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Sergei Gorshkov Galina Gorshkova Barbara Colorni Hillel Gordin 《Journal of the World Aquaculture Society》2004,35(2):167-177
To produce a monosex female population of European sea bass Dicentrarchus labrax, fry were fed dry diets containing dosages of 12.5, 25, and 50 mg/kg food of either the natural estrogen estradiol-170β(E2) or the synthetic estrogen 17α-ethynylestradiol (EE2) for 60 d starting at 88 d post-hatch (dph). A complete feminization (100%) was achieved in all E2-treated groups at the age of 11 mo (330 dph). All affected fish had ovaries similar in size and histological structure to those of control females. In the E2-treated groups, feminized fish were heavier and longer than untreated controls (males and females combined). In control groups females exhibited significantly higher body weight and total length than males. Untreated females from control groups and females from the group treated with E2 at 12.5 mg/kg food had similar body weight, suggesting that in sea bass growth is related to phenotypic sex. In the Entreated groups, survival rates were similar to those of the control fish. A relatively high percentage of females was obtained in the EE2-treated groups (from 38.6 to 96.5%). However, the gonadal development in these fish was significantly suppressed and a dose-dependent reduction of gonadal sizes was evident. Treatments with the EE2 (12-5, 25, and 50 mg/kg food) resulted in many fish having abnormal (2.9-5.4-39.8%, respectively) and sterile (0.6-6.0-21.6%, respectively) gonads. Effects also included significantly lower weight and shorter length when compared with controls. Furthermore, fish fed with EE2 at the dosage of 50 mg/kg food had high mortality rate. A simple protocol was developed for the complete feminization in sea bass in which the fry (80-100 dph) were fed to satiation two times daily with a diet containing 12.5 me of E2/ks food for a period of 60 d. 相似文献
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R. M. Wallace D. Stanek S. Griese D. Krulak N. M. Vora L. Pacha V. Kan M. Said C. Williams T. H. Burgess S. S. Clausen C. Austin J. Gabel M. Lehman L. N. Finelli G. Selvaggi P. Joyce F. Gordin D. Benator A. Bettano S. Cersovsky C. Blackmore S. V. Jones B. D. Buchanan A. I. Fernandez D. Dinelli K. Agnes A. Clark J. Gill M. Irmler D. Blythe K. Mitchell T. J. Whitman M. J. Zapor S. Zorich C. Witkop P. Jenkins P. Mora D. Droller S. Turner L. Dunn P. Williams C. Richards G. Ewing K. Chapman C. Corbitt T. Girimont R. Franka S. Recuenco J. D. Blanton K. A. Feldman 《Zoonoses and public health》2014,61(8):560-570
This article describes and contrasts the public health response to two human rabies cases: one organ recipient diagnosed within days of symptom onset and the transplant donor who was diagnosed 18 months post‐symptom onset. In response to an organ‐transplant‐related rabies case diagnosed in 2013, organ donor and recipient investigations were conducted by multiple public health agencies. Persons with potential exposure to infectious patient materials were assessed for rabies virus exposure. An exposure investigation was conducted to determine the source of the organ donor's infection. Over 100 persons from more than 20 agencies spent over 2700 h conducting contact investigations in healthcare, military and community settings. The 564 persons assessed include 417 healthcare workers [5.8% recommended for post‐exposure prophylaxis (PEP)], 96 community contacts (15.6% recommended for PEP), 30 autopsy personnel (50% recommended for PEP), and 21 other persons (4.8% recommended for PEP). Donor contacts represented 188 assessed with 20.2% recommended for PEP, compared with 5.6% of 306 recipient contacts recommended for PEP. Human rabies cases result in substantial use of public health and medical resources, especially when diagnosis is delayed. Although rare, clinicians should consider rabies in cases of encephalitis of unexplained aetiology, particularly for cases that may result in organ donation. 相似文献
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Monthly sampling showed typically a large diurnal trend in dissolved oxygen and temperature with a slight trend also in dissolved inorganic nitrogen but not in phosphate or silica. There is a high uptake of all these nutrients in the pond as shown by the difference between the input water and pond water. Temperature in the pond decreased to a minimum of 15°C in February and then increased to 33°C in July. In the autumn there was relatively high primary productivity (PP) supported mainly by nutrients in the inflow. PP decreased to a minimum in winter, probably due to decreasing temperature and light, then increased to a summer maximum together with planktonic biomass, and diurnal oxygen variation. The increase was due mainly to increased temperature and nutrient supply from food input. These data were used to explain the incidence of fish mortalities mainly in mid-summer. The importance of frequency of sampling in such a dynamic system is discussed. 相似文献
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Growth is arrested in male and female Sparus aurata during gonadal recrudescence and spawning. Growth and feeding rates of fish exposed to a constant long photoperiod () were significantly higher than those of fish under a natural photoperiod. When the experimental photoperiod was shortened, fish underwent gonadal recrudescence and reduced feeding, and their growth was arrested. Fish under the long photoperiod regime reached the commercial weight of 350 g six months earlier than the controls. 相似文献
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Modelling of fish pond temperatures and salinities requires application of fundamental energy and mass balance equations. Temperatures and salinities can then be simulated, given the hydrological characteristics and simple weather data. Results of several temperature estimation experiments of 1 and 5 days duration are discussed. The results indicate that pond temperatures can be accurately estimated if the transfer coefficients are known. While salinity estimation is discussed, experiments were not performed, since the temperature experiment indirectly used the salinity data. 相似文献
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I. Paperna A. Colorni H. Gordin G.Wm. Kissil 《Aquaculture (Amsterdam, Netherlands)》1977,10(3):195-213
The predominant diseases occurring in Sparus aurata cultured in sea water at Elat were bacteria-contaminated skin lesions, gill rot and septicemia. These developed mainly in fish stressed and injured following handling. Bacteria involved were Gram-negative and myxobacteria which were controlled by application of Nitrofurazone. Ectoparasitic infections were generally sporadic and insignificant, however, on three occasions the ciliate Trichodina sp. and the monogenean Furnestia echeneis caused morbidity and mortality of epizootic proportion. Ectoparasites were successfully controlled by application of formalin. A diet-related disease, visceral granuloma, appeared in fish fed on certain artificial diets containing fish meal but not in fish fed on fresh mussels or fish meat. Pathological symptoms included extreme granuloma following hypertrophy of the kidneys and spleen and focal lesions in other organs. Hatchery-bred fish suffered from episodes of extreme infections of epitheliocystis, the monogenean F. echeneis, gill rot due to myxobacteria and skeletal deformations coupled with tumours of the swim bladder. 相似文献
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Monthly budgets for nitrogen and phosphorus for a marine fish pond in Eilat were determined for the period September 1983 to June 1984. The ponds are operated as a semi-open system, 41% of the pond water being replaced each day by water from a nearby seawater well. Only 29% of the phosphorus and 36% of the nitrogen are incorporated into harvestable fish flesh (Sparus aurata or Mugil sp.). The remainder reaches the pond as uneaten food, fish faeces or excreted matter, and it is then available to support high levels of phytoplankton and heterotrophic activity. The total input of nutrients supplied to the ponds showed a seasonal trend, with the lowest amount being supplied at the beginning of the sampling period (October) (5.2 moles N/day, 0.25 moles P/day), and increasing in June to 10.6 moles N/day, 0.57 moles P/day. All the increase was due to the amount of food fed. A large proportion (70–80%) of the excess nutrients was exported from the system as dissolved or particulate matter in the overflow. Because of this the water quality of the ponds has remained at levels which have enabled 6.5–12 tons fish/ha to be cultured without regular drying of the ponds. Oysters have been grown on the plankton carried out with the overflow. The ponds have a surplus of nutrient inflow in October/November (1.9 moles N/day, 0.06 moles P/day), a small deficit of N (0.4 moles/day), and surplus of P (0.01 moles/day) in spring, and a large surplus again in May and June of 1.3 moles N/day, 0.11 moles P/day. In all, 60–120% of the nutrient inputs are directly accounted for. 相似文献
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