奥尼罗非鱼的养殖

我场生产的奥尼鱼雄性率为85％～90％,当年3～3．i。m的奥尼鱼种经过180天白饲养,其平均规格达到450范,现将主要技术措施总结如下：一、池过准备面积以3～5亩为宜,池民平坦,蓄水深度保持1．sin。在养鱼种前10天,亩按60～’0公斤生石灰用量全池泼洒青塘,以调节底记及杀灭     

奥尼罗非鱼池塘养殖试验

经过92d的池塘养殖,12亩池塘共产奥尼罗非鱼5848.0kg,平均亩产487.3kg,最大规格为562g,平均规格为466.7g,平均成活为91%,饵料投喂以颗粒配合饲料为主,米糠、麦麸为辅。投入产出比为1∶1.54。     

奥尼罗非鱼养殖试验

为引进优新品种,引导渔农致富,我们在近湖养殖场10亩塘进行奥尼罗非鱼养殖试验,并取得了成功,现将该工作试验小结如下： 一、材料和方法     

奥尼罗非鱼海水养成技术

为了充分利用虾池资源,进一步发展海水养殖业,从１９９４年开始各地利用闲置虾池进行罗非鱼养殖试验。以海水水源为主,兼用少量淡水,人工控制养成期间各阶段的池水盐度。经过几年的养殖实践证明,海水养殖罗非鱼,投入少,养殖周期短,生长迅速,当年养成,当年见效,肉味更加鲜?..     

奥尼罗非鱼的养殖技术

1奥尼罗非鱼的特点 (1)生长速度快：放养3～10cm的鱼苗，精养4～5个月可达800g以上。(2)抗病力强，极少发生鱼病。(3)对环境的适应力强 ①耐低氧。其窒息点为0．07～43．23mg／l，在溶氧比较低的肥水中也能正常生长。     

奥尼罗非鱼消化系统的组织学研究

采用石蜡切片法研究了奥尼罗非鱼(Oreochromis niloticus ×O.aureus)的消化系统组织结构.消化道分段明显,有胃的分化,胃呈"U"型,腺体丰富,肌层分内纵外环2层,有些部位3层.消化道管壁有粘膜层、粘膜下层、肌层和外膜层组成.除口咽腔上皮有复层扁平细胞组成外,其余各段均为复层柱状上皮;食道肌层发达,有平滑肌和横纹肌组成.从前肠至后肠皱褶形态各异,数量逐渐减少,各段均有许多杯状细胞.肝脏为实心腺体,肝小叶分界不明显,肝胰脏未完全分离,少部分胰腺组织散布在肝脏内.     

奥尼罗非鱼反季节养殖试验

据长江水产研究所(喻清明等，1987)报道：雄性罗非鱼生长速度在4月龄开始明显地比雌性罗非鱼快，而且一直保持着这种差异。罗非鱼绝对增长量以4～8月龄最快，群体生长速度以10～12月龄最快；奥尼罗非鱼是由雄性奥利亚罗非鱼与雌性尼罗罗非     

奥尼罗非鱼鱼苗的捕捞技术要点

笔者从事奥尼罗非鱼鱼苗的繁殖生产多年,在奥尼鱼苗捕捞的操作过程中,每次捉苗都很难捉干净鱼塘中的鱼花。这些漏网的鱼花,存塘的时间越长,生长的规格就越大。当它们长到八九朝时,就会猛吃刚孵出的小鱼苗。如果不能及时将一定数量的存塘鱼种清     

Thermal and Chemical Properties of Gelatin from Tilapia (Oreochromis niloticus) Scale

ABSTRACT

Gelatin from the scale of Nile tilapia was extracted and characterized chemically, thermally, and structurally. Scales of Nile tilapia were subjected to acid pretreatment and extraction with water at 60°C. The process yielded 12.1% (m/m) on a dry basis. The 6.67% gelatin solution had a gel strength of 233.5 ± 14g. The amino acid composition revealed that 20.02% was comprised of imino acids and glycine (34.49%) as the most abundant amino acids. The scale gelatin had α1, α2, and β subunits and was thermally stable up to 200ºC. The Fourier transform infrared spectrum showed absorption in the regions of amides A, I, II, and III. The characterization of tilapia scale gelatin showed that the obtained product was similar to commercial gelatin, thereby demonstrating its potential application.     

不同盐度下3种罗非鱼的Na+-K+-ATPase活性比较

在盐度为0、10、20、30时测定了萨罗罗非鱼(Sarotherodon melanotheron)、尼罗罗非鱼(Oreochromis niloticus)和以色列红罗非鱼(Oreochromis sp.)鳃和肾中Na+-K+-ATPase活性。结果表明:(1)不同盐度对不同组织的Na+-K+-ATPase活性有显著影响,鱼的品种及其他交互作用对Na+-K+-ATPase活性均无显著影响;(2)在实验盐度范围内,无论是鳃和肾,萨罗罗非鱼、尼罗罗非鱼和以色列红罗非鱼的Na+-K+-ATPase活性均随盐度的升高而增高;3种罗非鱼中,萨罗罗非鱼的Na+-K+-ATPase活性随盐度的升高增大最为剧烈,以色列红罗非鱼次之,尼罗罗非鱼最小;低盐度时尼罗罗非鱼的Na+-K+-ATPase活性相对较高,高盐度时萨罗罗非鱼的Na+-K+-ATPase活性相对较高,Na+-K+-ATPase的活性与罗非鱼的耐盐能力有着一定的联系;(3)盐度大于7.19和11.94时,萨罗罗非鱼鳃中的Na+-K+-ATPase活性分别开始高于以色列红罗非鱼和尼罗罗非鱼;盐度大于18.42时,萨罗罗非鱼肾中的Na+-K+-ATPase活性开始高于尼罗罗非鱼;(4)除了在盐度20和30中的尼罗罗非鱼及盐度30的以色列红罗非鱼,是肾中的Na+-K+-ATPase活性高于鳃外,其他均为鳃中的Na+-K+-ATPase活性高于肾,肾中Na+-K+-ATPase活性在不同盐度之间的变化较鳃剧烈;罗非鱼的鳃比肾在渗透压调节上起的作用更大。     

木薯粉在罗非鱼饵料中的适口性研究

选择健康的吉富罗非鱼为试验鱼,比较不同水平木薯粉之间的诱食效果以及木薯粉与豆粕、次粉的适口性,评价木薯粉在罗非鱼饵料中的应用效果。结果表明,(1)40%、30%木薯粉组的诱食活性显著高于10%、20%木薯粉组(p0.01),40%与30%木薯粉之间没有显著差异(p0.05)。(2)罗非鱼对木薯粉与豆粕、次粉的适口性依次为豆粕木薯次粉。     

棉酚对罗非鱼（Oreochromisniloticus）离体精子毒性作用的研究

新鲜采取的尼罗罗非鱼精液在加入棉酚的精子保存液中28℃下培养。高达10mM 的乙酸棉酚也不影响精子在一小时内的存活率。罗非鱼精子的存活率在培养三小时后存活率显下降，而低浓度棉酚（25－100μM）显提高罗非鱼精子的 存活率。 本对上述实验结果进行了讨论。     

60个家系吉富品系罗非鱼初期阶段的生长比较

本文对这60个家系的吉富罗非鱼(Oreochromis niloticus)在生长初期阶段的3个多月时间内的生长情况进行了比较分析,结果显示:经过3个多月的培育,60个家系共1831尾吉富罗非鱼的总体平均体重为102.4±38.9g。第59号家系的平均体重最大,为178.0±40.0g;第9号家系的平均体重最小,为64.1±18.6g。最大个体出现在第59号家系中,为271.7g,最小个体出现在第20号家系中,为22.0g。从家系水平上看,生长速度相差2倍,从个体水平上看,最大个体的体重是最小个体的12倍多。表明吉富罗非鱼各家系及个体间的生长速度存在较大差异,既有进行选育的基础,也有进行长期选育的必要。     

Changes During Chilled Storage of Whole Tilapia and Short-Term Frozen Storage of Tilapia Fillets

This study evaluated the physicochemical changes in Nile tilapia (n = 82, 373.71 ± 61.91 g) refrigerated for up to 92 h and in the frozen fillets. The tilapias were captured with nets, slaughtered by ice and water shock (1:1) in a temperature of approximately 2°C for 30 min, and stored refrigerated at 4°C in polystyrene boxes containing ice. The fish were filleted, and filets were weighed and frozen. The drip loss and protein were determined after 23 days of frozen storage. After 4 h of storage, all fish were in full rigor mortis. The pH of the muscles decreased for up to 45 h of the storage period. The fillets obtained from tilapia stored for more than 72 h lost more weight and protein. Thus, the filleting or processing of tilapia should be done before 72 h of cold storage, since deterioration of the fish starts to occur after this period.     

尼罗罗非鱼肠道淀粉酶高产菌株的筛选及耐酸、耐高温特性的研究

研究了从健康罗非鱼肠道中筛选出的活力为195 U/ml的淀粉酶高产菌株的耐酸耐高温能力。结果表明,该菌株最高耐受温度为80℃,20 min;在50~60℃时稳定性强,可保持正常生长,维持高菌体量;最适生长pH值为6,在强酸性条件下能存活,并维持缓慢生长。由此表明,该菌株在微生态饲料添加剂生产上具有重要潜在价值。     

尼罗罗非鱼卵黄脂磷蛋白的分离纯化与性质鉴定

采用Sephacryl S-300过滤层析和DEAE-Sepharose Fast Flow离子交换层析相结合的方法从尼罗罗非鱼(Oreochromis niloticus)成熟卵子匀浆液中分离纯化出了一种高分子量的蛋白。该蛋白能被Schiff试剂、甲基绿和苏丹黑B着色,Western blot显示能被金鱼卵黄脂磷蛋白(lipovitellin,Lv)多克隆抗血清特异性识别,在非变性条件下分子量约为560 k D,在SDS变性条件下分子量约为112 k D,结果表明分离纯化的蛋白是一种含有糖、磷、脂基团的蛋白,符合鱼类Lv的性质,且与金鱼Lv有免疫交叉反应,从蛋白的性质和免疫原性以及分子量大小等角度判断,本研究获得的高纯度蛋白为尼罗罗非鱼卵黄脂磷蛋白;纯化的罗非鱼Lv在反复冻融、37℃及60℃处理条件下均未出现降解,表明罗非鱼Lv比鱼类卵黄原蛋白(Vitellogenin,Vtg)更为稳定。研究结果为罗非鱼Lv抗体的制备奠定了基础。     

尼罗罗非鱼Xbp1-S基因克隆及表达分析

为了了解尼罗罗非鱼(Oreochromis niloticus)细胞转录因子Xbp1-S(On Xbp1-S)的基因序列特征及其在无乳链球菌(Streptococcus alactolyticus)应激和在B细胞分化中的作用,应用RACE克隆技术获得的On Xbp1-S基因全长1380 bp,包括开放阅读框ORF为1155 bp,5?端非编码区(5?UTR)长127 bp,3?端非编码区(3'UTR)长98 bp。On Xbp1-S序列分析推测该基因编码384个氨基酸,分子量为41.32 k Da,理论等电点为4.36。同源性分析显示,On Xbp1-S基因与其他鱼类的聚为一支,其中,与南极鳕(Notothenia coriiceps)相似性最高。荧光定量PCR及Western-blot结果显示,On Xbp1-S在各组织中均有表达,m RNA水平上在肝脏中表达量最高,蛋白水平上在胸腺中表达量最高,而在肌肉中表达量最低。无乳链球菌应激后,On Xbp1-S基因在肝脏和脾脏中的表达趋势相似,均在应激期间出现表达量上调,在192 h出现峰值。另外,免疫组化分析发现,On Xbp1-S因子在不同分化程度B细胞亚类中的表达呈现差异,在成熟B细胞中呈现高表达,而在未成熟B细胞中几乎不表达。研究结果表明,On Xbp1-S参与尼罗罗非鱼对无乳链球菌的免疫防御,和在B细胞分化中起作用。本研究将为进一步研究On Xbp1-S因子应答病原菌侵染的机理及促进B细胞分化机制提供理论依据。     

Productivity and Economics of Nile Tilapia Oreochromis niloticus Cage Culture in South-East Brazil

ABSTRACT

Fish cage culture is an intensive, continuous-flow fish farming system, allowing intensive exploitation of water bodies with relatively low capital investment. This study aimed to determine the production function of Nile tilapia, Oreochromis niloticus, in cages; the profit-maximizing biomass at 300–400 and 500–600 fish per m³ for cages of different volumes; and the influence of water body conditions in fish performance. Feed intake, survival rate, and water temperature were monitored daily; dissolved oxygen, pH, and transparency of water were monitored each 15 days. Caged tilapia were fed daily on commercial, floating pellets (32% crude protein) at 0900, 1300, and 1700, and feeding rate was adjusted based on weight gain and survival rate. Data were analyzed statistically by ANOVA (P = 0.05) and regression analysis; the Mitscherlich function was chosen to represent the production function. Carrying capacity of both stocking densities reached 200 kg/m³ and no differences were found (P > 0.05) regarding accumulated biomass and individual average weight over time. The larger stocking density yielded larger accumulated biomass and had better feeding efficiency and no differences between individual average weights of fish at both densities were observed (P > 0.05). Profit-maximizing biomass at 500–600 fish/m³ was 145 kg/m³ and at 300–400 fish/m³ was 121 kg/m³. Cage farming of Nile tilapia at 500–600 fish/m³, individual average weight 283 g, presented many advantages: optimization of space and production time, better feed efficiency, higher fish production per unit volume of cages, and increased profitability.