蝇蛆粉替代鱼粉对凡纳滨对虾生长的影响

为探讨凡纳滨对虾饲料中用蝇蛆粉替代鱼粉的可行性及适宜的添加比例,研究了蝇蛆粉替代饲料中部分鱼粉对凡纳滨对虾(Litopenaeus vannamei)生长、成活和饵料系数的影响。饲喂试验共持续了65 d。结果显示:当蝇蛆粉替代鱼粉添加量为7%时,试验中期(32 d)和末期对虾增重率(WGR)和特定生长率(SGR)均显著高于其他组(P<0.05)。在低于7%添加范围内,随着蝇蛆粉添加水平的增加对虾WGR和SGR逐渐提高,超过7%后,对虾WGR和SGR逐渐下降。试验中期和末期,17%添加组饵料系数均显著高于其余各组(P<0.05),7%添加组饵料系数略高于对照组但差异不显著。无论是中期还是末期,蝇蛆粉替代鱼粉对凡纳滨对虾的成活率未产生显著影响(P>0.05)。在凡纳滨对虾饲料中添加7%的蝇蛆粉替代鱼粉可促进对虾生长,利用蝇蛆粉替代对虾饲料中的部分鱼粉是可行的。     

酵母培养物和芽孢杆菌对凡纳滨对虾生长、蛋白酶活性和免疫性能的影响

研究了饲料中添加酵母培养物(益康XP)和芽孢杆菌(Bacillus)制剂对凡纳滨对虾(Litopenaeusvannamei)生长、肌肉成分、蛋白酶活性和免疫功能的影响。在基础饲料(对照组)中分别添加0.075%益康XP、0.100%益康XP、0.200%芽孢杆菌,饲养均重(5.57±0.21)g的凡纳滨对虾45 d。结果表明,添加0.075%益康XP、0.100%益康XP、0.200%芽孢杆菌分别提高凡纳滨对虾增重率17.24%、12.29%、20.18%,降低饲料系数14.28%、9.77%、12.03%,提高蛋白质效率16.49%、10.05%、12.98%(P<0.05);添加酵母培养物和芽孢杆菌对凡纳滨对虾肌肉组成成分没有影响(P>0.05);0.075%益康XP组、0.100%益康XP组、0.200%芽孢杆菌组肝胰脏蛋白酶活性较对照组分别提高25.24%、15.22%、54.92%(P<0.05);各试验组肠蛋白酶活性与对照组相比有所提高,但均未达到显著水平(P>0.05);0.100%益康XP、0.200%芽孢杆菌组凡纳滨对虾血清酚氧化酶活性、溶菌酶活性和超氧化物歧化酶活性均显著高于对照组(P<0.05);攻毒实验表明,感染溶藻弧菌后,芽孢杆菌组对虾第1、3、4天的累积死亡率均显著低于对照组(P<0.05),第4天时的免疫保护率达到27.1%,而添加益康XP对累积死亡率无显著影响(P>0.05)。综上所述,饲料中添加酵母培养物益康XP和芽孢杆菌均能改善凡纳滨对虾生长性能和消化功能,芽孢杆菌能增强凡纳滨对虾对溶藻弧菌的抗感染功能。     

家蝇蛆粉替代鱼粉对凡纳滨对虾生长、抗氧化和免疫指标的影响

设计6种等氮等能的试验饲料,以评价不同比例的家蝇蛆粉替代鱼粉对凡纳滨对虾幼虾生长性能、抗氧化以及非特异性免疫指标的影响。选用960尾体质量为(0.56±0.03)g的凡纳滨对虾随机分为6组,分别投喂用家蝇蛆粉替代鱼粉的6种饲料,替代比例(等蛋白替代)分别为0、20%、40%、60%、80%和100%,记为G0、G20、G40、G60、G80和G100。45 d的养殖试验结果显示,G20~G60组凡纳滨对虾的增重率(WGR)与对照组相比差异不显著(P>0.05),G80、G100组WGR显著降低(P<0.05)。除G40组外,各替代组凡纳滨对虾的特定生长率(SGR)均显著低于对照组(P<0.05)。G100组摄食量(FI)显著低于其它各组(P<0.05)。当替代水平不超过60%时,家蝇蛆粉对凡纳滨对虾的饲料系数(FCR)、蛋白质效率(PER)、蛋白质沉积率(PPV)和肝胰指数(HSI)影响不显著(P>0.05);随替代水平的继续增加,FCR和HSI显著升高,PER和PPV显著降低(P<0.05)。替代组对虾肥满度(CF)和存活率(SR)均不同程度的高于对照组,但差异不显著(P>0.05)。随家蝇蛆粉替代水平的增加,全虾粗蛋白、钙(Ca)和总磷(P)含量显著升高(P<0.05),粗脂肪含量显著降低(P<0.05),干物质和灰分含量差异不显著(P>0.05)。各替代组对虾血清和肝胰腺超氧化物歧化酶(SOD)活性、血清丙二醛(MDA)含量与对照组相比差异不显著(P>0.05),G80和G100组肝胰腺MDA含量显著高于对照组(P<0.05)。血清酚氧化酶(PO)活性随家蝇蛆粉替代量的增加而显著降低,其中G20组显著高于其它各组(P<0.05)。肝胰腺碱性磷酸酶(AKP)活性随添加量的增加而显著降低(P<0.05)。家蝇蛆粉替代鱼粉对凡纳滨对虾的血细胞总数(THC)、血清一氧化氮(NO)含量、AKP活性和肝胰腺PO活性、NO含量影响不显著(P>0.05)。     

低聚木糖对凡纳滨对虾生长、体组成和非特异免疫的影响

采用单因子试验设计在凡纳滨对虾(Litopenaeus vannamei)基础日粮中添加不同浓度的低聚木糖,分别为0(对照组)、0.01%、0.03%、0.05%,共4个处理,每个处理3个重复,饲养56 d,研究了低聚木糖对凡纳滨对虾生长性能、体组成和非特异免疫的影响。结果显示:低聚木糖对对虾末重、增重率和特定生长率均无显著影响(P>0.05),但试验组对虾末重、增重率和特定生长率均高于对照组,试验组饵料系数均较对照组下降,其中0.03%组饵料系数显著低于对照组(P<0.05),试验组饲料效率较对照组均有提高,其中0.03%组获得显著提高(P<0.05);血清免疫指标过氧化物酶(POD)、超氧化物歧化酶(SOD)、溶菌酶(LSZ)和酚氧化酶(PO)活力试验组均较对照组有所增加,分别提高了1.27%~5.16%(P>0.05)、0.17%~8.93%(P>0.05)、9.24%~12.61%(P>0.05)和4.17%~66.67%(P<0.05),血清蛋白含量增加了9.72%~39.64%(P<0.05);试验组体蛋白含量较对照组升高,其中0.01%组虾体蛋白质含量最高,且显著高于空白组(P<0.05)。在凡纳滨对虾料中添加低聚木糖有促进生长、降低饵料系数和提高饲料效率的趋势,并提高对虾非特异免疫力的趋势,对对虾体组成除蛋白质外没有显著影响。     

辣椒碱在凡纳滨对虾饲料中的应用研究

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。     

灵芪菌质对凡纳滨对虾生长及非特异性免疫的影响

在基础饲料中添加灵芝与黄芪共发酵产物——灵芪菌质,探讨灵芪菌质对凡纳滨对虾生长性能及非特异性免疫指标的影响。试验选用平均体质量(0.51±0.03)g的凡纳滨对虾幼虾,随机分为5组,每组3个重复,每个重复30尾虾。采用单因子试验设计,在基础饲料中分别添加0%、0.5%、1.0%、1.5%、2.0%的灵芪菌质。试验虾在水温为22～30℃的循环玻璃纤维水槽中饲喂60d。试验结果表明,添加1%灵芪菌质组与对照组相比,对虾相对质量增加率提高了31.88%(P<0.05),饵料系数降低了14.37%(P<0.05),成活率提高了15.16%(P<0.05);对虾血清酚氧化酶活力和超氧化物歧化酶分别提高了99.94%(P<0.05)和26.79%(P<0.05)。添加1.5%灵芪菌质处理组与对照组相比,对虾酸性磷酸酶活力和碱性磷酸酶活力分别提高了128.44%(P<0.05)和111.55%(P<0.05),对凡纳滨对虾的副溶血弧菌攻毒免疫保护率高达73.34%(P<0.05)。本次试验,凡纳滨对虾溶菌活性与灵芪菌质添加量呈一定的正相关(y=1.802x+11.104,r2=0.9378,P<0.05)。添加灵芪菌质可显著提高凡纳滨对虾的生长性能,改善其非特异性免疫力。     

饲料中添加食盐对凡纳滨对虾生长及风味的影响

以初始体重为5.27±0.20g的凡纳滨对虾为研究对象,分别在饲料中添加0、0.5%、1.0%和2%的盐,配制成4种实验饲料,在盐度为1.5和30的水体中喂养50d,探讨饲料中添加盐对凡纳滨对虾生长性能、虾体成分和碱性磷酸酶活性及风味的影响.结果表明,在盐度为1.5时,饲料中添加盐的各组饲料其特殊增长率(SGR)比对照组均有显著提高(P<0.05);饲料中添加盐组的饲料系数(FCR)均比对照组低(P<0.05),饲料中盐的添加量为2.0%时,饲料系数(FCR)达到最低(P<0.05);饲料中添加盐有助于提高对虾的成活率(P<0.05);随着饲料中盐添加量的增加,对虾体蛋白质含量有增加的趋势,而虾体脂肪含量和水分有下降的趋势;随着饲料中盐添加量的增加,凡纳滨对虾肌肉游离氨基酸中必需氨基酸、非必需氨基酸及游离氨基酸总量有增加趋势,甘氨酸、丙氨酸和谷氨酸等呈鲜味氨基酸都大幅度增加;对虾的色泽、嗅觉、味觉及组织等多项指标的感官评价显示,饲料中添加盐2.0%组的综合感官指标优于对照组及其他实验组;饲料中添加盐可显著提高凡纳滨对虾肝胰脏碱性磷酸酶活性,而且随着饲料中盐的添加量的增加,其酶的活性显著上升(P<0.05).当盐度为30,饲料中添加盐显著降低特殊增长率(SGR)(P<0.05),而且随着盐度的增加,其影响加重;饲料中添加盐显著增加对虾的饲料系数(FCR)(P<0.05).     

家蝇蛆粉替代鱼粉对凡纳滨对虾肌肉营养成分、氨基酸和肌苷酸含量的影响

采用等蛋白替代方式,以家蝇蛆粉(housefly maggot meal)分别替代饲料中0、20%、40%、60%、80%和100%的鱼粉,配制6种等氮等能的饲料,饲养初始体质量(0.56±0.03)g的凡纳滨对虾(Litopenaeus vannamei),相应记为G0、G20、G40、G60、G80和G100实验组。养殖45 d后测定对虾肌肉的常规成分和氨基酸、肌苷酸含量,研究家蝇蛆粉对凡纳滨对虾肌肉品质的影响。结果显示,凡纳滨对虾肌肉粗蛋白和灰分含量随家蝇蛆粉替代水平的增加而升高,其中G100组粗蛋白含量和G80、G100组灰分含量显著高于G0组(P<0.05);水分和粗脂肪含量各组之间差异不显著。各组肌肉游离氨基酸中谷氨酸、丙氨酸等鲜味氨基酸和游离鲜味氨基酸总量之间无显著性差异;除G40组外,G20-G100组游离必需氨基酸总量显著高于G0组(P<0.05);与G0组相比,替代组游离精氨酸含量显著增加(P<0.05),游离赖氨酸含量随替代水平的增加而显著降低(P<0.05);G20组游离氨基酸总量显著高于G0组(P<0.05),其他各组之间差异不显著。替代组肌肉结合氨基酸中天冬氨酸、谷氨酸、甘氨酸和丙氨酸等鲜味氨基酸、必需氨基酸和氨基酸总量与G0组相比差异均不显著。G20-G80组肌肉肌苷酸含量与G0组相比差异不显著,G100组显著升高(P<0.05)。结果表明,当家蝇蛆粉替代鱼粉水平不超过60%时,除凡纳滨对虾肌肉游离精氨酸含量显著升高外,对肌肉常规营养成分组成和必需氨基酸、鲜味氨基酸和肌苷酸含量无显著性影响。     

酵母提取物替代鱼粉对凡纳滨对虾消化机能的影响

为探明使用经氨基酸平衡后的酵母提取物替代鱼粉对凡纳滨对虾消化机能的影响,分别用酵母提取物替代饲料中15 %(B)、30 %(C)、45 %(D)、60 %(E)和100 %(F)的鱼粉,配制6种等氮、等能的试验饲料投喂凡纳滨对虾(6.328±0.630 g),以鱼粉含量为25 %的饲料为对照组(A)。饲养7 d后开始收集粪便,测定凡纳滨对虾对饲料的表观消化率。养殖试验结束后,研究酵母提取物替代鱼粉对凡纳滨对虾消化酶的影响。试验结果:凡纳滨对虾对各组饲料均具有较高的干物质表观消化率(77.96 %~81.21 %)和粗蛋白表观消化率(87.19 %~92.82 %)；各替代组饲料的表观消化率均高于对照组,其中C、E和F组的干物质表观消化率显著高于对照组(P<0.05),粗蛋白表观消化率随酵母提取物用量的增加而显著增加(P<0.05)；凡纳滨对虾肝胰腺中类胰蛋白酶的活性随饲料中酵母提取物用量的增加而显著升高(P<0.05),脂肪酶的活性随饲料中酵母提取物用量的增加而显著降低(P<0.05)；肝胰腺中淀粉酶活性最高的为C组；各替代组凡纳滨对虾的肠胰蛋白酶活性均高于对照组。结果表明,以氨基酸平衡酵母提取物替代饲料中的鱼粉可以提高凡纳滨对虾对饲料的消化机能。     

饲料中添加核苷酸对凡纳滨对虾幼虾生长、肠道形态及抗氧化酶活力的影响

本实验旨在研究外源核苷酸混合物对凡纳滨对虾(Litopenaeus vannamei)幼虾生长性能、体组成、中肠肠道形态和抗氧化酶活力的影响。选取960尾初始体质量为(1.01±0.02)g的凡纳滨对虾,随机分为8组,分别投喂基础饲料和添加5种核苷酸混合物(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=1∶1∶1∶1∶1,mix-NT)的实验饲料,各实验组添加量分别为0.1、0.2、0.4、0.6、0.8、1.0和1.2 g/kg饲料,养殖期为7周。结果显示,饲料中添加5种核苷酸混合物对凡纳滨对虾的特定生长率(SGR)和饲料系数(FCR)影响不显著(P>0.05)。外源核苷酸显著影响凡纳滨对虾全虾水分含量(P<0.05),但对全虾粗蛋白、粗脂肪和灰分含量影响不显著(P>0.05)。肝胰指数(HSI)随饲料中核苷酸添加量的增加而显著升高(P<0.05),在0.6 g/kg组达到最高。0.4 g/kg组的肝胰腺谷草转氨酶(GOT)和谷丙转氨酶(GPT)活力及尿酸(UA)含量最低,但与对照组相比差异均不显著(P>0.05)。中肠肠壁厚度和肠绒毛高度均随着核苷酸添加量的增加呈先升高...     

Dietary Supplementation of a Purified Nucleotide Mixture Transiently Enhanced Growth and Feed Utilization of Juvenile Red Drum, Sciaenops ocellatus

Abstract.— Commercial nucleotide products have been shown to enhance early growth as well as immunity and disease resistance in aquacultured fish. Thus, we investigated effects of a purified nucleotide mixture on growth and health of young red drum. The nucleotide premix, containing salts of cytidine, uridine, adenosine, and guanidine, was coated with binders, freeze-dried, and grounded to powder. A fish-meal-based diet was supplemented with 0.03, 0.1, or 0.3% by weight of the coated nucleotide mixture or with 0.2% Optimûn^® (Chemoforma Co., Basel, Switzerland), a commercial nucleotide product. The experimental diets were maintained isonitrogenous and isocaloric by adjusting amounts of casein, gelatin, and alanine. Five replicate groups of 12 juvenile red drum (10.2 ± 0.2 g/fish, mean ± SD) were fed each experimental diet for 4 wk, followed by an assay of neutrophil oxidative radical production and a bacterial challenge via intraperitoneal injection of Vibrio harveyi at 2.9 × 10⁷ colony-forming units/g fish. Fish fed all diets supplemented with various levels of purified nucleotides showed significantly ( P  < 0.01) enhanced weight gain and feed efficiency during the first week of feeding compared to fish fed the basal diet. However, the dietary effects became less significant during the following 3 wk of feeding. The transient growth-enhancing effect of dietary nucleotides observed in the present study may explain the conventional controversy about nucleotide effects on fish growth. Dietary supplementation with nucleotides had no influence on terminal whole-body composition.     

Serum biochemical and non-specific immune responses of rainbow trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>) to dietary nucleotide and chronic stress

The aim of the present study was to investigate whether supplementary nucleotide “Optimun” mitigates the adverse effects of chronic overcrowding in Oncorhynchus mykiss. Two experimental diets [control and nucleotide-supplemented (0.2 %)] and two rearing densities (10 and 30 kg m^?3) were combined to have four experimental treatments. The fish were reared for 45 days under different densities using different diets. At the end of the trial, FCR of the fish in higher density was significantly higher than those of the lower density. Nucleotide had no significant effects on growth performance and survival rate. Supplemented nucleotide significantly increased blood hematocrit, whereas it decreased serum total protein, total immunoglobulin (Ig) and creatinine. Overcrowding significantly increased serum glucose and total protein level and decreased serum lysozyme activity, but supplemented nucleotide produced no improvement in these items. No significant effect of overcrowding and dietary nucleotide was observed on serum cortisol. Supplemented nucleotide significantly increased serum urea under low stocking density. Overall, the results showed that 0.2 % “Optimun” had no positive effects on rainbow trout and also caused some immunological and metabolic problems. These findings are not in accordance with those obtained in the same species, with same nucleotide source and level, but acute stress; thus, further studies are encouraged on this topic.     

Density and Water Exchange-Dependent Growth and Survival of Litopenaeus setiferus Postlarvae

This present study was designed to investigate the effects of stocking density and water exchange on the growth rate, survival and performance index of L. setiferus postlarvae under controlled laboratory conditions. The experiment was done with postlarvae (PL10 to PL40) at densities of 50, 150, 250 and 350 shrimp/m² and various different water exchanges rate per day (0, 6, 12 and 18%). The maximum growth rate was obtained for shrimp with 12% water exchange per day at all densities. A reduction of the maximum growth rate was observed in relation to density with the highest values in shrimp stocked in a density of 50 and 150 shrimp/m² (mean value of 0.53 mg/d) and the lowest in shrimp stocked in a density of 350 shrimp/m² (0.24 mg/d). The multiple regression equation obtained to relate performance index (growth rate* survival : PI), shrimp density (X₁) and water exchange (X₂) was: PI = 0.31 + (0.001) X₁+ 0.039 X₂+ 2.28 × 10⁻⁶ X₁²+ (−0.0017) X₂²+ (0.000026)X₁X₂, R ²= 0.78; P > 0.03. According to this equation the optimum shrimp density-water exchange comhination was between 5 to 12% of water exchange at stocking density of between 50 and 150 shrimp/m². Salinity, ammonia-N and nitrite-N increased according to the time spent in tanks without water exchange. With no (0%) water exchange, water quality parameters measured were outside the optimum for L. setiferus postlarvae. The use of optimum density and water exchange in a nursery system for L. setiferus with optimum variables established is proposed.     

The Effect of K-Lactate Salt and Liquid Smoke on Bacterial Growth in a Model System

The effects of a commercial lactate salt formulation—containing potassium lactate (KL) and potassium acetate (KA)—and liquid smoke (LS) on the growth of selected lactic acid bacteria (LAB; Carnobacterium maltaromaticum, Carnobacterium inhibens, Lactococcus lactis, Lactobacillus curvatus, and Enterococcus faecalis), fish spoilage bacteria (Photobacterium phosphoreum, Pseudomonas putida, and Vibrio vulnificus), and Listeria innocua, were examined in a tryptic soy broth model system at 20ºC based on BioScreen data. The most pronounced inhibition effect on growth of bacteria was seen in the presence of 6% KL + 0.4% KA, used either combined with LS or alone. Only a minor inhibition effect on growth was found in the presence of LS alone. The only exception was Lactobacillus curvatus, which grew quite well in the presence of LS compared to control medium. The growth of Vibrio vulnificus was prevented in 6% KL + 0.4% KA, and significantly inhibited in the presence of 3% KL + 0.2% KA. When V. vulnificus was grown in NaCl, KA, and KL + KA, it was observed that KL + KA had a better inhibition effect than sodium salt within the same concentration range.     

Effects of Sodium Alginate and Chitosan Coating Combined with Three Different Essential Oils on Microbial and Chemical Attributes of Rainbow Trout Fillets

ABSTRACT

Meat products, such as fish meat, are known to be susceptible to undesirable chemical and microbial reactions that characterize spoilage. In this study, the effect of a sodium alginate and chitosan coating incorporated with Mentha piperita, Artemisia dracunculus, and Zataria multiflora essential oils on chemical and microbial attributes of rainbow trout meat was evaluated during storage at 4°C. Chemical and microbial assays were performed on rainbow trout fillets with alginate and chitosan coatings and 0.2% concentration of test essential oils. The results showed that the alginate coating with essential oils significantly decreased production of thiobarbituric acid (TBA) and total volatile basic nitrogen (TVBN) and reduced the growth of foodborne spoilage bacteria during storage at 4ºC. At day 12, the best results were obtained in chitosan coating + Z. multiflora, with 5.96 ± 0.12, 4.93 ± 0.12, and 3.83 ± 0.2 for total viable counts, psychrotrophic bacterial count, and lactic acid bacteria count, respectively. Moreover, the lowest amounts of chemical analysis were observed in chitosan coating + Z. multiflora at the final day (0.54 ± 0.03 and 20.31 ± 0.1 for TBA and TVBN, respectively). Our study revealed that essential oils can be used as effective natural components against undesirable chemical and microbial reactions in fish meat.     

牛磺酸对鲤生长及血清T_3、T_4含量的影响

用牛磺酸作为饲料添加剂,以0.2%、0.4%、0.6%、0.8%的剂量将牛磺酸添加到基础饲料中,以基础饲料为对照,饲喂重(40.73±3.92)g的鲤60 d后,测定鱼体的相对增重率、饲料系数、血清中三碘甲状腺原氨酸(T3)及甲状腺素(T4)的含量,结果表明:牛磺酸显著地提高鲤的生长速度和血清甲状腺素的含量(P<0.05),极显著地提高鲤的血清三碘甲状腺原氨酸的含量(P<0.01),对饲料系数没有显著影响(P>0.05)。血清T3、T4含量的提高,是牛磺酸促进鱼体生长速度加快的重要原因之一。     

Effect of ration on the growth and energy budget of Chinese longsnout catfish, Leiocassis longirostris Günther

The effect of ration on growth and energy budget of Chinese longsnout catfish was investigated in a growth trial. Fish of initial body weight of 6.5 g were fed at six ration levels (RLs): starvation, 0.8%, 1.6%, 2.4%, 3.2% of body weight per day, and apparent satiation for 8 weeks. Fish were weighed biweekly to adjust feed amount. The results showed that specific growth rate in wet weight, protein and energy increased logarithmically with increased RLs. The relationship of specific growth rate in wet weight (SGRw, % day^?1) and RL (%) was a decelerating curve: SGRw=?0.62+3.10 Ln(RL+1). The energy budget equation at satiation was: 100 IE=12.94 FE+5.50(ZE+UE)+40.07 HE+41.49 RE, where IE, FE, (ZE+UE), HE, RE are food energy, faecal energy, excretory energy, heat production and recovered energy respectively. Body composition was slightly but significantly affected by ration size except for protein content. The most efficient ration based on the relationship between RL and feed efficiency ratio in energy (FERe) was 1.8% of body weight per day.     

Effects of temperature, salinity and irradiance on the growth of the toxic dinoflagellate Gymnodinium catenatum (Dinophyceae) isolated from Hiroshima Bay, Japan

ABSTRACT: Temperature and salinity ranges in which Gymnodinium catenatum (Hiroshima Bay strain) showed specific growth rates higher than 0.2/day were approximately 20–30°C and 20–32. The specific growth rate (μ), expressed as a polynomial equation as functions of temperature ( T ; °C) and salinity ( S ) were μ = (−6.84 × 10⁻⁴ T ² + 0.0354 T – 0.213) × (−1.03 × 10⁻³ S ² + 0.0579 S – 0.548)/0.31; the maximum growth rate (0.31/day) was obtained at 25°C and 30. From a comparison with field data recording temperature, salinity and light intensity, this species may be expected to bloom from summer to autumn in Hiroshima Bay.     

外源核苷酸对斑点叉尾(鱼回)生长及肠道组织发育的影响

以斑点叉尾(鱼回)幼鱼为试验对象,研究不同水平外源核苷酸对其生长和肠道发育的影响.在基础饲料中分别添加0.0%(对照组)、0.02%、0.05%和0.1%的外源核苷酸.结果表明,在斑点叉尾(鱼回)幼鱼日粮中添加外源核苷酸,促生长作用不显著(P>0.05),但可显著促进肠道组织的发育(P<0.05).     

Effects of dietary nucleotides on growth,physiological parameters and antioxidant responses of Juvenile Yellow Catfish Pelteobagrus fulvidraco

The effects of nucleotides on growth, and physiological and antioxidant parameters were evaluated by feeding Pelteobagrus fulvidraco diets supplemented with 0, 0.2, 0.4, 0.6, 1.0 or 1.5 g kg^?1 of nucleotides respectively. All nucleotide groups showed higher specific growth rate, feed efficiency, protein efficiency ratio, whole‐body lipid content and serum cholesterol concentrations than the control group, but the significant difference was seen only between fish from the 1.5 g kg^?1 nucleotide group and fish from the control group. Whole‐body ash content in fish from the 0.6 g kg^?1 nucleotide group, and liver superoxide dismutase and catalase in fish from the 0.4 g kg^?1 nucleotide group were significantly higher than those in fish from the control group. Respiratory burst activity was significantly higher in fish from the 0.6, 1.0 and 1.5 g kg^?1 nucleotide groups than in fish from the control. This finding was accompanied by lower liver concentrations of thiobarbituric acid‐reacting substances in fish from the same groups compared to those from the control group. The results indicate that dietary nucleotides could improve growth and antioxidant responses in juvenile yellow catfish.