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1.
Oocysts and/or sporocysts were detected in 50 litters and 37 bitches of 100 coproscopically examined dog families in Southern Germany. Oocysts of Isospora spp. were excreted by 41 of the 50 positive litters, 36 and 16 litters shedding oocysts of Isospora ohioensis/burrowsi and I. canis, respectively. Sporocysts of Sarcocystis spp. and oocysts of Hammondia heydorni were detected in 12 and 7 litters, respectively. The excretion rates of the dams were arranged analogous to the detection of oocysts of Isospora spp. in 25 animals. Sporocysts of Sarcocystis and oocysts of H. heydorni were excreted by 19 and 6 dams, respectively. With regard to husbandry conditions distinct differences were established only for Isospora spp., because dog families kept in kennels always revealed higher excretion levels than dog mothers and their litters kept indoors. Excretion intensities increased directly proportional to the number of additional adult dogs and the number of litters born per year/stock, reaching maximum values of 80-100%. Analysis revealed no breed-related differences.  相似文献   

2.
Toxocara canis, Toxascaris leonina, hookworms, Trichuris vulpis, Strongyloides, Hammondia heydorni, Sarcocystis spp., Isospora canis and Isospora ohioensis and/or Isospora burrowsi of at least 9 species were detected in 100 randomly selected dog families in Southern Germany. Examinations carried out 5 to 9 times at weekly intervals revealed a monoinfection in 37 litters, infection with two parasite species in 28 litters, with three species in 10 litters and with four species in 6 litters. During the investigation period, 29 of the examined litters did not excrete helminth eggs, and, of these, 19 also did not excrete oocysts/sporocysts. In order of decreasing frequency among the dog families, the excretion extent of the litters and their mothers was as follows: Toxocara canis 67% and 45%, Isospora ohioensis/burrowsi 36% and 24%, Sarcocystis spp. 12% and 19%, Isospora canis 16% and 8%, Hammondia heydorni 7% and 6%, hookworms 6% and 7% and Toxascaris leonina 3% and 8%, respectively. Trichuris vulpis and Strongyloides eggs were only detected in 6 and 3 of the bitches, respectively.  相似文献   

3.
In this epidemiological study 100 litters of Southern Germany were investigated. 70 litters were kept on farms and 30 litters originated from mother cats kept indoors. At least 9 species were detected in litters from farms, 77.1% of these litters were infected with T. cati, 1.4% with hookworms, 10% with Capillaria, 10% with H. taeniaeformis, 67.1% with I. felis, 48.6% with I. rivolta, 17.1% with Toxoplasma/Hammondia, 4.3% with C. parvum and 1.4% with Giardia. In litters kept indoors only 5 species were established. 3.3% were infected with T. cati, 46.6% with I. felis, 33.3% with I. rivolta, 6.6% with Giardia and 3.3% with C. parvum. Analogous differences as regards to the keeping conditions existed also for the mother cats.  相似文献   

4.
To determine the helminth fauna of wild boars, stomachs and intestines of 124, lungs of 62, and livers of 39 animals from 5 enclosures in Southern Germany were examined. The evaluation of the species composition revealed at least 13 species: Metastrongylus apri, M. salmi, M. pudendotectus, Physocephalus sexalatus, Hyostrongylus rubidus, Globocephalus longemucronatus, Ascaris suum, Trichuris suis, Oesophagostomum dentatum, O. quadrispinulatum, Fasciola hepatica, C. tenuicollis and Capillaria. The most frequently isolated species was M. salmi with 91.9%, followed by G. longemucronatus with 91.1%, M. apri with 88.7%, M. pudendotectus with 87.1%, P. sexalatus with 51.6%, O. dentatum with 46%, T. suis with 30.6%, H. rubidus with 14.5%, A. suum with 12.1% and O. quadrispinulatum with 8.1%. Differences in the prevalence of infection, determined for animals up to 1 year old, 1-2 year-old and adults, were minimal for Metastrongylus spp. and G. longemucronatus. P. sexalatus, T. suis and A. suum, however, occurred more often in 1 year old, whereas H. rubidus, O. dentatum and O. quadrispinulatum were isolated more often from adults. A correlation of the infection rate with the sex of the animals was not found.  相似文献   

5.
The extent and frequency of bloodworm digging in northeast North America has never been investigated, making bloodworm fishery management difficult and an assessment of ecological impact impossible. We examined the spatial and temporal patterns of bloodworm digging by surveying 13 mudflats in mid-coast Maine using monthly aerial photography. We used ArcGIS to “georeference” spatial information into the photographs, allowing us to quantify the area of the mudflat disturbed by digging. Of the 122 ha of flats we monitored, almost 48% was dug in 2006, and 24% was dug in 2007, corresponding to 57.9 ha and 24.8 ha, respectively. Individual flats in this study were dug as much as 155% and as little as 0% annually, but rarely were they dug more than once a year as studies assessing the impact of digging on soft-sediment communities have assumed. Digging activity peaked in early spring with a smaller peak in August. On average, 3% of the visual evidence of digging faded each month. Except for those erased by winter storms and ice scour, no dug strip faded before 5 months of age, therefore flats could be monitored every 4–5 months for an accurate estimate of digging activity. Our results allow us, for the first time, to estimate the impact of digging on the bloodworm resource and to design realistic experiments to measure the impact of digging on the soft-sediment community and non-target species.  相似文献   

6.
7.
南海鸢乌贼水声学测量和评估相关技术研究   总被引:1,自引:0,他引:1  
利用双频(38 kHz、120 kHz)Simrad EK60和频率分别为70 kHz和120 kHz的2部Simrad EY60科学探鱼仪于2013年获得的南海鸢乌贼( Sthenoteuthis oualaniensis)声学调查资料,对鸢乌贼的目标强度( TS)和空间分布、浮游动物的干扰、频差技术的应用等内容进行了分析。结果表明,以灯光罩网取样对鸢乌贼TS进行现场测量是可行途径;自然条件下鸢乌贼声学映像不明显,光诱条件下鸢乌贼开始聚集,22:00前主要分布于10~50 m和55~80 m水层,22:00后主要分布于10~35 m、50~75 m和115~155 m水层;浮游动物和深海鱼类是鸢乌贼声学探测的重要干扰,尤其是夜间,设置积分阈要考虑不同时间段的影响;频差技术是鸢乌贼声学映像鉴别的重要方法,应深入研究。  相似文献   

8.
南美白对虾的生物学及其养殖技术要素   总被引:7,自引:0,他引:7  
南美白对虾 (Penaeusvannamei)又称万氏对虾、白肢虾、白对虾、白虾等 ,原产于太平洋沿岸水域 ,尤以厄瓜多尔沿岸最为集中 ,为热带型种类 ,是当今世界上公认的养殖产量最高的三大优良虾种之一。其壳薄体肥、肉质鲜嫩、生长快、抗逆性强 ,深受消费者的欢迎。我国自 1988年引进该虾并人工繁殖成功 ,目前产量高达 30 0~ 35 0kg/亩。1 生物学特性1 1 生活习性自然栖息区为泥质海底 ,水深 0~ 72m ,水温 2 5~32℃ ,盐度 2 8‰~ 34‰ ,pH值 8 0± 0 3。成虾多生活在沿岸水域 ,幼虾则喜欢在饵料丰富的河口区觅食生长。该…  相似文献   

9.
Fourteen years (1996–2009) of juvenile Chinook salmon, Oncorhynchus tschawytscha (Walbaum), migration data on the regulated Stanislaus River, California, USA were used to evaluate how survival, migration strategy and fish size respond to flow regime, temperature and spawner density. An information theoretic approach was used to select the best approximating models for each of four demographic metrics. Greater cumulative discharge and variance in discharge during the migration period resulted in higher survival indices and a larger proportion of juveniles migrating as pre‐smolts. The size of pre‐smolt migrants was positively associated with spawner density, whereas smolt migrant size was negatively associated with temperature and positively associated with discharge. Monte Carlo techniques indicated high certainty in relationships between flow and survival, but relationships with juvenile size were less certain and additional research is needed to elucidate causal relationships. Flow is an integral part of the habitat template many aquatic species are adapted to, and mismatches between flow and life history traits can reduce the success of migration and the diversity of migratory life history strategies. The analyses presented here can be used to assist in the development of flow schedules to support the persistence of salmon in the Stanislaus River and provide implications for populations in other regulated rivers with limited and variable water supply.  相似文献   

10.
Although a large number of fish species have been introduced into Guangdong Province in Southern China, a few species, such as tilapia (Tilapia spp.), North African catfish Clarias gariepinus Burchell, mrigal carp, Cirrhinus mrigala (Bloch) and the sucker mouth catfish (Hypostomus sp.), have established natural populations and can be considered “successful invaders” in large rivers. The specific mechanisms underlying these contrasting results among different introduced fish species remain understudied. The relationship between multiple abiotic–biotic factors and the success of four invasive species was investigated using survey data for the Guangdong Province river ecosystem. In contrast to previous studies that have considered species‐specific traits, the focus was on economic, ecological and anthropogenic factors to predict invasion success. Four main predictive indicators were found: (1) successful invaders were of low or no commercial value; (2) successful invaders tolerated a wide range of environmental conditions, including poor water quality; (3) biodiversity loss accelerated the growth of non‐native populations; (4) human disturbance facilitated population growth and spread of invasive fish species. To lessen the impacts of invasive fish species, the selection of breeding species and breeding areas, maintenance of water quality and reduction in water pollution, protection of the diversity of fish species and reduction of human interference should be addressed.  相似文献   

11.
Thyroid hormone concentrations in unfertilized eggs of 26 species of various freshwater, marine and diadromous teleosts were examined, together with changes in their concentrations during egg development in some species. Significant quantities of both thyroxine (T4) and triiodothyronine (T3) were found in eggs of all species examined. Mean T4 and T3 concentrations in eggs varied from 0.04 (marbled sole) to 15.00 ng/g (chum salmon), and from 0.07 (goldfish) to 9.95 ng/g (Pacific herring), respectively. T4 concentrations were significantly greater than T3 concentrations in eggs of most freshwater fishes, whereas T3 concentrations were greater in seawater fishes. During the course of development, thyroid hormones in eggs decreased markedly before hatching. These findings suggest that thyroid hormones are consistently present in teleost eggs, and thus may play an important role in the egg development.  相似文献   

12.
13.
缢蛏(Sinonovacula constricta)是我国传统的四大海水养殖贝类之一,养殖过程中易受病原菌感染而造成大量死亡和经济损失。Toll样受体(Toll-like receptor, TLR)是目前研究最多的模式识别受体,在无脊椎动物的先天性免疫中发挥着重要作用。研究缢蛏TLR分子特征及其免疫功能对预防和控制病原菌感染至关重要。本研究从缢蛏基因组序列中鉴定出42个TLR基因(ScTLR),其中,33个编码典型的TLR蛋白,其他9个为TLR样蛋白。根据蛋白结构域特点,将典型的TLR蛋白分为2大类4个亚类,一类为多半胱氨酸簇TLR (mccTLR),包括1个P型TLR和7个sPP型TLR;另一类为单半胱氨酸簇TLR (sccTLR),包括16个sP型TLR和9个Ls型TLR。与其他9种软体动物TLR基因的类型和数目比较结果显示,缢蛏基因组中未发现其他软体动物中存在的V型和Twin-TIR型TLR,起源古老的mccTLR类群在软体动物中没有大规模的扩张,而起源较晚的sccTLR类群却发生了大规模的扩张。荧光定量PCR分析显示,6种ScTLR在检测的7种组织中普遍表达,且在血细胞、鳃和肝胰腺组织中高表达。最后,副溶血弧菌(Vibrio parahemolyticus)胁迫12 h和48 h的缢蛏鳃和肝胰腺转录组数据分析显示,副溶血弧菌感染前后9个TLR基因在鳃或肝胰腺中的表达量发生显著变化,6个基因(ctg118.25、ctg118.26、ctg356.25、ctg774.6、ctg681.6和ctg1513.5)在感染12 h或48 h后的鳃组织中表达差异显著,前5个基因表达量上调,仅ctg1513.5表达量下调;3个基因(ctg467.9、ctg2496.3和ctg903.17)在感染12 h或48 h后的肝胰腺中表达差异显著,其中,ctg467.9和ctg2496.3表达量下调,ctg903.17表达量上调。综上所述,本研究结果将为深入探讨不同TLR基因在缢蛏天然免疫中发挥的作用提供研究基础。  相似文献   

14.
The genetic structure of the gadiform fish species, burbot Lota lota L., was investigated across Germany to derive management options for facilitating the preservation of genetic diversity. Sequence analysis of the mitochondrial control region (n = 244) and microsatellite analysis (n = 861) of specimens from 20 sites revealed genetic structuring between major river basins, and particularly between lake and river habitats. The admixture zone between the Eurasian and West European phylogenetic clades in Lake Constance was confirmed and expanded to include the drainage basins of the rivers Rhine and Schlei/Trave. Haplotype distribution and private haplotypes in single river basins indicated population differentiation and imply that German burbot constituted an important part of the entire species' diversity. The derived genetic structuring has implications for future stocking programmes and the preservation of the adaptive potential of burbot, a guiding species for oligotrophic lakes in Europe.  相似文献   

15.
华南沿海牡蛎重金属含量特征及其风险评估   总被引:7,自引:0,他引:7  
根据2009年对华南沿海部分海域的近江牡蛎和太平洋牡蛎的监测数据,对产品中重金属元素Cd、Cu、Pb、As、Hg和Zn的含量水平、分布与变化特征进行了分析讨论;采用点评估方法,计算Cd、Cu、Pb、As、Hg和Zn的膳食暴露量,对牡蛎产品的食用安全性进行风险评估。结果表明,调查海域牡蛎样品中Cu、Zn、Cd的含量较高,其值分别为92.0、268、1.32 mg/kg(湿重,下同);Hg、As、Pb的含量低,其值分别为9.21、0.11、0.26 mg/kg。不同海域、不同养殖季节的牡蛎产品中重金属元素的含量具有明显的差异。与无公害水产品质量标准的限量值相比,调查海域牡蛎产品中Cu、Zn、Pb、Hg、As的含量符合产品质量标准,Cd的含量超过产品限量标准值。由于元素间的相互作用,牡蛎产品Zn的含量高、Cd的含量低,Zn的可利用性阻止对Cd的吸收,牡蛎产品中的Cd不会对健康造成危害。风险评估的结果显示,每周食用适量的牡蛎,重金属的膳食摄入量低于世界卫生组织/联合国粮食和农业组织的食品添加剂联合专家委员会(JECFA)推荐的暂定每周耐受摄入量,处于安全范围内。  相似文献   

16.
通过白斑综合征病毒(WSSV)感染实验,利用实时定量PCR技术研究了中国明对虾(Fenneropenaeus chinensis)应答病毒侵染后,已知的3种抗菌肽(对虾肽)在肝胰腺、肌肉、肠和鳃4种组织中的差异表达情况.结果显示,虽然3种抗菌肽表现出明显的组织表达特异性,即在不同组织中的表达趋势和表达丰富度存在明显的差异,但是就同一个组织而言,3种抗菌肽在1~120 h WSSV侵染区间内的表达趋势基本一致,在0 h(未侵染病毒)时,3种抗菌肽的表达量极低(为0);在6~24 h期间,检测到明显的表达量;48~120 h期间,3种抗菌肽的表达量总体呈现下降的趋势.这暗示3种抗菌肽在对虾机体内可能具有相似的生物学功能.在此基础上,本研究对各类型中国明对虾抗菌肽的SNP位点进行了筛选,进一步对不同SNP类型与抗WSSV或易感WSSV的关联程度进行了分析,结果显示3种抗菌肽基因的SNP位点很少,且在抗性和易感对虾群体内不存在明显的偏向分布.  相似文献   

17.
To determine the intensity of helminth infection and egg output with regard to age and sex of wild boar, stomachs and intestines of 124, lungs of 62, and livers of 39 animals from 5 enclosures in Southern Germany were examined. The evaluation of the intensity of infection showed 579.4 worms per animal for Hyostrongylus rubidus, 510.4 for Globocephalus longemucronatus, 476.9 for Oesophagostomum dentatum, 476.9 for O. quadrispinulatum, 254.2 for Metastrongylus pudendotectus, 176.9 for M. salmi, 140 for Physocephalus sexalatus, 56.9 for M. apri, 45.4 for Trichuris suis, and 3.3 for Ascaris suum. 33.6 liver flukes per infected wild boar were also found. Additionally 2 metacestodes of Taenia hydatigena on the serous liver coat of an adult sow were found. The worm burden with respect to age of the animals showed no or only minimal age related differences, whereas a large number of O. dentatum and O. quadrispinulatum was found in adults compared to younger wild boars. The evaluation of the intensity of infection with regard to sex of the animals showed higher values only for H. rubidus, O. dentatum, O. quadrispinulatum and P. sexalatus in males compared to female wild boars. The egg output intensity in the samples taken from the rectum was in average 3300 EpG for A. suum, 450.4 EpG for Oesophagostomum, 445.9 EpG for Globocephalus, 220 EpG for Trichuris, 207.9 EpG for Metastrongylus, 190.8 EpG for Hyostrongylus and 67 EpG for Capillaris. The egg output with respect to age showed higher values in younger wild boars than in adults.  相似文献   

18.
Experiments on the intensive cultivation of Pacific white shrimp, Penueus vunnumei, in ponds in South Carolina were begun in 1985 at the Waddell Mariculture Center. A preliminary study involved two 0.1 ha ponds stocked at an average of 43 postlarvae/m2, with management practices based on those used in Taiwan for intensive pond culture of Penueus monodon. Harvest yields averaged 6,757 kg/ha for one crop, demonstrating the technical feasibility of such intensive culture of P. vannumei. In 1986, 2.5 ha of ponds at the Waddell Center (six ponds totaling 2.0 ha at 40 postlarvae/m2 and two totaling 0.5 ha at 60/m2) yielded a total of 13,606 kg (5,442 ke/hn). These results were obtained even though aeration and water exchange rates were substanthlly reduced and South Carolina experienced its worst heat wave and drought. This served as a pilot-sde, proof-ofconcept test. Tank studies in 1985 and 1986 showed little effect of stocking density on shrimp growth rate at densities of 20–100 animals/m2. This was confirmed in ponds in 1987 when no differences in growth rates were observed at densities of 20–100 postlarvae/m2. Harvest biomass increased directly with stocking density in all trials, reaching a maximum of 12,680 kg/ha/crop at 100 shrimp/m2 in 1987. Initial attempts to intensify production in the nascent South Carolina shrimp farming industry occurred in 1986, when approximately 32 ha of private ponds were stocked at densities of 10–32 postlarvae/m2. Farm harvests increased with stocking density, with maximum yield of 3,656 kg/ ha/crop. This trend toward intensification in the private sector is continuing, and in 1987 maximum harvests from private ponds were 5,050 kg/ha from a 0.3 ha pond and 4,625 kg/ha from a 1.5 ha pond. Prospects for further implementation of intensive culture in the private sector appear excellent, with yields of ≥ 10,000 kg/ha/crop expected from private farms within the next few years.  相似文献   

19.
Three different concentrations (107, 105 and 103 TCID50 ml-1) of infectious pancreatic necrosis virus (IPNV) serotype Sp isolated from Atlantic halibut, Hippoglossus hippoglossus L., were used to bath-challenge Atlantic halibut yolk-sac larvae. The larvae challenged with 107 TCID50 ml-1 suffered significantly higher cumulative mortality than the other challenged groups and the control group, and affected individuals displayed necrosis of the intestine, liver and kidney. In larvae from the groups challenged with 107 and 105 TCID50 ml-1, IPNV was detected by immunohistochemistry and in situ RNA/DNA hybridization in the intestine, liver and kidney. In addition, some individuals stained IPNV-positive in the heart and eye/brain region. Detection by in situ hybridization did not appear to be more sensitive than immunohistochemistry. However, background staining was virtually absent in comparison with immunohistochemistry, and the staining seemed to be more distinctly localized to the cytoplasm of infected cells. The results show that farmed halibut yolk-sac larvae can be infected by IPNV immediately after hatching, with resulting high mortality. As the larvae are not immunologically mature at this stage of development, vaccination is not recommended.  相似文献   

20.
Sustainability issues are becoming increasingly important in Western food consumption. This research aims at identifying ways to increase the market share of sustainable fish from aquaculture by analyzing consumer awareness and preferences for sustainable aquaculture products and by drawing conclusions on improving communication in the German market. An integrative research approach was used: it began with an inventory of sustainable seafood products on the German market, followed by qualitative and quantitative consumer research, and ending with a stakeholder workshop, which reflected on the research outcome with practitioners. Sustainability and country of origin proved to be of minor relevance to the vast majority of the consumers interviewed. Indeed, attributes such as freshness, taste, and price frequently ranked higher. Like most of the other consumers, the small consumer segment that is generally interested in sustainability issues of food also often lacks knowledge of fish farming and its products. Consequently, communication of sustainability in aquaculture is challenging, and the development of this market requires concerted actions along the whole value chain, with the retail sector as the main actor.  相似文献   

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