饲料中0(R0,对照组),15%(R15),30%(R30)和45%(R45)的鱼粉蛋白,配制成4组等氮等能饲料,喂养(58.00±2.69)g中华鲟(Acipenser sinensis)幼鱼10周,每组设3个重复,研究SPC对中华鲟幼鱼生长性能、饲料利用率,以及血脂和体成分的影响。结果显示,随替代比例的增加,中华鲟幼鱼的增重率(WG)、特定生长率(SGR)、饲料效率(FE)和蛋白质效率(PER)逐渐降低,肥满度和肝体指数无显著性差异(P>0.05)。FE在R30组出现显著差异(P<0.05),WG、SGR和PER在R45组出现显著性差异(P<0.05)。随替代比例的增加,血浆高密度脂蛋白胆固醇含量无显著变化(P>0.05),胆固醇(CHOL)、甘油三脂(TG)和低密度脂蛋白胆固醇(LDL-C)含量逐渐降低。CHOL、TG和LDL-C含量在R30组出现显著差异(P<0.05)。随替代比例的增加,肌肉和肝脏水分逐渐升高,脂肪逐渐降低,蛋白含量无显著差异(P>0.05)。R30和R45组的肌肉和肝脏水分含量显著高于R0组(P<0.05),脂肪含量显著低于R0组(P<0.05)。结果表明:在本试验条件下,综合考虑生长性能、饲料利用、血脂和体成分等指标,中华鲟幼鱼饲料中SPC替代鱼粉蛋白的比例可达30%。     

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。     

不同类型硒对黑鲷幼鱼生长及血清免疫指标的影响

在水温(27±1)℃下,将初始体质量为(13.00±0.20)g的黑鲷幼鱼放入容积为310L(水体260L)的微流水玻璃缸内,投喂含蛋白41.57%、脂肪13.63%等氮等能基础饲料(对照组)及在其中添加2.35mg/kg硒化多糖和0.88mg/kg的亚硒酸钠(使外源硒添加量均为0.4mg/kg)的试验饲料8周,研究了不同类型的外源硒对黑鲷幼鱼生长性能、体组成和血清免疫指标的影响。试验结果显示,黑鲷幼鱼摄食添加了硒化多糖和亚硒酸钠的饲料时,其特定生长率、血清免疫球蛋白M、补体C3、补体C4的含量以及肝脏和肌肉中硒的含量均显著高于对照组(P0.05),且添加硒化多糖组的上述指标显著高于添加亚硒酸钠组(P0.05);饲料中添加硒化多糖和亚硒酸钠对黑鲷幼鱼的形体指标和体组成无显著影响(P0.05)。试验结果表明,添加适量的外源硒能显著提高黑鲷幼鱼的生长性能和血清免疫活性,且有机硒的生物利用率显著高于无机硒。     

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。     

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...     

Effect of dietary replacement of fish meal by soybean protein concentrate on growth performance and phosphorus discharging of juvenile black sea bream,Acanthopagrus schlegelii

The 8‐week experiment was conducted to evaluate the effects of partial replacement of fish meal (FM) with soybean protein concentrate (SPC) on juvenile black sea bream, Acanthopagrus schlegelii (10.70 ± 0.04 g). Diets were formulated to replace FM protein by SPC at 0, 8, 16, 24, 32 or 40% (designated as T1, T2, T3, T4, T5 and T6, respectively). Diets except T1 were supplemented with phytase at 2000 phytase activity U kg^?1. The results showed that survival rate, growth performance and feed utilization were not significantly affected by increasing dietary SPC. Fish fed diet T3 had higher feed intake compared to those fed T1, T2 and T5 diets. Whole body compositions of black sea bream were significantly influenced by SPC replacing FM except for protein, ash and phosphorus content. Condition factor of fish was significantly lower in T2 than that of fish in T3 group. Apparent digestibility coefficients (ADCs) of dry matter was higher in fish fed T6 diet than those of fish fed T1 and T2 diets, ADCs of phosphorus increased with dietary SPC level up to T3 and then decreased. The results obtained in this study indicate that FM protein could be effectively replaced by SPC protein with phytase in diet of black sea bream.     

Dietary substitution of fishmeal by alternative protein with guanosine monophosphate supplementation influences growth,digestibility, blood chemistry profile,immunity, and stress resistance of red sea bream, <Emphasis Type="Italic">Pagrus major</Emphasis>

We determined the effects of complete fishmeal (FM) replacement by alternative protein (soy protein concentrate, SPC) with guanosine monophosphate (GMP) supplementation on growth, digestibility, immunity, blood chemistry profile, and stress resistance of juvenile red sea bream, Pagrus major. FM protein of a FM-based control diet (FM0) was replaced with 33.3 (FM33.3), 66.6 (FM66.7), and 100% (FM100) by SPC protein, and each replacement group was supplemented with 0.4% GMP to formulate four experimental diets. Each diet was randomly allocated to triplicate groups of fish (4.8 g) for 56 days. Results demonstrated that fish fed diet group FM33.3 had the significantly highest final weight, weight gain-specific growth rate, and feed intake. Meanwhile, in comparison to control, growth performance and feed utilization did not significantly differ with 66.7% FM replacement by SPC with GMP supplementation. Apparent digestibility coefficient of protein and lipid also followed a similar trend. All growth, feed utilization, and digestibility parameters were significantly lower in FM100 diet group. Blood urea nitrogen (BUN) and triglycerides (TG) increased (P < 0.05) with increasing FM replacement level by SPC. Interestingly, total cholesterol level reduces with the increasing level of FM replacement by SPC with GMP supplementation. Fish fed FM0 diet group showed the best condition of both oxidative and freshwater stress resistance. Meanwhile, FM33.3 and FM66.7 diet groups showed acceptable conditions. Innate immune responses enhanced with the increasing FM replacement level by SPC with GMP supplementation. In conclusion, FM could be replaced ≤66.7% by SPC with GMP supplementation in diets for red sea bream without any adverse effects on fish performances.     

Necessity of dietary taurine supplementation for preventing green liver symptom and improving growth performance in yearling red sea bream Pagrus major fed nonfishmeal diets based on soy protein concentrate

The necessity of dietary taurine supplementation for preventing green liver symptom and improving growth performance of red sea bream Pagrus major fed nonfishmeal (non-FM) diets was investigated. Yearling red sea bream (initial body weight, 580 g) were fed for 36 weeks on non-FM diets based on soy protein concentrate (SPC) supplemented with taurine at levels of 0%, 0.5%, 1.0%, 1.5%, and 2.0%. Specific growth rate (SGR) and feed conversion ratio (FCR) of fish fed the taurine-unsupplemented SPC diet were markedly inferior. In these fish, incidence of green liver was markedly higher and was accompanied by a decrease of tissue taurine concentration and an increase of hepatopancreatic bile pigment content. The green liver symptom was mainly caused by an increase of hemolysis since the erythrocytes became osmotically fragile due to taurine deficiency. Physiological abnormality and growth performance (SGR and FCR) were markedly improved by taurine supplementation to the SPC diets. These results indicate that dietary taurine supplementation is necessary for yearling red sea bream fed non-FM diet based on SPC to maintain normal physiological condition and growth performance.     

Studies on the green liver in cultured red sea bream fed low level and non-fish meal diets: Relationship between hepatic taurine and biliverdin levels

SUMMARY: The aim of this study was to investigate the cause of green liver in red sea bream fed substitute protein diets. Red sea bream Pagrus major was given either of the following diets for 28 weeks: (1) control diet (50% fish meal), (2) low level fish meal diet (15% fish meal), and (3) non-fish meal diet (0% fish meal). The green liver was observed in all groups tested, but the incidence was much higher in the experimental diet groups. The feeding of substitute protein diets reduced plasma triglyceride and cholesterol levels. However, there was no significant difference in plasma hepatic enzyme activities and plasma bile salts concentration among the treatments. Fish fed the substitute protein diets showed low hepatic taurine levels with an appearance of a biliverdin in the liver. Moreover, the proportion of ditaurobilirubin to total biliary bile pigments was significantly lower in fish fed the substitute protein diets. These data indicate that feeding of substitute protein diets did not induce any cholestatic hepatobiliary obstructions and that the low hepatic taurine level was one of the probable factors responsible for the occurrence of green liver in red sea bream fed substitute protein diets.     

Partial Replacement of Fish Meal by Fermented Soybean Meal in Diets for Black Sea Bream,Acanthopagrus schlegelii,Juveniles

The effect of fish meal (FM) substitution with fermented soybean meal (FSBM) in the diets of the carnivorous marine fish, black sea bream, Acanthopagrus schlegelii, was investigated. An 8‐wk feeding trial was conducted with black sea bream (11.82 ± 0.32 g; mean initial weight) in indoor flow‐through fiberglass tanks (25 fish per tank). Six isonitrogenous and isoenergetic diets were formulated, in which FM was replaced by FSBM at 0% (control diet), 10% (FSBM10), 20% (FSBM20), 30% (FSBM30), 40% (FSBM40), or 50% (FSBM50), respectively. Each diet was fed to triplicate groups of fish twice daily to apparent satiation. The results showed that there was no difference in survival of black sea bream during the feeding trial. Fish fed the FSBM10 or FSBM20 diet showed comparable growth performance compared with fish fed the control diet (P > 0.05), whereas more than 30% replacement of FM adversely affected weight gain and specific growth rate (P < 0.05). Feed intake was significantly lower for fish fed the FSBM50 diet compared with fish fed the control diet. Feed conversion ratio (FCR) tended to increase with increasing dietary FSBM with the poorest FCR observed for fish fed the FSBM50 diet. Protein efficiency ratio and protein productive values showed similar patterns. Apparent digestibility of nutrients significantly decreased with increasing dietary FSBM level. With the exception of protein content, no significant differences in whole body and dorsal muscle composition were observed in fish fed the various diets. Fish fed the FSBM50 diet had significantly lower intraperitoneal ratio than fish fed the control or FSBM10 diet. Hepatosomatic index and condition factor were unaffected by dietary treatments. This study showed that up to 20% of dietary FM protein could be replaced by FSBM protein in the diets of juvenile black sea bream.     

Effects of diet supplementation with white tea and methionine on lipid metabolism of gilthead sea bream juveniles (Sparus aurata)

A growth trial was performed with gilthead sea bream juveniles (Sparus aurata) to evaluate the effect of diet supplementation with white tea and methionine on fish performance and lipid metabolism. For that purpose, four diets were formulated: a fish meal–based diet (Control) and diets identical to the control diet but supplemented with 2.9 % white tea (Tea), 0.3 % methionine (Met) or 2.9 % white tea plus 0.3 % methionine (Tea + Met). Growth performance and feed efficiency parameters, whole-body and liver composition, plasma metabolites concentration and liver glucose 6-phosphate dehydrogenase (G6PDH), malic enzyme (ME) and fatty acid synthetase (FAS) activities were determined. Feed intake was higher in fish fed methionine–supplemented diets, whereas this parameter and growth was decreased in fish fed white tea supplementation. Feed efficiency and protein efficiency ratio were not affected by diet composition. Plasma HDL cholesterol and total lipids concentration were higher in fish fed white tea–supplemented diets. Whole-body lipid, plasma glucose, liver glycogen concentration and liver G6PDH, ME and FAS activities were lower in fish fed white tea–supplemented diets. Results of the present study indicate that methionine seems to act as a feed attractant in diets for sea bream juveniles. Additionally, white tea is an important modulator of lipid metabolism in sea bream juveniles.     

Growth,Feed Utilization,and Glycemic Response in European Sea Bass,Dicentrarchus labrax,Juveniles Fed Carbohydrate of Different Complexities

The effect of dietary carbohydrate complexity on growth, feed utilization, and glycemia was studied in European sea bass juveniles. Four isonitrogenous (50% crude protein) and isolipidic (15% crude lipids) diets were formulated to contain 20% pregelatinized maize starch (PGS diet), dextrin (DEX diet), maltose (MAL diet), or glucose (GLU diet). No effect of dietary carbohydrate complexity on growth was noticed. Feed efficiency and protein efficiency ratio were lower in fish fed the GLU diet than in the other groups, whereas the opposite was observed for feed intake. Plasma glucose peaked 3–4 h after feeding in fish fed the MAL and GLU diets, whereas in fish fed the PGS and DEX diets the peak was reached 5–6 h after feeding. Peak plasma glucose concentration (13 mmol/L) was higher in fish fed the GLU diet than the other diets (9 mmol/L). Shorter hyperglycemia duration was observed in fish fed the MALT and GLU diets (6 h) than the PGS and DEX diets (10 h). Complex carbohydrates delayed plasma glucose concentration peak compared with simple sugars, whereas the opposite was observed for hyperglycemia duration. Overall, dietary maltose, dextrin, and starch were apparently better utilized as energy source than glucose by European sea bass juveniles.     

Effects of partial substitution of dietary fish meal by fermented soybean meal on growth performance,amino acid and biochemical parameters of juvenile black sea bream Acanthopagrus schlegeli

A feeding trial was conducted to evaluate the effect of replacing fish meal protein with fermented soybean meal (FSM) on the growth performance, feed utilization, amino acid profile, body composition, morphological parameters, activity of antioxidant and digestive enzymes of black sea bream (Acanthopagrus schlegeli) juvenile. Five isonitrogenic and isolipidic diets were prepared with levels of 0 (control), 80, 160, 240 and 320 g kg^?1 FSM. Triplicate groups (40 fish per tank) of juvenile black sea bream with initial weight of 1.17 ± 0.04 g were hand‐fed to visual satiation at three meals per day for 8 weeks. The fish fed diets containing different levels of FSM had no significant differences regarding survival and specific growth rate compared with control group. Feed and protein efficiency ratios of fish fed diet containing 320 g kg^?1 FSM were significantly lower than those of control group. Daily feed intake and daily protein intake of fish fed diet containing 240–320 g kg^?1 were significantly higher than those of control group. Hepatosomatic index and condition factor of fish were not affected by different dietary FSM level. Fish fed diets containing 240–320 g kg^?1 FSM had significantly higher visceral somatic index than control group. Whole body proximate and amino acid compositions of fish were not affected by dietary FSM level. The activity of digestive enzymes in the intestine was not affected by dietary FSM level. The activity of glutathione peroxidase in liver was significantly higher for fish fed the diet containing 160 g kg^?1 FSM compared with control group. This study showed that up to 40% fish meal in the diets of juvenile black sea bream could be replaced by fermented soybean meal with supplementation of methionine, lysine and taurine.     

Role of taurine deficiency in inducing green liver symptom and effect of dietary taurine supplementation in improving growth in juvenile red sea bream <Emphasis Type="Italic">Pagrus major</Emphasis> fed non-fishmeal diets based on soy protein concentrate

This study was conducted to investigate the mechanism of green liver symptom induction and the effect of dietary taurine supplementation on growth performance in juvenile red sea bream fed non-fishmeal diets based on soy protein concentrate (SPC). Juvenile fish (initial BW 72 g) were fed for 20 weeks on SPC diets supplemented with taurine at levels of 0, 1.0, and 2.0%. In the taurine-unsupplemented SPC diet group, specific growth rate (SGR) and feed conversion ratio (FCR) were significantly inferior (P < 0.001), and incidence of green liver was observed in 70% of fish. In this group, hepatopancreatic and plasma taurine concentrations were lowest (P < 0.05), hepatopancreatic content of bile pigments was highest (P < 0.05), and osmotic tolerance of erythrocytes was inferior (P < 0.05) among the dietary treatment groups. Serum osmolality of all treatment groups was at similar levels. These physiological abnormalities as well as SGR and FCR were improved by dietary taurine supplementation. These results indicate that the mechanism for induction of green liver symptom is bile pigment overproduction due to increased hemolysis because erythrocytes become osmotically fragile due to dietary taurine deficiency. Taurine supplementation of SPC diets is essential for maintaining normal physiological condition and growth performance in juvenile red sea bream.