罗非鱼鳃霉样真菌的显微观察

2014年5月在云南省养殖罗非鱼的鳃组织中发现一种鳃霉样真菌,经水浸片镜检和组织学观察,结果发现:低倍镜下,鳃丝可见大量鳃霉样真菌菌丝体,菌丝体分布于鳃丝表面及鳃小片内;高倍镜下,可见菌丝体内的孢子。菌丝体主要位于鳃上皮组织及鳃小片的血管中,菌丝体内可见多核原生质体、双核体、单核体以及成熟孢子,有的单核体内有大量嗜酸性颗粒,成熟孢子呈圆形、胞质致密、染色深,位于血管中的孢子为多核、厚壁单体孢子。由于大量菌丝体的存在,鳃组织结构杂乱,鳃小片间大量细胞的增生使相邻的鳃小片粘连在一起,鳃丝呈棒状;鳃组织上皮层大多坏死,有轻微淤血,含有大量成熟孢子的鳃组织坏死严重。     

34 ℃水温下吉富罗非鱼对饲料脂肪的需求量

为研究34 ℃水温下吉富罗非鱼对饲料脂肪的需求量,选用初始体质量为(50.88±1.57) g的吉富罗非鱼360尾,随机分成6组(每组设3个重复,每重复20尾),饲喂脂肪含量分别为0.22%(对照组)、2.83%、4.98%、7.45%、9.23%和12.47%的6种纯化饲料,在34 ℃水温下饲养56 d后,测定并分析了吉富罗非鱼的生长性能、体成分、部分血清生化和肝脏脂肪代谢酶活性等指标。结果显示,随饲料脂肪水平升高,吉富罗非鱼增重率、特定生长率、蛋白质效率与蛋白质保留率均呈现先上升后下降的趋势,饲料系数和摄食率呈现相反的趋势;12.47%实验组肝体比显著高于其他实验组,其他指标组间无显著性差异。饲料脂肪水平对吉富罗非鱼的成活率无显著影响。对照组全鱼粗脂肪含量显著低于其他实验组;当饲料脂肪含量为7.45%~12.47%时,肌肉粗脂肪含量显著高于对照组;肝脏粗脂肪含量在饲料脂肪含量为2.83%~9.23%时较对照组显著降低。血清甘油三酯和总胆固醇随饲料脂肪水平升高呈现先下降后上升的趋势;肝脏脂肪酶和脂蛋白酯酶活性随脂肪水平的增加呈上升趋势,在12.47%组达到最大值;肝脂酶的活性呈先上升再下降最后趋于稳定的趋势,在脂肪水平为2.83%时最高, 显著高于其他各组。经回归分析,在34 ℃水温下,吉富罗非鱼要获得最佳的增重率、蛋白质效率和最低饲料系数对饲料脂肪的需求量分别为4.92%、5.67%和6.49%。     

利用蛋白抗体芯片筛选盐胁迫下红罗非鱼鳃差异表达蛋白

为从蛋白角度探索红罗非鱼(Oreochromis mossambicus♀×O.niloticus♂)在盐胁迫环境下的调节适应机制,本研究采用蛋白抗体芯片结合串联质谱技术初步筛选了盐胁迫下红罗非鱼鳃组织的差异表达蛋白,并通过免疫组化和免疫印迹技术对候选差异蛋白进行了验证。结果显示,共筛选获得181个表达量有显著差异的蛋白质(变化倍数≥1.5),包含上调蛋白142个,下调蛋白39个。挑选5个蛋白进行质谱鉴定得到3个蛋白质:中间丝蛋白(intermediate filament protein,IF)、转运蛋白63(translocation protein 63,SEC63)、蛋白质二硫键异构酶A3(protein disulfide-isomerase A3,PDIA3)。免疫组化结果显示,在淡水、盐度组中,IF和PDIA3在鳃小片基部均有阳性反应,且随盐度升高,阳性反应呈先降低后增强的趋势,SEC63无阳性反应。Western blot结果显示,在淡水和盐度组中,IF和PDIA3两种蛋白均有表达,并且随盐度升高呈现先降低、再升高的变化趋势,SEC63蛋白无明显目的条带;在30盐度组中,胁迫早期,IF蛋白表达量降低,48 h达到最低值,72 h有明显回升,PDIA3蛋白表达量在胁迫后96 h显著升高(P0.05)。根据研究结果推测,IF和PDIA3是在盐胁迫环境下红罗非鱼鳃组织的响应蛋白,它们分别在细胞骨架、内质网功能维持中发挥重要调节作用。     

尼罗罗非鱼表皮和鳃黏膜共生菌结构特征及其与鱼体健康状况相关关系

黏膜及其表面的共生菌群是鱼类抵御外界不利环境的第一道屏障。为探索养殖罗非鱼表皮和鳃黏膜共生菌菌群的结构特征是否与其健康状况间存在相关关系,本研究运用高通量测序技术,以无乳链球菌腹腔注射攻毒48 h后存活和濒死尼罗罗非鱼为检测对象,检测攻毒前后罗非鱼表皮和鳃黏膜共生菌群落结构差异。结果显示,健康尼罗罗非鱼表皮和鳃黏膜共生菌均存在优势菌群,主要为特吕珀菌属、硫杆菌属、弓形杆菌属、海单胞菌属和弧菌属。人工感染无乳链球菌后存活尼罗罗非鱼表皮和鳃黏膜共生菌菌群与感染前无显著差异;与存活组相比,濒死尼罗罗非鱼的表皮和鳃黏膜共生菌菌群多样性下降,其中弓形杆菌属、假交替单胞菌属、海单胞菌属、假单胞菌属和弧菌属等含量显著下降,链球菌属含量占总菌群的55.30%±1.24%,表明养殖尼罗罗非鱼表皮和鳃黏膜共生菌群落结构可能与其健康状况相关。     

尼罗罗非鱼幼鱼饲料的适宜脂肪需要

选用初始体质量为(46.14±4.67)g的尼罗罗非鱼(Oreochromis nilotica)360尾,随机分成6组(每组4重复,每重复15尾),分别饲喂添加鱼油水平为0%(对照组)、3%、6%、9%、12%和15%的纯化饲料(实测脂肪水平为0.20%、2.70%、6.11%、8.04%、11.13%和14.85%)。饲养8周后,以尼罗罗非鱼幼鱼的生长、体组成、血清生化及脂肪代谢酶活性等指标为判断依据,确定其饲料的脂肪需要量。结果表明,随饲料脂肪水平的升高,尼罗罗非鱼的增重率、特定生长率以及蛋白质效率均呈现先上升后下降的趋势,饲料系数呈现先下降后上升的趋势。饲料脂肪水平的升高使尼罗罗非鱼肝体比及全鱼和肌肉的脂肪含量显著增加(P<0.05)。随饲料脂肪水平的升高,尼罗罗非鱼血清总胆固醇和甘油三酯含量呈先上升后下降的趋势,各实验组显著高于对照组(P<0.05);血清高密度脂蛋白含量呈先上升后稳定的趋势;血清谷丙转氨酶和谷草转氨酶活性均在饲料脂肪水平为6.11%时最小,在14.85%时达到最大。随饲料脂肪水平的升高,尼罗罗非鱼脂蛋白酯酶、肝脂酶和肠道脂肪酶活性均呈先升高后下降的趋势,脂肪酸合成酶活性显著下降(P<0.05)。对增重率、蛋白质效率、饲料系数和血清高密度脂蛋白胆固醇进行回归分析得出,尼罗罗非鱼幼鱼饲料最适脂肪水平分别为8.86%,9.75%,9.40%和8.30%,因此确定尼罗罗非鱼幼鱼饲料适宜的脂肪需要量为8.30%～9.75%。     

罗非鱼的营养需要

罗非鱼原产于非洲,因其食性杂、繁殖力强、疾病少,肉味鲜美,颇受消费者和生产者的欢迎,且成为我国小水库、池塘、网箱和工厂化养殖的重要品种。本文就近年来国内外对罗非鱼的营养方面研究进展进行综述,为国内罗非鱼配合饲料生产提供参考。一、蛋白质和氨基酸有关罗非鱼对蛋白质的需要,学者以尼罗罗非鱼为研究对象较多,不同的研究者所获得的结果差异不大,黄忠志等（1985）利用酪蛋白和植物蛋白分别对3g和4g的尼罗罗非鱼在水温23－28℃下进行试验,蛋白质在饲料中为31％时生长最快;Cruz（1975）试验得出蛋白质适宜范围为20％－30％…     

饲料脂肪水平对吉富罗非鱼体脂沉积及脂肪酸组成的影响

研究了饲料脂肪水平对吉富罗非鱼(Genetic Improvement of Farmed Tilapia,GIFT)的部分形体指标、肌肉肝脏及腹腔脂肪组织的脂肪沉积及脂肪酸组成的影响,同时探讨了鱼体对饲料脂肪酸的吸收利用能力.实验设置饲料脂肪水平分别为1.73%,3.71%,5.69%,7.67%,9.64%,16.55%共6个梯度组,每组3个重复,饲养90 d.结果显示:5.69%,7.67%及9.64%脂肪组吉富罗非鱼肥满度较高1.73%和16.55%脂肪组的肝体指数显著高于其他实验组(P<0.05);除了1.73%脂肪组,其他各组中饲料脂肪水平越高,鱼体的脏体指数越高.7.67%脂肪组吉富罗非鱼肌肉脂肪含量显著高于3.71%组(P<0.05),同时显著低于16.55%组(P<0.05),但是其肝脏中脂肪含量与其他各组差异均不显著(P>0.05);饲料脂肪水平越高,鱼体的脂肪含量越高,同时不饱和脂肪酸在总脂肪酸中的比例越高.结果表明,饲料脂肪水平影响吉富罗非鱼的部分形体指标,尤其对肝脏形态的影响较为明显.饲料中过多的脂肪容易在肌肉和肝脏组织中沉积,同时鱼体的脂肪含量和脂肪酸组成能够反映饲料的脂肪水平和脂肪酸组成.本研究旨在为饲料脂肪水平的合理设置及脂肪营养对脂肪代谢的调控提供参考.     

鲤鱼鳃组织结构及鳃对重金属离子的耐受性

采用不同浓度的重金属对鲤鱼进行不同时间的中毒试验，构成了鳃组织的耐量试验。试验表明，当超过鳃的耐受量时，鳃发生了不同阶段的病变。在低浓度短时间作用下，鳃组织分泌的粘液增多。随着浓度的增加和时间的延长，鳃组织出现鳃血管扩充、充血，呼吸上皮肿胀，鳃小片呈棍棒状，相邻几条鳃丝发生融合，形成一片细胞板。有些鳃细胞脱离。病状严重时造成鳃小片坏死、解体导致鳃功能的损害和破坏。     

奥尼罗非鱼5种组织中4种同工酶的研究

用聚丙烯酰胺凝胶垂直梯度凝胶电泳法对奥尼罗非鱼肾脏、肝脏、眼睛、肌肉和心脏等5种组织的酯酶(EST)、乳酸脱氢酶(LDH)、苹果酸脱氢酶(MDH)、超氧化物歧化酶(SOD)进行了初步研究,并分析了这4种酶的同工酶位点及酶谱表型。结果表明:奥尼罗非鱼的4种同工酶系统具有明显的组织特异性;EST由7个基因位点编码;LDH酶带多于大多数硬骨鱼典型的5条酶带;MDH和SOD都具有线粒体型和上清液型2种类型。     

长毛对虾黄鳃病组织病理的研究

长毛对虾黄鳃病是我省对虾养殖中发病较普遍、流行甚广、威胁最严重的病害之一。近十几年来,人们越来越深入地进行虾类病理学研究,以便准确地弄清导致对虾生理病态紊乱和虾体防御的机制及病原体在体内进行的合成作用。B.Z.Bian(1981),S.Egusa(1983),I.Dykova(1988),I.G.Nash(1988)等在对虾黑鳃病、红鳃病、弧菌病和单孢子虫病的组织病理学方面进行了广泛的研究。随着对虾养殖的发展,我国也开始了虾病的组织病理研究。盂庆显等(1989)开展了中国对虾红腿病的组织病理观察;叶孝经(1990)对中国对虾红足病进行了病理学初步研究;刘正义、张聪洲(1987)报道了斑节对虾外寄生原虫症、细菌性败血症、铁末沉积症的病理病征。但有关长毛对虾黄鳃病的组织病理研究,则未见报道。为此本文对长毛对虾黄鳃病的鳃和肝胰腺组织病理变化进行初步研究,现报道如下。     

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。     

三种生态环境下尼罗罗非鱼免疫因子的比较

随机选取海水池塘(盐度28)和淡水池塘养殖及水库天然增殖的3种不同生态环境下、体质量为200~500g的尼罗罗非鱼为研究材料,采用生物化学方法测定3种生态环境尼罗罗非鱼血清中碱性磷酸酶、酸性磷酸酶、过氧化物酶、谷胱甘肽还原酶的活性和蛋白质量浓度。结果显示,3种生态环境中罗非鱼血清中碱性磷酸酶和酸性磷酸酶活力差异不显著(P0.05),其余各组间罗非鱼血清中过氧化物酶和谷胱甘肽还原酶的活性及血清蛋白质量浓度差异显著(P0.05),酶活力和蛋白质量浓度依次为:水库海水池塘淡水池塘。试验结果表明,水库天然增殖的尼罗罗非鱼具有较高的磷酸酶活性。     

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”     

Streptococcus agalactiae Vaccination and Infection Stress in Nile Tilapia,Oreochromis niloticus

Abstract

The stress response following intraperitoneal (IP) injection of a non-adjuvant Streptococcus agalactiae vaccine in cultured warmwater Nile tilapia, Oreochromis niloticus, has not been investigated. Further, little or no information is available on stress following S. agalactiae infection and what effect, if any, vaccination has on susceptibility to infection. The objective of this study was to develop preliminary information on the associations between vaccination, stress, and infection. Blood glucose levels were used to evaluate stress in the fish at different time intervals following vaccination and challenge with S. agalactiae. Blood glucose levels were measured in vaccinates and controls at 0, 2, 6, 24 hours, and 28 days post-immunization (0 hours pre-challenge), and at 2,6, 24,48,72, and 312 hours following challenge with 1.5 × 10⁴ colony forming units (CFU) of S. agalactiae/fish. Significant increases in blood glucose levels were observed only in association with the injection of the vaccine and at 2 hours after injection. After S. agalactiae challenge, both controls and vaccinates had significantly (P < 0.05) higher blood glucose values at 2, 24,48, and 72 hours than at 0 hours. However, blood glucose levels in vaccinates were significantly (P < 0.05) lower than the controls at 24, 48, and 312 hours. Blood glucose levels and mortality of the infected controls were significantly correlated (r² = 0.9236, P = 0.0134). The cumulative mortality of the vaccinates and controls was 10% and 60% after 13 days post-challenge, respectively. The relative percent survival (RPS) was 83.4. Our results indicate that the vaccine was efficacious against S. agalactiae and induced short-term stress in tilapia. These preliminary results also suggested, for the first time, that vaccination may significantly reduce the infection stress associated with S. agalactiae infection in tilapia.     

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     

Evaluation and Nutrient Quality of Detoxified Jackbean Seeds,Cooked in Distilled Water or Trona Solution,as a Substitute for Soybean Meal in Nile Tilapia,Oreochromis niloticus,Diets

ABSTRACT

Jackbean, Canavalia ensiformis, seeds were detoxified using eight different wet thermal detoxification methods in either distilled water (5% w/v) or trona (NaCO₂.NaHCO₃.2H₂O) solution. The effects of the detoxification methods on hemagglutinating, antitryptic and urease activities, and on the digestibility coefficient of crude protein and gross energy in the jackbean seeds were investigated. Cracked jackbean seeds cooked (100°C) in trona solution for one hour proved to be more effective as a method of inactivating the antinutritional factors in jackbean seeds. Dried detoxified jackbean seed meals were incorporated in dry practical diets providing 20% or 30% of total protein and fed to Nile tilapia, Oreochromis niloticus, fingerlings (mean weight, 6.7 g) twice daily to apparent satiation for 70 days. Mortality was low and no abnormal fish behavior was noted even when the detoxified jackbean meals provided 30% of total protein in diet. Growth and feed utilization indices, were similar (P > 0.05) between the diet in which cracked jackbean seeds cooked in water provided 20% of total protein and in diets in which cracked jackbean seeds cooked in trona solution provided 20% or 30% of total protein. Carcass composition and hepatosomatic index showed no definite trend among O. niloticus fingerlings fed the experimental diets.     

Spontaneous diploidization of the maternal chromosome set in Nile tilapia (Oreochromis niloticus L.) eggs

Spontaneous diploidization of the maternal chromosome set (SDM) in Oreochromis niloticus is described here for the first time. The SDM phenomenon was observed in progeny of only one XY neofemale out of 11 such neofemales from which eggs had been fertilized with UV‐irradiated sperm: this treatment produced only the expected haploid embryos from the other females. SDM progeny were produced from three different batches of eggs from this female. No significant differences in survival at different stages of embryonic development were observed between the SDM and the diploid control group. The maternal inheritance of SDM progeny was verified using multilocus DNA fingerprinting. Only diploid karyotypes were observed in these fish and diploid control groups. In both the SDM and control groups, sex ratios were significantly skewed towards males (93.3% and 65.0% males respectively). The actual mechanism of SDM in eggs from this particular female remains unknown.     

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。     

Fisheries by-catch and processing waste meals as ingredients in diets for Nile tilapia, Oreochromis niloticus

Digestibility, feeding and growth studies were conducted with Nile tilapia using diets containing fishery by‐catch and processing waste meals. Three meals manufactured from sorted fisheries by‐catch (MBM, from mixed benthic species, SPM, from small pelagic species, CAM, from mixed catfish species) one from tuna cannery waste (TCW) and one commercial anchovy meal (COM) were tested. By‐catch and processing waste meals had lower protein, lower lipid and higher ash contents than anchovy meal. The meals were all highly digestible and no significant differences (P≥0.05) were observed between apparent protein digestibility measurements. Five feeds, containing fish meal as the major protein ingredient, were formulated and fed to triplicate groups of 30 juvenile tilapias for 9 weeks. Survival, weight gain, specific growth rate (SGR), feed conversion ratio, protein efficiency ratio, phosphorus retention and whole body proximate composition were compared. Weight gain and SGRs were similar for each treatment group and compared favourably with the results obtained from juvenile tilapia elsewhere. Growth was the highest for CAM (P≤0.05), which contained both the highest essential amino acid levels and the highest ash content. Phosphorus retention was significantly lower in fish fed with high ash meals, MBM, CAM and TCW (P≤0.05) than in fish fed with the lower ash meals COM and SPM. Overall, the fisheries by‐catch and processing waste meals evaluated in this study are suitable protein ingredients for juvenile tilapia feeds.