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1.
细菌性疾病是中国海水养殖鲆鲽类的主要病害,为全面了解病原菌种类,本研究对1999~2012年从山东、江苏、河北、天津等沿海地区养殖场发病鲆鲽鱼类中分离得到的124株优势菌株进行了16S rRNA基因测序和系统发育学分析。将基因序列与GenBank核酸序列数据库进行相似度比对分析,结果显示,有83株与弧菌属(Vibriosp.)细菌相似度最高,11株与气单胞菌属(Aeromonas sp.)细菌相似度最高,4株与爱德华氏菌属(Edwardsiella sp.)细菌相似度最高,26株为其他15种属的细菌。根据系统发育学分析结果,进一步将66株菌鉴定为16个种,优势种为溶藻弧菌(V.alginolyticus)、哈氏弧菌(V.harveyi)、鳗弧菌(V.anguillarum)、杀鲑气单胞菌(A.salmonicida)和迟缓爱德华氏菌(E.tarda)。选择其中的9株鳗弧菌和4株迟缓爱德华氏菌进行人工感染实验,结果显示,其中7株鳗弧菌和3株迟缓爱德华氏菌对大菱鲆(Scophthalmus maximus)有较强的致病性。研究结果可为阐明中国海水养殖鲆鲽类的流行病发生历史、病原种类、病原监测及疾病控制提供重要参考。  相似文献   
2.
分析商品南极磷虾粉、自制酶解磷虾粉的主要营养成分(氨基酸和脂肪酸)组成,同时采用生化方法比较了5种鲽形目鱼肉蛋白的氨基酸组成。以5种鲽形目鱼肉蛋白为参比蛋白,利用必需氨基酸指数、氨基酸比值系数分和关联度分析法评价南极磷虾粉作为鲽形目鱼饲料蛋白源的营养价值,同时对2种磷虾粉的氟含量进行了分析。结果显示,鲽形目鱼肉(干样)中含有16种常见氨基酸,其中,7种为人体必需氨基酸,4种为呈味氨基酸(总量分别为28.52%–38.03%、25.26%–33.56%);5种鲽形目鱼氨基酸组成均符合 FAO/WHO 的理想模式。南极磷虾粉和酶解磷虾粉的粗蛋白分别为60.84%和68.60%,粗脂肪分别为12.08%和10.79%,达到了规定鱼粉的一级品甚至特级品的指标。酶解处理后蛋白含量显著升高(P<0.05),脂肪含量显著下降(P<0.05),灰分含量无差异(P>0.05)。从必需氨基酸指数(EAAI)来看,EAAI 均大于0.95,磷虾粉的必需氨基酸与鲽形目鱼的必需氨基酸拟合度较高。从氨基酸比值系数分(SRC)和关联度分析法来看,2种磷虾粉对于鲽形目鱼的必需氨基酸平衡性较好,相关系数与鱼粉相差不大。氟含量方面,酶解后磷虾粉的氟含量[(331.21±6.70) mg/kg]显著降低(P<0.05),低于欧盟标准(350 mg/kg)。综合来看,2种磷虾粉氨基酸平衡性较好、营养价值较高,是优质蛋白源。  相似文献   
3.
[目的]研究鲽鱼骨蛋白胨的制备工艺并对其在细菌培养中的应用进行了初步探讨。[方法]采用乙酸和胃蛋白酶提取鲽鱼骨蛋白胨,以蛋白提取率为指标,在单因素试验基础上,采用正交试验优化制备工艺,并对鲽鱼骨蛋白胨作为氮源在细菌培养中的应用进行了研究。[结果]鲽鱼骨蛋白胨提取的最佳工艺条件为:提取时间20 h、提取温度40℃、料液比1∶50 g/m L、胃蛋白酶加酶量3 000 U/g,在此条件下鲽鱼骨蛋白胨的提取率为55.62%。蛋白胨产品的氨基酸种类齐全。通过细菌培养试验发现,对于大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌,鲽鱼骨蛋白胨的培养效果与市售细菌学蛋白胨相似。[结论]鲽鱼骨蛋白胨能够提供细菌生长所需要的氮源营养,可作为氮源应用于细菌的培养。  相似文献   
4.
In this study, we determined the color vision and spectral sensitivity of pointhead flounder, slime flounder, and red halibut by recording electrophysiological S-potentials from isolated retinas; this basic data was collected to aid the selection of appropriate colors and effective wavelengths for selective fishing gear for sustainable fisheries. Four kinds of L-response and one C-response were recorded in the pointhead flounder and red halibut. Two kinds of L-response were recorded in the slime flounder. The occurrence of a C-response indicates the possession of color vision. The C-responses show that the pointhead flounder has superior distinction from blue to yellow, and red halibut has superior distinction from blue and green to red. The most frequently recorded L-responses indicate high spectral sensitivity at 544 nm in pointhead flounder and 518 nm in slime flounder and red halibut. All recorded L- and C-responses indicate sensitivity to ultraviolet wavelengths.  相似文献   
5.
鲆鲽类白化机理的研究进展   总被引:4,自引:1,他引:3  
鲆鲽类体色白化,在苗种生产过程中常见。很多学者对其进行过研究,然而关于白化的机理仍然不清楚。本文就近年来国内外有关鲆鲽类白化机理的研究从营养、遗传、环境、生理等方面进行综述。  相似文献   
6.
Abstract

Attempts to rear summer flounder, Paralichthys dentatus, in net pens have suffered from high mortality during the month after fish were transferred from a nursery facility to pens. We investigated whether exposing summer flounder to increased (and constant) current velocity in the nursery stage would condition them for better performance in cages. Three experiments were conducted with different water velocities in tanks, using fish of 124±4 g (exposed to 0, 15, or 30 cm/sec for 60 d), 257±12 g (exposed to 0, 20, or 40 cm/sec for 60 d) and 387±13 g (exposed to 0, 15, or 30 cm/sec for 30 d), in a raceway system with adjustable paddlewheels. For all of the size groups of fish, survival was significantly reduced at the highest current velocity. For both 124-g and 257-g fish, growth in the medium-velocity treatment was significantly better than that in the control (0 cm/sec) treatment, which in turn was better than that in the high-velocity treatment. For 387-g fish, growth at medium velocity was significantly greater than that at high velocity; control fish were lost due to a system malfunction. Food consumption data from the 257-g fish showed that the fish in medium velocity grew most because they consumed significantly more food during the experiment than did fish in the control, which in turn consumed significantly more than fish in high velocity. Similarly, 387-g fish in medium velocity consumed the most food, but the difference was not significant in this case. At the end of the laboratory experiment with 124-g fish, fish from the control and medium-velocity treatments were moved to cages in Narragansett Bay, Rhode Island, where currents of about 1 knot (approx. 55 cm/second) are routine. After three weeks in the cages, no significant differences in survival were observed (control = 83±12%; medium velocity = 81±2%). Subsequent damage to some of the cages and escapement of the fish precluded further statistical analysis of survival, as well as any growth measurements. At the end of the laboratory experiment with 387-g fish, fish from medium- and high-velocity treatments were moved to the cages; however, survival in this case was very low (<10% in all cages), perhaps due to heavy waves from an offshore hurricane. We conclude that current velocities of 15-20 cm/second in the nursery improve growth of juvenile summer flounder, that current velocities of 30-40 cm/second are excessive, but that increased current velocity in the nursery does not improve fish survival upon transfer to cages.  相似文献   
7.
Grading of cultured flatfish is essential to maintain even sizes and to avoid potential feeding dominance or cannibalism. Current hand-grading and forced mechanical grading methods result in labour costs and additional stress to animals, reducing their growth performance. This study tested a self-grading system allowing turbot (Scophthalmus maximus) to self-grade, based on size, between tank sections within 8000 L tanks designated as “Graded (G)” and “Non-Graded (NG)”. The grading success (percentage of graded animals/total gradable individuals) with stimuli (light, feeding sequence and colour of the grading device) and without stimuli was analyzed over 9 days. Mean grading success without stimuli was 38.1 ± 11.5%. Grading success was not improved by changes in feeding sequence (30.6 ± 10.2%) or altered colour of the grading device (30.9 ± 13.8%). Marked increases in grading success were obtained by adding a light source to the G section (52.9 ± 12.4%), and by combining the presence of a light source and the feeding sequence (57.9 ± 14.4%). The combination of light sources and changes to the colour of the self-grading device resulted in the highest mean grading success (72.1 ± 18.2%) overall. Light and colour stimuli combined yielded the highest self-grading maximum (88.36 ± 5.3%), achieved on day 6 after experimental onset. A three-parameter asymptotic exponential equation was fitted to the data from each stimulus and parameters describing the curves of all conditions are reported. The present results indicate that the tested self-grading systems for turbot can be highly efficient if used with the appropriate stimuli. Self-grading systems operating at the measured levels of success offer a viable alternative to stressful grading events, avoiding significant commercial disadvantages as well as improving animal welfare and performance.  相似文献   
8.
Tank bottom surface is an important question to take into account in flatfish aquaculture considering the intimate contact that the fish have with it. The most usual materials in aquaculture tank surfaces are inert materials such as epoxy resins or plastics with null porosity, and cement that presents a high alkalinity, roughness and porosity. To improve the cement characteristics, silica fume admixture is usually added in construction industry. The aim of this study was to evaluate the effect of three types of tank bottom surfaces on growth and welfare over a Solea senegalensis population. Moreover, the degree of fin erosion, the appearance of skin lesions and malpigmentation patterns were also monitored. The bottom surfaces tested were plain cement (CE), the same plain cement blended with silica fume (10%) (SF) and epoxy coated surface (EP). Specific growth rate for each bottom surface were compared. The Image Processing Activity Index (IPAI) was used to evaluate the Senegalese sole welfare. Higher SGR and lower IPAI values were obtained in the surface of cement with silica fume, suggesting a higher welfare. The use of plain cement affected negatively the performance of fish, probably due to the high pH and alkalinity of the water in direct contact with fish skin. The null porosity of EP seems to be related to the main cause of higher activity level of fish kept on it outcoming in lower growth. Silica fume that is frequently use to improve the mechanical characteristics of plain cement, also provides benefits in terms of fish welfare.  相似文献   
9.
The effect of dietary protein reduction balanced by an increase in carbohydrate (starch) level on growth performance, feed utilization and intermediary metabolism of Senegalese sole juveniles was evaluated at two temperatures, 12 and 18°C. For that purpose two isolipidic (16% lipids) diets were formulated to contain 550gkg?1 protein and 90gkg?1 starch (diet HP:LC), and 450gkg?1 protein and 200gkg?1 starch (diet LP:HC). Each experimental diet was fed to triplicate groups of 20 fish (initial body weight: 15.9g) within each temperature. Diets had no effect on growth and feed utilization. Temperature affected growth but not feed efficiency, with fish growing more at 18°C. Fatty acid synthetase and glutamate dehydrogenase activities were higher at 12°C than at 18°C while activity of the other measured enzymes was not affected by water temperature. Glucokinase and malic enzyme activities were lower while fructose 1,6‐bisphosphatase activity was higher in fish fed the HP:LC diet. Our data suggest that protein can be reduced from 550 gkg?1 to 450 gkg?1 by increasing starch level in high lipid diets for Senegalese sole juveniles without affecting overall performance. A reduction in protein content through an increase in dietary starch decreases hepatic gluconeogenesis. Increasing temperature from 12°C to 18°C improves fish growth but does not affect feed efficiency.  相似文献   
10.
The wedge sole is a target species in the fisheries of the Gulf of Cadiz (Spain). Having reared them to commercial size, we have studied reproduction and breeding in captivity of the wedge sole in this work here. The breeders adapt easily to captivity, and they can spawn in less than 1 year in captivity. The relative fecundity is relatively high, 1.06–2.33 · 106 eggs kg−1 per spawning season (mean 1.6 ± 0.1). Larval SGR is high, 7.2 ± 0.2% day−1 (range 5.8–9.1), similar to other cultured flatfish species. In 1 year, some individuals reach market size and can release eggs, registering SGRs of 1.39–1.66% day−1 (mean 1.56 ± 0.01). This species presents some very different characteristics with respect to other farmed flatfishes (turbot, halibut and Senegal sole, mainly), so that it is necessary to develop new techniques to optimise its cultivation. In the present work, the first results are presented on the biology of the wedge sole in captivity.  相似文献   
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