不同盐度对尼罗罗非鱼存活和生长性能的影响

为评估选育耐盐尼罗罗非鱼(Oreochromis niloticus)在高盐度水体中的生长性能,在塑料盒(80cm×60cm×60cm)中设置盐度21‰、24‰、27‰和29‰共四个盐度梯度处理进行耐盐鱼苗的生长性能比较研究。养殖40d的生长结果表明,随着盐度的逐步增加,选育尼罗罗非鱼苗存活率呈明显下降的趋势,且日增重、增重率以及特定生长率等指标也均呈下降趋势。耐盐选育尼罗罗非鱼可以在29‰的盐度下正常生长,且存活率可达80%以上,本试验为尼罗罗非鱼在半咸水地区养殖提供基础数据。     

水体盐度与饲料脂肪含量对尼罗罗非鱼生长、营养组成和肉质的影响

为研究水体盐度和饲料脂肪含量对尼罗罗非鱼生长、营养组成和肉质的影响,本实验设置0、8和16共3个盐度梯度,每个梯度分别投喂中脂(6%)和高脂(12%)饲料,投喂初始体质量为(5.0±0.2) g的尼罗罗非鱼8周,并测定生长性能、血清生化指标、肌肉营养成分和肉质相关指标。结果显示,在中脂饲料投喂下,与对照组(盐度为0)和高盐组(盐度为16)相比,中盐组(盐度为8)的尼罗罗非鱼具有最大终末体质量、躯壳比、脂体比、肌肉蛋白质含量、肌肉氨基酸和乳酸含量和总产肉率,但其饲料系数、脏体比、肝体比和肌肉p H值显著降低;而中脂高盐组的尼罗罗非鱼其饲料系数、肥满度、脏体比、肝体比、全鱼总脂、肝脏甘油三酯、血糖、血清乳酸和血清甘油三酯含量、血清谷草转氨酶活性较高,但全鱼和肌肉水分、全鱼灰分、产肉率和肌肉离心失水率降低。在高脂饲料投喂下,随着盐度的上升,其终末体质量、成活率和脂体比降低,但饲料系数、脏体比、肝体比和肥满度增大。其中,高脂中盐组尼罗罗非鱼的肌肉蛋白以及氨基酸含量显著降低,而高脂高盐组的全鱼灰分、肝脏甘油三酯、血糖、谷草转氨酶活性、肌肉总脂、肌肉甘油三酯和磷脂含量显著提高,但全鱼总脂、肝糖原、...     

不同盐度下尼罗罗非鱼、萨罗罗非鱼和以色列红罗非鱼幼鱼生长、成活率及肥满系数的差异

用1m×1m×1m的实验网箱,在盐度分别为0、10、20及30的水体中进行尼罗罗非鱼(Oreochromisniloticus)、萨罗罗非鱼(Sarotherodonmelanotheron)和以色列红罗非鱼(Israeliredtilapia)幼鱼的养殖实验。结果表明:(1)盐度、鱼的种类及盐度-鱼类的交互作用都对3种罗非鱼的生长及体重变异系数有显著影响(P<0 05);3种罗非鱼的成活率和肥满系数只受鱼的种类影响(P<0 05);盐度、盐度-鱼类的交互作用对其都无显著影响。(2)生长和盐度之间的回归关系在尼罗罗非鱼和以色列红罗非鱼较显著,在萨罗罗非鱼显著性较差。(3)尼罗罗非鱼和以色列红罗非鱼的生长随着盐度的降低而加快,萨罗罗非鱼的生长随着盐度的降低而减慢。在3种鱼中,盐度在6 9以下时,尼罗罗非鱼生长最快;盐度7 4～28 7时,以色列红罗非鱼生长最快;盐度高于29 0时,萨罗罗非鱼生长最快。(4)在实验的4种盐度下,萨罗罗非鱼的成活率都高于以色列红罗非鱼和尼罗罗非鱼,而除了在淡水中外,以色列红罗非鱼的成活率又都高于尼罗罗非鱼;萨罗罗非鱼的肥满系数都显著高于尼罗罗非鱼和以色列红罗非鱼,而以色列红罗非鱼的肥满系数和尼罗罗非鱼的没有显著差异。     

尼罗罗非鱼五品系生长性能评估

在我国黄河流域,长江流域及珠江流域三个农业生态区,山东青岛,上海,浙江湖州及广州四个地区,在网箱,水泥池及池塘三种水体,单养或混养系统里,对五个尼罗罗非鱼品系,即吉富品系,“７８”吕系,“８８”品系,“埃及”品系以及“美国”品系,进行生长性能的评估。评估分一龄和二龄阶段跟踪进行,共十七个试验。生长性能试验结果证明,不论是在青岛,湖州,上海还是在广州不论是池塘、水泥池,还是网箱养殖,不论是混养还是养     

饲料中添加甜菜碱对尼罗罗非鱼生长_肌肉组成和消化率的影响

甜菜碱是甜菜加工副产品中提取的甘氨酸甲基内酯,甜菜碱以前仅限于作为动物营养的甲基供体,参与氨基酸的合成和协同作用。作为人类医学上的恢复胃酸的药物及肝脏保护性治疗剂等［朱仲贤１９７９］,参与氨基酸的合成和协同作用。甜菜碱作为鱼类的饲料添加剂的主要作用是...     

在四种盐度中饵料蛋白质水平对尼罗罗非鱼幼鱼的生长、饵料转换和蛋白质利用的影响

在盐度分别为0％，5‰，10‰和15％的水中，七种蛋白质含量为10-48％的人工饵料对平均体重为24mg的尼罗罗非鱼幼鱼的生长和饵料转换的影响。在饵料的蛋白质含量为28～30％时，尼罗罗非鱼幼鱼始终生长较好。饵料蛋白质含量达30％，在10‰盐度中的幼鱼生长最好，蛋白质含量更高时，幼鱼在淡水中生长最好。饵料蛋白质含量达30％时，饵料转换率增加，超过30％则减少。饵料转换率在10‰盐度中比其他盐度的水高得多。     

氯化胆碱对尼罗罗非鱼生长影响的对比试验

<正> 胆碱(choline)是动物营养的必要成份,作为甲基的供体产生乙酰胆碱,在生理上起着各种重要的作用.1985年我们分别在室内外进行氯化胆碱对尼罗罗非鱼生长影响的对比试验。试验是以生长比速、饲料系数、脂肪蓄积率及蛋白质利用率为评定指标。三次试验结果表明,对照组比胆碱组稍好,但两者差异不显著(p>0.05)。可以认为在本试验条件下,饲料中胆碱含量已满足尼罗罗非鱼生理上的需要,没有添加氯化胆碱的必要。     

红罗非鱼和尼罗罗非鱼正反交后代体色和生长性能的评价

用台湾红罗非鱼 (以下简称台红 )和吉富品系尼罗罗非鱼 (以下简称吉富 )进行杂交 ,观察正反杂交后代的体色分离和生长差异。结果表明 :(1)正反杂交子代的体色均出现分离 ,台红 (♀ )×吉富 (♂ )子代的体色以全红和花斑为主 ,两者的比例为 1∶1,吉富 (♀ )×台红 (♂ )子代中红色个体的比例为 83.8% ,优于红罗非鱼自行繁衍之后代。 (2 ) 12 2d网箱试验的结果表明 ,正反交子代及其亲本的日增重率由高到低依次为吉富 >反交〔吉富 (♀ )×台红 (♂ )〕 >正交〔台红 (♀ )×吉富 (♂ )〕 >台红。 4种鱼的生长速度存在极显著的差异 (P =0 .0 0 0 2 0 )。正交和反交子代的日增重率分别比台红提高 18.4 %和 2 4 .5 %。若考虑到种内的体色 ,日增重率存在极显著的体色间差异 (P =0 .0 0 2 3)。总之 ,反交子代具有红色个体比例高、生长速度快等优势 ,可应用于生产     

盐度胁迫对尼罗罗非鱼肝脂肪酸组成与脂代谢相关基因表达的影响

为探讨盐度胁迫对尼罗罗非鱼（）肝脂肪酸代谢的影响,本研究分别在盐度8和盐度16的水体中对尼罗罗非鱼进行两周的胁迫实验,比较盐度胁迫过程中肝脂肪酸组成变化,以及脂蛋白脂肪酶（lipoprotein lipase,LPL）、苹果酸酶（malic enzyme,ME）和过氧化物酶体增殖物激活受体α亚基（peroxisome proliferator-activated receptor,PPAR-α） mRNA表达量变化。结果表明,胁迫12 h,盐度组血浆渗透压升至最高,16盐度组血浆渗透压显著高于8盐度组（<0.05）,96 h后饱和脂肪酸含量逐渐恢复至初始水平;胁迫期间,盐度组单不饱和脂肪酸含量显著低于淡水组（<0.05）。盐度组脂蛋白脂肪酶（LPL）、苹果酸酶（ME）、过氧化物酶体增殖物激活受体α亚基（PPAR-α） mRNA表达量均显著高于淡水组（<0.05）。结果表明,盐度胁迫影响了肝脂肪酸组成和脂代谢过程。本研究旨在为鱼类渗透调节中脂类能量利用提供基础资料。     

不同养殖模式对尼罗罗非鱼（Oreochromis niloticus）生长、免疫性能及水质的影响

为探讨循环水养殖模式(RAS组)和池塘养殖模式(池塘组)对尼罗罗非鱼生长、免疫性能及水质影响的变化规律,开展了为期8周的养殖试验。结果表明：(1)RAS组中鱼体增重率(WGR)(597.36±169.79)显著高于池塘组(470.98±142.99)(P < 0.05),但饲料转化率(FCE)(1.17±0.02)却显著低于池塘养殖系统(1.47±0.03)(P < 0.05)。特定生长率(SGR)和肥满度(CF)也高于池塘养殖系统,但差异不显著(P > 0.05);(2)在第4周和第8周分别测定了鱼体胃和肠中消化酶活性显示,第4周时,RAS组中肠蛋白酶活性值(1387.56±278.43)显著高于池塘组(1129.99±382.67)(P < 0.05);第8周时,肠脂肪酶活性(18.11±4.28)显著高于池塘组(12.89±8.00)(P < 0.05);(3)在第4周和第8周分别测定了鱼体肝胰脏、头肾和血清中碱性磷酸酶(ALP)、溶菌酶 (LSZ)和总超氧化物歧化酶(T-SOD)活性,显示整体上RAS组免疫性能低于池塘组;(4)每周测定水体氨态氮和亚硝态氮含量显示,RAS组氨态氮维持在0.0067 ~ 0.0212 mg / L区间内,亚硝态氮含量位于0.0027 ~ 0.0087 mg / L范围内,均低于池塘组。     

Effect of a Dietary Mixture of Beneficial Bacteria on Growth Performance,Health Condition,Chemical Composition,and Water Quality of Nile Tilapia,Oreochromis niloticus Fingerlings

ABSTRACT

Effects of dietary supplementation of Bifidobacterium longhum, Bifidobacterium thermophilum, Bacillus subtilis, and Lactobacillus acidophilus on growth performance, health condition, body chemical composition, and water quality of Nile tilapia (Oreochromis niloticus) fingerlings were evaluated. Five experimental treatments in triplicate were fed a diet containing 30% crude protein supplemented with variable inclusion of bacterial mixture: control, T1, T2, T3, and T4 containing 0, 1.0, 2.0, 3.0, and 4.0 g bacterial mixture/kg diet, respectively. Fish fed the T4 diet had the highest final body weight, weight gain, specific growth rate, thermal growth coefficient, feed intake, and the best feed conversion ratio. No significant differences in body chemical composition of fish were observed in terms of dry matter, crude protein, lipid, ash, and energy content among all treatments. Probiotic supplementation showed no noticeable differences on haematological and biochemical blood parameters, except for packed cell volume, albumin, albumin/globulin ratio, aspartate transaminase, glucose, uric acid, triglycerides, and cholesterol. Conclusively, Nile tilapia fingerlings diet supplemented with evaluated probiotic with an optimal dietary supplementation of 4 g/kg diet improved growth performance and fish health without a negative impact on water quality. This supplementation could therefore be used as a probiotic in Nile tilapia fingerlings diet.     

Dietary leucine requirement of Juvenile Nile tilapia,Oreochromis niloticus

An 8‐week feeding trial was conducted to evaluate the effects of dietary leucine on growth performance, feed utilization, body composition and non‐specific immune responses of juvenile Nile tilapia. Five isonitrogenous and isoenergetic diets were formulated to contain graded levels of L‐leucine (5.3, 8.1, 10.9, 13.2, 15.6 and 18.1 g kg^?1 diet, respectively) from dietary ingredients and crystalline L‐leucine. Each diet was randomly assigned to triplicate groups of 20 juvenile fish (1.94 ± 0.01 g) three times daily to apparent satiation. Results showed that the weight gain (WG) and specific growth rate (SGR) increased as dietary leucine concentrations increased from 5.3 to 13.2 g kg^?1 and then decreased slightly with further increase in dietary leucine concentrations. Quadratic regression analysis (y = ?522.6x² + 1304.x + 132.6, R² = 0.684) on weight gain against dietary leucine levels indicated that the optimal dietary leucine requirement was estimated to be 12.5 g kg^?1 diet (corresponding to 43.1 g kg^?1 of dietary protein). Leucine supplementation had no impact on the survival and body composition of tilapia. Serum lysozyme activity of fish fed diet containing 13.2 g kg^?1 leucine significantly increased compared to fish fed diet containing 5.3 g kg^?1. Serum superoxide dismutase activity and immunoglobulin M (IgM) concentration were not significantly affected by dietary leucine supplementation.     

The Use of American Ginseng (Panax quinquefolium) in Practical Diets for Nile Tilapia (Oreochromis niloticus): Growth Performance and Challenge with Aeromonas hydrophila

This study was carried out to evaluate the effect of American ginseng (AG), Panax quinquefolium, on growth and resistance to Aeromonas hydrophila in Nile tilapia, Oreochromis niloticus. Ginseng was included in practical test diets at rates of 0.0 (control), 0.50, 1.0, 2.0, or 5.0 g/kg diet. Fish (9.1 ± 0.3 g) were distributed into quadricated 100-L aquaria at a density of 20 fish per aquarium. Fish in all treatments were fed up to satiation twice daily for 8 weeks. After the feeding trial, fish of each treatment were intraperitoneally injected with pathogenic A. hydrophila and kept under observation for 10 days. Highest growth was obtained at 1.0 – 5.0 g AG/kg diet. The survival of fish challenged by A. hydrophila increased with increasing AG levels in fish diets. Cost-benefit analysis indicated that ginseng supplementation could reduce per kg costs by 15% with an optimum inclusion level of 2.0 g/kg.     

Dissolved Oxygen Level and Stocking Density Effects on Growth,Feed Utilization,Physiology, and Innate Immunity of Nile Tilapia,Oreochromis niloticus

A factorial design with three levels of dissolved oxygen (DO)—low 1.0–1.5 mg/l (LDO), medium 2.5–3.0 mg/l (MDO), and normal 6.0–6.5 mg/l (NDO)—and two stocking densities—0.2 g/l (SD1) and 0.4 g/l (SD2)—tested the interaction between oxygen and stocking density on juvenile tilapia performance. After the feeding trial, fish were intraperitoneally injected by pathogenic bacteria, Aeromonas hydrophila, and fish mortality was observed for 10 days post challenge. Highest growth was observed in the NDO-SD1 group. Reduction in DO concentration from 6.5 to 3.0 or 1.5 mg/L caused a reduction in fish growth and feed intake, which increased significantly by increasing fish density. Crude protein and total lipid in whole-fish body decreased significantly at LDO, while total lipid content decreased also at high SD. Glucose, activities of aspartate amninotransferase and alanine aminotransferase, creatinine, and uric acid in fish sera increased significantly, while total protein and total lipid decreased significantly at LDO and/or high density. Lowest fish immunity was observed in the LDO-SD2 group, suggesting that stress was maximized under LDO conditions and/or at high density.     

Geosmin and Off-Flavor in Nile Tilapia (Oreochromis niloticus)

Abstract

The concentration of geosmin (1,10-trans-dimethyl-trans-9-decaol) in fresh tilapia were analyzed by applying high-vacuum distillation, extraction and gas chromatography techniques. The distribution of geosmin in the fish was determined by examining tissues from various parts of tilapia, along with the rates of geosmin absorption and purging. Analysis showed that when geosmin was added to fish flesh at concentrations ranging from 2.8 to 390 μg per kg of flesh, the rate of recovery was 51 to 89%. Sensory evaluation detected muddy flavor in freshwater tilapia with geosmin content ranging from 7.55 to 9.85 μg/kg of fish flesh. However, panelists failed to detect muddy flavor in brackish water tilapia that contained geosmin only in the range of 1.5 to 2.6 μg/kg. Among various tissues of the fish, the intestines contained the highest geosmin concentration, and appeared in descending order in the abdominal, skin and muscle tissues. After holding for 2 h in water with 5 and 50 μg/l geosmin, tilapia absorbed 17.6 and 42.2 μg/kg geosmin in the flesh, respectively. Holding the fish over longer periods in water with higher geosmin content resulted in a greater amount of absorption. In contrast, transferring muddy-flavored fish to static clean water purged geosmin from the fish but it required at least 16 days to eliminate the muddy flavor.     

Optimization of Phosphorus Fertilizer in Supplemental Feed‐Fed Based Nile Tilapia (Oreochromis niloticus) Ponds

An experiment was conducted in earthen ponds at the Asian Institute of Technology, Thailand to determine different phosphorus fertilizer dose effects on Nile tilapia production, water quality variables, nutrient utilization and cost‐benefit under supplemental feeding. Five phosphorus fertilization rates were used as treatments e.g. 100%, 75%, 50%, 25% and 0% of 7 kg P ha week^?1. Nitrogen fertilization rate was fixed at 28 kg N ha week^?1 for all the treatments. Sex‐reversed Nile tilapia were stocked at 3 fish m^?2, and 30% CP floating feed fed at 50% satiation feeding rate. Nutrient budget showed higher phosphorus fertilizer input resulted in higher phosphorus sink in the sediment. Mean weight, mean weight gain, daily weight gain and net yield were not significantly different among treatments (P > 0.05). Total Kjeldahl nitrogen, total phosphorus and soluble reactive phosphorus were significantly different among treatments. Economic analysis showed phosphorus fertilization resulted in positive net returns. Though the gross income was not affected by different fertilization rates, significantly lowest cost was found in the treatment using 25% phosphorus fertilizer. It can be concluded from the research that 25% phosphorus fertilization might be used as an alternative strategy of Nile tilapia pond culture in terms of economic return and nutrient loss in sediment.     

尼罗罗非鱼淀粉酶性质的初步研究

研究了尼罗罗非鱼(Oreochromis niloticus)肝脏淀粉酶的基本性质及金属离子对该鱼淀粉酶活性的影响。结果表明:罗非鱼淀粉酶活力的最适pH是6.5,最适底物浓度是2%。研究金属离子对该鱼淀粉酶活力影响,一价金属离子K+、Li+、Na+对酶活力影响较小;二价金属离子Cu2+对酶活力具有抑制作用,Zn2+对酶活力无明显影响;三价金属离子Al3+对酶活力具有抑制作用,但效果不是很强烈,Fe3+对酶活力具有明显的激活作用;碱土金属Mg2+、Ca2+对淀粉酶活性有激活作用,而Ba2+对酶具有抑制作用;重金属离子Cd2+、Pb2+有明显的抑制作用。     

吉富等品系尼罗罗非鱼的起捕率差异

在常规土质鱼池中进行了吉富“８８”、“７８”和埃及等四品系尼罗罗非鱼的起捕率比较试验。结果表明吉富品系的三网累计起捕率显著地高于其他品系（Ｐ〈０．０１）。１９９５年的试验中，吉富的三网累计起捕率为６７％、“８８”为３８％，“７８”为２３％，埃及为２２％。１９９６年的试验中，吉富的三网累计起捕率为８１．５％，“８８”为６２％，试验结果表明吉富品系尼罗罗非鱼的起捕率较高。