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Abstract. A normally free-living hymenostomatid ciliate was found to be the cause of heavy infections of gills, viscera and body muscle in Atlantic and Pacific marine fishes kept in the New York Aquarium. Of special interest is the fact that the parasites, usually with food vacuoles filled with blood cells and cellular debris, caused extensive damage to the body muscle; the other infected organs showed no characteristic tissue reactions. The immediate cause of death is attributed to the exceptional load of the parasite on the gills, thus interfering with normal respiratory function.
The ciliate, isolated from a recent outbreak, is described in detail, and shows many characteristics of Uronema marinum Dujardin, a species that has been reported as free-living in salt water; the form reported here differs from the type and other members included in this species, by the presence of less than three rows of bipolar meridians. This facultative parasite is described in detail and compared with other genera. 相似文献
The ciliate, isolated from a recent outbreak, is described in detail, and shows many characteristics of Uronema marinum Dujardin, a species that has been reported as free-living in salt water; the form reported here differs from the type and other members included in this species, by the presence of less than three rows of bipolar meridians. This facultative parasite is described in detail and compared with other genera. 相似文献
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水环境中镉是公认毒性最大、蓄积性最强的重金属之一,易富集于水生生物体内,对其生理代谢产生毒性效应,并通过食物链传递,威胁人类健康。本文以鱼类为代表性水生生物,综述了镉对鱼类的毒理效应研究进展。鱼类食性和摄食途径的差异造成镉在其体内的积累和分布具有生物特异性与组织差异性。水体镉浓度超标可导致鱼类的鳃和肝脏等组织结构与功能完整性受到不同程度损害,并对鱼类的抗氧化防御系统、生殖调控、非特异性免疫系统与基因表达等产生毒性效应,其毒性效应随镉暴露浓度、暴露时间、鱼类种类、发育阶段和性别不同而异。同时,鱼类的抗氧化防御系统和免疫系统在镉诱导的氧化损伤中发挥了重要的保护作用。通过总结国内外研究进展,展望今后的研究方向,为更加深入研究镉的毒理效应及机制,进而更好地控制水环境中镉污染,保护水生态环境和水生生物,以及为人类提供安全的水产品提供科学依据。 相似文献
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The brown shrimp, Crangon crangon, is the most important target of the coastal crustacean fisheries in the German Bight. In order to evaluate the relation between the abundance of ovigerous females and larvae in spring and the recruitment success in autumn, we first analysed the seasonal appearance of ovigerous females and larvae from weekly samples throughout 2012. The spawning season in the German Bight extends over several months comprising multiple unsynchronized spawning events. The minimum shares of ovigerous females appeared in early autumn, and the highest shares in late winter bearing mostly early egg stages. We defined the putative start of the reproductive cycle for November when the frequency of ovigerous females started to increase. There was no distinct separation between winter and summer eggs, but a continuous transition between large eggs spawned in winter (the early spawning season) and batches of smaller eggs in spring and summer. Larval densities peaked in April/May. Consequently, regular annual larval surveys from 2013 to 2016 were scheduled for April/May and extended to six transects covering the inner German Bight. Ovigerous females were most abundant in shallow waters above the 20‐m isobaths, which also explained regional differences in abundance between the regions off North Frisia and East Frisia. No relation was obvious between the number of larvae in spring and recruited stock in autumn. Due to the short lifespan of C. crangon, the combination of various abiotic factors and predator presence seems to be the principal parameters controlling stock size. 相似文献
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M. C. LUCAS 《Aquaculture Research》1993,24(3):355-364
Abstract. The food of brown trout, Salmo trutta L., and rainbow trout, Oncorhynchus mykiss (Walbaum). in a small stillwater put-and-take fishery in Surrey, England was examined by stomach content analysis of fish caught by angling between the months of April and September 1985. Overall, brown and rainbow trout tended to utilize different food sources. Mann-Whitney U-tests showed most major food items to be eaten in significantly different amounts, the most important exceptions being chironomid pupae and adult Diptera. In all months except April, rainbow trout utilized mainly midwater food, particularly Cladocera. Brown trout fed mainly on benthic food organisms and fish. Spearman rank correlations showed diets to be dissimilar during this period, with significant negative correlations in May and August. These results indicate an absence of interspecific competition for food, and imply spatial separation of brown and rainbow trout. In April both brown and rainbow trout fed extensively on the temporary bottom fauna, mainly trichopteran and megalopteran larvae, and diets were significantly positively correlated. 相似文献
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以1.0×106CFU·m L~(-1)拟态弧菌(Vibrio mimicus)浸浴感染黄颡鱼(Pelteobagrus fulvidraco),于第0、第4、第8、第16、第24、第36、第48、第60、第72小时剖杀取样,研究病理损伤及病原菌的体内动态分布。结果显示,皮肤肌肉、鳃、肠道出现病变最早,其中皮肤肌肉损伤最严重。第16小时表皮变性、坏死,鳃上皮肿胀,肠绒毛水肿;第24~第48小时表皮坏死、脱落,真皮严重出血,肌纤维变性、坏死,鳃出血,上皮局部坏死,肠上皮变性与灶性坏死;第48~第72小时皮肤肌肉坏死更严重,形成溃疡灶,鳃灶性坏死。肾、肝、脾与心36 h后相继出现不同程度的淤血、出血,变性和灶性坏死。q PCR检测发现,第4小时即在鳃、肠、皮肤肌肉检出病菌,细菌含量分别为1.3×102CFU·mg~(-1)、2.6×102CFU·mg~(-1)、4.7×102CFU·mg~(-1);鳃与皮肤肌肉中菌量随时间延长而增加,第72小时皮肤肌肉中菌量达到4.5×107CFU·mg~(-1);第24小时后相继在肾、肝、脾、心检出病菌,菌量介于1.9×10~4.7×102CFU·mg~(-1)之间。结果表明皮肤、鳃和肠道是病菌的入侵位点,并在体内多组织、器官分布。 相似文献
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Springtime fasting was used as a means to reduce the incidence of early maturation in freshwater cultured male chinook salmon Oncorhynchus tshawytscha (Walbaum) of New Zealand origin. The experiment was started with yearling fish at the beginning of September (spring) and completed in the following April (autumn) at the time of expected maturation. Feeding was restricted for 2 months (September-October) and 3 months (September-November) by offering food only on alternate weeks. In April, the control group, full fed throughout, had a significantly higher incidence (60%) of mature males then the two groups that had been fasted for 2 or 3 months in the spring. There was little difference in maturation rate in the latter groups (21% and 24%). Growth was depressed during fasting, relative to controls, but the mean weight of the group fasted for 2 months was not significantly different to that of the controls by April. 相似文献
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Sequential ichthyoplankton surveys were used to determine the spatial and temporal distribution of eggs and larvae over coastal spawning grounds of Atlantic cod (Gadus morhua) in Smith Sound, Trinity Bay, Newfoundland, during the spring and summer of 2006 and 2007. Egg densities showed similar patterns for both years with two peaks in abundance in spring (March–April) and late summer (late July). A clear progression of development stages (1–4) was observed in spring and summer in 2006 and summer in 2007, suggesting retention of eggs within the Sound during these periods. Modelled predictions of vertical egg distributions indicated eggs were broadly distributed near the surface during spring (March–April), but were concentrated below the pycnocline (>10 m) within the inner portions of the Sound during the summer months (July–August). Back‐calculated peaks in spawning based on water temperatures were estimated at 11 and 4 April for 2006 and 2007, respectfully, with late season peaks centred on 21–24 July for both years. Environmental data indicated cooler water temperatures and periods of high wind stress in spring, and warmer, calmer periods late summer, consistent with higher retention and faster development times on the spawning grounds later in the season. We conclude that spring and summer spawning events result in different distributions of early life stages and may lead to different distributions of juvenile and adult fish. 相似文献
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Kaddour Bouderoua Jacques Mourot Faiza Benmehdi-Tabet-Aoull Ghalem Selselet-Attou 《Journal Of Aquatic Food Product Technology》2013,22(4):412-420
The variation of morphometrics, mineral content, and fatty acid composition of sardines was determined in relation to season and site of catch in the Mediterranean Sea. Sardines were caught in two regions of the Algerian coast: Mostaganem and Béni-Saf. In both sites, the contents of phosphorus (223 and 211 mg 100 g?1) and sodium (95 and 10 mg 100 g?1) were higher in June than in February. Total lipid content was related to the season, being low in winter (2.9%) and high in summer (11.3%). The fatty acid composition shows a high content of polyunsaturated fatty acids (PUFA) dominated by n-3 fatty acids eicosapentaenoic acid (EPA C20:5 n-3; 10%) and docosahexaenoic acid (DHA C22:6n-3; 25%). However, the content of n-6 fatty acids was relatively low both in winter (3.4%) and summer (4.7%). The saturated fatty acid (SFA) content was appreciable in sardines, which range from 34% to 37% according to season. This is in agreement with the literature related to the Mediterranean sardine. 相似文献
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Energetics of reproduction and spawning migration for Pacific saury (Cololabis saira) 总被引：1，自引：0，他引：1
Y. Kurita 《Fish physiology and biochemistry》2003,28(1-4):271-272
Pacific saury is a small (up to 35 cm SL) pelagic fish, feeding actively in the food-rich sub-arctic water (10–12 °C) during summer (June – August) and spawning in the food-poor sub-tropical water (20–22 °C) during winter (December – April). Changes in protein, lipid, and energy content for 30 cm standardized fish from August to February were examined. Accumulated body reserves were abundant in the feeding season, most of them being expended during southward migration, and almost exhausted in the active spawning season. Thus it is indicated that most of the allocated energy to egg production was derived from the energy of food consumed during spawning season. 相似文献
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Atsushi Kawabata Hirotsune Yamaguchi Seigo Kubota Masayasu Nakagami 《Fisheries Science》2011,77(3):291-299
We examined individual growth and fatness in the 1975–2002 year classes of Japanese sardine. Samples were collected at the feeding grounds in the Pacific waters off northern Japan during drastic fluctuations in the population in the 1970s to 2000s. Growth rates for ages 1–3 of the 1979–1988 year classes, which included low-recruitment year classes subsisting during the high population levels of the 1980s, were apparently slower than for other year classes. There was no obvious trend when comparing year classes, growth during the first year of life (age 0), and maximum body length (BL) at age ≥5. The condition factors (CF, indicating fatness) for adult sardines of BL ≥19 cm in the 1979–1983 year classes during the maximum population level of the mid-1980s were significantly lower than for other year classes. However, there were no apparent trends in CF variations for small sardines of BL <19 cm. The apparent decreases in growth rate and fatness were strongly related to the cumulative sum of population abundance that each year class experienced. It is thought that insufficient food owing to the density-dependent effect of an abundant population at feeding grounds resulted in a decrease in the growth rate for small-bodied sardines that are investing their energy intake in body growth, and a decrease in fatness for large-bodied adults that are accumulating fat for the next reproduction. 相似文献
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栉孔扇贝不同组织中镉的微区分布特征及其变化规律 总被引：2，自引：1，他引：1
为阐明扇贝特异性富集镉(Cd)的机理,研究了栉孔扇贝不同组织中Cd的微区分布特征,并结合Cd的生物动力学实验研究了其变化规律。结果显示空白对照组栉孔扇贝内脏、鳃和性腺组织的Cd主要分布在类金属硫蛋白(MTLP)和细胞器中,闭壳肌组织中Cd主要分布在MTLP(占84.6%)。在Cd的富集实验中,内脏和鳃组织中MTLP和富含金属颗粒(MRG)中Cd的含量和所占百分比升高最显著,而细胞器中Cd的百分比明显下降;性腺组织中MTLP、细胞器和MRG组分中Cd的含量均明显升高,其中MRG中Cd的百分比升高,MTLP和细胞器中Cd的百分比逐渐下降;闭壳肌组织中MTLP和MRG中Cd的含量均显著上升,其中MRG组分中Cd的百分比显著升高。在释放Cd的实验中,内脏和鳃组织的MTLP中Cd的含量显著下降,而细胞器、热敏感蛋白(HSP)和MRG中Cd的含量和所占百分比逐渐升高,性腺组织各亚细胞组分中Cd含量均明显下降,但各亚细胞组分中Cd的百分比变化不明显;闭壳肌组织MTLP和MRG中Cd的含量下降,且MRG组分中Cd所占的百分比不断下降。本研究首次表明栉孔扇贝不同组织中Cd在亚细胞组分中的分布特征不同,并且在富集和释放Cd的过程中,内脏和鳃组织中的Cd在各亚细胞组分中不断发生调节和重新分配。 相似文献
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混合重金属对翡翠贻贝的积累与排放规律研究 总被引：5，自引：1，他引：4
通过对翡翠贻贝（Mytilus edulis）进行混合重金属积累与排放的慢性实验,研究了重金属铅（Ph）、锌（Zn）、铜（Cu）、镍（Ni）、镉（Cd）、铬（Cr）、汞（Hg）和砷（As）的混合溶液在翡翠贻贝体内的积累规律和排放规律。结果表明,翡翠贻贝对Ph、Zn、Cu、M、Cd、Cr、Hg和As的富集和排放规律性较强,在累积实验中,翡翠贻贝体内各种重金属含量随着时间的推移明显呈上升趋势,翡翠贻贝对重金属Pb,Cu,Ni,Cd,Zn、As、Cr和比有较强的累积能力,可很好地指示海水中这些重金属的污染;在排放实验中,翡翠贻贝体内各重金属含量随时间的推移呈下降趋势,但排放曲线都较平缓,表明翡翠贻贝在实验过程中,释放体内重金属较缓慢。 相似文献
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栉孔扇贝在镉污染胁迫下消化盲囊组织的转录组分析 总被引：1，自引：0，他引：1
镉(Cd)作为生物非必需、毒性极强的蓄积性重金属,易通过食物链进入人体,严重威胁人类健康。扇贝相对于其他贝类具有特异性蓄积镉的能力,成为水产品安全领域关注的焦点。为了阐释扇贝高蓄积镉的分子机制,本研究以镉胁迫的栉孔扇贝(Chlamys farreri)消化盲囊组织为研究对象,通过转录组测序技术进行基因转录水平分析。通过比较转录组拼接获得105071个unigene和3800个差异基因,对所得unigene进行功能注释,发现这些基因集中在蛋白绑定、细胞黏附、免疫应答、细胞凋亡和能量代谢等方面。对这些蛋白的分子功能进行注释,发现该类蛋白主要属结合蛋白(40.45%)、催化活性蛋白(34.27%)和转运蛋白(5.62%)。这些功能基因和预测通路为理解扇贝体内解毒和免疫系统奠定了基础。获得的转录组数据为深入研究双壳贝类应对海洋污染物的分子机制提供了丰富的基因资源。 相似文献
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Dietary Lactobacillus plantarum supplementation decreases tissue lead accumulation and alleviates lead toxicity in Nile tilapia (Oreochromis niloticus) 
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下载免费PDF全文 Pollution by the heavy metal lead (Pb) has become a threat to both aquaculture and food safety. In this study, the protective effects of a selected probiotic with good Pb binding capacity (Lactobacillus plantarumCCFM8661) against waterborne Pb exposure were evaluated in Nile tilapia (Oreochromis niloticus). One hundred and eighty fish were divided into four groups as control, Pb‐only, Pb‐plus‐CCFM8661 and CCFM8661‐only. Fish were exposed to a dose of waterborne Pb level at 1 mg L?1 for 4 weeks, and the probiotic was administered at 108 CFU g?1 in fish diet twice daily. The results showed that dietary supplementation of CCFM8661 ameliorated the growth performance and prevented the death of Pb‐exposed fish. Cotreatment with Pb and CCFM8661 also effectively decreased Pb accumulation in kidney, liver, gonad, brain, gills and muscle. Moreover, the administration of this probiotic alleviated Pb‐induced oxidative stress, recovered digestive enzyme activities and blood δ‐aminolevulinic acid dehydratase activity, reversed alterations in innate immune status and decreased the frequencies of the nuclear abnormalities in peripheral blood erythrocytes of fish. These results suggested that CCFM8661 may be a novel dietary supplement against Pb toxicity at least in tilapia. 相似文献
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Katsuyuki HAMASAKI Hideyuki IMAI Nobuhiko AKIYAMA Kyohei FUKUNAGA 《Fisheries Science》2004,70(6):988-995
ABSTRACT: Females of the swimming crab Portunus trituberculatus were cultured under natural temperature and high temperature (21°C) conditions to examine ovarian development and oviposition from autumn (October) to the beginning of breeding season in the following spring (May). Ovaries developed because of vitellogenesis of oocytes from October to December and their developmental state did not change during the overwintering period from December to March. In spring, from late March to mid May, some ovaries reached prematuration and maturation stages and ovipositions began from mid–late April under natural temperature conditions. Females reared in tanks of high temperature regimes oviposited earlier than those reared in tanks of natural temperatures. The number of days to oviposition tended to decrease with advancement of the beginning times (early February to late April) of culture of females under high temperature regimes; induced ovipositions were achieved more easily with increasing photoperiod from c . 12 h in early February to c . 14 h in late April. Therefore, it is inferred that the temperature and photoperiod are important environmental factors controlling ovarian development and oviposition. 相似文献
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Patrick Ogwok Mohammed Luyima Sserunjogi Andrew Kiri Amegovu Vincent Makokha 《Journal Of Aquatic Food Product Technology》2013,22(4):331-344
Fatty material from Nile perch belly flaps, a major processing by‐product, was assessed for variation in fat content, fatty acid composition, vitamin A content, and level of contaminants in relation to capture site and season. Nile perch from Lake Victoria had higher material yield and omega-3 fatty acids (FAs) but lower content of vitamin A than those from Lake Albert. Levels of omega-3 FAs (4.36–20.20%) and vitamin A (2.83–7.88 mg/100 g of oil) were generally high. Levels of lead and cadmium showed significant variation with site. Material weight and vitamin A contents were higher, whereas FAs were lower in fish captured during the dry season than those in the wet season. 相似文献
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Thamizhselvan Surya Robinson Jeya Shakila Narayanan Asha Hema Malini Mani Palanikumar Venkatesan Alamelu 《Journal Of Aquatic Food Product Technology》2018,27(3):394-404
The formation of biogenic amines in Indian oil sardines (Sardinella longiceps) collected from the Tuticorin coast of South India and treated with delayed salt-curing was investigated. Sardines were wet salt-cured in whole and gutted forms and examined in fresh and after 6, 9, 12, and 15 h delayed conditions at ambient temperature (32 ± 2°C) at four stages of salt-curing process for quality parameters and formation of biogenic amines. Moisture content decreased from 76% to 11.3% in salting followed by drying. Similarly, water activity reduced from 0.96 to 0.74 in salt-cured sardines. In contrast, total volatile base nitrogen content increased from 79 to 3,590 mg kg–1 in salt-cured sardines. Halophilic count of sardines was higher (8 log cfu g–1) after salting and decreased in drying stages. The 15 h delayed salt-cured whole sardines had higher histamine contents (1,568.27 mg kg–1), cadaverine (4,059.84 mg kg–1), putrescine (1,604.95 mg kg–1), and tyramine (862.94 mg kg–1) on the final day of drying. Whole sardines had higher biogenic amines and halophilic bacterial counts than the gutted sardines. The whole and gutted sardines salt-cured up to a delay of 6 and 12 h, respectively, at ambient temperature yielded the acceptable quality products with respect to biogenic amines. 相似文献
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Volker Koch Jose Manuel Mazón Suástegui Francisco Sinsel Miguel Robles Mungaray & Daniel Dunn 《Aquaculture Research》2005,36(5):505-512
This study examined the effects of density and growing season on growth and survival of juvenile lion's paw scallops (Nodipecten subnodosus) in Estero San Buto, a mangrove channel in Bahía Magdalena, Mexico. Scallops were kept in plastic mesh bags in oyster trays at three population densities (500, 1000 and 2000 organisms per tray, or low medium and high density respectively) over a period of 2 months from October to December 2001 and from February to April 2002. Growth (shell height increment) was measured every 7–12 days and mortality was evaluated at the end of the experiment (dead shell count). Overall growth was fast (0.24–0.38 mm day?1) in comparison with other pectinids. Significant differences were found for both, density and season, with faster growth occurring at lower densities and during the fall season when the water temperature was higher. Mortality was low (0.5–3.0% 60 day?1) except for the high‐density treatment in the fall (44% 60 day?1). Crowding together with high water temperatures and increased metabolic oxygen demand of the scallops and possibly competition for food were the probable reasons for this high mortality. Overall, mortality was lower in the spring, when temperatures were lower, O2 values were higher and food was more abundant. 相似文献