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1.
Viral haemorrhagic septicaemia (VHS) is a well-characterized disease of rainbow trout, Oncorhynchus mykiss, which has also caused economic losses in marine turbot farms in the British Isles. We have previously demonstrated that turbot, Scophthalmus maximus, are susceptible to isolates of viral haemorrhagic septicaemia virus (VHSV) that are endemic in the marine environment, highlighting a potential risk to marine aquaculture. Given the increasing interest in the intensive rearing of additional aquaculture species such as Atlantic cod, Gadus morhua, and Atlantic halibut, Hippoglossus hippoglossus, this study aimed at investigating the susceptibility of these species to VHSV. Both species were found to be largely resistant to VHS following immersion challenge with a selection of 18 isolates, representing the known marine VHSV genotypes. Only one and two VHSV-associated mortalities occurred out of a total of 1710 and 1254 halibut and cod, respectively. These findings suggest that there is a low direct risk to the development of commercial cod and halibut aquaculture from the existing endemic reservoir of VHSV. This study, coupled to field observations has, however, highlighted the fact that both species can become infected with VHSV. The known adaptability of RNA viruses, together with the selection pressures associated with intensive aquaculture would thus advocate a cautious approach to VHSV surveillance within these emerging industries. 相似文献
2.
Full-fat soybean meal in diets for Atlantic halibut: growth, metabolism and intestinal histology 总被引：1，自引：0，他引：1
B. GRISDALE-HELLAND S.J. HELLAND G. BAEVERFJORD & G.M. BERGE 《Aquaculture Nutrition》2002,8(4):265-270
Isonitrogenous and isocaloric diets containing 0, 18 or 36% toasted full-fat soybean meal (FFSM) were fed to Atlantic halibut. The diets were fed to five tanks of fish each for 34 days (period 1). Four tanks from each treatment were then retained in the growth experiment for a further 32 days (period 2), while the groups of fish from one tank from each of the 0 and 36% FFSM groups were split and transferred to two metabolism tanks each. The initial weight of the fish in the growth trial was 169 ± 1 g (mean ± SEM, n =12; weight range 89–253 g) and the final weight was 317 ± 5 g. There was no significant effect of dietary treatment on specific growth rate (range, 0.8–1.1% day−1 ), feed consumption (0.5–0.7% body weight day−1 ), feed efficiency (1.3–1.6 g wet gain g dry feed−1 ), protein retention (48–55%) or energy retention (49–57%). The fat, protein and energy concentrations in the fish increased during the trial and were not affected by the diet. The hepatosomatic index in fish fed with 36% FFSM diet was significantly lower (1.7%) than in the other groups (2.2%) ( P < 0.05). No differences in intestinal morphology were observed between dietary treatments and no pathological reactions were identified in any of the samples. In the metabolism trial, there were no significant differences in oxygen consumption or ammonia excretion between fish fed with 0 and 36% FFSM diets. In conclusion, up to 36% FFSM may be added to diets for Atlantic halibut without negative effects on growth, feed efficiency or intestinal morphology. 相似文献
3.
Total ammonia content (TAmm) and excretion (JAmm), and ionic content (K+, Na+, Cl-) have been studied in embryos and yolk-sac larvae of Atlantic halibut (Hippoglossus hippoglossus L.) maintained in darkness (6 °C and 34% S) or in light (light-arrested, nonon-hatching embryos). The TAmm of the eggs increased from 250-300 nmol ind-1 during the first 5-10 days post fertilization (dPF) to 400-500 nmol ind-1 at the time of natural hatching in darkness. TAmm did not start to decrease before 2-5 days after hatch, and yolk-sac larvae had a higher TAmm compared to the light-arrested embryos of the same age and batch. JAmm increased exponentially rom about 0.05 nmol ind-1 h-1 at 10 dPF to about 3 nmol ind-1 h-1 at hatch. Embryos undergoing hatching showed a significantly higher JAmm than non-hatching, light-arrested embryos of the same age. The content of K+ in distilled water rinsed eggs declined from about 0.85 µmol ind-1 at 2-4 dPF to about 0.15 µmol ind-1 at hatch, while that of Cl- remained constant at about t 0.85 µmol in-1, and that of Na+ increased slowly from 0.10 to 0.20 µmol ind-1 . Based on the measured ions, there was an anionic deficit in the egg, especially during the first week of development. When exposed to increased ambient total ammonia (0-27 mM NH4Cl), no mortality occurred, and no significant increase was found in the TAmm of the Atlantic halibut egg before 9.2 dPF despite an estimated large inward diffusion gradient for the un-ionized ammonia species (NH3). The delayed release of TAmm comp ared to embryos and yolk-sac larvae of other marine teleosts, may relate to the deep-water spawning of the Atlantic halibut, and the buoyancy regulation of the yolk-sac larvae. 相似文献
4.
Comparative pathogenicity of Vibrio spp., Photobacterium damselae ssp. damselae and five isolates of Aeromonas salmonicida ssp. achromogenes in juvenile Atlantic halibut (Hippoglossus hippoglossus) 
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下载免费PDF全文 Juvenile Atlantic halibut (~100 mg, Hippoglossus hippoglossus) were exposed to Vibrio proteolyticus, a Vibrio spp. isolate, Photobacterium damselae ssp. damselae and five different isolates of Aeromonas salmonicida ssp. achromogenes via an hour‐long bath immersion to ascertain their variation in pathogenicity to this fish species. Results were analysed using Kaplan–Meier survival analysis. Analysis of the data from challenges using A. salmonicida ssp. achromogenes revealed three survival values of zero and a spread of values from 0 to 28.43. Challenges using a Vibrio spp isolate, V. proteolyticus and P. damselae resulted in Kaplan–Meier survival estimates of 31.21, 50.41 and 57.21, respectively. As all bacterial species tested could induce juvenile halibut mortalities, they must all be considered as potential pathogens. However, the degree of pathogenicity of A. salmonicida is isolate dependent. 相似文献
5.
Spiny dogfish (Squalus acanthius) comprises a significant unwanted bycatch on demersal longlines set for halibut and cod in shelf waters of the east and west coasts of North America. In this laboratory study, attacks on baits were tested in the presence of two different rare earth materials (neodymium–iron–boride magnets and cerium mischmetal) believed to deter elasmobranch catch. Experiments were made with spiny dogfish and with Pacific halibut (Hippoglossus stenolepis) in pairwise tests of the rare earth materials and inert metal controls. Dogfish attacked and consumed baits tested with cerium mischmetal at a lower frequency than controls. Times to attack the baits were significantly higher in the presence of mischmetal, as were numbers of approaches before first attack. The time differential between mischmetal and control treatments and the number of baits consumed converged with increasing food deprivation (1 h, 2 d, and 4 d), but treatment differences were always significant. Cerium mischmetal appeared to be irritating to dogfish and may disrupt their bait detection and orientation abilities. Magnets also appeared to irritate dogfish but provided no protection for baits in feeding trials. Pacific halibut showed no reaction whatsoever to the rare earth magnets or cerium mischmetal. Mischmetal, therefore, may be useful in reducing spiny dogfish bycatch in the halibut fishery. Disadvantages in using mischmetal in commercial operations are expense, hazardous nature, and relatively rapid hydrolysis in seawater. 相似文献
6.
The individual food intake of each fish in each of four groups of Atlantic halibut, Hippoglossus hippoglossus (L.) (mean weight: 422 g) was monitored by direct observation over a period of 21 days. Gross feed conversion efficiency (= growth·feed intake?1), net feed conversion efficiency and maintenance ration were estimated by regression analysis. Specific growth rates were found to be linearly related to weight-specific consumption at a temperature of 8–9°C: growth = 1.922· feed intake ? 0.242. Maintenance ration was 0.126% of body weight day?1. The gross feed conversion efficiency increased asymptotically with increasing feed intakes and growth rates, and was found to approach 1.9 at high growth rates (0.5 on a dry weight basis). One feeding per day seemed to be sufficient for maximum food intake and growth rate. 相似文献
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8.
T. Haugen A. Kiessling R.E. Olsen E. Slinde 《Aquaculture (Amsterdam, Netherlands)》2006,261(2):565-579
Atlantic halibut (Hippoglossus hippoglossus), 1630 ± 510 g at the start of the experiment were reared in tanks for 1 year and subjected to three different environmental regimes; Continuous light and Constant temperature (CC), Natural light and Constant temperature (NC) or Natural light and Ambient temperature (NA). Two diets were fed, where 50% of the dietary lipids were either herring oil or soybean oil supplemented. The fish were sampled in May, August and November the first year, and February and May the following year. The CC groups grew better than the NC and NA groups from May to November, and as a result had a significantly (p < 0.05) higher weight by the end of the experiment. This difference did however not affect muscle fibre size distribution, or the chosen muscle quality attributes texture, fat content, water or fat loss of the fillet. These quality attributes were influenced by season and body weight, whereas diet had no significant effect. The NA group had lower fat content of the fillet than the other environmental regimes in August, November and Mayend, and fat content increased with increasing fish weight. Water and fat losses were lowest in November and February. The diet influenced the fatty acid profile of the musculature; the triacylglycerol fraction reflecting the dietary treatment while the polar fraction was less influenced by diet. The hardness of the fillet was not influenced by the environmental regimes, but by season, and hardness was at its lowest in August, and increased towards the following spring. The muscle fibre distribution varied only with season, and neither treatment nor diet had any effect on the muscle growth dynamics. Recruitment of new fibres seemed mainly to occur during winter, signified by maximum occurrence of fibres < 500 μm2 by the end of the experiment in May. 相似文献
9.
Atlantic halibut (Hippoglossus hippoglossus) vitellogenin: induction,isolation and partial characterization 总被引：1，自引：0，他引：1
Birgitta Norberg 《Fish physiology and biochemistry》1995,14(1):1-13
Vitellogenin (VTG) synthesis was induced by repeated injections of estradiol-17 in juvenile Atlantic halibut (Hippoglossus hippoglossus). VTG eluted as a large, phosphoprotein containing peak on DEAE-Sephacel chromatography of plasma from estradiol-17 treated juvenile and mature female, but not mature male halibut. A purification procedure for Atlantic halibut VTG was developed, where VTG was precipitated with MgCl2, EDTA and distilled water, and the precipitated protein submitted to anion exchange chromatography on DEAE-Sephacel. Precipitated VTG eluted as a broad, partly dissociated peak on DEAE-Sephacel, when chromatography was run at 4°C, but the protein appeared intact when analysed both by SDS PAGE and native PAGE. DEAE-Sephacel chromatography at room temperature resulted in an irregular elution pattern and a dissociated protein fraction, as analysed by SDS PAGE. Biochemical characterization of VTG showed that the molecular mass of the monomer was ca 160 kDa, as estimated by SDS-PAGE. The total lipid content was 19.8% w/w, with 64%, or 12.7% of the total weight, as phospholipid. Protein bound phosphorus constituted 0.62% w/w of halibut VTG. Plasma dilution curves from mature and maturing female halibut were parallel with a dilution curve from halibut egg yolk homogenate in an homologous RIA. Plasma from mature male, but not juvenile halibut crossreacted with the VTG antiserum. 相似文献
10.
Assessment of sex and evaluation of ovarian maturation of fish using ultrasonography 总被引：6，自引：0，他引：6
Ultrasonography is a non‐invasive method that can be used to assess sex and maturity of fish. This study was conducted to examine the feasibility of using ultrasound images to sex juvenile and mature halibut Hippoglossus hippoglossus (Linnaeus), mature winter Pleuronectes americanus (Walbaum) and yellowtail flounder Pleuronectes ferruginea (Storer) and mature haddock Melanogrammus aeglefinus (Linnaeus). In females, both immature and mature ovaries were relatively easy to distinguish, but in males only mature testes were consistently distinguishable. Ovarian maturation of haddock and ovulatory cycles of halibut may also be assessed using ultrasound. 相似文献