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1.
在基础饲料中添加不同水平蛋氨酸锌(添加水平分别为0、50、150 mg Zn/kg)并饲喂凡纳滨对虾,养殖14 d后,取样测定对虾鳃组织中Toll受体mRNA和溶菌酶mRNA的表达水平以及肝胰腺、肌肉和血淋巴中超氧化物歧化酶(SOD)和溶菌酶(LSZ)活性,并进行溶藻弧菌人工急性感染试验。结果表明,凡纳滨对虾肝胰腺及肌肉中锌蓄积水平随饲料锌添加量的增加而显著增加(P<0.05),肝胰腺中锌蓄积更明显。添加50 mg Zn/kg组(锌含量为73.25 mg Zn/kg饲料)对虾鳃组织中的Toll受体mRNA和溶菌酶mRNA表达量均显著高于未添加锌组和添加150 mg Zn/kg组(P<0.05)。添加50 mg Zn/kg组对虾肌肉、肝胰腺和血淋巴中溶菌酶活性显著高于未添加锌组(P<0.05)。添加50 mg Zn/kg组对虾肝胰腺和血淋巴中的SOD活性也显著高于未添加锌组,但与添加150 mg Zn/kg组无显著差异。而肌肉中SOD活性在添加150 mg Zn/kg组中最高。经溶藻弧菌人工急性感染后,添加50 mg Zn/kg组对虾半致死时间和全致死时间大于未添加锌组和添加150 mg Zn/kg组。本研究表明,相比摄食未添加锌组饲料和添加150 mg Zn/kg组饲料,凡纳滨对虾的免疫抗菌机能在摄取添加50 mg Zn/kg(锌含量为73.25 mg Zn/kg饲料)饲料时得到改善。  相似文献   

2.
以凡纳滨对虾为试验对象,探讨在饲料中添加2 mg/kg的辣椒碱对凡纳滨对虾生长、免疫等方面的影响。试验结果表明,与对照组相比,试验组饲料中添加2 mg/kg辣椒碱后,凡纳滨对虾的生长性能指标显著改善,成活率、饲料系数显著优于对照组(P<0.05),血清中谷草转氨酶(AST)、谷丙转氨酶(ALT)含量显著高于对照组(P<0.05),肝胰腺免疫抗氧化指标(MDA、SOD、CAT)水平及健康状况亦有所提升。  相似文献   

3.
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%。  相似文献   

4.
抗菌肽对凡纳滨对虾生长和血清非特异性免疫指标的影响   总被引：3，自引：0，他引：3  
为考察抗菌肽对凡纳滨对虾(Litopenaeus vannamei)生长、饲料利用和免疫能力的影响,分别在基础组饲料中添加0 mg/kg(对照组)、300 mg/kg、400 mg/kg和500 mg/kg抗菌肽,投喂平均体重为(0.8±0.1 g)的凡纳滨对虾6周。结果表明,饲料中添加抗菌肽后,凡纳滨对虾的成活率均显著高于对照组(P<0.05);300 mg/kg抗菌肽组的增重率和饲料系数分别为509.10%、1.33,较对照组提高增重率8.76%(P<0.05),降低饲料系数12.5%(P<0.05),而添加400 mg/kg、500 mg/kg抗菌肽对增重率、饲料系数无显著影响,但显著提高了肌肉粗脂肪含量,各处理组在肌肉粗蛋白、水分含量上无显著差异;300 mg/kg、400 mg/kg抗菌肽组的血清碱性磷酸酶、超氧化物歧化酶、谷丙转氨酶、谷草转氨酶及400 mg/kg抗菌肽组的溶菌酶均显著高于对照组。上述研究表明,饲料中添加300 mg/kg抗菌肽,可显著提高凡纳滨对虾成活率和增重率,降低饲料系数;添加400 mg/kg抗菌肽,对血清非特异性免疫指标有提高作用,凡纳滨对虾饲料中抗菌肽的添加量建议为300～400 mg/kg。  相似文献   

5.
选用960尾初始体重为(0.43?0.01) g 的凡纳滨对虾,随机分为8组,分别投喂基础饲料和7种添加核苷酸混合物(mix-NT)的试验饲料,5种核苷酸(5′-腺苷酸∶5′-胞苷酸∶5′-尿苷酸二钠∶5′-肌苷酸二钠∶5′-鸟苷酸二钠)按照质量比为1∶1∶1∶1∶1(W/W)混合,添加量分别为0.1、0.2、0.4、0.6、0.8、1.0和1.2 g/kg 饲料,试验周期为5周。结果显示,当mixNT添加量为0.4 g/kg饲料时,凡纳滨对虾的增重率(WGR)、特定生长率(SGR)和摄食量(FI)显著高于对照组(P<0.05),饲料系数(FCR)比对照组降低5.5%(P>0.05)。0.6和1.0 g/kg mix-NT添加组的蛋白质沉积率(PDR)显著高于对照组(P<0.05)。试验组对虾存活率(SR)和肝胰指数(HSI)均不同程度的高于对照组,但差异不显著(P>0.05)。饲料中添加mix-NT对全虾粗脂肪、灰分含量的影响显著(P<0.05),各mix-NT添加组的全虾干物质和粗蛋白含量均高于对照组,但差异未达到显著水平(P>0.05)。肝胰腺RNA含量和总蛋白(TP)含量均随饲料中mix-NT添加量的增加而升高,其中0.2~1.0 g/kg组的肝胰腺RNA含量显著高于对照组(P<0.05),TP含量差异未达到显著水平(P>0.05);各mixNT添加组的肠道TP含量均显著高于对照组(P<0.05),0.4和0.6 g/kg组的肠道RNA量极显著高于对照组(P<0.01)。外源mix-NT显著降低血清尿酸(UA)含量(P<0.05),但对TP、谷丙转氨酶(GPT)、高密度脂蛋白(HDL)含量无显著影响(P>0.05)。当mix-NT添加量为1.2 g/kg 饲料时,血清中谷草转氨酶(GOt)活性显著性升高(P<0.05)。鳃和肌肉酚氧化酶(PO)活性均在0.4 g/kg组达到最大,其中0.1～0.6 g/kg 组的鳃PO活性显著高于对照组(P<0.05),而各组肌肉PO活性无显著差异(P>0.05)。凡纳滨对虾肝胰腺和血清中溶菌酶(LZM)活性随饲料中mix-NT添加量的增加而显著升高(P<0.05)。结果表明,饲料中添加一定量的5种核苷酸混合物能显著提高凡纳滨对虾幼虾的增重率、特定生长率、摄食量、蛋白质沉积率、全虾粗脂肪和灰分含量,一定程度提高全虾粗蛋白和肝胰腺总蛋白含量,显著增加肝胰腺RNA、肠道总蛋白和RNA含量,提高对虾的非特异性免疫功能。  相似文献   

6.
李静  李晓丽  王玲  鲁康乐  宋凯  张春晓 《水产学报》2022,46(10):1848-1859
[目的]本实验旨在研究低鱼粉饲料 中添加羟基蛋氨酸硒(HMSe)对凡纳滨对虾(Litopenaeus vannamei)生长性能、抗氧化能力及抗亚硝酸盐胁迫的影响。[方法]实验选用初始体质量为(0.90±0.05)g的凡纳滨对虾,分别投喂HMSe添加水平为0.000、0.375、0.750、1.500和2.250 mg/kg的实验饲料,命名为HMSe0 、HMSe1、HMSe2、HMSe3和HMSe4,每组3个重复,养殖8周。养殖实验结束后,进行12 h 的亚硝酸盐胁迫实验。[结果]结果表明,凡纳滨对虾的终末体质量(FBW)、增重率(WG R)和饲料效率(FE)随着饲料中HMSe水平的增加呈现先升高后下降的趋势,并在HMSe2组达到峰值。随着饲料中HMSe水平的提高,对虾全体和肌肉中的硒含量均显著增加,而全虾粗蛋白和粗脂肪的含量呈现先升高后降低的趋势,并分别在HMSe2组和HMSe1组达到最大值。HMSe4组中凡纳滨对虾的血清谷胱甘肽过氧化物酶(GSH-Px)和肝胰腺过氧化氢酶(CAT)活性显著高于HMSe0组。亚硝酸盐胁迫显著影响凡纳滨对虾的存活率。与胁迫前比较,胁迫后对虾肝胰腺中MDA含量升高,GST、CAT和T-SOD的活性降低,而补充适量的HMSe可减轻这些负面影响。根据凡纳滨对虾胁迫后成活率的二次多项式回归分析,低鱼粉饲料中凡纳滨对虾的HMSe最适添加量为1.350 mg/kg。[结论]综上所述,在低鱼粉饲料中添加0.750~1.350 mg/kg HMSe,能够提高凡纳滨对虾的生长性能、饲料利用率和抗亚硝酸盐胁迫的能力。  相似文献   

7.
袁野  黄晓玲  陆游  马红娜  周歧存 《水产学报》2016,40(9):1349-1358
为研究饲料中不同泛酸水平对凡纳滨对虾生长性能、饲料利用及血清指标的影响,实验配制6种等氮等脂(41%粗蛋白质和8%粗脂肪)的实验饲料,泛酸添加水平分别为0(对照组)、50、100、150、300和600 mg/kg,饲料中实测泛酸水平分别为20.9、69.3、99.0、150.2、304.4和513.6 mg/kg。选用初始体质量为(0.73±0.12)g的凡纳滨对虾720尾,随机分为6组(每组3个重复,每个重复40尾),进行为期8周的养殖实验。结果显示,饲料中不同泛酸水平对凡纳滨对虾增重率和特定生长率的影响不显著;对照组凡纳滨对虾成活率显著低于泛酸添加组,然而各泛酸添加组的成活率组间差异不显著。随着泛酸水平从20.9 m.g/kg增加到99.0 mg/kg时,饲料效率和蛋白质效率显著提高,而随着泛酸水平的进一步增加,饲料效率和蛋白质效率显著降低。饲料中泛酸水平对凡纳滨对虾全虾和肌肉主要成分无显著性影响。对照组对虾血清葡萄糖含量显著低于泛酸各添加组,然而泛酸各添加组之间无显著差异;投喂150.2 mg/kg泛酸组血清甘油三酯含量显著低于对照组和513.6 mg/kg;而血清总蛋白和胆固醇含量不受饲料中泛酸水平的影响。随着饲料中泛酸水平由20.9 mg/kg增至150.2 mg/kg,血清超氧化物歧化酶活力显著提高,而随着饲料中泛酸水平的进一步增加,血清超氧化物歧化酶活力显著降低;饲料中泛酸水平为99.0mg/kg组凡纳滨对虾血清总氧化能力显著高于其他各组;投喂对照组和泛酸水平为69.3mg/kg组的凡纳滨对虾血清丙二醛含量最高,投喂泛酸水平为150.2 mg/kg组血清的丙二醛含量显著低于其他各组。以凡纳滨对虾的饲料效率和蛋白质沉积率为评价指标,通过折线模型分析得到凡纳滨对虾泛酸最适需要量分别为113.40和119.87mg/kg。  相似文献   

8.
本实验旨在研究饲料中添加酵母水解物对凡纳滨对虾在低盐度胁迫条件下非特异性免疫和抗氧化能力的影响。选取凡纳滨对虾[初始体质量（15.82±0.08）g],平均分为2组,对照组投喂基础饲料（Y0）,实验组投喂添加了3%酵母水解物的实验饲料（Y3）,在室内养殖15d后分别放入盐度为4‰（S4）和28‰（S28）的水体中进行盐度胁迫实验,每组6个重复,每个重复30尾虾（根据饲料和盐度不同组合,分组命名为Y0S4、Y0S28、Y0S3、Y0S28）。结果表明：饲料中添加3%酵母水解物对凡纳滨对虾血清酚氧化酶（PO）、总一氧化氮合成酶（TNOS）活性没有显著影响,但低盐度胁迫1h时,Y3S4组PO、TNOS活性显著高于Y0S4组;盐度因素对PO、TNOS活性产生显著影响,低盐度胁迫1h时,S28组PO、TNOS活性显著高于S4;饲料中添加3%酵母水解物显著提高了凡纳滨对虾肝胰腺超氧化物歧化酶（SOD）活性;盐度因素对酸性磷酸酶（ACP）活性产生了显著影响,S28组ACP活性显著高于S4。由此可见,在饲料中添加酵母水解物能够提高凡纳滨对虾肝胰腺SOD活性,提高对虾的抗氧化能力;在遭遇低盐度胁迫时,对虾能迅速恢复PO、TNOS活性至正常水平,从而提高凡纳滨对虾的抵抗不良环境的能力。  相似文献   

9.
硒源对凡纳滨对虾生长、体组成和抗氧化能力的影响   总被引：1，自引：0，他引：1  
水温(29.0±1.3)℃,将初始体质量(0.41±0.01)g的凡纳滨对虾随机分为4组,每组3个重复,饲养在室内循环水养殖系统中,投喂基础饲料(对照组)及在此饲料中分别添加硒含量相等(0.30mg/kg)的亚硒酸钠、酵母硒和蛋氨酸硒的4种饲料,养殖56d,比较了不同硒源对凡纳滨对虾生长、体组成和抗氧化能力的影响。试验结果表明,蛋氨酸硒组对虾的生长性能显著高于对照组和亚硒酸钠组(P0.05)。外源硒可显著影响对虾体蛋白和脂肪含量(P0.05),蛋氨酸硒组对虾机体营养成分显著优于其他组(P0.05)。添加外源硒组对虾的血清总抗氧化能力和谷胱甘肽过氧化物酶活性显著高于对照组(P0.05)。蛋氨酸硒组对虾血清丙二醛含量显著低于其他组(P0.05)。由此得出,饲料添加0.3mg/kg的硒能在一定程度上提高凡纳滨对虾的生长和抗氧化能力,蛋氨酸硒优于酵母硒和亚硒酸钠。  相似文献   

10.
以在基础饲料中分别添加黄霉素4mg/kg、12mg/kg、24mg/kg和48mg/kg的饲料作为试验组,以不添加黄霉素的饲料作为对照组,制成5种试验饲料,在室内饲养凡纳滨对虾(Litopenaeusvannamei)8周,研究黄霉素对凡纳滨对虾生长性能和非特异性免疫功能的影响。结果表明:饲料中添加黄霉素能显著提高凡纳滨对虾的生长和饲料利用率,黄霉素的促生长作用与其能增加对虾蛋白质沉积率有关,凡纳滨对虾饲料中长期添加黄霉素的适宜添加量为4mg/kg。  相似文献   

11.
The efficacy of hot‐water extract of tropical brown seaweed, Sargassum cristaefolium (SCE), supplemented in diets on immune response, stress tolerance, and disease resistance of Litopenaeus vannamei to Vibrio parahaemolyticus was evaluated. Shrimp were fed diets containing graded levels of SCE (0, 250, 500, 750, and 1000 mg/kg). The results showed that shrimp fed all diets containing SCE had significantly higher (P < 0.05) immune response in total hemocyte count (THC), differential hemocyte count (granular and hyaline cells), and phagocytic activity than those of shrimp fed the control diet. Similarly, in low dissolved oxygen stress tolerance test and the challenge test with V. parahaemolyticus, survival rates of shrimp fed all diets containing SCE were significantly higher (P < 0.05) (83–93% in stress test and 27–47% in challenge test) than those of shrimp fed the control diet (77 and 3.3%, respectively). These results suggest that oral administration of SCE at 500 and 750 mg/kg can be effectively used to enhance immune response, stress tolerance, and resistance of white shrimp, L. vannamei, against V. parahaemolyticus infection. These findings also confirm that using dietary SCE as immunostimulant is effective at increasing the nonspecific immune system in penaeid shrimp, L. vannamei.  相似文献   

12.
The effect of dietary astaxanthin on growth, survival, and stress tolerance was determined in postlarval Litopenaeus vannamei. An experiment was performed with postlarval shrimp (mean initial wet weight 1.2 mg) fed four isoenergic and isonitrogenous diets containing four supplemented levels of astaxanthin (0, 100, 200, and 400 mg/kg diet, respectively). Shrimp fed diets containing 100, 200, and 400 mg astaxanthin/kg diet for 30 d showed higher weight gain (WG, %) and survival compared to the control (without supplementation of astaxanthin). Specific growth rate (SGR, %/day) and final body wet weight (FBW, mg) showed the same pattern as WG. There were no significant differences in growth performance (FBW, WG, and SGR) among the groups fed the diets with astaxanthin supplementation at the termination of feeding trial. Survival of shrimp in the control and 100 mg/kg diet treatments was significantly lower than that of shrimp in the treatments with 200 and 400 mg/kg diet. After 9 d of a stress tolerance test, survival of shrimp in the 200 and 400 mg astaxanthin/kg treatments was significantly higher than that of shrimp in the 0 and 100 mg astaxanthin/kg treatments (P < 0.05). We concluded from this experiment that astaxanthin was a necessary ingredient for the development of larval L. vannamei. Considering the effect of astaxanthin on both, growth performance and survival of postlarval L. vannamei, the level of astaxanthin supplemented in the diet should be between 100 mg and 200 mg/kg of diet.  相似文献   

13.
李忠帅  马甡  单洪伟  王腾  肖威 《水产学报》2021,45(11):1825-1834
为探究亚硝态氮胁迫下凡纳滨对虾[体长为(6.8±0.3) cm,体质量为(4.0±0.6) g]体内亚硝态氮的时空分布与能量代谢相关酶活性的响应,实验设置0(对照组)、0.8、4.0和8.0 mmol/L 4个处理组,进行持续96 h的亚硝态氮胁迫实验和12 h的恢复实验。结果显示,凡纳滨对虾死亡率与胁迫浓度呈现显著的正相关性。胁迫6 h内,亚硝态氮在凡纳滨对虾鳃、血淋巴、肠道、肝胰腺和肌肉组织中明显积累,且积累量与胁迫浓度呈现正相关。相同胁迫浓度组,亚硝态氮在对虾鳃中积累最多,肌肉中最少,鳃中的积累量约为肌肉的3倍。Na~+-K~+-ATP酶活性在0.8和4.0 mmol/L组对虾肝胰腺和肌肉中显著升高,而在8.0 mmol/L组的肌肉中显著降低。胁迫各组对虾肝胰腺AMPK活性显著上升,且与胁迫浓度呈现正相关性。恢复期间,除血淋巴(8.0 mmol/L组)外,各组织中亚硝态氮1 h恢复效率均超过50%,且肝胰腺和鳃的恢复效率最高,达到74%以上。血淋巴、鳃、肠道中亚硝态氮恢复到对照组水平的时间最短,均在6 h以内,而水体中亚硝态氮含量显著升高。以上研究表明,胁迫下亚硝态氮会在对虾组织中迅速积累,并引起能量代谢进程的加快;胁迫解除后,积累在体内的亚硝态氮能够迅速排出体外,以减轻毒性影响。本研究结果将为缓解亚硝态氮对养殖对虾毒性效应的研究提供参考。  相似文献   

14.
The aim of this study was to investigate effects of dietary geniposide (GP) on growth performance, flesh quality, and lipid metabolism of grass carp, Ctenopharyngodon idella (95.2 ± 0.6 g), fed seven different diets, including a control diet; Eucommia ulmoides (EU)–supplemented diet (20 g/kg); and GP‐supplemented diets containing 100, 200, 400, 600, and 800 mg/kg GP, respectively. Weight gain rate was significantly improved (P < 0.05) and feed conversation ratio was significantly decreased (P < 0.05) by supplementation of EU. Grass carp fed 100–800 mg/kg GP‐supplemented diets showed significantly higher total collagen and alkaline‐insoluble collagen content in muscle than control (P < 0.05). Contents of total collagen and the alkaline‐insoluble collagen content in the skin of grass carp were significantly increased by dietary 600–800 mg/kg GP and EU (P < 0.05). Fish fed diets containing 600–800 mg/kg GP showed significantly lower muscle crude lipid content than the EU, control, and 100–400 mg/kg GP groups (P < 0.05). Fish fed 400–800 mg/kg GP diets had significantly higher muscle fiber density and lower muscle fiber diameter and serum triglyceride level than the control (P < 0.05). In conclusion, supplementation of GP could improve flesh quality, but not growth of grass carp. The supplemental level of GP for improving flesh quality was estimated to be a 400–600 mg/kg diet.  相似文献   

15.
A 10‐week growth trial was run to evaluate effects of myo‐inositol (MI) on growth performance, haematological parameters, antioxidative capacity and salinity stress tolerance of Litopenaeus vannamei. Six practical diets supplemented with graded levels of MI (designated as MI0, MI600, MI1200, MI2400, MI 3600 and MI4800 for 448.8, 974.2, 1568.0, 2810.6, 3835.5 and 4893.6 mg/kg diet, respectively) were fed to six replicate groups of L. vannamei (mean initial body weight 0.63 ± 0.00 g). The results showed that significant increment of growth performance was observed in shrimp fed MI600 diet than those fed MI1200 diet. Lipid concentration in whole body of the shrimp fed MI600 diet was significantly increased. Shrimp fed MI0 diet had lower total protein (TP) as compared to shrimp fed the MI‐supplemented diets (except MI4800 diet). In general, lower activities of antioxidant enzymes and higher malondialdehyde (MDA) content in haemolymph and hepatopancreas were recorded in shrimp fed MI0 diet, compared to those fed the MI‐supplemented diets. Reduced survival after 7‐h salinity stress was present in shrimp fed MI0 diet as compared to those fed MI4800 diet. Dietary MI requirement for glutathione peroxidase activity of L. vannamei was 2705 mg/kg diet.  相似文献   

16.
The influence of protein and energy levels on growth rate, survival, pre- and post-prandial oxygen consumption, ammonia excretion, haemolymph glucose (HG), glycogen in digestive gland and osmotic pressure (OP) in white shrimp Litopenaeus vannamei (Boone) and L. setiferus (Linne) juveniles was studied. Diets containing a high-quality protein at a protein/energy (P/E) ratio of 16, 26, 31 and 36 mg kJ−1 were fed at 20% of shrimp body weight of two sizes: < 1 g and > 1 g. Both species showed a optimum P/E ratio of 36 mg kJ−1 (33–44% protein and 6–23% carbohydrate) in juveniles < 1 g. For shrimp > 1 g, L. setiferus showed a higher growth rate in the diet with 16 mg kJ−1 (27% protein; 32% carbohydrate) and L. vannamei between 26 and 36 mg kJ−1 (33–44% protein and 6–23% carbohydrate). In both experiments, the growth rate of L. vannamei was 2–3 times that observed in L. setiferus. Routine oxygen consumption and apparent heat increment (AHI) of L. setiferus juveniles was two times higher than that observed in L. vannamei juveniles, which could indicate that L. setiferus has a higher metabolic rate. The O/N ratio varied according to protein level, with higher values (O/N = 180) with a 16-mg kJ−1 diet and lower values (O/N = 73) with a 36-mg kJ−1 diet in L. setiferus juveniles. A similar variation in O/N ratio was obtained in L. vannamei fed with all diets with an interval between 22 and 50. An inverse relation between ammonia excretion and HG, and digestive gland glycogen (DGG) in relation to an increase in the P/E ratio indicate that both shrimp species are well adapted to use carbohydrates and/or proteins from their diet. The higher values of hyper-osmotic capacity (hyper-OC) were observed in L. setiferus < 1 g fed with 36 mg kJ−1 and the lowest in L. vannamei < 1 g fed with 31 mg kJ−1. Intermediate values of hyper-OC were observed in both species fed all diets indicating that osmotic factors of juveniles < 1 g of both species are more affected by the P/E ratio than juveniles > 1 g. All results showed that juveniles > 1 g of both species are less dependent of P/E ratio than juveniles < 1 g. Litopenaeus vannamei is a most tolerant shrimp species with a high capacity to use a wide range of dietary P/E ratios for growth, which may be due to its lower energy requirements. Litopenaeus setiferus showed a lower capacity to accept different P/E ratios but the optimum P/E ratio obtained with this species shows that L. setiferus accept diets with a high carbohydrate level as well. These results demonstrate that there are nutritional and physiological differences that explain the differences that have been observed when both species were cultured in commercial ponds.  相似文献   

17.
Abstract.— Growth, histological lesions, and biochemical changes were investigated in channel catfish Ictalurus punctatus fed various concentrations of moniliformin with or without fumonisin B1. Channel catfish (average initial weight, 1.5 g) were fed diets formulated to contain 0, 20, 40, 60, and 120 mg moniliformin/kg; 0, 20, and 40 mg fumonisin B1/kg, or two combinations of moniliformin and fumonisin B1 for 10 wk. Fish fed diets with the lowest concentration of moniliformin or fumonisin B1 (20 mg/kg diet) had significantly (P < 0.05) less weight gain than the control fish. Increasing the level of moniliformin in the diets resulted in a linear decrease in weight gain. Overall mortality of fish was 4% and not related to treatment effects. Hematocrit was significantly (P < 0.05) lowered by 60‐mg moniliformin/kg diet or 40‐mg fumonisin B1/kg diet. Dose‐dependent increases in serum pyruvate concentration and ratio of free sphinganine to free sphingonine were obtained with increasing concentration of dietary moniliformin and fumonisin B1, respectively. Mean serum pyruvate level was significantly (P < 0.05) higher in fish fed the diet containing 60‐mg moniliformin/kg diet. Addition of fumonisin B1 (40 mg/kg) to the diet containing 40‐mg moniliformin/kg significantly increased the serum pyruvate level above that of the control. Also, the lowest concentration of fumonisin B1 (20 mg/kg diet) significantly (P < 0.05) increased the ratio of sphingolipids. Combinations of moniliformin and fumonisin B1 at levels of 20:40 and 40:40 mg/kg diet did not significantly change the effect of fumonisin B1 on the ratio of sphingolipids. The only tissue lesions observed in liver and heart were smaller nuclei of cells in livers of fish fed diets containing the two highest levels of moniliformin and the combinations of the two toxins.  相似文献   

18.
A 25‐day experiment was conducted to evaluate the optimal lipid level for postlarval Litopenaeus vannamei. Shrimp (1.7 mg) were fed five isonitrogenous diets containing grade levels of lipid (96.6, 114.3, 128.5, 136.5 and 154.5 g/kg diet, respectively). Each diet was assigned to four tanks (500 shrimp), and shrimp were fed six times a day. Weight gain was increased with the increasing dietary lipid levels, and the highest weight gain was observed in shrimp fed diet with 154.5 g/kg lipid (p < 0.05). On the contrary, the survival was lowest in shrimp fed the L15.45 and highest in shrimp fed the L11.43. Triglyceride in hepatopancreas was increased, and cholesterol was decreased with the increasing dietary lipid. Pyruvate kinase and AMPK mRNA expression were highest in shrimp fed the L12.85. Malondialdehyde in whole body was positively correlated with the dietary lipid levels. The mRNA expression of SOD and Caspase 3 was highest in shrimp fed the L12.85. After hypoxia stress, shrimp fed the L12.85 showed highest survival. The mRNA expression of superoxide dismutase and Akirin was highest in shrimp fed the L11.43 and L15.45, respectively. Based on the survival after 25‐day feeding trail and after the hypoxia stress, the optimal dietary lipid for postlarval L. vannamei should be 118–124 g/kg.  相似文献   

19.
The effects of diets containing different levels of essential oils from savory Satureja khuzestanica Jamzad and myrtle Myrtus communis L and an immunity complement were investigated on growth, survival, nutritional indices, serum biochemistry, and hematology of farmed rainbow trout, Oncorhynchus mykiss, fry (n = 4500; 5 ± 2 g). The essential oils were dosed as 300 and 500 mg/kg diet. After 60 d, the fish fed 300 mg/kg of the essential oils showed the highest counts of white blood cells (P < 0.05). The same treatment revealed the greatest levels of hematocrit, total protein, and albumin, but glucose and cholesterol values significantly decreased compared with the control (P < 0.05). Feeding fish with 300 mg/kg of the essential oils led to highest records of specific growth rate and survival rate but the lowest feed conversion ratio (FCR), and those fed with immunity complement attained the lowest values of growth parameters. The fry fed with immunity complement and 300 mg/kg of myrtle essential oil achieved the highest and lowest FCR values, respectively. The results indicate that dietary supplementation of 300 mg/kg of the above essential oils exert positive impacts on the growth performance, feeding efficiency, and hematological factors in O. mykiss.  相似文献   

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