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1.
几种淡水鱼在冻藏过程中鲜度变化研究   总被引:5,自引:1,他引:4  
吴成业  叶玫 《淡水渔业》1994,24(1):16-18
本文以淡水养殖的鲢,鳙、罗非鱼为对象,利用IQF冻结设备在-30℃下冻结,并在-18℃的冷藏冻中贮成.通过对鱼肉鲜度指标K值,VBN、FAA-N、pH值以及蛋后质变性指标的测定,探讨鱼肉在冷冻贮藏过程中质量的变化情况.实验结果表明,K值和ATPase活性对反映淡水鱼低温冻藏过程中的鲜度变化有着良好的规律性。  相似文献   

2.
淡水鱼类出血病主要分为细菌性出血病和病毒性出血病,细菌性出血病在发生频率和危害程度方面都远远高于病毒性出血病(如草鱼呼肠弧病毒出血病等),所以本文重点就淡水鱼类细菌性出血病作浅析。 淡水鱼类细菌性出血病又称为细菌性败血症和暴发性出血病等,是我国养鱼史上危害鱼种类最多、流行地区最广、流行季节最长、造成损失最大的一种急性传染病。其危害鱼类有鲤鱼、鲫鱼、团头鲂、鲢鱼、鳙鱼、草鱼、黄鳝等多种淡水鱼类,全国20多个省、市、自治区流行此病,流行季节从2月底至11月底,水温在 9—36℃之间,尤以水温在 28℃…  相似文献   

3.
淡水鱼类出血病成因浅析   总被引:1,自引:0,他引:1  
淡水鱼类出血病主要分为细菌性出血病和病毒性出血病,细菌性出血病在发生频率和危害程度方面都远远高于病毒性出血病 (如草鱼呼肠弧病毒出血病等 ),所以本文重点就淡水鱼类细菌性出血病作一浅析。   淡水鱼类细菌性出血病又称为细菌性败血症和暴发性出血病等,是我国养鱼史上危害鱼种类最多、流行地区最广、流行季节最长、造成损失最大的一种急性传染病。其危害鱼类有鲤鱼、鲫鱼、团头鲂、鲢鱼、鳙鱼、草鱼、黄鳝等多种淡水鱼类,全国 20多个省、市、自治区流行此病,流行季节从 2月底至 11月底,水温在 9~ 36℃之间,尤以水温在 28℃…  相似文献   

4.
化学冰保鲜非鲫的研究   总被引:12,自引:1,他引:11       下载免费PDF全文
曾名涌 《水产学报》1997,21(4):443-448
以纯水冰作对比,研究了分别含有0.1%山梨酸钾和0.5%低分子壳聚糖的冰对非鲫的保鲜效果,感官评定,以及细菌总数,TVB-N和K值的定量分析结果表明:山梨酸钾冰和LMW-C冰的保鲜效果明显优于纯水冰,其保鲜期比纯水冲中保鲜的非鲫延长6天以上。但是,采用K值和TVB-N值作鲜度指标所得出的结果有明显差异。  相似文献   

5.
“四大家鱼”对暴发性鱼病的抗病力的种间差异↑(*)   总被引:4,自引:0,他引:4  
嗜水气单胞菌所引起的暴发性鱼病,是近年来危害我国淡水养殖业的主要病害之一。本文报导草鱼、青鱼、鳙、鲢对该病的抗病力的差异及机理的研究结果。在菌液浓度为6.0×10 ̄8CFU/ml(10°,10 ̄(-1),10 ̄(-2),10 ̄(-3)四个稀释度),注射剂量为0.3ml/尾时,半数致死生(LD_(50))分别是草鱼10 ̄(-0.48),青鱼10 ̄(1.25),鳙10 ̄(-1.37),鲢10 ̄(-2.19),差异显著(P<P_(0.05))。四种鱼的白细胞吞噬百分率存在极显著差异(P<P_(0.01)),其中草鱼极显著地(P<P_(0.01))强于其他三种鱼。四种鱼的补体替代途径(C_3旁路)杀菌力12小时测定结果的大小顺序是草鱼>青鱼>鳙>鲢,差异显著(P<P_(0.05))。草鱼的补体总量极显著地(P<P_(0.01))低于鲢、鳙。四种鱼的红细胞C_3b受体花环率存在显著差异(P<P_(0.05)),顺序为鳙>鲢>草鱼>青鱼。“四大家鱼”对暴发性鱼病的抗病力的种间差异,不仅同它们的免疫力的大小有关,也同它们对特定病原的易感性的大小有关。  相似文献   

6.
<正>细菌性败血症的流行时间为每年的3-11月,高峰期常为5-9月,日常养殖水温在9~36℃时均有流行。该病主要对鲢、鳙、鲫、团头鲂、草鱼、鲤鱼、黄颡鱼等淡水鱼类危害较大。一、基本情况湖北武汉市新洲区新建村陶师傅一主养白鲢  相似文献   

7.
作者比较了团头鲂、草鱼、鲤鱼血清对草鱼出血病病毒(GCRV-854)的中和效价,发现团头鲂的血清中和效价高达6300,并测得其春夏秋冬的中和效价无明显差异。用提纯的病毒蛋白偶联上Sepharose4B作为亲和层析柱,成功地从团头鲂血清分离到了抗GCRV-854的蛋白质因子。  相似文献   

8.
为检验鱼其鳅幼鱼短时间在水簇箱内的应激反应,在几个小时内将鱼其鳅幼鱼以0-1尾/L密度放在500- 700L海水中经受不断的温度和含盐量变化。记录了以鳃搏动速度为标志的呼吸频率以及在水箱中身体方向和位置的行为方式。换气速度对温度变化很敏感,随温度升高而直线上升,直到近30 ℃时,出现死亡在内的应激症状。把温度降到16℃可以使换气速度减慢,但此时鱼停止进食,也没有死亡现象。把含盐量从35 ‰降到0‰对换气速度没有显著影响,没有死亡现象,对进食活力(9-5 ‰,唯一测到的值) 没有显著影响。与含量0‰时所有鱼在1h 测试中都存活了。在高温下鱼的行为以及鱼其鳅在水中溶氧较低时的反应与许多淡水鱼在高温下的行为是相似的。这些显而易见的行为反应体现了养殖中刺激性的情况。鱼其鳅对广温和广盐变化的短时间耐受以后研究长时间耐受以扩展可能的养殖条件提供了参考。  相似文献   

9.
草鱼养殖过程中经常使用食盐药浴,以便在高渗环境下杀死病原体。研究食盐药浴后草鱼代谢酶变化,有助于了解食盐药浴对草鱼机体生理免疫的影响。将草鱼(Ctenpharyngodonidella)分别暴露于食盐浓度为0、2%、3%、4%水体中浸浴10min,然后置入水簇箱中饲养,分别在药浴后12h、24h、36h取样,测定其血清中超氧化物歧化酶(SOD)和溶菌酶(LSZ)活性变化。结果显示,与对照组相比,血清SOD活性在12h时,2%组中显著上升(P<0.05),3%、4%组显著下降(P<0.05);24h取样时,2%、3%组中无显著差异(P>0.05),4%组显著下降(P<0.05);36h取样时,各组间均无显著差异(P>0.05);血清LSZ活性各组间均无显著差异(P>0.05)。食盐能引起草鱼SOD活性变化,而对溶菌酶活性影响不大;表明食盐对草鱼不同代谢酶有不同的反应模式,抗氧化酶SOD对食盐应激有敏感的生理应答。  相似文献   

10.
草鱼干扰素诱生条件的研究   总被引:7,自引:0,他引:7  
邵健忠 《水产学报》1999,23(2):122-127
草鱼干扰素诱生条件与规律的研究结果显示,病毒分染草鱼牾 能迅速诱导IFN的合成,24h即可在血清中检测到IFN活性,3d后活性达到高峰。草鱼IFN的合成受温度,病毒种类,病毒剂量,鱼体营养状况等因素的影响。25℃水温下诱生的IFN活性明显高于15℃和8℃。  相似文献   

11.
The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.  相似文献   

12.
Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.  相似文献   

13.
14.
Growth hormone (GH) and reproduction: a review   总被引:5,自引:0,他引:5  
Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.  相似文献   

15.
In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.  相似文献   

16.
17.
Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg?1 protein) than essential amino acids (425.82 ± 9.15 g kg?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.  相似文献   

18.
Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL?1 (1.25 ng well?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.  相似文献   

19.
Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).  相似文献   

20.
The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg–1 fish·h–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g–1·ml–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min–1·g–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min–1·g–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.  相似文献   

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