尼罗罗非鱼生理雌鱼的实验研究

采用雌性激素处理刚孵化出膜的尼罗罗非鱼(Oreochromis niloticus)YY基因型鱼苗,可使性别未分化的合子全部转化为生理雌鱼.该YY型生理雌鱼的卵巢发育正常,具有繁殖机能,可为采用二系配套(YY△♀×YY♂)技术大量生产尼罗超雄鱼提供种源保证.     

静水池塘养殖尼罗罗非鱼试验

根据尼罗罗非鱼繁殖生物学特点,结合本地区养殖季节,采用驯化养鱼技术,使尼罗罗非鱼在整个养殖中无法繁殖后代,从而解决静水池塘养殖尼罗罗非鱼的繁殖过剩,商品规格小的问题。9.8亩池塘投放春繁平均体重5克的尼罗罗非鱼鱼种132.3公斤,饲养95天,平均亩净产526公斤,每尾平均体重250克,增重倍数40倍,饵料系数1.29。     

尼罗罗非鱼越冬驯化研究初报

尼罗罗非鱼(Tilapia nilotica)除了具有生长快,繁殖力强,食性广,饵料杂,抗病力强,耐低氧等优点外,还具有肉质细嫩,味道鲜美和少刺的特点,深受养鱼户(场)的喜爱,也倍受市场的欢迎。但此鱼原产热带,栖息环境最适温度是24～32℃,临界致死水温低限为9.5℃,高限为45℃,当水温降至14℃时,摄食量减少或完全停止,若长期处于14℃低温或继续下降时则死亡。因此,我们不得不动用     

烂泥田放养尼罗罗非鱼试验

<正> 长汀县1982年11月引进尼罗罗非鱼亲鱼200多尾,并在河田温泉池塘安全越冬。1983年繁殖鱼苗7万多尾,同年8月,将1.4万尾尼罗罗非鱼投放于烂泥田(种过早稻的水田)中。经过三个月的养殖,收获商品鱼2300斤。与此同时,我们对饲养在烂泥田中的尼罗罗非鱼进行了生长、食性等方面的观察,现将试验情况报告如下。材料与方法 1.烂泥田的选择与清整。早稻收割后,选择田埂较高(1-2尺)的烂泥田修整、加固,进出水口用竹篾编织物拦住,蓄水0.5-1尺,亩用30-50斤生石灰消毒。 2.培植轮叶黑藻。在长有许多轮叶黑藻     

尼罗罗非鱼海水池塘养殖试验

在５０亩废虾池进行尼罗罗非鱼以海水为主的养成试验，３－４月向池塘注淡水深６０ｃｍ，投放鱼种时只注海上，使水深升至１．３ｍ，盐度为１５，简化了罗非鱼种的盐度驯化程序，避免了幼苗过度繁殖。起捕时盐度为２２。１２０天养成商品鱼，平均亩产３６４ｋｇ。本试验养成的罗非鱼肉味鲜美，生长速度比纯淡水快１０％。鉴定认为：本研究属省内先进水平。     

尼罗罗非鱼海水驯化养殖试验

<正> 尼罗罗非鱼(Ti-lapia nilotica)(以下简称罗非鱼)个体大(原产地最大者有11斤),食性杂,生长快,繁殖力强,适应性广(耐酸、耐碱),易驯养,疾病少,肉     

单雄性罗非鱼与尼罗罗非鱼池塘养殖对比试验

在两口条件基本一致的池塘中，按80:20池塘主养模式进行主养单性奥尼罗非鱼和尼罗罗非鱼对比试验，亩产奥尼罗非鱼822公斤，亩纯收益3130元；亩产尼罗罗非鱼720公斤，亩纯收益316.62元。奥尼罗非鱼平均个体300克，尼罗罗非鱼平均个体168克。奥尼鱼较尼罗罗非鱼生长快42.6%。     

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。     

棉酚对金鱼、罗非鱼的毒性作用初探

用乙酸棉酚含量为１‰的鱼粉饲料分别饲喂性成熟的金鱼和二月龄尼罗罗非鱼。四个月后，试验组金鱼、罗非鱼与对照组鱼在体重增长、饲料效率、特定生长率、性腺重及性重比（性腺重／鱼体重）方面的差异不明显，表明饲料中棉籽饼水平的棉酚含量（０．０３％～０．０５％），既不影响这两种鱼的正常摄食和生长，也不影响其正常的性成熟和繁殖。     

尼罗罗非鱼吉富品系养殖推广中试研究

在山东青岛、浙江湖州和广东番禺等地选定３２个养殖户进行吉富尼罗罗非鱼推广试验，分别以当地养的尼罗罗非鱼“７８”品系、“８８”吕系及尼奥发交钱赤对照，比较研究了各项养殖性能。（１）吉富鱼的绝对增重率分别比三种对照鱼快２２．４％１７．６％和２６．０％；瞬时增重率分别比三种对照鱼快１２．１％、９．５％和７．７％；差异都显著。（２）平均成活率分别比对照组高６．８％、６．２％和１．５％；但吉富品系同“８８”     

罗非鱼鳃组织中脂肪氧合酶的性质研究

试验结果表明脂肪氧合酶最适反应温度为30℃,最适pH为10.0和4.0。在pH10.0的条件下,最适底物浓度为2.5×10-4mol/L,Km值为0.073mmol/L,Vmax值为3.08×104U/mgprotein.min。EDTA对该酶有较强的抑制作用。而在pH4.0的条件下,最适底物浓度为5×10-4mol/L,BHA、BHT、TBHQ等抗氧化剂有较强的抑制作用。     

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     

Physicochemical Properties of Pepsin-Solubilized Collagen Extracted from Nile Tilapia (Oreochromis niloticus) Scale

ABSTRACT

The aim was to investigate the physicochemical properties of pepsin-solubilized collagen (PSC) extracted from fish scales of Nile tilapia. The results indicated that Nile tilapia scales are rich in collagen. Therefore, the scales are a promising cost-effective collagen source. The conversion of hydroxyproline to collagen was 12.9. Based on the patterns of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), PSC comprised at least two different α chains, α1 and α2, and was classified to be type I with no disulfide. Fourier transform infrared spectroscopy spectrum showed that the bands of amide A, I, and II of PSC were found at 3,301, 1,631, and 1,239 cm^?1 wavelength. The content of imino acids was 187 residues per 1,000 total amino acid residues. Maximum solubility was observed at pH 4, and minimum was at pH 7. Almost no change in solubility was observed in the presence of NaCl up to 2% (w/v), and the decrease was more pronounced with increasing NaCl concentration. The temperature of denaturation was 35.4°C. Results show that PSC has physicochemical properties that can be applied in the cosmetics, biomedical, pharmaceutical, and food industries.     

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。     

尼罗罗非鱼(Oreochromis niloticus) cyp19a1a原核表达与蛋白纯化

为表达和纯化尼罗罗非鱼(Oreochromis niloticus)cyp19a1a蛋白,本研究从尼罗罗非鱼卵巢提取总RNA,反转录获得cDNA模板后,利用设计的引物PCR扩增cyp19a1a ORF区1200 bp片段,双酶切后连接到pET-28a(+)表达载体上,经酶切验证和DNA测序鉴定,证明成功构建了pET-28a-cyp19a1a原核表达载体。将表达载体转化到大肠杆菌(E.coli)BL21中,优化IPTG诱导浓度和诱导时间。结果显示,在0.5 mmol/L IPTG诱导8 h后,cyp19a1a重组蛋白大量表达,并以包涵体形式存在。通过Ni2+-NTA层析柱和切胶纯化,获得与预期片段大小一致的表达蛋白,并用Western blotting验证了纯化的蛋白为目的蛋白。本研究为制备cyp19a1a抗体和研究高温对cyp19a1a蛋白表达的影响提供了重要的基础。     

Cortisol Response of Nile Tilapia,Oreochromis niloticus (L.), to Temperature Changes

Abstract

Nile tilapia, Oreochromis niloticus (L.), is a commercially-valuable fish species with high nutritional value. As a result of the intensive aquaculture of this species, handling, transport, and environmental changes that causes stress on these fish are unavoidable. The objective of this study was to determine the effects of gradual and acute temperature changes on juvenile tilapia. No significant difference (P > 0.05) was found among serum cortisol levels in juvenile tilapia when the water temperature was gradually increased from 27°C to 32°C, or 40°C, and maintained for 1 hour, although the levels were five times pretreat-ment levels. When tilapia acclimated to 27°C were subjected to 18°, 27°, 30°, 32°, 34°, 36°, 38°, or 40°C water for 10 minutes in a water bath, followed by a recovery period of 10 minutes at 27°C in the original aquaria, no significant difference (P > 0.05) in cortisol levels was observed among treatments except for significantly elevated levels at 38°C and 40°C. When tilapia acclimated to 27°C were subjected to the same temperature exposures but given a recovery period of 60 minutes at 27°C in the original aquaria, there was no significant (P > 0.05) increase in cortisol levels in tilapia among treatments from 18° to 36°C; but there was a significant (P > 0.05) increase between values from those treatments at 38° and 40°C. Acute temperature changes initiated the cortisol response as early as 10 minutes in fish following exposure to 38°C or 40°C and resulted in significant increases in the 38°C and 40°C treatments following 1 hour of recovery at 27°C. These results have implications for the management of tilapia during bacterial challenge, vaccination, and handling and transport during aquacultural activities.     

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。