感染累枝虫对黄颡鱼血液生化指标的影响

为探究感染累枝虫(Epistylis sp.)的黄颡鱼(Pelteobagrus fulvidraco)病愈过程中血液生化指标的变化规律,测定了患病鱼和经药物治疗痊愈及健康的黄颡鱼的血清皮质醇、葡萄糖、乳酸(LD)含量以及碱性磷酸酶(AKP)、乳酸脱氢酶(LDH)、谷草转氨酶(AST)、谷丙转氨酶(ALT)的活性。结果显示,患病组黄颡鱼血清皮质醇、血糖含量和AST活性均显著高于痊愈组(P0.05),血清ALT活性与痊愈组无显著差异(P0.05)。与患病组相比,痊愈组黄颡鱼血清LD含量,LDH和ALP活性均显著升高(P0.05)。与健康组相比,痊愈黄颡鱼血清皮质醇含量和ALT活性无显著差异(P0.05),而葡萄糖、LD含量,LDH、AKP和AST活性则差异显著(P0.05)。结果表明,累枝虫的寄生引起了黄颡鱼显著的应激反应,使鱼体非特异性免疫能力下降;经治疗痊愈后的黄颡鱼的非特异性免疫力可恢复正常,鱼体应激反应消失并表现出正常的游泳行为。     

水霉病对草鱼血液生化指标和肌肉泛素-蛋白酶体系统的影响

本研究探讨了感染水霉病后草鱼(Ctenopharyngodon idellus)的血液生化特性和肌肉泛素-蛋白酶体系统(UPS)活性变化。随机选取患病和健康草鱼各10尾,测定血清葡萄糖(GLU)、白蛋白(ALB)、总蛋白(TP)、胆固醇(CHO)及甘油三酯(TG)含量和乳酸脱氢酶(LDH)、碱性磷酸酶(ALP)、谷草转氨酶(AST)及谷丙转氨酶(ALT)活性,检测肌肉nrf2、hsp70、hsp90和UPS相关基因表达,并定量测定了肌肉组织泛素化蛋白水平。结果显示,感染水霉病草鱼的血清CHO、ALB、TP和TG浓度显著下降,AST和LDH活性显著提高,患病草鱼肌肉组织nrf2、hsp70和hsp90的mRNA表达量显著升高。水霉病显著上调了肌肉chip、ub、psma2、psmc1、murf1和mafbx的mRNA表达水平和泛素化蛋白含量。感染水霉病改变了草鱼血清生化指标,诱导草鱼机体产生细胞应激反应,显著上调了骨骼肌泛素-蛋白酶体系统的活性。研究结果可为水霉病的诊断和防治提供科学的参考依据。     

“狂游症”中华鲟幼鱼血液生化指标初步研究

检测了"狂游症"中华鲟(Acipenser sinensis)幼鱼(体长(27.2±3.1)cm,体重(152.3±41.2)g)的血液生化指标。结果显示,患病中华鲟谷丙转氨酶(ALT)、谷草转氨酶(AST)、碱性磷酸酶(ALP)、乳酸脱氢酶(LDH)、尿素(UREA)、肌酐(CREA)等指标较健康中华鲟显著升高(P<0.05),其中ALT、AST、ALP、LDH、UREA差异极显著(P<0.01),患病鱼胆汁酸(TBA)、总胆固醇(CHOL)有所升高,但不显著;患病中华鲟α-淀粉酶(α-AMY)、总蛋白(TP)、白蛋白(ALB)、球蛋白(GLO)、总胆红素(TBIL)、葡萄糖(GLU)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-CHOL)等指标较健康中华鲟显著降低(P<0.05),其中TBIL、GLU、HDLCHOL差异极显著(P<0.01)。     

不同脂肪源对黄颡鱼幼鱼生长性能、体成分、血清生化指标、体组织脂肪酸组成及抗氧化能力的影响

为研究不同脂肪源对黄颡鱼幼鱼生长性能、体成分、血清生化指标、体组织脂肪酸组成及抗氧化能力的影响,进行为期8周的养殖实验。实验配制了4种分别添加有椰子油(CO)、苏子油(PO)、葵花籽油(SO)、鱼油与葵花籽油1∶1混合油(FO/SO)的等氮等脂的饲料,喂养平均初始体质量为(1.52±0.00)g的黄颡鱼幼鱼。实验结果显示:不同脂肪源对黄颡鱼终末体质量(FBW)、增重率(WGR)、特定生长率(SGR)和成活率(SR)均无显著影响,对饲料系数(FCR)影响显著,各组SR均在95%以上。各组间的肝体比(HSI)、肥满度(CF)均有显著性差异,而脏体比(VSI)和肠脂比(IPR)无显著性差异。HSI和CF均以鱼油与葵花籽油1∶1混合油(FO/SO)组最高,葵花籽油(SO)组最低。黄颡鱼的鱼体水分、粗蛋白和灰分不受饲料脂肪源的影响,而椰子油(CO)组的粗脂肪含量显著高于其他3组,为10.51%,剩余3组间无显著性差异。饲料中脂肪源对黄颡鱼肌肉、肝脏组织脂肪酸组成和含量影响显著,并且肌肉和肝脏中脂肪酸含量变化与饲料中相应脂肪酸含量变化基本一致,椰子油(CO)组组织中饱和脂肪酸(SFA)含量最高,苏子油(PO)组组织中亚麻酸(ALA)和n-3 PUFA含量最高,葵花籽油(SO)组组织中亚油酸(LA)和n-6 PUFA含量最高,而鱼油与葵花籽油1∶1混合油(FO/SO)组组织中脂肪酸较为均衡。黄颡鱼血清中的总蛋白(TP)、白蛋白(ALB)、球蛋白(GLOB)、白蛋白/球蛋白(A/G)、谷草转氨酶(AST)、总胆固醇(CHOL)、甘油三酯(TG)、血糖(GLU)、肌酸激酶(CK)含量不受饲料脂肪源的影响。各组黄颡鱼肝脏中超氧化物歧化酶(SOD)、丙二醛(MDA)、谷胱甘肽S转移酶(GST)活性有显著差异。椰子油(CO)组的SOD和GST活性最高,而MDA含量最低。研究表明,在添加豆油的基础上,椰子油、苏子油、葵花籽油和鱼油与葵花籽油1∶1混合油都可以用作黄颡鱼饲料的脂肪源;证实了鱼体组织中脂肪酸组成基本可以反映饲料脂肪酸组成,并且说明了黄颡鱼具有延长和去饱和ALA和LA的能力。     

蟋蟀粉替代鱼粉对黄颡鱼幼鱼生长性能、肌肉氨基酸组成和血清生化指标的影响

为研究蟋蟀(Gryllus bimaculatus)粉替代鱼粉对黄颡鱼(Pelteobagrus fulvidraco)幼鱼生长性能、肌肉成分和血清生化指标的影响,以黄颡鱼幼鱼[(2.0±0.13) g]为研究对象,分别使用蟋蟀粉替代0 (对照组)、15%、30%、45%和60%的鱼粉配制成5组等氮等能的实验饲料,分别记为T0、T15、T30、T45和T60组。实验幼鱼在室内循环水系统进行为期10周的养殖实验。结果显示,随着蟋蟀粉替代量的增加,黄颡鱼幼鱼生长呈先增加后降低的趋势;T30组的终末均重(FBW)、增重率(WGR)和特定生长率(SGR)最高,且均显著高于T0组;T30组的饲料系数(FCR)显著低于T0和T15组;T30的肝体比(HSI)显著高于T0和T15,而与T45和T60组无显著差异。与T0组相比,各替代组的脏体比(VSI)、摄食量(FI)、肥满度(CF)和成活率(SR)均无显著差异。黄颡鱼幼鱼肌肉必需氨基酸(EAA)含量中,T60组肌肉中精氨酸(Arg)和缬氨酸(Val)含量显著高于T0组;且蟋蟀粉替代不同比例的鱼粉对黄颡鱼幼鱼肌肉中的总呈味氨基酸(TFAA)含量均未产生显著影响。T30、T45和T60组血清中的葡萄糖(GLU)含量显著高于T0组;相反,其总胆固醇(TCHO)含量显著低于T0组。在本研究条件下,蟋蟀粉替代不同比例的鱼粉不影响黄颡鱼幼鱼的生长性能和肌肉氨基酸含量,且能增加血清GLU和降低TCHO含量,以30%的蟋蟀粉替代鱼粉比例能生长最佳,且优于对照组。本研究对揭示蟋蟀粉在黄颡鱼饲料中替代鱼粉应用的可行性、为今后昆虫蛋白源在水产饲料中的开发提供科学依据。     

在不同饲料中添加加热灭活的植物乳酸杆菌P-8对大菱鲆幼鱼抗氧化能力和血清生化指标的影响

将植物乳酸菌P-8以灭活的形式添加到大菱鲆幼鱼的两种基础饲料中,旨在研究灭活植物乳酸杆菌(HK-LP)对大菱鲆饲料中豆粕替代鱼粉的影响。试验结束时取血测定血清超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、丙二醛(MDA)、碱性磷酸酶(ALP)、谷草转氨酶(AST)、谷丙转氨酶(ALT)活力和总蛋白(TP)、胆固醇(TCHO)、甘油三酯(TGK)含量。结果显示,D因素和P因素在AST、ALP、TGK和SOD有显著交互作用(P0.05)。D因素ALT、TCHO、TP、TGK、MDA和SOD有显著性影响(P0.05);P因素对SOD、ALP、AST、ALT、TGK和TP有显著性影响(P0.05),且对血清生化指标ALP、AST、ALT、TGK和TP有极显著影响(P0.01),血清TCHO、MDA呈下降趋势,但未达到显著水平(P0.05),CAT呈上升趋势,但未达到显著水平(P0.05)。由此得知,在豆粕替代45%鱼粉蛋白饲料中添加一定浓度的灭活乳酸杆菌P-8对大菱鲆幼鱼血清生化指标和抗氧化能力有显著性影响。     

脱脂亮斑扁角水虻幼虫粉替代鱼粉对黄颡鱼幼鱼生长性能、营养素沉积率、血清生化指标和消化酶活性的影响

为研究脱脂亮斑扁角水虻幼虫粉(DBSFLM)替代鱼粉对黄颡鱼幼鱼生长性能、营养素沉积率、血清生化指标和消化酶活性的影响,本实验选用平均体质量为(1.67±0.01) g的黄颡鱼幼鱼480尾,随机分为4个处理组,分别投喂基础饲料(T0)和实验饲料[脱脂亮斑扁角水虻幼虫粉分别替代鱼粉20%(T20)、40%(T40)和60%(T60)],每个处理组3个重复,每个重复40尾鱼,养殖8周。结果显示,随着DBSFLM替代量的增加,黄颡鱼生长呈先增加后降低的趋势;T20组的终末均重、增重率和特定生长率最高,且显著高于T60组;实验组T20和T60的摄食量显著高于对照组和T40组;实验组的腹脂指数、灰分和钙沉积率呈下降趋势,其中T60组的腹脂指数、T40和T60组的灰分和钙沉积率达到显著水平;与对照组T0相比,实验组的肥满度、脏体比、肝体比、肠体比和胃体比、蛋白质、脂肪和磷沉积率及黄颡鱼体蛋白、体脂肪和灰分均没有显著差异;血清胆固醇和甘油三脂显著降低,高密度/低密度脂蛋白胆固醇显著升高,实验组T40的胃蛋白酶活性有增加趋势、肠道胰蛋白酶活性显著增加。研究表明,在本实验条件下,脱脂亮斑扁角水虻幼虫粉替代鱼粉不影响黄颡鱼幼鱼的生长性能和体组成含量,并可降低腹脂指数、血清甘油三酯、胆固醇含量及灰分、钙的沉积率,还可增加蛋白酶活性,以20%替代比例生长最佳,且优于对照组。     

运输对养殖黄颡鱼血液生化和肌肉物性分析指标的影响

测定了在10.4~11.2℃下运输4 h后不同时间(0 h、1 h、3 h、6 h、12 h、1 d、3 d、7 d和20 d)养殖黄颡鱼(Pelteobagrus fulvidraco)血液生理生化指标和肌肉物性分析指标的变化。结果显示,运输引起了黄颡鱼血清皮质醇和血糖浓度的显著升高(P0.05),在运输结束12 h后恢复到正常水平。运输后鱼体血清超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性和总抗氧化能力(T-AOC)均有显著性升高,随着恢复时间的推移逐渐回降到正常水平;但过氧化物酶(POD)活性并未出现显著性差异,维持稳定的水平。运输后肌肉硬度、弹性、胶黏性、凝聚性、咀嚼性、回复性等物性分析指标均显著性降低。除了凝聚性和咀嚼性之外,其他肌肉物性分析指标在运输结束72 h后恢复到正常水平。研究表明,长途运输造成了养殖黄颡鱼的应激反应,对肌肉物性特征产生了显著的影响,但运输后的恢复可使鱼体抗氧化能力和肌肉物性分析指标回复到正常水平。     

皮质醇混饲投喂对黄颡鱼幼鱼生长及外周血细胞的影响

采用皮质醇混饲投喂的试验方法,模拟自然条件下的慢性应激,观察和分析了应激激素皮质醇对黄颡鱼(Pelteobagrus fulvidraco)幼鱼生长和外周血细胞的效应。试验组饲料中皮质醇添加剂量为100 mg/kg,日投饵率为3%,试验期5周。结果表明:(1)外源皮质醇通过减少肠道黏膜皱褶和促进糖异生作用使黄颡鱼幼鱼增重受阻;(2)外源皮质醇使黄颡鱼幼鱼外周血白细胞数量显著减少、淋巴细胞百分比显著降低,但是中性粒细胞和单核细胞百分比则呈上升趋势;(3)外源皮质醇能促进红细胞增生,增加黄颡鱼幼鱼外周血红细胞数量。     

饲料中小球藻添加量对杂交黄颡鱼“黄优1号”生长性能的影响

开展了饲料中小球藻添加量对杂交黄颡鱼“黄优1号”生长性能和抗氧化能力影响试验。共设置5组,分别为1个对照组(G0)和4个处理组(G1—G4)。其小球藻的添加量分别为0.00%(G0),2.50%(G1),5.00%(G2),7.50%(G3)和10.00%(G4)。于养殖的第28和56天,测定杂交黄颡鱼“黄优1号”鱼体生长指标和抗氧化能力指标。结果表明,随着饲料中小球藻含量的增加,杂交黄颡鱼“黄优1号”的体质量增加率和特定体质量增加率呈上升趋势,并显著高于对照组(P<0.05),饵料系数呈下降趋势,肝体指数较对照组无显著差异(P>0.05)。抗氧化能力方面,饲料中添加小球藻可以显著提高杂交黄颡鱼“黄优1号”肝脏和血清中超氧化物歧化酶、过氧化氢酶和谷胱甘肽过氧化物酶的活性,能降低鱼体内丙二醛含量。指出,饲料中添加小球藻不仅可以促进杂交黄颡鱼“黄优1号”的生长,并提高其抗氧化能力。     

光照颜色对虹鳟行为反应、血浆皮质醇和生化指标的影响

光照是影响鱼类行为、生理以及生长的主要环境因子之一。为研究光照颜色对虹鳟行为反应、血浆皮质醇、生化指标的影响,实验根据鱼类行为学研究方法,分别将白、红、黄、蓝和绿5种光照颜色灯带铺设在室内试验水槽中央底部,将虹鳟放置在水槽同一侧,观察虹鳟在水槽中穿越灯带尾次数及行为反应;根据行为生理学研究方法,分析比较在不同光照颜色下虹鳟血浆皮质醇、总蛋白(TP)、白蛋白(ALB)、甘油三酯(TG)、总胆固醇(TC)、谷草转氨酶(AST)、谷丙转氨酶(ALT)的含量差异。结果显示:5种光照颜色下虹鳟穿越灯带尾次数均低于空白组,其中黄光、白光条件下穿越灯带尾次数均显著低于空白组和其余3种光照颜色,红光、蓝光、绿光和空白组之间无显著差异。黄光条件下血浆皮质醇浓度显著高于空白组和其余4种光照颜色,空白组和其余4种光照之间无显著差异。5种光照颜色下总蛋白(TP)、白蛋白(ALB)、甘油三酯(TG)、总胆固醇(TC)、谷草转氨酶(AST)、谷丙转氨酶(ALT)均具有显著差异。研究表明,虹鳟比较适应蓝光和绿光,对黄光和白光有一定的趋避反应,且黄光的趋避效果最强;虹鳟可通过自身生理调节以适应不同的光照颜色变化。     

光照对中华鲟幼鱼生长及血液生化指标的影响

测定了自然光周期(对照组,白天平均76 lx、晚上0 lx)、全光照(940 lx)和全避光(0 lx)三种光照周期下养殖70 d的中华鲟幼鱼生长指标(体重、全长、体长)及血液生化指标。结果显示,3种光照周期下的中华鲟幼鱼的生长无显著性差异。全避光组中华鲟幼鱼血液中总蛋白(TP)、白蛋白(ALB)、球蛋白(GLB)含量最低,与对照组有显著性差异,与全光照组无显著性差异;甘油三酯(TRIG)、肌酐(CREA)和谷草转氨酶(AST)含量最高,TRIG与对照组有显著性差异,与全光照组无显著性差异,CREA与全光照组和对照组均有显著性差异,AST均无显著性差异。全光照组中华鲟血液中血清总胆固醇(TC)、总胆红素(T-BIL)、谷丙转氨酶(ALT)、谷草转氨酶(AST)含量最低,但与全避光组和对照组均无显著性差异;葡萄糖(GLU)、尿素氮(BUN)含量最高,与全避光组和对照组均有显著性差异。对照组的乳酸脱氢酶(LDH)和碱性磷酸酶(ALP)含量最高,LDH与全光照组和全避光组均无显著性差异,ALP与全光照组和全黑暗组均有显著性差异。三种光照周期下的无机离子含量除Mg2+外,Na+、K+、Cl-、Ca2+、P3+都没有显著性差异。     

草鱼细菌性烂鳃病血液指标观察

用柱状嗜纤维菌感染草鱼引起细菌性烂鳃病,然后对试验草鱼进行血液生理生化指标的检测和分析.其中检测的指标包括红细胞计数( RBC)、血红蛋白的测定(Hb)、谷丙转氨酶(ALT)、谷草转氨酶(AST)、甘油三酯(TG)、α-淀粉酶(α- Amylase)、胆碱酯酶(CHE)、碱性磷酸酶(ALP)、总蛋白(TP)、总胆固醇(...     

Plasma biochemical responses of the omnivorous crucian carp (<Emphasis Type="Italic">Carassius auratus</Emphasis>) to crude cyanobacterial extracts

Healthy crucian carp (Carassius auratus) were treated by intraperitoneal (i.p.) injection of crude cyanobacterial extracts at two doses, 50 and 200 μg MC-LR equiv kg⁻¹ BW. High mortality (100%) was observed within 60 h post injection in the high-dose group. In the treated fish, activities of four plasma enzymes, alanine aminotransferase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH), all showed substantial increases, with both dose and time-dependent effects. These increases of enzyme activity indicate severe impairment occurred in the liver of crucian carp over time. Plasma concentrations of energy-related biomolecules including glucose (GLU), cholesterol (CHO), triglyceride (TG), and total protein (TP) showed marked changes in the high-dose group, possibly a nutritional imbalance correlated with the liver injury caused by intraperitoneal exposure to crude cyanobacterial extracts.     

Effects of long-term silymarin oral supplementation on the blood biochemical profile of rainbow trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>)

Silymarin, an extract from “milk thistle” (Silybum marianum) plant is traditionally used as herbal medicine. The present study was conducted to investigate the clinical effects and possible side effects of silymarin on biochemical blood parameters of rainbow trout (Oncorhynchus mykiss). Fishes were treated with 0 (control), 100, 400, and 800 mg of silymarin per kg of food during 4 weeks. Plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), creatine kinase (CK), glucose, total protein, creatinine, triglyceride, cholesterol, urea, uric acid and liver cellular total antioxidant, and protein content were measured after 7, 14, and 28 days of silymarin treatment. The results showed that oral administration of silymarin in fish significantly reduced plasma glucose and cholesterol levels and relatively increased plasma total protein and globulin concentrations (P < 0.05). Increasing plasma albumin levels indicate the important role of albumin in drug transportation in circulatory system of fish. Silymarin also stabilized cellular membrane structure and regulated the levels of AST, ALT, ALP, CK, and LDH activity. In conclusion, on the basis of these results, oral administration of silymarin up to 400 mg per 1 kg of food has no side effect on blood biochemical and clinical parameters of fishes. However, oral administration of 800 mg/kg- of silymarin caused cytotoxicity and modifications in blood biochemical parameters of fish.     

Effects of Neutral Phytase Supplementation on Biochemical Parameters in Grass Carp,Ctenopharyngodon idellus,and Gibel Carp,Carassius auratus gibelio,Fed Different Levels of Monocalcium Phosphate

Two 8‐wk studies were conducted to evaluate the effects of neutral phytase supplementation on hemato‐biochemical status, liver biochemical parameter, and intestinal digestive enzyme activity of grass carp, Ctenopharyngodon idellus, and gibel carp, Carassius auratus gibelio, fed with different levels of monocalcium phosphate (MCP). The control diet was prepared with 2% MCP but without phytase (P2.0). The other three experimental diets were prepared with the addition of 1.5, 1.0, and 0.5% MCP, respectively, when supplemented with 500 U/kg neutral phytase in each diet and designated as PP1.5, PP1.0, and PP0.5, respectively. The results indicated that the serum alkaline phosphatase (ALP), alanine transaminase (ALT), and aspartate transaminase (AST) activities, as well as the albumin (ALB) content were increased in grass carp (P < 0.05) and gibel carp (P > 0.05) fed with phytase‐supplemented diets. Meanwhile, the serum cholesterol, high‐density lipoprotein, and total protein contents of the two species of fish were increased in comparison to the control. In addition, dietary phytase inclusion did not significantly affect hepatic ALP, ALT, and AST activities in the two species of carp fed with different levels of MCP. Amylase activity increased in foregut and hindgut of both species when fed with the phytase‐supplemented diets while lipase activity was reduced in the foregut and hindgut in both fish. This study suggests that neutral phytase supplementation increases serum ALP, ALT, and AST activities but does not notably affect these enzyme activities in the liver of the two species of carp when fed different levels of MCP. On the other hand, amylase activity increased while lipase activity was reduced in the intestine of the species of carp fed with phytase‐supplemented diets.     

Effect of Coriolus versicolor polysaccharides on the hematological and biochemical parameters and protection against Aeromonas hydrophila in allogynogenetic crucian carp (Carassius auratus gibelio)

The effect of dietary intake of Coriolus versicolor Polysaccharides (CVP) on the hematological and biochemical indices of Allogynogenetic crucian carp (Carassius auratus gibelio) was investigated. Fish were fed CVP supplemented diets (0, 0.25, 0.5, 1.0, 2.0 or 4.0 g CVP kg^?1) for 56 days. The RBC, WBC counts, hemoglobin content, ESR in blood and TP, ALT, AST, ALP, GLU, CHO, TG, and BUN in serum were measured on day 0, 14, 28, 42, and 56. After feeding of 56 days, fish were infected with Aeromonas hydrophila and mortalities were recorded. The results indicated that feeding crucian carp with suitable dose of CVP enhanced the RBC, WBC counts, hemoglobin and TP content, ALP activity, and decreased the ESR, ALT, AST, GLU, CHO, TG and BUN. There was no effect in fish at low dose (0.25 g kg^?1). Unexpectedly, the higher CVP dose used here (2.0 and 4.0 g kg^?1) has a negative effect in fish. The results of challenge experiment indicated that a moderate level of CVP in the diet (1.0 g kg^?1) was the most effective to enhance the survival of fish after infected with A. hydrophila. In summary, the use of CVP, as dietary supplements, can improve the innate defense of crucian carp providing resistance to pathogens.     

饲料蛋白质水平与投喂频率对吉富罗非鱼幼鱼生长及部分生理生化指标的影响

为探讨饲料蛋白质水平与投喂频率对罗非鱼生长及生理健康的影响,采用2×3双因子实验,研究饲料蛋白质水平(36.27%和26.02%)与投喂频率(1、2和3次/d)对吉富罗非鱼幼鱼生长、体成分、血清指标和肝胰脏结构的影响。养殖周期为42 d,结果表明:随饲料蛋白质水平的增加,实验鱼的末体质量(FW)、增重率(WGR)、特定生长率(SGR)、饲料效率(FE)、肥满度(CF)、去内脏全鱼灰分(EWA)、内脏水分(VM)、高密度脂蛋白胆固醇(HDLC)水平显著升高(P0.05),而摄食率(FI)、脏体比(VSI)、饲料成本(FC)、去内脏全鱼粗脂肪(EWF)、内脏粗脂肪(VF)、肝胰脏粗脂肪(HF)显著降低(P0.05);随投喂频率的增加,实验鱼的FW、WGR、SGR、肝体比(HSI)、CF、FC、EWF、VF、HF,血清中的总胆固醇水平(TCHO)、HDLC、低密度脂蛋白胆固醇(LDLC)、总蛋白(TP)、甘油三酯(TGK)水平显著升高(P0.05),而FE、蛋白质效率(PER)、去内脏全鱼水分(EWM)、EWA、VM、肝胰脏水分(HM)显著降低(P0.05)。饲料蛋白质水平和投喂频率对实验鱼的FW、WGR、SGR、VM和HDLC的交互作用显著(P0.05)。投喂26.02%蛋白质水平饲料的实验鱼,肝胰脏细胞肿大变形,呈现透明的空泡化,出现细胞核偏移;而投喂36.27%蛋白质饲料的实验鱼,大多数肝细胞胞浆清晰,可观察到的肝细胞空泡面积较小。综合考虑,饲料蛋白质含量为36.27%是适合吉富罗非鱼幼鱼的,其适宜的投喂频率为2次/d以上,可根据罗非鱼市场情况进行调节。     

Effects of dietary nucleotides supplementation on rainbow trout (Oncorhynchus mykiss) performance and acute stress response

This experiment was conducted to examine the effect of dietary nucleotides (NT) on fish performance and acute stress response on fingerling rainbow trout (23 g ± 0.01, mean weight ± SEM). Five experimental diets according to different levels of supplemented nucleotides (0, 0.05, 0.1, 0.15, and 0.2%) were assayed on experimental fish for 8 weeks. Growth, hematological parameters (hematocrit, hemoglobin, erythrocyte, lymphocyte, and neutrophil count), serum proteins (globulin, albumin), and plasma enzymatic activity (alkaline phosphatase, ALP; aspartate transaminase, AST; lactate dehydrogenase, LDH; alanine transaminase, ALT) were assayed. At the end of feeding trial, fish fed the control and 0.2% diets were subjected to handling and crowding stress. Modulatory effects of nucleotides on acute stress response (cortisol and glucose) and plasma electrolytes (Na⁺, Cl⁻, K⁺, and Ca²⁺) were studied. The percentage of body weight gain (WG) and feed efficiency (FE) of fish were better when the fish were fed 0.15–0.2% diets. Fish fed the nucleotide-supplemented diets tended to have lower levels of serum enzymes including ALP, AST, LDH, and ALT. Plasma cortisol levels of fish fed on 0.2% diet under handling and crowding stress were significantly lower than fish fed the control diet at all post-stress time intervals. In our study, fish fed nucleotide-supplemented diet had significantly lower concentrations of glucose compared to those fed the basal diet. The concentrations of sodium, chloride, calcium, and potassium of fish fed the control diet were significantly lower than in fish fed nucleotide-supplemented diet. Dietary nucleotides administration seems to promote growth and to enhance resistance against handling and crowding stress in fingerling rainbow trout.