性类固醇激素对动物生长有一定的影响,但其对鱼类雌、雄生长差异的影响机理尚不清楚。为进一步了解动物雌雄生长差异的内在原因,本文通过在体注射和荧光定量PCR方法,比较了性类固醇激素(E_2、MT)对尼罗罗非鱼雌鱼和雄鱼的生长及对垂体G...性类固醇激素对动物生长有一定的影响,但其对鱼类雌、雄生长差异的影响机理尚不清楚。为进一步了解动物雌雄生长差异的内在原因,本文通过在体注射和荧光定量PCR方法,比较了性类固醇激素(E_2、MT)对尼罗罗非鱼雌鱼和雄鱼的生长及对垂体GH、肝脏GHR1、IGF-I m RNA表达的影响。结果表明:性类固醇激素E2和MT对尼罗罗非鱼的生长及生长轴相关基因的表达均有显著的影响,并且这种影响存在明显的性别二态性。E_2明显促进雌鱼的生长但不显著影响雄鱼的生长,MT显著促进雄鱼和雌鱼的生长;E2可使雌鱼垂体GH和肝脏GHR1、IGF-I的m RNA水平显著升高(P<0.05),但降低雄鱼垂体GH和肝脏GHR1的m RNA表达;MT显著提高雄鱼垂体GH和肝脏GHR1、IGF-I m RNA水平(P<0.05),但降低雌鱼垂体GH的m RNA表达,促进雌鱼肝脏GHR1 m RNA的表达,但对雄鱼肝脏GHR1的促进作用明显大于雌鱼(P<0.05)。上述结果表明,性类固醇激素对不同性别尼罗罗非鱼的生长及生长轴相关基因的m RNA表达有不同的影响,表现出明显的性别二态性,提示不同性别鱼体内性类固醇激素水平的不同可能是导致尼罗罗非鱼雌雄生长二态性的另一内在原因。展开更多
Palm oil is of great potential as one of the sustainable alternatives to fish oil(FO) in aquafeeds.In this present study,five isonitrogenous diets(32% crude protein) with elevated palm oil levels of 0%,2%,4%,6% and 8%...Palm oil is of great potential as one of the sustainable alternatives to fish oil(FO) in aquafeeds.In this present study,five isonitrogenous diets(32% crude protein) with elevated palm oil levels of 0%,2%,4%,6% and 8% were used during an 8-week feeding trial to evaluate its effects on RNA/DNA ratio and lipoprotein lipase(LPL) and Myo D m RNA expressions in muscle of Oreochromis niloticus.The results showed that RNA,DNA content as well as ratio of RNA to DNA were significantly affected(P < 0.05),in each case the highest was recorded in fish group subjected to 6% palm oil level.There was a strong positive correlation between nucleic acid concentration(RNA concentration and RNA:DNA ratio) and specific growth rate(SGR),protein efficiency ratio(PER),while a negative correlation existed between nucleic acid concentration(RNA concentration and RNA:DNA ratio) and feed conversion ratio(FCR).The m RNA expressions of LPL and Myo D in muscle were not significantly affected by the different palm oil levels,although the highest expression was observed in fish fed with 6% palm oil level.There also existed a strong positive correlation between the m RNA expression of LPL,Myo D and SGR,PER,while their correlation with FCR was negative.In conclusion,elevated palm oil affected the RNA,DNA concentration as well as RNA/DNA ratio significantly,although the m RNA expression of LPL and Myo D were not affected significantly by elevated palm oil levels.展开更多
In the present study, RAPD technique was used to analyze the geneticrelationship between two cultured populations in china, oreochromis aureus and a niloticus,and the application of this technique in species identific...In the present study, RAPD technique was used to analyze the geneticrelationship between two cultured populations in china, oreochromis aureus and a niloticus,and the application of this technique in species identification was also investigated. Resultsrevealed that no DNA polymorphism was detected within the population of O.aureus andpolymorphism in varying degrees was observed among individuals. Similarity index andgenetic distance calculated have no remakable difference with data reported by others. RAPDanalysis using mixed samples was also tested in this experiment. In addition, someelectrophoregrams of amplification products also suggested the occurrence of geneticintrogression between the two cultured tilapia populations. Conclusively, RAPD technique isa rapid and efficient method for studying genetic polymorphism within and between differentpopulations, and RAPD markers can be used to identify different fish populations.展开更多
为了调查广东省惠州、肇庆、珠海、湛江4个吉富罗非鱼主养区链球菌病的流行情况和耐药性,并进一步分析β-内酰胺酶基因与青霉素类药物的耐药性关系。本实验通过传统的方法对菌株进行分离纯化,扩增特异性基因cfb以及16s r DNA对各菌株进...为了调查广东省惠州、肇庆、珠海、湛江4个吉富罗非鱼主养区链球菌病的流行情况和耐药性,并进一步分析β-内酰胺酶基因与青霉素类药物的耐药性关系。本实验通过传统的方法对菌株进行分离纯化,扩增特异性基因cfb以及16s r DNA对各菌株进行鉴定;采用k-b法测定分离菌株的药物敏感性;通过PCR检测β-内酰胺酶类基因在分离菌株中的分布情况,并用Statistic6.0统计分析各β-内酰胺酶基因与青霉素类药物的耐药关系。实验结果表明,吉富罗非鱼无乳链球菌的阳性率从高到低的顺序为惠州(46.46%)>湛江(43.24%)>肇庆(17.30%)>珠海(4.17%);药敏结果显示各地区无乳链球菌分离株对青霉素(耐药率为94.29%)和磺胺二甲基嘧啶(耐药率为86.40%)普遍耐药,对恩诺沙星最为敏感(耐药率为3.99%);β-内酰胺酶基因分布与细菌耐药性统计结果显示,无乳链球菌基因组中的9个β-内酰胺酶基因在各分离菌株中的分布呈高度多态性,其中SAG0658基因与氨苄青霉素抗性显著相关,提示SAG0658基因在无乳链球菌耐氨苄青霉素过程中发挥主要作用;此外,9个β-内酰胺酶基因与青霉素抗性无相关性,说明其在菌株对青霉素耐药过程中并未发挥明显作用,提示分离菌株对青霉素的耐药性可能依赖其他途径。展开更多
文摘性类固醇激素对动物生长有一定的影响,但其对鱼类雌、雄生长差异的影响机理尚不清楚。为进一步了解动物雌雄生长差异的内在原因,本文通过在体注射和荧光定量PCR方法,比较了性类固醇激素(E_2、MT)对尼罗罗非鱼雌鱼和雄鱼的生长及对垂体GH、肝脏GHR1、IGF-I m RNA表达的影响。结果表明:性类固醇激素E2和MT对尼罗罗非鱼的生长及生长轴相关基因的表达均有显著的影响,并且这种影响存在明显的性别二态性。E_2明显促进雌鱼的生长但不显著影响雄鱼的生长,MT显著促进雄鱼和雌鱼的生长;E2可使雌鱼垂体GH和肝脏GHR1、IGF-I的m RNA水平显著升高(P<0.05),但降低雄鱼垂体GH和肝脏GHR1的m RNA表达;MT显著提高雄鱼垂体GH和肝脏GHR1、IGF-I m RNA水平(P<0.05),但降低雌鱼垂体GH的m RNA表达,促进雌鱼肝脏GHR1 m RNA的表达,但对雄鱼肝脏GHR1的促进作用明显大于雌鱼(P<0.05)。上述结果表明,性类固醇激素对不同性别尼罗罗非鱼的生长及生长轴相关基因的m RNA表达有不同的影响,表现出明显的性别二态性,提示不同性别鱼体内性类固醇激素水平的不同可能是导致尼罗罗非鱼雌雄生长二态性的另一内在原因。
基金supported by China Agriculture Research System (CARS-49)Shanghai Collaborative Innovation Center for Aquatic Animal Genetics and Breeding (ZF1206)
文摘Palm oil is of great potential as one of the sustainable alternatives to fish oil(FO) in aquafeeds.In this present study,five isonitrogenous diets(32% crude protein) with elevated palm oil levels of 0%,2%,4%,6% and 8% were used during an 8-week feeding trial to evaluate its effects on RNA/DNA ratio and lipoprotein lipase(LPL) and Myo D m RNA expressions in muscle of Oreochromis niloticus.The results showed that RNA,DNA content as well as ratio of RNA to DNA were significantly affected(P < 0.05),in each case the highest was recorded in fish group subjected to 6% palm oil level.There was a strong positive correlation between nucleic acid concentration(RNA concentration and RNA:DNA ratio) and specific growth rate(SGR),protein efficiency ratio(PER),while a negative correlation existed between nucleic acid concentration(RNA concentration and RNA:DNA ratio) and feed conversion ratio(FCR).The m RNA expressions of LPL and Myo D in muscle were not significantly affected by the different palm oil levels,although the highest expression was observed in fish fed with 6% palm oil level.There also existed a strong positive correlation between the m RNA expression of LPL,Myo D and SGR,PER,while their correlation with FCR was negative.In conclusion,elevated palm oil affected the RNA,DNA concentration as well as RNA/DNA ratio significantly,although the m RNA expression of LPL and Myo D were not affected significantly by elevated palm oil levels.
文摘In the present study, RAPD technique was used to analyze the geneticrelationship between two cultured populations in china, oreochromis aureus and a niloticus,and the application of this technique in species identification was also investigated. Resultsrevealed that no DNA polymorphism was detected within the population of O.aureus andpolymorphism in varying degrees was observed among individuals. Similarity index andgenetic distance calculated have no remakable difference with data reported by others. RAPDanalysis using mixed samples was also tested in this experiment. In addition, someelectrophoregrams of amplification products also suggested the occurrence of geneticintrogression between the two cultured tilapia populations. Conclusively, RAPD technique isa rapid and efficient method for studying genetic polymorphism within and between differentpopulations, and RAPD markers can be used to identify different fish populations.
文摘为了调查广东省惠州、肇庆、珠海、湛江4个吉富罗非鱼主养区链球菌病的流行情况和耐药性,并进一步分析β-内酰胺酶基因与青霉素类药物的耐药性关系。本实验通过传统的方法对菌株进行分离纯化,扩增特异性基因cfb以及16s r DNA对各菌株进行鉴定;采用k-b法测定分离菌株的药物敏感性;通过PCR检测β-内酰胺酶类基因在分离菌株中的分布情况,并用Statistic6.0统计分析各β-内酰胺酶基因与青霉素类药物的耐药关系。实验结果表明,吉富罗非鱼无乳链球菌的阳性率从高到低的顺序为惠州(46.46%)>湛江(43.24%)>肇庆(17.30%)>珠海(4.17%);药敏结果显示各地区无乳链球菌分离株对青霉素(耐药率为94.29%)和磺胺二甲基嘧啶(耐药率为86.40%)普遍耐药,对恩诺沙星最为敏感(耐药率为3.99%);β-内酰胺酶基因分布与细菌耐药性统计结果显示,无乳链球菌基因组中的9个β-内酰胺酶基因在各分离菌株中的分布呈高度多态性,其中SAG0658基因与氨苄青霉素抗性显著相关,提示SAG0658基因在无乳链球菌耐氨苄青霉素过程中发挥主要作用;此外,9个β-内酰胺酶基因与青霉素抗性无相关性,说明其在菌株对青霉素耐药过程中并未发挥明显作用,提示分离菌株对青霉素的耐药性可能依赖其他途径。
