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1.
Abstract. Intravascular injection of purified 70-kDa protease or GCAT-LPS from Aeromonas salmonicida , or both, invariably led to consumptive coagulopathy within 2h in Atlantic salmon, Salmo salar L. By entering the coagulation cascade at two different levels, the two enzymes work in concert in thrombus formation, the significance being that circulatory failure is probably the major cause of death in acute furunculosis. Only intravascular injection of GCAT-LPS led to consumptive coagulopathy in rainbow trout, Oncorhynchus mykiss (Walbaum), despite the fact that trout received only half the GCAT dose, and/or four times the protease activity administered to salmon. These results indicate that salmon is, by far, the most susceptible to protease and suggest that rainbow trout is the most susceptible to GCAT-LPS. The substrate profile of the purified protease gave supporting evidence that it works as activated coagulation factor X. The protease is inhibited in vitro by antithrombin and by α2-macroglobulin and both inhibitors are consumed in vivo in response to intravascular administration of the enzymes, thus showing a potential for AT and α2M to inhibit the protease also in vivo. Provided such plasma antiprotease activities are correlated with resistance to the disease, and the inhibitors show genetic variation they would be promising candidates for indirect selection and hence a means to prevent furunculosis independently of vaccines. Circulating inhibitors of GCAT-LPS remain to be identified.  相似文献   

2.
Abstract. Haematological variations were studied in a European eel population, Anguilla anguilla L., naturally infested by the sanguivorous nematode Anguillicola crassus. This occurred off the Swedish Baltic coast in an area receiving heated cooling water from a nuclear power station. The erythrocyte count, haematocrit, leucocrit, haemoglobin concentration, mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentrations, the various cell types in peripheral blood, serum iron concentration, the amount of total serum protein, and scrum protein fractions α 1 , β1 , α 2, β 2 and γ were all measured. Each variable was correlated to: (1) the intensity of infestation, i.e. number of parasites per host; and (2) a parasitization index, i.e. the weight of parasites per somatic weight of the host. Most variables showed no or only minor reactions to the infestation. However, a marked increase in the γ -fraction of scrum proteins, reduced lymphocyte numbers and increased granulocyte numbers are indicative of a humoral and cellular immune response.  相似文献   

3.
Abstract. Consumptive coagulopathy was induced within 4 h in Atlantic salmon, Salmo salar L., by injecting purified serine protease from Aeromonas salmonicida into the dorsal aorta. Pretreatment with a bolus intravascular injection of (human) antithrombin (AT) or (bovine) α2-macroglobulin (α2M) just prior to injection of the protease alleviated the in vivo pro-coagulant effects of the enzyme, but could not hinder the development of consumptive coagulopathy. In fish receiving only saline as pretreatment, the coagulopathy was evident even after 28h, but the fish were not overtly sick. The addition of the exogenous inhibitors increased the fish's natural protection against the bacterial exotoxin, suggesting that both AT and α2M are of importance for the outcome of the pathologic process. Results further indicate that while AT in vivo was mainly directed against generated thrombin and activated coagulation factor X (FXa), α2M inhibited the protease directly.  相似文献   

4.
This study was undertaken to quantify the rate of nitrogen excretion by the cultured Japanese flounder as a function of body weight and water temperature. Measurements of the did rate of nitrogen excretion for the cultured flounder were made at mean water temperature of about 16, 19, and 23 C. The excretion rate of nilmgen was estimated by adding the nitrogen excreted in the forms of ammonia and urea nitrogens. The diurnal pattern in the excretion rate of nitrogen was governed mainly by the feeding time. The proportions of excreted ammonia to total nitrogen were 77.9% at 16 C, 84.5% at 19 C, and 83.2% at 23 C. The average was 81.9%. The relationship between the body weight and excretion rate of nitrogen ( EN , mg N/fish per h) is expressed as EN =α,.W', where α, = nitrogen excretion rate at temperature 0 . The parameter α, is dependent on water temperature, such that α, =α20 Q01(0–200) where α20= nitrogen excretion rate at 20 C, and Q01, = temperature coefficient. The values of the kinetics parameters for the cultured flounder were found to be γ = 0.57, α20= 0.060, and Q01= 1.12.  相似文献   

5.
The pharmacokinetic properties of flumequine following a single intravascular injection (10 mg kg–1 fish) were studied in sea bass, Dicentrarchus labrax (L.), 120 g held at 18 °C. The absorption half life ( t 1/2α) and the elimination half life ( t 1/2β) of the drug were calculated to be 1.05 and 10.71 h, respectively. Tissue penetration of flumequine seemed to be moderate because both the apparent volume of distribution of the drug at steady-state ( V d(ss)) and the extensive apparent volume of the central compartment ( V c) were found to be small (1.51 and 0.626 L kg–1). The mean residence time ( MRT ) was short (09.73 h) and the total clearance (CLT) of the drug was rapid (0.156 L kg–1 h–1).  相似文献   

6.
Viable, diploid gynogenetic (gynogenotes) paddlefish Polyodon spathula were produced by activating eggs with ultraviolet-irradiated shovelnose sturgeon Scaphirhynchus platorynchus spermatozoa and heat shocking. Without irradiation treatment, sturgeon spermatozoa appeared to activate the eggs (up to gastrulation), but did not result in any viable hybrids. Experiment 1 determined that heat-shock treatment of 35 C for a 2-min duration within the interval of 2–22 min post-activation resulted in highest yield of gynogenotes (12–19%) from eggs incubated at 18 C. Experiment 2 applied the heat shock treatment at 35 C from 14.0 to 28.0 min in 2-min intervals after activation at 18 C for a larger scale of gynogenetic production. Both experiments showed that the best yields of gynogenotes were obtained when the heat shock treatment occurred at 16, 18, and 20 min after activation. When these times were expressed in terms of τ0. units (duration of one mitotic cycle of synchronous cell division related to water temperatures), optimal activations were 0.26, 0.29, and 0.32τ0 (τ0@ 18 C = 63.5 min). Experiment 3 tested the utility of τ0. at two different pre-shock incubation water temperatures of 18 C and 16 C, and determined that there was no significant interaction in percentage of viable gynogenotes between two different incubation temperatures and the mitotic intervals (0.21, 0.26, 0.31, 0.36, 0.41τ0) tested. Best survival of gynogenotes occurred when eggs held at either pre-shock incubation water temperatures were shocked at 0.26τ0 All gynogenotes examined were histologically confirmed to have ovarian tissue and were determined to have similar oocyte development to that of normal female (control) paddlefish.  相似文献   

7.
ABSTRACT:   A field experiment was conducted in the Matsumae area of Hokkaido, Japan, during June and July 2002, to investigate the effects of different entrance designs on the catch efficiency of fish traps by fishing with commercial traps (entrance inclination angle [α] = 37°; funnel length of entrance [ L f ] = 22 cm) and experimental traps. The experimental traps were of the same size and similar design as commercial traps, with different entrance inclination angles (trap E1: α = 46°; E2: α = 27°; E3: α = 0°; all L f  = 22 cm) or funnel lengths (E4: α = 37°, L f  = 8 cm). In total, 2200 fish during 200 trap hauls were captured. The catch was significantly higher using both traps E2 and the commercial trap than with trap E3 ( P  < 0.05), and the catch of trap E2 was higher than that of the commercial trap. There were no significant differences in mean fish body length or the frequency distributions of body length among trap types (E1, E2, E3 and commercial). The funnel length of the entrance also affected the catch of traps. Trap E4 had significantly higher catches than the commercial trap ( P  = 0.04) when traps were deployed for a 1-day soak time. Fish body length frequency distributions did not differ between trap E4 and the commercial trap. The results showed that catch can be greatly affected by trap entrance designs.  相似文献   

8.
We reasoned that by challenging large numbers of Atlantic salmon families with the causative agents of furunculosis, infectious salmon anaemia (ISA) and infectious pancreatic necrosis (IPN), we could show unequivocally that resistance to these diseases expresses moderate‐to‐high levels of additive genetic variation, and that the resistances are weakly correlated genetically. We tested this reasoning by challenging Atlantic salmon from 920 (approximately) full‐sib families with the causative agents of furunculosis and ISA, and fish from 265 of these families with the causative agent of IPN. Additive genetic variation and genetic correlations were estimated by fitting a threshold liability model to the resistances assessed as binary traits. Resistance to furunculosis, ISA and IPN was moderate –to highly heritable. The marginal posterior means for heritability on the underlying liability scale were 0.37 for resistance to ISA, and 0.55 and 0.62 for resistance to IPN and furunculosis. Genetic correlations between the resistances were weak (?0.11 to 0.07). These levels of additive genetic variation indicate that resistance to furunculosis, ISA and IPN will respond to selection. The weak genetic correlations indicate that it should be relatively easy to improve resistance to the diseases simultaneously. We believe that there is now strong evidence that selectively breeding Atlantic salmon for resistance can be highly successful.  相似文献   

9.
ABSTRACT:   A quantitatively major collagen was isolated from the pepsin-solubilized collagen preparation of the mantle by differential salt precipitation and phosphocellulose column chromatography, and its constituent α components (α1 and α2) were purified by phosphocellulose column chromatography. The subunits were demonstrated to be genetically distinct from each other by peptide mapping and amino acid analysis. The amino acid composition calculated from those of the α1 and α2 components in 2 : 1 ratio coincided well with that of the major collagen from the mantle. These results suggest that the major collagen in the mantle of the oyster may have a heterotrimer structure (α1)2α2.  相似文献   

10.
Abstract. Tiger shrimp, Penaeus monodon Fabricius, post-larvae (32·0±3mg, 1·43±0·03 cm) were exposed to control, 0·12, 0·60, 1·20 and 2·40mg/l ammonia-N (un-ionized plus ionized ammonia as nitrogen) which is equivalent to control, 6,32,63 and 126μg/1 NH3-N (un-ionized ammonia as nitrogen) for 8 weeks in 25 ppt, as pH of 7·85–8·18 and 26–28°C by static renewal method. Growth in weight and length of the shrimps exposed to 1·20 and 2·40 mg/l ammonia-N were significantly lower (P < 0·05) than those exposed to control. The EC50 (concentration that reduced growth by 50% of that of the controls) was 1·33 mg/l ammonia-N, 70 μg/l NH3-N for weight gain, and 2·35 mg/1 ammonia-N, 123μg/l NH3-N for length gain of P. monodon post-larvae. The'maximum acceptable toxicant concentration'(MATC) of ammonia-N and NH3-N for P. monodon post-larvae was 0·60mg/l and 32μg/l, respectively after 6 weeks of exposure.  相似文献   

11.
Abstract. Arctic charr, Salvelinus alpinus (L.), from the same full-sib family were reared under two different densities for 97days at 10°C. In one treatment density was adjusted every 2 weeks by means of a tank enclosure to a density of 50kg/m3. In the other treatment the density was allowed to increase as fish biomass increased to 50kg/m3. Density had no significant effect on the variation observed in individual fish weights over the course of the growth trial. Density had a significant effect on the relationship between fish weight and specific growth rate. The increasing density treatment had an overall higher mean specific growth rate of 0·1%/day.  相似文献   

12.
Abstract. Infectivity of Flexibator columnaris to loach, Misgurnus anguillicaudatus (Blecker, Günther), was studied with variation conditions and the presence of other bacteria in the water medium. Invasion of fish by the poathogen varied with different water conditions. The highest prevalence of infection was observed in an experimentally formulated water containing 0·03% NaCl 0·01% KCl, 0·002% CaCl22H2O and 0·004% MgCI2 6H2O. The percentage of infection in tap water was similar to that of the formulated water. The infeetion rate was low in the individual salt solutions, and no infection occurred in distilled water. Even in the formulated water, the pathogen failed to infect the fish when Citrobacter freundii, Aeromonas hydrophila or Pseudomonas fluorescens were present at densities 100 times that of F. columnaris. However, in such cases, the numbers of F. columnaris in the mucus of the fish body surface did not increase much throughout the experimental period. In contrast, F. columnaris suceessfully invaded the fish in the presence of either Streptococcus sp., Flavobacterium flavescens or Flavobacterium fuscum , even when the numbers of these bacteria were 1000 times that of F. columnaris. In this ease, F. columnaris gradually increased its numbers on the fish body surface.  相似文献   

13.
Abstract. The effect of four environmental conditions was investigated upon sperm output in turbot, Scophthalmus maximus (L.), submitted to three different rhythms of stripping. Males kept under a natural light cycle and under a 6-month contracted light programme released a similar sperm output in terms of total volume of semen produced per fish during the experimental period (4·9 ± 0·9ml), mean sperm concentration (29·4 ± 2·8 × 109 spermatozoa/ml) and total sperm number (163·2 ± 40·5 × 109 spermatozoa). Attempts to stimulate spermiation for a second time just after the end of the natural reproduction period resulted in the release of low sperm output (total volume of semen: 1·6 ± 0·4 ml; mean sperm motility: 2 min 36s ± 0 min 47s; mean sperm concentration: 47·6 ± 10·2 × 109 spermatozoa/ml; total sperm number: 84·5 ± 25·3 × 109 spermatozoa). Stripping frequency had no effect on total volume of semen, mean sperm motility and total sperm number. Monthly collection did not modify sperm samples in relation to stripping rank. However, decreasing volume, motility and sperm concentration were observed when males were stripped fortnightly and weekly. During the natural spawning period, the presence of females in the tank enhanced mean sperm motility (from 3 min 27s + 0 min 52s to 6 min 38s ± 1 min 38s).  相似文献   

14.
Pharmacokinetics of oxolinic acid in gilthead sea bream, Sparus aurata L.   总被引：1，自引：0，他引：1  
This is the first study on the pharmacokinetic parameters of oxolinic acid (OA) in gilthead sea bream, Sparus aurata L. The kinetic profile of OA was studied after a single intravascular injection (20 mg kg−1) in 100 g fish at 20 °C. The distribution half-life ( t 1/2α) and the elimination half-life ( t 1/2β) of the drug were found to be short (0.51 and 12.60 h, respectively). The drug penetration from the plasma to the tissues was adequate as the apparent volume of distribution of the drug at steady-state ( V d(ss)) was found to be 2.11 L kg−1. The mean residence time ( MRT ) of OA was short (14.25 h) and the total clearance rate ( Cl T) of the drug was low (0.15 L kg−1 h−1). The bioavailability ( F %) of OA following oral administration (30 mg kg−1) was also low (14%). Maximum values were observed for muscle at 0.5 h after injection, with levels declining as with subsequent sampling. At the first two time points (0.5 and 1 h) plasma levels of OA were higher than muscle, however, the reverse was evident for subsequent samples. Following oral administration, highest muscle levels were found at 16 h and, with the exception of the 24-h sampling, muscle OA concentrations were higher than plasma at all time points. The fast elimination of OA suggests short withdrawal times with reference to human consumption of treated fish.  相似文献   

15.
Abstract –  The role of endogenous and exogenous factors in regulating population dynamics of freshwater salmonids is still a matter of debate. The aim of the present work was to assess the relative importance of density-dependent and -independent factors in determining the survival of marble trout ( Salmo marmoratus ) yearlings in two populations living in Slovenian streams (Zakojska and Gorska). The investigation was performed by combining a classical life table analysis with Monte Carlo simulation. Size-dependent fecundity was estimated by stripping wild adults in the fish farm. A significant positive relationship was found between length of marble trout females and the number of eggs produced. Egg density was the major determinant of survival from eggs to age 1+ ( σ 0) in both streams. Residuals of the relationship between σ 0 and egg density were positively correlated with rainfall only in Zakojska, probably because, within a certain range, more intense rainfalls increases stream flow and, consequently, suitable habitat for trout. Our study shows how density-dependent and environmental factors can interact to determine the survival of marble trout during the first year of life.  相似文献   

16.
HIROHIKO  KAGAWA  HIDEKI  TANAKA  TATSUYA  UNUMA  HIROMI  OHTA  KOICHIRO  GEN  KOICHI  OKUZAWA 《Fisheries Science》2003,69(2):234-241
ABSTRACT:   The in vitro effects of 17,20β-dihydroxy-4-pregnen-3-one(DHP) and prostaglandins (PGE1, PGE2, PGF1α,PGF2α) on ovulation in the Japanese eel Anguillajaponica were examined. Oocytes with follicle layers at themigratory nucleus stage (approximately 850–900 µmdiameter) were removed using a polyethylene cannula from artificiallymatured fish. At concentrations of 10 and 100 ng/mL,DHP was found to induce both germinal vesicle breakdown and ovulation.The prostaglandins, except for PGE1, effectively inducedovulation of previously matured oocytes by DHP treatment in vitro .Prostaglandin F2α was the most effective. Asignificant increase in ovulation rate was observed even at a concentrationof 0.01 µg/mL PGF2α.Indomethacin blocked the in vitro ovulation induced by DHPand addition of PGF2α reversed indomethacin-blockedovulation. Actinomycin D and cycloheximide blocked DHP-induced ovulationand PGF2α reversed the effects of both inhibitors. Theseresults indicate that DHP induces ovulation through endogenous prostaglandinsynthesis in the follicle layers of the Japanese eel.  相似文献   

17.
Abstract. The effect on the growth of freshwater angelfish, Pterophyllum scalare (Lichtenstein) (Pisces; Cichlidae), of different densities of population and diet compositions was studied. The results show that increasing the population density from 50 fish/m2 to 200/m2 significantly decreased the rate of growth of fingerlings, and that this effect is correlated to the size of fish. No significant differences were observed in growth between diets containing 37%, 41% or 47% protein. However, the addition of live food (artemia) to the diet significantly raised the growth rate, especially in the higher protein diets.
Body composition shows no changes during the growth periods, with a mean of 64·68% body protein, 35·47% dry weight fat and no significant differences in the percentage of residual ash through the growth period.
The food conversion rate was very low, ranging from 1·15 to 1·31. Total production increased with density, from 4·0g/m2/day (50 fish) to 13·7g/m2/day (200 fish) over a period of 60 days.  相似文献   

18.
Abstract. A habitat suitability index (HSI) model for suspended tray culture of the Pacific oyster, Crassostrea gigas Thunberg, was constructed from existing information in the literature on oyster-environment relationships. In the model, biophysical data are used to rate aquaculture potential of coastal areas on a scale from 0.0 to 1·0. where 1·0 represents optimal conditions for growth and survival and 0·0 represents totally unsuitable habitat conditions. The model was tested with environmental, growth (increase in shell height) and secondary production (g· 100 oysters−1 day−1) data collected over a 14-month period for two age-classes of oysters transplanted to 10 locations along the coast of British Columbia. Canada. Regressions of HSI values calculated from entire study environmental data against oyster growth and secondary production were highly significant for both age-classes. Environmental data subsets representing short sampling programmers (1–3 months) resulted in HSI values significantly correlated to oyster growth, provided that some sampling occurred during periods of high food availability. HSI modeling techniques have potential application in site selection and coastal management of aquaculture.  相似文献   

19.
Abstract. The aim of this research was lo evaluate the effect of density and feeding level (initially 8 or 16kg/m3 and 1·3% or 2% of present biomass respectively) on productive traits, meat composition and water quality output in farmed rainbow trout, Oncorhynchus mykiss (Walbaum). Individual fish growth shows significant differences in relation to density and feeding level; feed conversion rate is positively Influenced by the lower feeding level and low rearing density. At low density, specific growth rate, protein efficiency ratio and coefficient of variation of individual final weights are more favourable than at high density. Dry matter and lipid composition of meat are positively affected by feeding level; whereas no differences are recorded on the amino acid and fatty acid profiles. Water quality shows differences due to density (NO3 and NH4+) and feeding level (NO2, NH4+ and P).  相似文献   

20.
ABSTRACT:   The aim of this study was to establish effective procedures for chromosome manipulation in greenling Hexagrammos otakii Jordan et Starks, which has enormous aquacultural potential. To accomplish this, temperature-dependent measurements of the mitotic intervals (τ0) were carried out. The τ0 in this fish was determined by averaging the duration of the first and third embryonic divisions at temperatures ranging 5–25°C. At higher temperatures, eggs developed faster and underwent more identical development. For greenling, τ0 were 341.1 ± 3.60 min at 5°C, 275.5 ± 4.53 min at 10°C, 189.7 ± 6.93 min at 15°C, 99.2 ± 8.27 min at 20°C and 34.2 ± 8.74 min at 25°C. There were strong, negative correlations between the τ0 and water temperatures at all temperatures studied ( Y  = −79.3 X  + 425.3, R 2 = 0.9968, where Y is the mitotic interval and X is the temperature).  相似文献   

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