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1.
选取蛹肽蛋白分别替代大菱鲆幼鱼配合饲料中0、15%、30%、45%、60%、75%的鱼粉,配制成6种等氮等能的饲料饲喂大菱鲆幼鱼(19.84±0.04 g)56 d,以研究蛹肽蛋白替代鱼粉的效果。结果显示,大菱鲆幼鱼的特定生长率、饲料效率随替代水平的升高而降低,30%及以上替代组显著低于对照组(P0.05);鱼体粗蛋白、粗脂肪水平随替代水平的升高而降低,分别在75%和30%及以上替代组显著降低,鱼体水分和灰分含量随替代的升高而升高,分别在75%和30%及以上替代组显著升高(P0.05)。摄食率随替代水平升高呈先上升后下降的趋势,在30%替代组呈现出最高的摄食率,且显著高于对照组(P0.05)。饲料干物质的表观消化率在42.53%-54.36%之间,且当替代水平达到75%时显著低于对照组(P0.05);而蛋白质表观消化率在71.67%-86.89%之间,仅45%和75%替代组显著低于对照组(P0.05)。各替代组肝脏超氧化物歧化酶活性均高于对照组,在45%和60%替代组出现显著性差异(P0.05)。综上所述,蛹肽蛋白可以替代大菱鲆幼鱼饲料中15%的鱼粉而不影响其生长摄食、饲料利用以及与消化、代谢、免疫相关的酶的活性。  相似文献   

2.
本研究旨在评价核糖蛋白替代大菱鲆(Scophthalmus maximus)饲料中鱼粉的潜力。采用单因素实验设计,设6个鱼粉替代水平。对照饲料(D1)中鱼粉含量为45%,通过添加核糖蛋白替代D1组饲料中鱼粉的0.5%(D2)、1%(D3)、2%(D4)、3%(D5)和4%(D6)。实验期间,每天分2次按饱食量投喂初始体重为(24.00±0.30)g大菱鲆幼鱼56 d。结果显示,幼鱼增重率、特定生长率、蛋白质效率随着核糖蛋白替代水平的变化呈先上升后下降趋势,均在D3组达到最高值,显著高于D5和D6组(P<0.05);饲料系数则呈相反趋势,在D3组达到最低值,显著低于D6组(P<0.05)。各替代组幼鱼血清胰岛素生长因子(IGF-1)和生长激素(GH)含量均显著低于对照组(P<0.05);核糖蛋白替代1%~3%的鱼粉后,显著提高了幼鱼肠道胰蛋白酶活性(P<0.05);幼鱼肠道α-淀粉酶活性在D4和D5组显著高于对照组(P<0.05);饲料中添加核糖蛋白替代鱼粉显著降低了幼鱼肠道脂肪酶活性(P<0.05)。各替代组幼鱼血清总蛋白、球蛋白含量和碱性磷酸酶活性均显著高于对照组(P<0.05);D3组溶菌酶活性显著高于D6组(P<0.05);各组间幼鱼血清白蛋白含量和超氧化物歧化酶活性无显著差异(P>0.05),但各替代组均显著提高了幼鱼血清白介素β1(IL-1β)和肿瘤坏死因子(TNF-α)含量(P<0.05);与对照组相比,D4~D6组血清总胆固醇和甘油三酯含量显著降低(P<0.05),低密度脂蛋白在D5和D6组显著降低(P<0.05);高密度脂蛋白在D4组显著升高(P<0.05)。血糖浓度呈先升高后降低的趋势,D3组显著高于对照组(P<0.05)。攻毒实验结果显示,D2组大菱鲆幼鱼48 h累积死亡率最低为56.45%。研究表明,饲料中添加核糖蛋白替代1%鱼粉时,大菱鲆幼鱼生长、消化酶活力及鱼体的免疫能力和抗细菌感染能力均达到最高。  相似文献   

3.
以鸡肉粉替代饲料中0%、20%、40%、60%、80%的鱼粉,配制5种等氮等能饲料。选取初始体质量为(22.82±0.08)g的大菱鲆幼鱼180尾,随机分为5组(每组3个重复,每重复12尾)分别投喂一种饲料,试验周期为8周。试验结果表明,鸡肉粉替代鱼粉对大菱鲆幼鱼终末体质量、特定生长率、饲料系数以及质量增加率产生显著影响(P0.05)。鸡肉粉替代鱼粉对大菱鲆幼鱼鱼体水分、粗蛋白、灰分、能量含量未造成显著影响(P0.05),鸡肉粉替代组粗蛋白含量比对照组略微升高,粗脂肪含量比对照组显著降低(P0.05),鸡肉粉替代组之间的粗脂肪含量无显著差异(P0.05),但有升高的趋势。鸡肉粉替代40%鱼粉时,血清谷草转氨酶、谷丙转氨酶活力显著高于对照组(P0.05)。鸡肉粉替代鱼粉对肝脏谷丙转氨酶、谷草转氨酶活力影响显著(P0.05)。鸡肉粉替代鱼粉对主要营养成分的表观消化率产生显著影响(P0.05)。本试验结果表明,鸡肉粉替代20%的鱼粉对大菱鲆幼鱼生长最为有利。  相似文献   

4.
玉米蛋白粉替代鱼粉对大菱鲆摄食、生长及体组成的影响   总被引：3，自引：2，他引：1  
以鱼粉和玉米蛋白粉作蛋白源,配制6种等氮等能的饲料。其中5种饲料(C0、C12、C25、C38和C50.5)分别含有0%、12%、25%、38%和50.5%的玉米蛋白粉以替代相应的鱼粉蛋白。其余1种饲料(C50.5CAA)是在饲料C50.5基础上补充1.8%晶体氨基酸混合物(L-lysine:1.2%,L-arg:0.6%)。经7周的生长试验,结果表明随着饲料中玉米蛋白粉替代水平的升高,大菱鲆(12.51±0.02)g的摄食率、特定生长率、饲料效率和蛋白质效率均显著下降。饲料中玉米蛋白粉含量为50.5%时,大菱鲆摄食率显著低于其他处理组(P<0.05)。当饲料中玉米蛋白粉含量超过25%时,大菱鲆特定生长率显著低于对照组(C0)(P<0.05)。当饲料中玉米蛋白粉含量超过38%时,饲料效率和蛋白质效率与对照组(C0)相比显著下降(P<0.05)。C50.5CAA组的摄食率、特定生长率和蛋白质效率与C50.5组相比都有升高的趋势,但差异不显著。而饲料中添加晶体氨基酸显著提高了大菱鲆的饲料效率(P<0.05)。饲料中玉米蛋白粉替代鱼粉对大菱鲆鱼体水分、粗蛋白、粗脂肪及灰分含量均无显著影响。饲料中玉米蛋白粉替代鱼粉对大菱鲆血清甘油三酯和尿素氮含量也不产生显著影响,然而,随着饲料中玉米蛋白粉含量升高,血清总胆固醇含量显著下降(P<0.05)。  相似文献   

5.
研究了大豆浓缩蛋白(SPC)替代鱼粉对大菱鲆生长及生理生化指标的影响。5种饲料分别含有0、12.0%、25.0%、37.0%和49.5%的SPC以替代相应的鱼粉,并分别添加0、0.83%、1.65%、2.48%和3.30%的必需氨基酸混合物(L-lysine∶DL-methionine∶L-leucine∶Lvaline∶L-threonine=18∶6∶3∶2.5∶2)以平衡各组饲料的氨基酸组成。每种饲料投喂3个水族箱(300 L),每个水族箱放养实验鱼16尾,实验鱼初始体质量为(31.1±0.1)g。经过9周生长实验,结果显示随着饲料中SPC替代水平的升高,大菱鲆摄食率、特定生长率均显著下降(P0.001)。然而,当使用0~37.0%的SPC替代鱼粉时,各处理组饲料效率和蛋白质效率未出现显著差异(P0.05)。饲料中SPC替代鱼粉对大菱鲆鱼体水分、粗蛋白、粗脂肪及灰分含量均无显著影响(P0.05)。各处理组干物质和粗蛋白的表观消化率之间也未出现显著差异(P0.05)。研究表明,在本实验条件下SPC不能作为大菱鲆饲料中替代鱼粉的有效蛋白源,造成SPC替代效果较差的主要原因是其对大菱鲆饲料适口性的显著影响。  相似文献   

6.
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%。  相似文献   

7.
为研究大豆小肽蛋白替代鱼粉对黄颡鱼(Pelteobagrus fulvidraco)生长性能、体成分、消化酶活性和抗氧化功能的影响,以30%鱼粉组为对照组(A0),大豆小肽蛋白分别替代17%、33%和50%的鱼粉作为实验组(A17、A33和A50),配制4种等氮配合饲料。每组设置4个重复,每个重复饲喂30尾平均体重为(3.7±0.6) g的黄颡鱼幼鱼,进行为期80 d的饲养实验。结果显示,A17组生长性能与对照组无显著差异(P>0.05),A33组除增重率(WGR)显著高于对照组外(P<0.05),其余指标均与对照组无显著差异(P>0.05)。A50组饵料系数(FCR)显著高于对照组和其他实验组(P<0.05),增重率、特定生长率(SGR)及蛋白质效率(PER)显著低于对照组和其他实验组(P<0.05)。各实验组肥满度(CF)和脏体比(VSI)与对照组无显著差异(P>0.05)。大豆小肽蛋白替代鱼粉对黄颡鱼全鱼水分、灰分和粗蛋白含量无显著影响(P<0.05);然而,当大豆小肽蛋白替代鱼粉水平从33%升高至50%时,鱼体粗脂肪含量显著降低(P<0.05)。各实验组肠脂肪酶和肠淀粉酶活性显著高于对照组(P<0.05),A33和A50组胃淀粉酶显著高于对照组(P<0.05)。大豆小肽蛋白替代鱼粉对黄颡鱼肝胰脏丙二醛(MDA)活性无影响。综上所述,黄颡鱼配合饲料中鱼粉替代量小于33%时,黄颡鱼生长性能最佳,且对鱼体肝脏抗氧化功能无不利影响。本研究首次探究大豆小肽蛋白替代鱼粉对黄颡鱼生长等的影响,以期为黄颡鱼饲料配制和大豆小肽蛋白的使用等提供参考。  相似文献   

8.
分别用大豆浓缩蛋白(SPC)替代饲料中0(R0,对照组),15%(R15),30%(R30)和45%(R45)的鱼粉蛋白,配制成4组等氮等能饲料,喂养(58.00±2.69)g中华鲟(Acipenser sinensis)幼鱼10周,每组设3个重复,研究SPC对中华鲟幼鱼生长性能、饲料利用率,以及血脂和体成分的影响。结果显示,随替代比例的增加,中华鲟幼鱼的增重率(WG)、特定生长率(SGR)、饲料效率(FE)和蛋白质效率(PER)逐渐降低,肥满度和肝体指数无显著性差异(P>0.05)。FE在R30组出现显著差异(P<0.05),WG、SGR和PER在R45组出现显著性差异(P<0.05)。随替代比例的增加,血浆高密度脂蛋白胆固醇含量无显著变化(P>0.05),胆固醇(CHOL)、甘油三脂(TG)和低密度脂蛋白胆固醇(LDL-C)含量逐渐降低。CHOL、TG和LDL-C含量在R30组出现显著差异(P<0.05)。随替代比例的增加,肌肉和肝脏水分逐渐升高,脂肪逐渐降低,蛋白含量无显著差异(P>0.05)。R30和R45组的肌肉和肝脏水分含量显著高于R0组(P<0.05),脂肪含量显著低于R0组(P<0.05)。结果表明:在本试验条件下,综合考虑生长性能、饲料利用、血脂和体成分等指标,中华鲟幼鱼饲料中SPC替代鱼粉蛋白的比例可达30%。  相似文献   

9.
为研究亚麻籽油替代不同鱼油水平对大菱鲆幼鱼[初始体质量为(5.89±0.02)g]生长、脂肪酸组成以及肝脏和肌肉脂肪沉积的影响,以亚麻籽油分别替代0、33.3%、66.7%和100%鱼油,配制4种等氮等脂饲料。每组饲料随机投喂3组实验鱼,饱食投喂,养殖周期为92 d。结果发现,饲料亚麻籽油水平并未显著影响大菱鲆幼鱼存活率(SR)和特定生长率(SGR),但显著影响其摄食率(FI)、饲料效率(FE)和表观净蛋白利用率(ANPU)。随饲料亚麻籽油水平升高,FI显著升高,而FE和ANPU显著下降,且其均在100%亚麻籽油组分别达到最大值或最小值。饲料亚麻籽油水平并未显著影响大菱鲆饲料脂肪表观消化率、肝体比和肌肉脂肪含量。当饲料中亚麻籽油替代100%鱼油,鱼体肝脏脂肪含量显著高于全鱼油组。肝脏和肌肉脂肪酸组成与饲料脂肪酸组成相似。相对于全鱼油组,亚麻籽油替代组肌肉和肝脏中亚油酸和亚麻酸显著升高,而EPA和DHA含量显著下降。研究表明,大菱鲆饲料中亚麻籽油替代水平应低于66.7%,且大菱鲆饲料中n-3长链多不饱和脂肪酸含量需大于0.8%。  相似文献   

10.
李宜聪  廖凯  姬仁磊  方炜  徐丹  麦康森  艾庆辉 《水产学报》2019,43(11):2405-2412
为了研究饲料中添加茶多酚对大菱鲆生长、抗氧化能力及脂肪代谢相关基因表达的影响,以初始体质量为(13.51+0.31) g的大菱鲆幼鱼为实验对象,设计4组添加不同梯度茶多酚(0%、0.01%、0.02%和0.05%,干重添加量分别为0、100、200和500 mg/kg)的等氮等脂实验饲料,进行为期70 d的摄食生长实验。结果显示:①与对照组相比,饲料中添加0.01%～0.02%茶多酚显著提高了大菱鲆幼鱼增重率(WGR);饲料效率(FE)随饲料中茶多酚添加水平升高而升高,但各组间差异不显著;随饲料中茶多酚添加水平升高,大菱鲆肝体比(HSI)呈降低趋势,且显著低于对照组;②鱼体组成分析表明,投喂添加茶多酚饲料组大菱鲆鱼体和肝脏粗脂肪含量呈下降趋势,且在茶多酚添加水平为0.02%～0.05%时达到最低值,显著低于对照组;③与对照组相比,投喂添加茶多酚饲料组大菱鲆血清总抗氧化能力(T-AOC)及谷胱甘肽过氧化物酶(GSH-Px)活性显著升高,且各添加组间差异不显著;超氧化物歧化酶(SOD)活性随茶多酚的添加水平升高呈先升高后降低趋势,且在添加水平为0.02%时显著高于对照组;血清丙二醛(MDA)含量随茶多酚添加水平升高而降低,且在添加水平为0.02%～0.05%时显著低于对照组;④大菱鲆肝脏固醇调节元件结合蛋白1(SREBP-1)表达量随着饲料中茶多酚添加水平升高而降低,且在添加水平为0.02%～0.05%时达到最低值,显著低于对照组;脂肪酸合成酶(FAS)表达量随茶多酚添加水平的升高呈先降低后升高趋势,且在添加水平为0.02%时显著低于对照组;过氧化物酶体增殖物激活受体α(PPARα)表达量变化趋势与FAS相反,且在添加水平为0.02%时达到最高值。肉毒碱棕榈酰转移酶1(CPT1)表达量随饲料中茶多酚添加水平升高而升高,显著高于对照组,且各添加组间差异不显著。研究表明,高脂饲料中添加茶多酚能促进大菱鲆生长、降低肝脏脂肪过度沉积并提高血清抗氧化能力,高脂饲料中添加0.02%茶多酚是大菱鲆幼鱼生长的最适添加量。  相似文献   

11.
Anguilla luzonensis and A. huangi were each described in 2009 using eels obtained from northern Luzon Island. We examined the taxonomic status of these two groups of eels using morphological and molecular genetic characters. There were no significant differences in two vertebrae counts between eels of A. luzonensis and A. huangi. Mitochondrial 16S ribosomal RNA and cytochrome b genes sequences were obtained and compared among 28 specimens of A. luzonensis, the holotypes of A. luzonensis and A. huangi, and one specimen of the other 15 anguillid species. The specimens of A. luzonensis exhibited almost identical sequences, including the holotype, with only a few site differences, and the genetic difference between the holotypes of A. luzonensis and A. huangi was within the range of differences of specimens of A. luzonensis. The other anguillid species were genetically very different from A. luzonensis and A. huangi, although A. interioris is a closely related species. It is clear that A. luzonensis and A. huangi are the same species, and according to the principle of priority in zoological nomenclature, A. luzonensis Watanabe, Aoyama, and Tsukamoto, 2009 is the valid species name, and A. huangi Teng, Lin, and Tzeng, 2009 is a junior synonym of A. luzonensis.  相似文献   

12.
The effects of exposing the eggs of Pacific threadfin and amberjack eggs (AEs) to different concentrations of hydrogen peroxide for 5 min on hatch rate and survival were assessed in a series of experiments using a petri dish model rearing system. Despite significant inter‐batch variation in hatch rate, it was shown that eggs of both species could be safely exposed to up to 11 340 mg L−1 H2O2 for 5 min. Exposure to 34 230 mg L−1 H2O2 for 5 min was shown to be lethal to AEs at a late stage of development. In two further experiments, it was demonstrated that Pacific threadfin eggs were resistant to all tested concentrations of a range of polyvinylpyrrolidone iodine (PVP‐I) concentrations and contact times (up to 1000 mg L−1 PVP‐I for 10 min). The level of bacteria adhering to the eggs of both species was highly variable. Where eggs were heavily colonized (>104 cfu egg−1), hydrogen peroxide concentrations of at least 11 340 mg L−1, or PVP‐I concentrations higher than 500 mg L−1 for 10 min, were required for effective sterilization. In less colonized batches, rinsing in sterile seawater or exposure to lower (550 mg L−1) concentrations of H2O2 was sufficient to result in high apparent levels of surface sterility (<1 cfu egg−1).  相似文献   

13.
The purpose of this study was to evaluate the acute toxicity of lead for different life stages of shrimp, Litopenaeus vannamei, and to determine the effect of its sublethal concentrations on osmoregulatory capacity (OC) as well as the possible histological alteration in the gills of juvenile shrimp. The 24‐, 48‐, and 96‐h LC50 values for lead to L. vannamei increased progressively with increasing life stage, from nauplii < zoeae < mysis < postlarvae < juvenile. After 15‐d exposure to 3.25, 6.50, and 9.75 mg Pb/L, the OC values of exposed shrimp were reduced by 39, 73, and 157%, respectively compared to control animals. Compared to controls, the lead concentrations in gill tissues increased significantly by 127,500, 137,500, and 141,000% in shrimps exposed to 3.25, 6.50, and 9.75 mg Pb/L, respectively. After lead exposure, hemocytic congestion in efferent vessels and multiple hyperplasia were observed in gill filaments, resulting in narrowed hemolymphatic lacuna. The histopathological effects increased with increasing Pb concentration.  相似文献   

14.
Mosquitofish, Gambusia sp., have been spread throughout the world to biologically control mosquitoes. However, the fish has gained a reputation as an invasive species and has been implicated in displacing native aquatic species. Gambusia affinis are native to the southeastern United States and commonly occur in commercial channel catfish, Ictalurus punctatus, production ponds. We investigated effects of mosquitofish presence on zooplankton populations, water quality, disease occurrence, and fish production in experimental ponds. There were no differences between ponds with or without mosquitofish in numbers of calanoid copepods, cyclopoid copepods, total copepods, Bosmina sp., Ceriodaphnia sp., Moina sp., Daphnia sp., or total cladocerans. There were also no differences in copepod and cladoceran sizes. Copepod nauplii were more numerous during the summer months in ponds with mosquitofish. There were no differences in water quality variables (soluble reactive phosphorus, nitrate, nitrite, ammonia, total nitrogen, total phosphorus, pH) or phytoplankton density between ponds stocked with and without mosquitofish. Catfish production and disease occurrence were also similar between ponds with and without mosquitofish. Although mosquitofish may cause problems when stocked outside their native range, there does not appear to be any adverse effects of mosquitofish presence in catfish production ponds.  相似文献   

15.
The recruitment strategy of swimming crabs, Portunus trituberculatus, was investigated by field observations and numerical experiments in Hiuchi-Nada, Japan. Calculated dispersal patterns of zoeal and megalopal stages in a three-dimensional numerical model reproduce observed patterns accurately. The temporal change of vertical migration patterns between the 1st and 2nd zoeas and the 3rd and 4th zoeas plays an important role in the process of recruitment of P. trituberculatus from spawning ground to nursery ground.  相似文献   

16.
对驼背鲈(Chromileptes altivelis)的胚胎发育及仔、稚、幼鱼的形态特征进行了详细的观察与研究,描述了从受精卵到仔、稚、幼鱼各发育期的时间和形态特征变化。结果表明,在水温25-26℃、盐度30的海水中,受精卵历时27 h 25 min完成整个胚胎发育过程,经历从卵裂、囊胚、原肠、神经胚到肌节形成、各器官的逐渐形成、变化、完善等一系列的胚胎发育和变化过程;根据其卵黄囊消长情况、鳞片的覆盖状态、体色发生的不同变化以及第二背鳍和腹鳍的消长,将胚后发育分为仔、稚、幼鱼3个阶段。在水温22-26℃、盐度29-31、DO≥5 mg/L的条件下,2-3 d仔鱼卵黄囊消失,开口摄食;生长发育至31 d,仔鱼已变态进入稚鱼期;培育至57 d,稚鱼完成变态,成为幼鱼。第二背鳍棘和腹鳍棘的生长与收缩等石斑鱼类早期发育的共性生长特征及其体表特性体色变化特征为驼背鲈胚后发育过程中最明显的特征。  相似文献   

17.
As an intertidal species, Apostichopus japonicus is subject to diel and seasonal temperature fluctuations. Color variation is a distinct characteristic of A. japonicus, and a new color morph, purple A. japonicus, was recently found on the coast of Rushan, Weihai City. This study was conducted to compare the performance of green, white, and purple color morphs of A. japonicus at different water temperatures to help improving aquaculture technology and management. In this study, green, white, and purple color morphs of juvenile A. japonicus (1.5 ± 0.1 g) were cultured at 10, 14, 18, 22, and 26 C for 60 d, according to the suitable temperature range for sea cucumber growth. Temperature was shown to have a significant effect on growth, energy budget, and physiology of sea cucumbers (P < 0.05). Specific growth rates, feed conversion efficiencies, and the proportion of energy allocated to growth of all three color morphs were optimal at 18 C. Activities of the enzymes related with oxidative stress, immune response, and digestion were determined. Superoxide dismutase (SOD) and trypsin activities generally reached a maximum in all three color morphs at 18 C. The purple color morph of A. japonicus was higher in growth rate, food conversion efficiency, and proportion of energy allocated to growth than green and white color morphs at 18 and 22 C, consistent with its higher trypsin and SOD activity, indicating the mutual effect of growth and physiology. At 18, 22, and 26 C, the green color morph had the highest level of lysozyme activity and purple color morph had the lowest, indicating possible infection by external pathogens of green color morph, which might be caused by high temperature. These results suggested that the optimum temperature for culture of the three color morphs was approximately 18 C, the purple had a better adaption to high temperature, and the green and white color morphs may be more susceptible to thermal stress than the purple color morph.  相似文献   

18.
Mulloway (Argyrosomus japonicus) occur in estuarine and coastal waters surrounding Australia, Africa, India, Pakistan, China, Korea and Japan, where they are important in fisheries. This study identified that mulloway in south-eastern Australia had similar growth rates, but matured at smaller lengths and younger ages, to those in South Africa and Western Australia. Growth of both sexes was similar to about 5 years, after which females grew faster and attained a greater maximum length than males. Female mulloway matured at 4–5 years of age with a L50 of 68 cm, whereas males matured at 2–3 years of age with a L50 of 51 cm. The commercial fishery in New South Wales was characterised by declining catches and a reduction in the proportion of mulloway of mature lengths in landings. During 2002–2005 commercial landings were dominated (83%) by fish within 15 cm of the current minimum legal total length of 45 cm and aged 2 and 3 years (>80%), even though mulloway can attain lengths of 200 cm and live >30 years. Estimates of the rates of instantaneous total mortality ranged between 0.34 and 0.45, whilst the rate of instantaneous natural mortality (M) was estimated to be approximately 0.12. Yield-per-recruit analyses indicated that mulloway in New South Wales are being growth overfished and substantial increases in yield could be achieved by increasing the length at first harvest. Values of the spawning potential ratio were below 0.2 under a range of mortality estimates, suggesting that mulloway are at risk of recruitment overfishing. These results suggest that the spawning stock of mulloway in south-eastern Australia has been depleted and that remedial management action is required to protect this iconic species.  相似文献   

19.
Abstract

Effects of salinity on embryonic development and growth of African catfish, Clarias gariepinus, eggs and larvae were studied. Eggs were incubated at 27-29°C in 2,4,6,8, and 10 ppt sodium chloride. Rate of embryonic development was delayed in all salt solutions by 15, 15,28 and 30 minutes, in 2,4,6, and 8 ppt sodium chloride, respectively, when compared with the control group (0% salt); total mortality occurred at 12 hours after gastrula stage in the 10 ppt concentration. Percentage hatching was 45.1,47.7, 59.5,49.2, and 26.6% while percentage deformity was 10.4, 16.1, 52.0, 28.6, and 71.6% in 0, 2, 4, 6, 8, and 10 ppt salt treatments, respectively. There were significant differences (P <0.05) in the hatching percentage and in deformity percentage between 4, 6, and 8 ppt. Rate of yolk absorption was significantly faster in the control and 2 ppt salt treatments, but slower in 4, 6, and 8 ppt. Rate of increase in length was slower with increasing salinity. The optimum salinity for African catfish eggs and was between 0-2 ppt and acceptable up to 6 ppt. The results suggest that increasing salinity delayed hatching and development of African catfish eggs and larvae, respectively, as well as increased the deformity of the larvae.  相似文献   

20.
Abstract

Rainbow trout, Oncorhynchus mykiss, were raised in culture cages (1 m3) to determine the effect of stocking density on growth, survival, and percentage of market-size fish. Large fingerling rainbow trout (20-25 cm, 232 g average weight) were stocked into six cages located in a 0.4-ha pond. Two stocking densities (100 or 200 fish/cage) were used, and fish were grown for 140 days (2000-April 2001). Average total harvest weight (35.0 kg) in the low-density cages was approximately one-half the average total harvest weight (61.2 kg) in the high-density cages. Average weight gain (11.7 kg to 15.1 kg) and feed conversion (1.2 to 1.5) were also smaller for the low-density cages. Average survival was 96.7% for the low-density cages and 94.2% for the high-density cages, with the percentage of market-size fish (< 29 cm) averaging 50.3% and 52.0%, respectively. Production costs for the actual experiment and the revenues from fish sold at the end of the study were collected. An enterprise budget based on the experimental results for the two densities was developed to determine if a culture operation of this size would produce a net return. Production costs and revenues from the experiment resulted in a large negative return (-$3,124) and high breakeven price ($13.53/kg).  相似文献   

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