A comparison of retinol, retinal and retinyl ester concentrations in larvae of Atlantic halibut (Hippoglossus hippoglossus L.) fed Artemia or zooplankton   总被引：1，自引：0，他引：1  

M. Moren  I. Opstad  & K. Hamre 《Aquaculture Nutrition》2004,10(4):253-259

Atlantic halibut (Hippoglossus hippoglossus L.) larvae were fed enriched Artemia or zooplankton in duplicate tanks from 0 to 60 days after first‐feeding. Both diets and the larvae were analysed for vitamin A (VA) in order to confirm earlier findings, in which Artemia fed larvae had lower levels of VA compared with larvae fed zooplankton. Furthermore, we wanted to investigate the composition of the retinoids in the larvae. The results showed that Artemia and zooplankton contains low levels of VA, probably too low to sustain the assumed requirement. Nevertheless, larvae fed Artemia had the same level of retinal and retinol as larvae fed zooplankton. We found a significant lower level of retinyl esters in larvae fed Artemia. The total VA level was lower in larvae fed Artemia only at the end of the feeding trial after the onset of metamorphosis. Our conclusion is that feeding Artemia to Atlantic halibut larvae is not likely to cause VA deficiency.  相似文献   

Growth and feed utilization of large size rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar) reared in freshwater: diet and species effects, and responses over time     

P.A. Azevedo  S. Leeson  C.Y. Cho  & D.P. Bureau 《Aquaculture Nutrition》2004,10(6):401-411

Four diets differing in crude protein/crude lipid concentrations (CP/CL), 570/200, 510/220, 460/240, 430/260 (g kg^?1 dry diet) were fed to near‐satiety to rainbow trout (initial body weight, IBW = 268 g, domestic strain) and Atlantic salmon (IBW = 456 g, wild strain) for 308 days to determine the effect of diets, species and fish size on efficiency of feed, nitrogen (N) and energy utilization. Within species, weight gain, feed efficiency (FE), and energy retention efficiency (ERE, E gain/E intake) were not affected by diet (P < 0.05). N retention efficiency (NRE, N gain/N intake) increased linearly (P < 0.05) with decreasing CP/CL for both species. NRE and FE were higher for salmon compared with trout. Whole body CP of salmon was significantly (P < 0.05) higher, and lipid significantly (P < 0.05) lower, than those of trout. There was a significant (P < 0.05) linear decrease in FE as fish grew, regardless of diet and species. NRE linearly decreased (P < 0.0001) and lipid to protein deposition ratio (LD/PD) increased (P < 0.05) as trout grew. NRE linearly increased (P < 0.05) while ERE and LD/PD linearly decreased (P < 0.05) as salmon grew. Salmon appeared to rely to a greater extent on non‐protein energy‐yielding nutrients to support cost of growth than did trout.  相似文献   

Sea lice treatments, management practices and sea lice sampling methods on Atlantic salmon farms in the Bay of Fundy, New Brunswick, Canada   总被引：4，自引：0，他引：4  

Jillian D Westcott  K Larry Hammell  & John F Burka 《Aquaculture Research》2004,35(8):784-792

Proper monitoring of all stages of sea lice is imperative to ensure the strategic timing of treatments. Although sea lice receive close attention and management for production purposes, there are no regulations for the reporting of lice burdens on salmon farms in Atlantic Canada, nor are there officially standardized protocols for conducting sea lice counts in the field. The purpose of this study was to complete a survey of Atlantic salmon farms in the Bay of Fundy, NB, Canada. The survey addressed many aspects of sea lice monitoring and control, including methods for sea lice sampling at the site, types of treatments administered for control of sea lice and management practices and decisions regarding the control of sea lice. A total of 83 surveys were completed from July to December 2002. Twelve of the 60 respondents owned and/or operated more than one site and completed a survey for each of their sites at the time of the interview. The position of individuals surveyed included 48 site managers (representing 63 sites), three site owners (representing 11 sites), eight individuals who were both owner and manager (representing nine sites) and one site veterinarian (representing one site). Surveys were completed on 30 sites from the Limekiln Bay and surrounding areas, 23 sites from Grand Manan Island, 18 sites from Deer Island, six sites from Campobello Island and six sites from Passamaquoddy Bay. Fish farmers, in concert with their veterinarians, generally perform intensive monitoring and control practices. However, there is a continued reliance on emamectin benzoate (SLICE^®) for sea lice control on Atlantic salmon farms in the Bay of Fundy, which raises concerns regarding the potential for sea lice to develop resistance to the drug.  相似文献   

Prey extracts evoke swimming behavior in juvenile Atlantic halibut (Hippoglossus hippoglossus)     

S.Y. Yacoob  H.I. Browman 《Aquaculture (Amsterdam, Netherlands)》2007,270(1-4):570-573

This study tested the efficacy of prey extracts to induce food search behavior in juvenile (15–25 cm total length, 0 year group) Atlantic halibut (Hippoglossus hippoglossus). In square culture tanks, halibut responded to shrimp and squid extract by tightly turning towards the source of the stimulus and by swimming in circles for 2–5 min following stimulus delivery. Cod extract, or a synthetic mixture consisting of glycine, proline, betaine, arginine, and alanine, failed to evoke this behavior.  相似文献   

Heart and skeletal muscle inflammation in Atlantic salmon, Salmo salar L: a new infectious disease     

Kongtorp RT  Kjerstad A  Taksdal T  Guttvik A  Falk K 《Journal of fish diseases》2004,27(6):351-358

Heart and skeletal muscle inflammation (HSMI) is a disease syndrome of unknown aetiology first observed in farmed Atlantic salmon, Salmo salar, in 1999. In the present study we have demonstrated for the first time that HSMI is an infectious disease. It was induced in Atlantic salmon post-smolts after injection with tissue homogenate from farmed Atlantic salmon previously diagnosed with HSMI. The lesions were also induced in cohabitating salmon given a corresponding injection without tissue homogenate. Six weeks post-challenge the fish that had been injected with tissue homogenate developed a serious epicarditis and myocarditis with mononuclear cell infiltrations in compact and spongy layers of the heart. Similar lesions were found in cohabitants after 10 weeks. The lesions were consistent with samples from field outbreaks of HSMI. No lesions were found in control fish. A viral aetiology is strongly suggested, as no difference in disease induction between an inoculum containing antibiotics and a non-treated inoculum was found. Further investigations are required in order to make conclusions regarding the cause and pathogenesis of HSMI.  相似文献   

Efficacy of an equal blend of canola oil and poultry fat as an alternate dietary lipid source for Atlantic salmon (Salmo salar L.) in seawater. II: effects on haematology and immunocompetence   总被引：1，自引：0，他引：1  

Shannon K Balfry  Janice Oakes  Mahmoud Rowshandeli  Greg Deacon  Brent J Skura  & David A Higgs 《Aquaculture Research》2006,37(2):192-199

This research examined the haematological and immunological responses of quadruplicate groups of juvenile (～400 g initial weight) Atlantic salmon (Salmo salar L.) that had each been fed daily to satiation for 12 weeks one of three high‐energy extruded diets of identical composition except for the supplemental dietary lipid (234.7 g kg^?1) source. The three experimental diets varied in the composition of supplement lipid; diet 1 contained 100% anchovy oil (AO), while diets 2 and 3 replaced 29.8% and 59.7% of the AO (respectively) with a 1:1 blend of canola oil (CO) and poultry fat (PF). Immediately following the feeding trial, a random sample of fish from each diet was sampled for determination of baseline levels of various haematological and immunological parameters. Thereafter, duplicate diet groups were vaccinated (against Listonella anguillarum) and reared on their respective experimental diets for an additional 4 weeks. At that time, the remaining fish were sampled similarly, and the different parameters were measured again. Comparisons between the different diet treatment groups were made before and after vaccination. There were no significant diet treatment effects at either sample time, for haematocrit, differential leucocyte counts, erythrocyte counts, serum hemolytic activity or head kidney leucocyte respiratory burst activity. The fish fed diet 1 however, did show significantly higher post‐vaccination levels of peripheral blood leucocyte respiratory burst activity and higher serum antibody titres against L. anguillarum. The results suggest that the relatively low n‐6/n‐3 fatty acid ratios in the muscle and presumably other tissues of fish fed diet 1, may have resulted in a reduced production of immunocompromising eicosanoids than were produced in fish ingesting the other two diets that were based in part on the different amounts of the CO and PF blend. Long‐term studies are required to confirm this possibility.  相似文献   

Replacement of fish meal in salmonid diets by soya meal reduces phosphorus excretion     

Asbjørn Bergheim  Harald Sveier 《Aquaculture International》1995,3(3):265-268

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Diel migration patterns of Atlantic salmon smolts with particular reference to the absence of crepuscular migration   总被引：1，自引：0，他引：1  

A. T. Ibbotson  W. R. C. Beaumont  A. Pinder  S. Welton  M. Ladle 《Ecology of Freshwater Fish》2006,15(4):544-551

Abstract –  The real-time diel pattern of Atlantic salmon smolt migration was observed for 8 years using automatic resistivity counters verified by video surveillance. A clear dominant nocturnal migration was demonstrated early in the migration period, later becoming increasingly diurnal, until rates became approximately equal at day and night. Migration patterns were related to water temperature, such that when mean daily temperatures were below 12 °C, hourly rates of migration were significantly lower during the day than at night. When daily mean temperatures exceeded 12 °C, there was no significant difference between diurnal and nocturnal migration rates. Migration patterns showed a distinct suppression of migration at dawn and dusk throughout the migration period. It is hypothesised that this behaviour is an active decision and/or an adaptive strategy either to take advantage of increased food in the form of invertebrate drift or to reduce predation risk from actively feeding piscivores or both.  相似文献   

A review of interactions between cetaceans and fisheries in the Azores     

Mónica A. Silva  Miguel Machete  Dália Reis  Marco Santos  Rui Prieto  Carla Dâmaso  João Gil Pereira  Ricardo S. Santos 《水产资源保护:海洋与淡水生态系统》2011,21(1):17-27

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大西洋鲑性腺分化及热休克的影响   总被引：7，自引：2，他引：7  

赵维信  Y.Harache 《水产学杂志》1994,7(2):1-5

大西洋鲑性腺分化发生在孵出45－63天，约495－693度日。经热休克处理获得三倍体稚鱼，性腺在分化之前明显大于正常二倍体。雌性三倍体稚鱼性腺在细胞学分化时受抑，初级卵母细胞不能发育；雄性三倍体稚鱼性腺在细胞学分化阶段生长明显减慢，初级精母细胞尚能发育。  相似文献