玉米蛋白粉部分替代鱼粉对罗氏沼虾生长、氨基酸沉积率和肌肉营养成分的影响

分别用0%(对照组)、5%、10%、15%的玉米蛋白粉替代饲料中0%、9.10%、18.20%、27.30%的鱼粉,配制4种等氮等能的实验饲料,饲养罗氏沼虾(Macrobrachium rosenbergii)53 d后,测定其生长、饲料利用、肌肉营养成分和肌肉氨基酸沉积率,旨在为玉米蛋白粉在罗氏沼虾饲料中的应用提供科学依据.结果表明,5%玉米蛋白粉组虾的生长和饲料利用与对照组无显著差异(P＞0.05);10%玉米蛋白粉组的生长与对照组无显著差异(P＞0.05),但饲料系数明显高于对照组(P＜0.05)、蛋白质效率明显低于对照组(P＜0.05);15%玉米蛋白粉组虾的生长、饲料利用显著低于对照组、5%组和10%组(P＜0.05).玉米蛋白粉替代鱼粉不影响罗氏沼虾肌肉中的水分、粗蛋白、粗脂肪和粗灰分含量;也不显著影响肌肉氨基酸、必需氨基酸和呈味氨基酸总量(P＞0.05);对于单种氨基酸而言,除了10%和15%组的苏氨酸和15%组的丝氨酸含量显著低于对照组之外(P＜0.05),其他各组各种氨基酸含量与对照组均无显著性差异(P＞0.05).玉米蛋白粉替代鱼粉对氨基酸总量和必需氨基酸总量沉积率没有显著影响;必需氨基酸中赖氨酸、蛋氨酸和精氨酸的沉积率均较高;5%组和:10%组除了苏氨酸的沉积率显著低于对照组之外(P＜0.05),这2组的其余氨基酸沉积率与对照组均无显著性差异(P＞0.05);15%组除了丙氨基酸沉积率与对照组无显著差异之外(P＞0.05),其他氨基酸沉积率均显著低于对照组(P＜0.05).在本实验条件下,罗氏沼虾饲料中玉米蛋白粉的适宜用量为5%～10%,对鱼粉的适宜替代量为9.10%～18.20%.     

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%。     

发酵鱼溶浆替代鱼粉对大菱鲆幼鱼生长、抗氧化能力、蛋白质代谢及相关基因表达的影响

为研究发酵鱼溶浆(FSW)替代鱼粉对大菱鲆(Scophthalmus maximus)幼鱼生长、抗氧化能力、蛋白质代谢及相关基因表达的影响,实验设正对照组(50%鱼粉),负对照组(30%鱼粉),在负对照组基础上分别以2%、4%、6%、8%的FSW替代鱼粉,分别命名为FSW2、FSW4、FSW6和FSW8组,饲喂初始体重为(30.00±0.03) g的大菱鲆幼鱼8周。结果显示,各组间幼鱼成活率均无显著差异(P>0.05),FSW2~FSW8组幼鱼增重率、蛋白质效率与正对照组无显著差异(P>0.05),但均显著高于负对照组(P<0.05)。FSW2~FSW8组全鱼和背肌粗蛋白含量与正对照组无显著差异,但显著高于负对照组(P<0.05);负对照组全鱼和背肌粗脂肪含量显著高于其他组(P<0.05)。负对照组血清谷丙转氨酶(ALT)、谷草转氨酶(AST)和甘油三脂(TG)均显著高于正对照组(P<0.05),负对照组、FSW2 ~FSW8组血清中总胆固醇(T-CHO)、ALT和AST呈先降低后升高的趋势,肝脏中ALT和AST含量则呈相反趋势。负对照组血清中高密度脂蛋白胆固醇(HDL-C)含量显著低于正对照组(P<0.05)。负对照组肝脏中蛋白激酶A(PKA)、蛋白激酶C(PKC)和乳酸脱氢酶(LDH)活性均显著低于正对照组(P<0.05)。与正对照组相比,负对照组肠道中氨基酸转运载体b0at1和小肽转运载体pept1表达量上调,氨基酸转运载体cat1、pat1表达量差异不显著,FSW2~FSW8组b0at1、cat1、pat1和pept1表达量均显著高于正对照组和负对照组(P<0.05)。综上所述,饲料中添加FSW显著改善了实验鱼对饲料蛋白质的利用率,缓解了植物蛋白造成的生长性能下降。以增重率为评价指标,添加FSW可使饲料中鱼粉的使用量降低至22%,且鱼体在生长和体组成上与50%鱼粉组无显著差异。     

不同脂肪源对罗氏沼虾生长及体组织常见组分的影响

用5种不同脂肪源组合的饲料(Ⅰ.鱼油0.5%+豆油2.5%;Ⅱ.鱼油0.5%+菜籽油2.5%;Ⅲ.鱼油0.5%+花生油2.5%;Ⅳ.鱼油0.5%+亚麻油2.5%;Ⅴ.豆油1.5%+亚麻油1.5%)投喂体重为(2.22±0.04)g的罗氏沼虾(Macrobrachium rosenbergii)40 d,研究不同脂肪源对其生长及全虾和肌肉中水分、粗蛋白、粗脂肪含量的影响。结果显示:在生长方面,第Ⅴ组的罗氏沼虾增重显著高于Ⅱ组和Ⅲ组(P<0.05),Ⅰ组和Ⅳ组增重也显著大于Ⅱ组(P<0.05)。在体成分方面,Ⅰ组全虾总水分含量最低,显著低于Ⅲ组和Ⅳ组(P<0.05),其他各组间无显著差异(P>0.05);Ⅴ组全虾粗脂肪含量最高,显著高于其他各试验组(P<0.05);Ⅲ组全虾粗蛋白含量显著低于Ⅰ组、Ⅱ组及Ⅴ组(P<0.05);Ⅳ组肌肉总水分含量显著高于其他各组;肌肉粗脂肪和粗蛋白含量各试验组之间差异不显著(P>0.05)。     

玉米蛋白粉替代部分鱼粉对凡纳滨对虾摄食量、生长和肌肉成分的影响

以凡纳滨对虾幼虾［体重(0.013 6±0.001 0) g］为试验对象，以鱼粉、豆粕、肉粉和花生粕为蛋白源配制对照饲料，用玉米蛋白粉替代部分鱼粉配制3种与对照饲料等氮、等能的试验饲料，其中玉米蛋白粉用量为5%、10%和15%，分别替代鱼粉8.6%、17.2%和25.8%，饲喂凡纳滨对虾45 d，研究玉米蛋白粉替代部分鱼粉对凡纳滨对虾摄食量、生长和肌肉成分的影响。结果表明，（1）试验饲料中玉米蛋白粉用量不超过10%，对凡纳滨对虾日均摄食量没有显著影响（P>0.05）。（2）5%玉米蛋白粉组的生长效果最好，其相对增重率、增长率和饲料系数分别为2 542.8%、155.1%和1.58，前者显著高于对照组（P<0.05），后两者与对照组没有显著差异（P>0.05）；10%玉米蛋白粉组虾的生长和饲料系数与对照组没有显著差异（P>0.05）；15%组虾的生长显著低于对照组（P<0.05）。（3）玉米蛋白粉替代鱼粉对对虾肌肉的水分、粗蛋白、粗脂肪和粗灰分含量影响不显著（P>0.05）；对对虾肌肉氨基酸总量、必需氨基酸总量和呈味氨基酸含量以及必需氨基酸指数的影响也不显著（P>0.05）。（4）玉米蛋白粉在凡纳滨对虾饲料中的适宜用量为10%。     

饲料中蛋白质水平对克氏原螯虾生长性能及肌肉品质的影响

以初始平均体质量为(3.69±0.05)g的克氏原螯虾幼虾为研究对象,配制蛋白质水平分别为27.72%、30.09%、33.05%、35.31%和37.57%的5种等能、等脂的配合饲料,进行为期47 d的饲养试验,探索饲料中不同蛋白质水平对克氏原螯虾生长性能、肌肉质构特性、常规营养成分及氨基酸组成和含量的影响。结果表明:随着饲料蛋白质水平的增加,克氏原螯虾的增重率和特定生长率呈先上升后降低的趋势,其中饲料蛋白质水平为30.09%组虾的增重率、特定生长率显著高于其他各组(P<0.05);各组间饲料系数、虾体质量/体长比、肝体指数、得肉率以及成活率无差异统计学意义(P>0.05)。饲料蛋白质水平为27.72%组虾的肌肉硬度、咀嚼性显著高于饲料蛋白质水平为35.31%、37.57%组(P<0.05),饲料蛋白质水平为30.09%、33.05%组虾的肌肉弹性显著高于饲料蛋白质水平最低组(P<0.05),饲料蛋白质水平最高组虾的回复性显著低于其他各组(P<0.05),各组间虾肌肉内聚力无差异统计学意义(P>0.05)。随着饲料蛋白质水平的增加,克氏原螯虾的肌肉粗蛋白含量呈先升高后趋于稳定的变化趋势,饲料蛋白质水平为35.31%、37.57%组虾的肌肉粗蛋白含量显著高于饲料蛋白质水平最低组(P<0.05);各组间虾的肌肉水分、粗脂肪、灰分含量差异不具统计学意义(P>0.05)。肌肉总氨基酸、总必需氨基酸、总非必需氨基酸以及亮氨酸、赖氨酸、天门冬氨酸、谷氨酸随饲料蛋白的升高均呈先升高后趋于稳定的变化趋势。综合考虑生长性能、肌肉品质以及成本效益,建议克氏原螯虾饲料蛋白质水平为30.09%。     

发酵豆粕替代鱼粉对卵形鲳鲹生长和血清生化的影响

为探讨发酵豆粕替代鱼粉对卵形鲳鲹(Trachinotus ovatus)生长和血清生化的影响,该研究以鱼粉(fish meal,FM)为基础蛋白源配制了5组饲料[分别添加0%(FM)、25%(FSM25)、50%(FSM50)、75%(FSM75)和100%(FSM100)的发酵豆粕(fermented soybean meal,FSM)替代鱼粉]。为消除限制性氨基酸的影响,分别添加0%、0.10%、0.22%、0.35%和0.45%的赖氨酸及0%、0.14%、0.27%、0.41%和0.54%的蛋氨酸。结果显示,FSM25和FSM50组的增重率、特定生长率、肥满度和采食量与FM组无显著差异(P0.05),FSM100组饲料系数显著高于FM组(P0.05)。发酵豆粕各组的肌肉水分、灰分、粗蛋白和粗脂肪含量与FM组相比无显著差异(P0.05)。FSM75和FSM100组血清中的谷草转氨酶(AST)活性和总蛋白(TP)含量分别显著高于和低于FM组(P0.05),FSM100组谷丙转氨酶(ALT)和超氧化物歧化酶(SOD)活性显著高于FM组(P0.05)。FSM75和FSM100组肝脏IGF-1和GH基因表达量显著低于FM组(P0.05)。综上,在添加限制性氨基酸条件下,发酵豆粕替代鱼粉不超过50%不会对卵形鲳鲹产生不利影响,根据回归曲线得出最佳替代水平为17.5%。     

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。     

不同饵料配比条件下盐碱水池塘拟穴青蟹生长、营养及血清生化指标比较分析

为探究盐碱水池塘养殖条件下投喂不同饵料对池塘水质及拟穴青蟹生长、营养品质及血清生化指标的影响,实验设置青柳蛤、沙光鱼、鹰爪虾3种生物饵料组和1种人工配合饲料组,各组设置3个重复,实验周期4个月,分析各组池塘水质变化,并采用单因素方差分析（One-Way ANOVA）方法比较各组蟹的生长、营养及血清生化指标。结果显示：各组水温、盐度与pH差异较小,而溶解氧、氨氮、亚硝酸盐氮差异较大,其中,沙光鱼组溶解氧从11.5 mg/L降至9.2 mg/L,而氨氮、亚硝酸盐氮从养殖初期0.44 mg/L、0.022 mg/L上升到养殖末期的0.89 mg/L、0.05 mg/L;青柳蛤组蟹体重（334 g）、增重率（332.7 %）和特定生长率（0.076 %/d）显著（P<0.05）高于其他组,人工配合饲料组存活率最高,达到66.67 %,沙光鱼组肥满度（0.221 g/cm3）显著（P<0.05）高于其他组;青柳蛤组蟹肌肉必需氨基酸中的缬氨酸、蛋氨酸、异亮氨酸、苯丙氨酸含量及肝胰腺呈味氨基酸总量和鲜味氨基酸总量在各组中最高,人工配合饲料组肝胰腺必需氨基酸中的苏氨酸、亮氨酸、赖氨酸、组氨酸含量在各组中最高,鹰爪虾组肌肉呈味氨基酸总量和鲜味氨基酸总量在各组中最高,青柳蛤组肌肉与肝胰腺饱和脂肪酸、多不饱和脂肪酸、脂肪酸含量均为最高;青柳蛤组总蛋白含量显著（P<0.05）高于其他组,沙光鱼组总胆固醇显著（P<0.05）高于其他组,人工配合饲料组谷草转氨酶、甘油三酯、葡萄糖显著（P<0.05）高于其他组,相关性分析显示青柳蛤等生物饵料常规营养与拟穴青蟹各生长指标存在显著正相关（P<0.05）。研究结果表明,青柳蛤组拟穴青蟹生长、营养及血清蛋白质指标上具有显著优势,可以作为盐碱水池塘养殖拟穴青蟹的适口饵料。本研究将为拟穴青蟹北方盐碱水池塘养殖和推广提供数据参考。     

饲料添加中草药制剂对日本沼虾免疫因子的影响

在基础饲料的基础上,通过添加大青叶、鱼腥草等中草药煎液制成试验饲料,以基础饲料为对照.采用连续投喂的方法,饲喂日本沼虾30 d,研究中草药制剂对日本沼虾免疫因子的影响.采集日本沼虾肝胰脏,肌肉,分别测定了8种免疫指标活性.结果表明,中草药添加饲料组虾的酸性磷酸酶(ACP)、碱性磷酸酶(ALP)、超氧化物歧化酶(SOD)活性与对照组差异显著(P＜0.05),溶菌活性(UL)、抗菌活性(UA)、酚氧化酶活性(PO)、过氧化物酶活性(POD)作为虾肝胰脏、肌肉的免疫检测指标与对照组比较差异不显著(P＜0.05),但平均值比对照饲料组高.血凝活性在虾肝胰脏免疫指标中中草药组与对照组比较差异显著(P＜0.05),而在肌肉免疫指标中结果很难测出.试验结果表明,该中草药制剂的添加对增强日本沼虾的免疫水平具有一定的效果.     

Fishmeal can be totally replaced by plant protein blend at two protein levels in diets of juvenile Siberian sturgeon,Acipenser baerii Brandt

An 8‐week growth trial was conducted to evaluate the effects of a plant protein blend (PPB, comprised of soybean meal and wheat gluten meal) as fishmeal (FM) substitute on growth, nitrogen (N) and phosphorus (P) balance in Siberian sturgeon, Acipenser baerii Brandt. Two control diets were formulated to contain two protein levels (400 and 360 g kg^?1). At each protein level, FM was totally replaced by PPB with supplement of crystalline essential amino acids and mono‐calcium phosphate. Growth performance was not affected by dietary protein sources and protein levels. Fish fed the low‐protein diets had higher FI than that of the high protein groups, while fish fed the FM‐based diets had higher FI than that of fish fed the PPB‐based diets. N/P intake of fish showed linear relationship with total N/P loss. The productive P value was significantly affected by dietary protein sources, but no significant effects were shown on productive N value. The results suggest that Siberian sturgeon fed total plant‐based diets with balance of EAA could maintain normal growth performance and reduce total P excretion both at 360 and 400 g kg^?1 protein levels.     

Partial and total replacement of fishmeal by a blend of animal and plant proteins in diets for Seriola dumerili: Effects on performance and nutrient efficiency

A 154‐day trial was performed to assess the use of an alternative protein blend (corn gluten, krill and meat meal) as a substitute for fishmeal in diets for juvenile yellowtail, using four isolipidic (140 g/kg) and isoenergetic diets (24 MJ/kg) with the same digestible protein content (50%). The control diet was FM100, without replacement, and in FM66, FM33 and FM0, fishmeal was replaced at 33 g/kg, 66 g/kg and 100 g/kg, respectively. At the end of the experiment, no differences in growth parameters were observed. Fish fed the FM0 diet exhibited the lowest survival (23%). This high mortality may be due to different factors, such as a dietary amino acid imbalance or some antinutrient factors contained in the alternative ingredients. Feed intake, feed conversion ratio, digestible protein intake and protein efficiency ratio were similar in all diets. However, digestible energy intake and protein efficiency retention were lowest in fish fed the FM0 diet. Apparent digestibility coefficients for protein, energy and amino acids diminished as a substitution for fishmeal increased. Significant differences were observed in the diet whole‐fish body profile amino acid retention (AAR) ratio for the seven essential amino acids. In summary, total fishmeal replacement by the blend assayed was not feasible for yellowtail. The FM66 diet resulted in good growth, high survival and good nutrient efficiency.     

Essential amino acids supplementation to practical diets affects growth,feed utilization and glucose metabolism‐related signalling molecules of blunt snout bream (Megalobrama amblycephala)

Six diets were formulated to investigate the success of fish meal (FM) replacement by plant proteins; diet 1 reflected a commercial feed (8% FM), diet 3 contained 4% FM, and diet 5 was devoid of FM. Whereas, diet 2, diet 4, and diet 6 reflected diet 1, diet 3, diet 5, respectively, and supplemented with essential amino acid (EAA). At the end of 8‐week trial, there was no significant difference in survival rate. Significantly higher final weight, weight gain rate, and specific growth rate were recorded in the group fed diet 2 compared with the other treatments (except diet 4) (p < 0.05). Feed conversion ratio of fish fed diet 2 was significantly lower than those fed diets 1, 3, and 5 (p < 0.05). The lowest feed intake and highest protein efficiency rate were found in fish fed diet 2 (p < 0.05). There was no significant difference in whole body compositions between treatments. Plasma aspartate transaminases, alanine aminotransferase, and glucose were significantly affected by dietary treatments (p < 0.05), while plasma protein and albumin contents were not influenced by the treatments. The relative expression of target of rapamycin (TOR) and phosphatidylinositol 3‐kinase, regulatory subunit 1 (alpha) (PIK3R1) in fish fed diet 3 (4% FM) were significantly down‐regulated compared with those fed diet 6 for TOR and diets 4 and 6 for PIK3R1 (p < 0.05). Insulin receptor substrate 1 (IRS‐1) and janus kinase 3 (JAK3) expressions were fluctuated, with the higher levels in fish fed diets 4 and 6. In conclusion, the findings of this study indicate that plant protein mixture supplemented with EAA could be used to substitute FM in practical diet for Megalobrama amblycephala.     

Fishmeal replacement by mixed plant proteins and maggot meal on growth performance,target of rapamycin signalling and metabolism in juvenile turbot (Scophthalmus maximus L.)

Fishmeal could only be replaced by plant proteins at limited levels in aquafeeds, especially for carnivorous fish. In this study, an experiment was designed to evaluate the possibility of improving the utilization of plant proteins by maggot meal supplementation in turbot diet. Five diets were formulated: a reference diet (FM) containing 63% fishmeal and four experimental diets (35(0%), 35(3%), 40(0%), 40(3%)) in which fishmeal was substituted at different levels by plant proteins with 0–3% maggot meal. Turbot (4.90 ± 0.03 g) was fed with these diets for 9 weeks. Fishmeal was successfully replaced by plant proteins in turbot diet without growth reduction at 35% but not 40%. However, maggot supplementation (3%) at 40% plant protein replacement level achieved comparable growth performance with that of fishmeal. Maggot meal supplementation improved apparent digestibility coefficients, plasma hydroxyproline levels, intestine trypsin activities and activated target of rapamycin (TOR) signalling, all of which were decreased or down‐regulated after high plant protein replacement. Therefore, this study demonstrated maggot meal, a potential valuable protein source for turbot.     

Partial and total replacement of fishmeal with poultry by-product meal in diets for gibel carp, Carassius auratus gibelio Bloch

Triplicate groups of gibel carp Carassius auratus gibelio Bloch (initial body weight: 4.89 g) were fed for 8 weeks at 24.8–30.8°C with nine isonitrogenous and isoenergetic diets. The control diet (F1) used white fishmeal (FM) as the sole protein source. In the other eight diets (F2–F9), 40.5–100% of FM protein was substituted by poultry by‐product meal (PBM) at 8.5% increments. The specific growth rate (SGR), feed efficiency ratio, protein efficiency ratio, protein retention efficiency and energy retention rate for fish fed PBM diets (F2–F9) were all higher, but not always significantly, than those for fish fed F1. All apparent digestibility coefficients for fish fed PBM diets were lower than those for fish fed F1. Fish fed F1 had a significantly higher hepatosomatic index value than fish fed PBM diets (P<0.05). No significant (P>0.05) effect of diet was found in whole‐body moisture and fat content. Whole‐body protein and energy content for fish fed PBM diets were slightly higher than that for fish fed F1. The optimal replacement level of FM by PBM was estimated by second‐order polynomial regression to be 66.5% in protein.     

Salmon testes meal as a functional feed additive in fish meal and plant protein‐based diets for rainbow trout (Oncorhynchus mykiss Walbaum) and Nile tilapia (Oreochromis niloticus L.) fry

Fishery processing by‐products are a large resource from which to produce fishmeal and other products for a variety of uses. In this study, testes meal (TM) produced from pink salmon processing by‐product was evaluated as a functional ingredient in aquafeeds. Nile tilapia and rainbow trout fry were fed five isonitrogenous and isoenergetic experimental diets for 4 and 9 weeks respectively. Two diets were fishmeal‐based (FM) and three were plant protein‐based (PP). Salmon TM was added to the FM and PP diets at 7% to replace 20% of fishmeal protein (FMTM and PPTM respectively). An additional control diet was prepared in which fishmeal was added to the PP diet to supply an equivalent amount of protein as supplied by TM (PPFM). Inclusion of TM in both the FM‐ and PP‐based diets resulted in higher final body weights, although differences were only significant between rainbow trout fed FM or FMTM diets. Similar differences were calculated for other indices of fish performance, e.g. specific growth rate, feed conversion ratio, protein efficiency ratio and protein retention efficiency. Feed intake was significantly higher for fish fed FMTM compared with FM in rainbow trout. For tilapia, final weights were numerically higher, but not significantly different for fish fed diets containing TM compared with non‐TM diets (FM vs. FMTM; PP vs. PPTM). Performance of trout or tilapia fed the PPFM diet did not increase compared with the PP diet. The results indicate that TM addition to both FM and PP diets increased feed intake and also increased metabolic efficiency, demonstrating that TM can be a functional ingredient in aquafeeds.     

Effect of fishmeal replacement with Artemia biomass as a protein source in practical diets for the giant freshwater prawn Macrobrachium rosenbergii

A 30-day feeding experiment was conducted in 160-L plastic tanks to evaluate the potential use of Artemia biomass as a protein source in practical diets for postlarval Macrobrachium rosenbergii (initial mean weight of 12.12–12.29 mg). Nine isoenergetic and isonitrogenous experimental diets (approximately 40% crude protein) were formulated by replacing levels of the fishmeal (FM) protein difference either with dried or frozen Artemia (0, 25, 50, 75 and 100%). The 0% Artemia treatment, in which Peruvian FM was the only main protein source, was considered to be the control diet. The results showed that prawn postlarvae (PLs) fed the FM control diet had a lower survival (46%) compared with all Artemia diets. Significant differences ( P <0.05) were, however, only found at 75% and 100% Artemia protein inclusion levels (survival of 68–77%). A gradual increase in growth performance (live weight gain, specific growth rate and total length) of the prawns was achieved on increasing dietary inclusion of Artemia protein. Additionally, the size distribution exhibited the same response as growth performance. However, prawns fed the frozen Artemia diets showed a better performance than the ones fed the dried Artemia diets. It can be suggested that Artemia biomass may totally replace FM in practical diets for PLs of the freshwater prawn M. rosenbergii .     

Inclusion of rendered animal ingredients as fishmeal substitutes in practical diets for cuneate drum, Nibea miichthioides (Chu, Lo et Wu)

Potential of using rendered animal ingredients, poultry by‐product meal (PM), meat and bone meal (MBM), feather meal (FM) and blood meal (BM) to replace fishmeal in practical diets for cuneate drum Nibea miichthioides (Chu, Lo et Wu) was examined in a net pen experiment. A total of 10 dietary treatments were compared. Nine diets were formulated to contain 363 g kg⁻¹ digestible protein and 14.8 MJ kg⁻¹ digestible energy, and a dietary treatment consisting of raw fish (RF) served as reference. In the formulated diets, the control diet contained 350 g kg⁻¹ herring meal, whereas in the other eight diets, the fishmeal were replaced by MBM (30% fishmeal replacement), PM (50% fishmeal replacement), a blend of PM, MBM, FM and BM (30%, 50% and 80% fishmeal replacement), or a blend of PM, MBM and BM (30%, 50% and 80% fishmeal replacement), respectively. Cuneate drum fingerling (initial body weight 28 g) were fed the test diets for 8 weeks. Specific growth rate (SGR), final body weight (FBW), nitrogen retention efficiency (NRE), condition factor and contents of moisture, crude protein and crude lipid in carcass were not significantly different between fish fed the formulated diets. Fish fed the formulated control diet exhibited lower SGR and FBW, but higher FCR, NRE, hepatosomatic index and crude lipid content in carcass and liver than those of the fish fed the RF. Results of the present study indicate that combination of rendered animal protein ingredients can replace most of the fishmeal in practical diets for cuneate drum.