水解鱼蛋白对大菱鲆生长、体组成及肌纤维组织形态结构的影响

本实验设计6种等氮等脂的饲料，研究水解鱼蛋白对大菱鲆(Scophthalmus maximus L.)生长、饲料利用、体组成和肌肉纤维组织形态结构的影响。实验设2个对照组，正对照组鱼粉为44%，负对照组鱼粉为22%；设4个实验组，PH18A组为22%的鱼粉和18%的水解鱼蛋白，PH4.5A组为22%的鱼粉和4.5%的水解鱼蛋白，PH4.5B组为17%的鱼粉和4.5%的水解鱼蛋白，PH18B组为0.5%的鱼粉和18%的水解鱼蛋白。研究结果表明，PH4.5A组和PH18B组的特定增长率无显著差异(P>0.05)，但显著高于PH4.5B组和负对照组(P<0.05)，显著低于正对照组和PH18A组(P<0.05)；PH18A组的特定生长率显著高于正对照组(P<0.05)。正对照组和PH18A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)，但依次显著高于PH18B组、PH4.5A组和负对照组(P<0.05)；摄食率的变化趋势则相反。PH4.5B组和负对照组的粗脂肪和粗蛋白含量无显著差异(P>0.05)，显著低于正对照组和PH18A组(P<0.05)。6个处理组的大菱鲆肌肉总氨基酸、必需氨基酸和非必需氨基酸均无显著差异(P>0.05)。PH18A组的肌纤维横截面积显著高于PH18B组、正对照组、PH4.5A组、负对照组和PH4.5B组(P<0.05)，而PH18B组显著高于PH4.5B组(P<0.05)。PH18A组和PH18B组的肌纤维密度显著低于PH4.5B组(P<0.05)。研究表明，在高植物蛋白饲料中4.5%和18%的水解鱼蛋白，均可以提高大菱鲆的饲料效率和蛋白沉积率，促进大菱鲆的生长，且18%的水解鱼蛋白好于4.5%；同时，18%的水解鱼蛋白促进大菱鲆肌肉纤维横截面积的增加，促进大菱鲆的肌肉纤维密度的降低，而4.5%的水解鱼蛋白对大菱鲆肌纤维的横截面积和肌纤维的密度均无显著的作用。     

水解鱼蛋白营养组成及评价

利用分析化学方法对水解鱼蛋白、经超滤的水解鱼蛋白、鱼粉、酪蛋白、豆粕的营养成分进行了分析、评价.结果表明,经超滤的水解鱼蛋白的蛋白质含量显著高于未经超滤的水解鱼蛋白的蛋白质含量(P<0.05),超滤减少了水解鱼蛋白的脂肪含量,增加了水解鱼蛋白的灰分含量;水解鱼蛋白、经超滤的水解鱼蛋白、鱼粉、酪蛋白、豆粕氨基酸总量依次为62.24、62.34、50.78、74.33、37.36mg/100 mg,必需氨基酸占总氨基酸的比值(EAA/TAA)依次为47.41%、49.47%、49.90%、48.41%、49.25%;水解鱼蛋白含有丰富的牛磺酸;水解鱼蛋白和鱼粉含有丰富的碘和硒;水解鱼蛋白和鱼粉中维生素B2和B5含量较为丰富.水解鱼蛋白具有平衡的氨基酸组成,较高水平的牛磺酸和维生素B2、B5、丰富的微量元素碘和硒,是优质的蛋白原料.     

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.     

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(P0.05),但显著高于UF-20组(P0.05);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(P0.05),而显著高于UF-10、UF-20组(P0.05);UF-0、UF-5和UF-10三组鱼体粗蛋白、粗脂肪含量无显著差异(P0.05),但显著高于UF-20组(P0.05);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(P0.05),其他3组间无显著差异(P0.05);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(P0.05)。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。     

日粮中鱼蛋白水解物对黄颡鱼生长、体成分和血清生理指标的影响

为了探讨鱼蛋白水解物对黄颡鱼生产性能的影响,以日本鳀粉为对照,以实用型黄颡鱼饲料配方模式为基础开展实验:1以30.5%鱼粉为对照(FM),在相同配方模式下,以6%鱼蛋白水解物(MPH6)替代20%的鱼粉;2以30.5%鱼粉为对照(FM),在无鱼粉日粮中分别添加3%(FPH3)、6%(FPH6)、12%(FPH12)鱼蛋白水解物;共设计5组等氮等能实验日粮,在池塘网箱中养殖黄颡鱼[初始体质量(30.08±0.35)g]60 d。结果显示:与FM相比,FPH12在SGR、FCR、PRR和FRR方面均无显著差异,而MPH6、FPH3、FPH6组SGR降低了15.45%~24.39%,FCR升高了32.14%~42.86%,MPH6、FPH6差异显著,在PRR和FRR方面,MPH6、FPH3、FPH6组PRR降低了21.11%~27.78%,MPH6组FRR降低了41.51%;全鱼水分、粗蛋白、粗脂肪和灰分各组间差异不显著,FPH3、FPH6、FPH12肌肉多种游离氨基酸水平显著高于FM,其中Thr、Val、His与其在日粮中的水平显著相关;FPH6组HSI显著低于FM,鱼蛋白水解物对CP、VSI、肠体比的影响不显著;血清AST、ALT、HDL、LDL、TP、CHOL、TG无显著差异,FPH3组ALB显著低于FM。研究表明:黄颡鱼日粮中,12%鱼蛋白水解物(干物质)与30.5%鱼粉在生长速度、饲料效率、血清生理指标等方面具有一定的等效性;过高的植物蛋白日粮影响了黄颡鱼的生产性能;饲喂鱼蛋白水解物日粮使黄颡鱼肌肉游离氨基酸的含量升高,特别是呈味氨基酸的含量增加。     

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。     

低鱼粉饲料中添加低分子水解鱼蛋白对凡纳滨对虾非特异性免疫力和抗氧化能力的影响

以鱼粉水平为30%的饲料为高鱼粉饲料对照组，以豆粕替代高鱼粉饲料中50%鱼粉形成低鱼粉基础饲料，低鱼粉基础饲料添加0、0.5%、1.0%、1.5%和2.0%低分子水解鱼蛋白，配制 6种实验饲料，对初始体重为(0.44±0.02) g的凡纳滨对虾(Litopenaeus vannamei)幼虾进行48 d的养殖实验。实验结束后采集样品，测定肝胰腺酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、总超氧化物歧化酶(T-SOD)活力和丙二醛(MDA)含量，并分析肠道先天免疫缺陷基因(IMD)、对虾素3a分子(Penaiedin 3a)、溶菌酶(LZM)和Crustin相关免疫基因的表达量，以探讨低分子水解鱼蛋白对凡纳滨对虾非特异性免疫力和抗氧化能力的影响。结果显示，在低鱼粉饲料中添加适宜水平的低分子水解鱼蛋白能够显著提高对虾肝胰腺T-SOD、AKP和ACP的活力，降低MDA的含量；且1.5%低分子水解鱼蛋白能增加IMD、Penaiedin 3a、LZM和Crustin基因表达量。综上，凡纳滨对虾非特异免疫力和抗氧化能力的降低可能是影响植物蛋白源替代鱼粉的关键原因之一，而在饲料中补充1.0%–1.5%的低分子水解鱼蛋白可有效提高凡纳滨对虾抗病相关基因的表达量，增强其非特异免疫力和抗氧化能力。     

不同蛋白水解物对花鲈(Lateolabrax japonicus)生长性能及非特异性免疫的影响

实验以基础饲料组[含30％鱼粉蛋白(FM)]为对照组,用鱼蛋白水解物(FPH)、猪血蛋白水解物(PBPH)、酵母蛋白水解物(YPH)和豆粕蛋白水解物(SPH)分别替代配方中10％的鱼粉蛋白,配制成5组等氮等脂的饲料,喂养初始平均体重为31.99 g的花鲈(Lateolabrax japonicus)8周,探讨饲料中不同蛋白水解物对花鲈生长、饲料利用、体组成成分及非特异性免疫的影响.结果显示:各处理组实验鱼存活率在97.78％-98.89％之间,没有显著性差异(P＞0.05);FPH组与FM组的末重和特定生长率最高,两者之间没有显著差异(P＞0.05),但显著高于PBPH组、SPH组和YPH组(P＜0.05);FPH组饲料效率高于FM组、PBPH组和YPH组(P＞0.05),且显著高于SPH组(P＜0.05);各实验处理组鲈鱼摄食率没有显著差异(P＞0.05);FPH组蛋白效率比显著高于FM组、PBPH组、SPH组和YPH组(P＜0.05);FPH组、FM组和YPH组的蛋白质沉积率显著高于PBPH组和SPH组(P＜0.05).饲料中添加FPH和YPH会显著增加花鲈肝脏和血清中碱性磷酸酶、酸性磷酸酶、超氧化物歧化酶、溶菌酶活性和总抗氧化能力,显著高于FM组、PBPH组和SPH组(P＜0.05).FPH组的花鲈鱼体粗蛋白含量高于FM组和YPH组,但差异不显著(P＞0.05),FPH组显著高于PBPH组和SPH组(P＜0.05).综上所述,4种不同蛋白水解物替代鱼粉后投喂花鲈幼鱼,鱼蛋白水解物效果最好,其次是酵母蛋白水解物、猪血蛋白水解物和豆粕蛋白水解物.     

饲料中添加两种蛋白水解物对大菱鲆(Scophthalmus maximus L.)幼鱼生长性能及肠道组织学结构的影响

本研究共配制了3种等氮等脂的实验饲料,其中,对照组饲料使用15%鱼粉提供部分饲料蛋白,2个实验组饲料分别用鱼水解蛋白和鸡水解蛋白替代了饲料中10%的鱼粉蛋白。对初始体重为4.16 g左右的大菱鲆(Scophthalmus maximus L.)幼鱼进行了为期12周的投喂,研究了其对大菱鲆生长性能及肠道组织学结构的影响。结果显示,鱼水解蛋白组(PHf)的特定生长率、饲料效率、蛋白效率比和蛋白质沉积率较对照组(FM)无显著差异(P0.05),但显著高于鸡水解蛋白组(PHc)(P0.05);3组实验鱼的摄食率无显著差异(P0.05);PHf和PHc组的鱼体蛋白含量显著高于FM组(P0.05),3组实验鱼的脂肪含量无显著差异(P0.05)。PHf和PHc组的鱼体肌肉必需氨基酸含量显著高于FM组(P0.05)。PHf和PHc组的前肠和中肠黏膜皱襞高度大于FM组,且PHf组较FM组差异显著(P0.05);3组实验鱼的前肠和中肠上皮细胞的高度无显著差异(P0.05);FM组前肠和中肠的肠壁厚度大于其他2组,且显著大于PHf组(P0.05)。大菱鲆饲料中使用鱼水解蛋白替代部分鱼粉蛋白在生长性能及肠道组织学结构方面要优于使用鸡水解蛋白。     

不同蛋白水解物对花鲈(Lateolabrax japonicus)生长性能及非特异性免疫的影响

实验以基础饲料组[含30%鱼粉蛋白(FM)]为对照组,用鱼蛋白水解物(FPH)、猪血蛋白水解物(PBPH)、酵母蛋白水解物(YPH)和豆粕蛋白水解物(SPH)分别替代配方中10%的鱼粉蛋白,配制成5组等氮等脂的饲料,喂养初始平均体重为31.99 g的花鲈(Lateolabrax japonicus)8周,探讨饲料中不同蛋白水解物对花鲈生长、饲料利用、体组成成分及非特异性免疫的影响。结果显示:各处理组实验鱼存活率在97.78%–98.89%之间,没有显著性差异(P0.05);FPH组与FM组的末重和特定生长率最高,两者之间没有显著差异(P0.05),但显著高于PBPH组、SPH组和YPH组(P0.05);FPH组饲料效率高于FM组、PBPH组和YPH组(P0.05),且显著高于SPH组(P0.05);各实验处理组鲈鱼摄食率没有显著差异(P0.05);FPH组蛋白效率比显著高于FM组、PBPH组、SPH组和YPH组(P0.05);FPH组、FM组和YPH组的蛋白质沉积率显著高于PBPH组和SPH组(P0.05)。饲料中添加FPH和YPH会显著增加花鲈肝脏和血清中碱性磷酸酶、酸性磷酸酶、超氧化物歧化酶、溶菌酶活性和总抗氧化能力,显著高于FM组、PBPH组和SPH组(P0.05)。FPH组的花鲈鱼体粗蛋白含量高于FM组和YPH组,但差异不显著(P0.05),FPH组显著高于PBPH组和SPH组(P0.05)。综上所述,4种不同蛋白水解物替代鱼粉后投喂花鲈幼鱼,鱼蛋白水解物效果最好,其次是酵母蛋白水解物、猪血蛋白水解物和豆粕蛋白水解物。     

饲料中水解鱼蛋白对中国对虾非特异免疫的影响

在中国对虾基础饲料中用水解鱼蛋白替代0%、5%、10%和15%鱼粉蛋白,制成饲料投喂中国对虾30d,实验结束取样测定对虾生长指标并进行血细胞记数,以肝胰脏中的酸性磷酸酶、碱性磷酸酶、溶菌酶、超氧化物歧化酶活性和血清中的酸性磷酸酶、碱性磷酸酶、溶菌酶、超氧化物歧化酶、过氧化物酶、一氧化氮合酶活性为非特异免疫指标,探讨水解鱼蛋白作为免疫增强剂对中国对虾非特异性免疫效应的影响。结果表明,5%水解鱼蛋白替代鱼粉蛋白组对虾肝胰脏中酸性磷酸酶活性为0.54U/gprot,显著高于对照组和其他替代组(P<0.05);血液中总的血细胞数量最多,血清的酸性磷酸酶、碱性磷酸酶和溶菌酶活性均显著高于对照组和其他替代组(P<0.05),并且特定生长率最高。说明水解鱼蛋白作为免疫增强剂对中国对虾的非特异性免疫功能具有明显的增强作用。     

饲料中添加两种蛋白水解物对大菱鲆(Scophthalmus maximus L.)幼鱼生长性能及肠道组织学结构的影响

本研究共配制了3种等氮等脂的实验饲料,其中,对照组饲料使用15％鱼粉提供部分饲料蛋白,2个实验组饲料分别用鱼水解蛋白和鸡水解蛋白替代了饲料中10％的鱼粉蛋白.对初始体重为4.16g左右的大菱鲆(Scophthalmus maximus L.)幼鱼进行了为期12周的投喂,研究了其对大菱鲆生长性能及肠道组织学结构的影响.结果显示,鱼水解蛋白组(PHf)的特定生长率、饲料效率、蛋白效率比和蛋白质沉积率较对照组(FM)无显著差异(P＞0.05),但显著高于鸡水解蛋白组(PHc)(P＜0.05);3组实验鱼的摄食率无显著差异(P＞0.05);PHf和PHc组的鱼体蛋白含量显著高于FM组(P＜0.05),3组实验鱼的脂肪含量无显著差异(P＞0.05).PHf和PHc组的鱼体肌肉必需氨基酸含量显著高于FM组(P＜0.05).PHf和PHc组的前肠和中肠黏膜皱襞高度大于FM组,且PHf组较FM组差异显著(P＜0.05);3组实验鱼的前肠和中肠上皮细胞的高度无显著差异(P＞0.05);FM组前肠和中肠的肠壁厚度大于其他2组,且显著大于PHf组(P＜0.05).大菱鲆饲料中使用鱼水解蛋白替代部分鱼粉蛋白在生长性能及肠道组织学结构方面要优于使用鸡水解蛋白.     

1H NMR‐based metabolomics studies on the effect of size‐fractionated fish protein hydrolysate,fish meal and plant protein in diet for juvenile turbot (Scophthalmus maximus L.)

This study was designed to evaluate changes in the metabolic profile of liver and muscle of turbot (Scophthalmus maximus L.) fed fishmeal‐based diet, diets containing size‐fractionated fish protein hydrolysate and plant protein‐based diet using ¹H NMR‐based metabolomics approach combined with the growth. Fish protein hydrolysate (FPH) was obtained by enzymatic treatment, permeate fraction was obtained as UF by ultrafiltered step, and retentate fraction was retained as RF. FM diet contained fish meal used as a single protein source. Four other diets (PP, UF, FPH and RF) contained 180 g kg^?1 diet fish meal. 54, 55 and 55 g kg^?1 dry diet UF, FPH and RF were supplemented to UF, FPH and RF diets. All diets were formulated to be isolipidic and isonitrogenous fed to five triplicate groups of turbot (16.05 ± 0.03 g) for 68 days. O‐PLS‐DA in FM versus UF, FM versus FPH, FM versus RF and FM versus PP resulted in a reliable model for muscle and liver tissue, while O‐PLS‐DA in UF versus FPH and UF versus RF only showed metabolites changes in liver tissue. Results indicated that metabolite changes among the different treatments were consistent with the growth tendency.     

The effect of ultrafiltered fish protein hydrolysate level on growth performance,protein digestibility and mRNA expression of PepT1 in juvenile turbot (Scophthalmus maximus L.)

The intention of the study was to investigate the effect of ultrafiltered fish protein hydrolysate (UF) level on growth, feed utilization, apparent digestibility coefficients and proximal intestine peptide transporter 1 (PepT1) mRNA level for juvenile turbot (Scophthalmus maximus L.). Experimental diets (UF‐0, UF‐5, UF‐10, UF‐15 and UF‐20) were prepared containing about 68% plant protein, and fish meal protein was, respectively, replaced by 0%, 5%, 10%, 15% and 20% UF of dietary protein. Diet PP contained about 78% plant protein, and diet CAA contained about 10% crystalline amino acid mixture. All diets were fed to seven triplicate groups of turbot (initial weight 16.05 ± 0.03 g) for 68 days. Fish fed diet UF‐10 had an increasing tendency in growth compared with diets contained UF, while dietary UF level was not significantly correlated with specific growth rate and feed intake. Feed efficiency, protein efficiency ratio and protein productive value significantly correlated with dietary UF level, and fish fed diets contained low‐level UF had higher digestibility than that diets UF‐0, PP and CAA. There was a decreasing tendency in PepT1 expression level with dietary UF level. The results indicated that low‐level UF showed a positive effect on growth and feed utilization in juvenile turbot.     

Fish protein hydrolysate affected amino acid absorption and related gene expressions of IGF‐1/AKT pathways in turbot (Scophthalmus maximus)

The effects of fish protein hydrolysate (FPH) on growth, peptide and amino acid (AA) transporters, postprandial free AA and related gene expression of IGF‐1/AKT pathway were evaluated in turbot (Scophthalmus maximus). Three diets were formulated to contain the same low level of fishmeal; meanwhile 0, 45 and 180 g/kg FPH were, respectively, supplemented to the FF (FPH‐free), FL (FPH‐Low) and FH (FPH‐High) diets. Fish fed the FH diet improved the growth compared with the other groups. For peptide and AA transporters, PepT1, B⁰AT1, CAT1 and PAT1 mRNA levels in proximal or distal intestine decreased in fish fed the FH diet. The concentration of free total essential AAs in serum was higher in the FH treatment than that in the FF treatment at 2 and 6 hr after feeding. For IGF‐1/AKT pathway in muscle, IGF‐1, 4E‐BP1 and FoxO1 mRNA levels were the highest in the FH group, whereas IGF‐1R mRNA levels were the highest expression level in the FF group. In conclusion, down‐regulated AAs transport, alleviated the delayed postprandial peak of serum‐free AAs and increased muscle protein synthesis were observed to improve the growth when turbot was fed high FPH level diets containing a high plant protein.     

Application of different types of protein hydrolysate in high plant protein diets for juvenile turbot (Scophthalmus maximus)

A 10‐week feeding experiment was conducted to investigate the effects of different types of dietary protein hydrolysate (PH) on growth performance, body composition, trypsin activity and serum transaminase of juvenile turbot. Four high plant protein diets contained different types of PH, fish PH (FPH), yeast PH (YPH), pig blood PH (PBPH) and soy PH (SPH), replacing 10% fishmeal of the basal diet. The basal diet with 30% fishmeal and no PH was used as the control diet (C). Each diet was assigned to triplicate groups of 30 fish. The specific growth rate (SGR) was not significantly different between groups C and FPH, but groups C and FPH showed significantly higher SGR than other groups. The feed efficiency ratio (FER) and protein efficiency ratio (PER) were not significantly different among groups C, FPH and YPH, but groups PBPH and SPH showed significantly lower FER and PER than groups C and FPH. Group PBPH showed significantly higher hepatosomatic index than other groups except YPH. Fish fed YPH showed significantly lower whole‐body protein content, but significantly higher whole‐body lipid content than fish fed diets C, FPH and PBPH. The activities of serum GOT and GPT in group PBPH were higher than those in groups C, FPH and YPH. These results suggested that when used at a low level in high plant protein diets for juvenile turbot, FPH is a good alternative protein source and YPH also has the application potential, but PBPH and SPH can cause negative impacts on fish growth and health.     

Taurine alone or in combination with fish protein hydrolysate affects growth performance,taurine transport and metabolism in juvenile turbot (Scophthalmus maximus L.)

The study was conducted to investigate the effects of taurine (Tau) alone or in combination with fish protein hydrolysate (FPH) on growth performance, the expression of Tau transporter (TauT) and metabolic profile in juvenile turbot. FM, FPH0, FPH0+T, FPH10 and FPH10+T diets, respectively, contained 300, 150, 150, 80, and 80 g/kg fishmeal. FPH10 and FPH10+T diets contained 62 g/kg FPH. FPH0+T and FPH10+T diets were, respectively, prepared by supplementing the FPH0 and FPH10 diet formulations with 8 g/kg Tau. Specific growth rate was the highest in FM group and the lowest in FPH10 group. TauT mRNA levels in fish fed Tau supplemented diets were significantly lower than that in Tau unsupplemented diets. NMR‐based metabolomics analysis showed that Tau contents in liver of FPH0+T and FPH10+T were significantly higher than that of FM, FPH0 and FPH10. In muscle, Tau contents were significantly decreased in the FPH10+T versus FPH0 and the FPH10+T versus FPH10 comparisons. In conclusion, 62 g/kg FPH to replace fishmeal may not affect Tau synthesis, transport and metabolism. However, Tau supplemented alone or in combination with a certain level of FPH could reduce the requirement for Tau synthesis and transport and increased Tau levels in muscle and liver.