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Atlantic Halibut (atlantic + halibut)
Selected AbstractsQuality Characterization of Farmed Atlantic Halibut During Ice StorageJOURNAL OF FOOD SCIENCE, Issue 2 2006Christelle Guillerm-Regost ABSTRACT: A quality index method (QIM) was developed for farmed Atlantic halibut and together with instrumental, chemical, sensory, and bacteriological analysis, quality changes of halibut stored on ice for 26 d was evaluated. Two groups of fish were fed diets that differed only in the source of lipid, where 1 diet contained only marine oil sources and the other a 50/50 mixture of marine and soybean oil. Fish were slaughtered after 1 y and then stored on ice for 26 d. The fish were sampled on day 1, day 2, and every 2nd day after that. Dietary lipid sources had no effect on freshness, (ATP) degradation (K-value), texture, color, or liquid-holding capacity. The QIM scores increased with storage time, in particular the appearance and eyes parameters. The QIM is a good freshness indicator for halibut. The K-value was strongly correlated with storage time (r= 0.99), while total bacterial counts increased after 7 to 8 d of ice storage. The texture, liquid-holding capacity, and color were significantly affected by storage time during the early period of storage, probably due to rigor stiffness and rigor resolution. The texture, liquid-holding capacity, and color did not change significantly from approximately day 8 of storage until the end of the experiment at day 26. [source] Tissue tropism of nervous necrosis virus (NNV) in Atlantic cod, Gadus morhua L., after intraperitoneal challenge with a virus isolate from diseased Atlantic halibut, Hippoglossus hippoglossus (L.)JOURNAL OF FISH DISEASES, Issue 8 2009K Korsnes Abstract Atlantic cod, Gadus morhua, averaging 100 g, were experimentally challenged by intraperitoneal injection of nervous necrosis virus (NNV) originating from Atlantic halibut. Cod tissues, including blood, gill, pectoral fin, barbel, ventricle, atrium, spleen, liver, lateral line (including muscle tissue), eye (retina) and brain, were sampled at day 25 and 130 and investigated by real-time RT-PCR for the presence of NNV. Relative quantifications at day 130 were calculated using the 2,,,Ct method. Immunosuppression by injection of prednisolone-acetate was introduced for a 30-day period, and tissue sampled at day 180 and relative quantification estimated. No mortality or clinical signs of disease were observed in the challenged group. The challenge resulted in detection of NNV in blood, spleen, kidney, liver, heart atrium and heart ventricle at day 25, and by the end of the experiment NNV showed a clear increase in brain and retina, suggesting these to be the primary tissues for viral replication. There was no increase in the relative amount of NNV in blood, atrium, ventricle, spleen, liver and kidney. Corticosteroid implants resulted in a weak increase in virus RNA in spleen, kidney, liver and brain. These findings suggest that Atlantic cod is susceptible to infection with NNV from halibut. The observed tissue tropism patterns suggest an initial viraemic phase, followed by neurotrophy. Head-kidney is the best tissue identified for possible NNV detection by non-lethal biopsy, but detection was not possible in all injected fish. [source] Protection against atypical furunculosis in Atlantic halibut, Hippoglossus hippoglossus (L.); comparison of a commercial furunculosis vaccine and an autogenous vaccineJOURNAL OF FISH DISEASES, Issue 6 2003S Gudmundsdóttir Abstract Atlantic halibut, Hippoglossus hippoglossus (L.), was shown to be sensitive to infection by three different isolates of Aeromonas salmonicida ssp. achromogenes in pre-challenge tests using intraperitoneal (i.p.) and intramuscular (i.m.) injections as well as bath challenges. A commercial furunculosis vaccine, Alphaject 1200, and an autogenous vaccine, AAS, based on the challenge strain, induced immune protection as shown in challenge tests 8 weeks post-immunization. The survival rate of vaccinated fish after i.p. challenge was 100%, whereas mortality of control fish was 61%. Employing i.m. challenge, relative percentage survival induced by the furunculosis vaccine and the AAS vaccine was 47 and 44, respectively. Mortality of i.m. injected controls was 68%. Vaccinated fish behaved normally following vaccination but the weight gain was significantly reduced in vaccinated fish 8 weeks post-vaccination compared with control fish receiving phosphate-buffered saline. At the same time, intra-abdominal adhesions were observed in fish injected with either of the two vaccines or adjuvant alone. Antibody response against A. salmonicida ssp. achromogenes was detected in sera from fish receiving either vaccine. [source] A study of the susceptibility of Atlantic halibut, Hippoglossus hippoglossus (L.), to viral haemorrhagic septicaemia virus isolated from turbot, Scophthalmus maximus (L.)JOURNAL OF FISH DISEASES, Issue 4 2003T J Bowden Abstract The susceptibility of Atlantic halibut, Hippoglossus hippoglossus (L.), to viral haemorrhagic septicaemia virus (VHSV) was tested. Juvenile halibut of approximately 5 g weight were subjected to challenge by intraperitoneal injection, cohabitation and immersion to a VHSV isolate from an outbreak of the disease in turbot, Scophthalmus maximus (L.). The intraperitoneal injection gave the highest mortality rate of 28% after 50 days. The cohabitee group suffered 19% mortality rate and the immersion group only 2%. Control groups included turbot exposed either by intraperitoneal injection or immersion which suffered mortality rates of 93 and 50%, respectively. The results suggest that halibut are markedly less susceptible to VHSV than turbot. [source] Quality Characterization of Farmed Atlantic Halibut During Ice StorageJOURNAL OF FOOD SCIENCE, Issue 2 2006Christelle Guillerm-Regost ABSTRACT: A quality index method (QIM) was developed for farmed Atlantic halibut and together with instrumental, chemical, sensory, and bacteriological analysis, quality changes of halibut stored on ice for 26 d was evaluated. Two groups of fish were fed diets that differed only in the source of lipid, where 1 diet contained only marine oil sources and the other a 50/50 mixture of marine and soybean oil. Fish were slaughtered after 1 y and then stored on ice for 26 d. The fish were sampled on day 1, day 2, and every 2nd day after that. Dietary lipid sources had no effect on freshness, (ATP) degradation (K-value), texture, color, or liquid-holding capacity. The QIM scores increased with storage time, in particular the appearance and eyes parameters. The QIM is a good freshness indicator for halibut. The K-value was strongly correlated with storage time (r= 0.99), while total bacterial counts increased after 7 to 8 d of ice storage. The texture, liquid-holding capacity, and color were significantly affected by storage time during the early period of storage, probably due to rigor stiffness and rigor resolution. The texture, liquid-holding capacity, and color did not change significantly from approximately day 8 of storage until the end of the experiment at day 26. [source] Temperature effects on sex determination and ontogenetic gene expression of the aromatases cyp19a and cyp19b, and the estrogen receptors esr1 and esr2 in atlantic halibut (Hippoglossus hippoglossus)MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 12 2006Solveig van Nes Abstract The aromatase (CYP19) and estrogen receptor (ESR) play important roles in the molecular mechanism of sex determination and differentiation of lower vertebrates. Several studies have proven these mechanisms to be temperature sensitive, which can influence the direction of phenotypic gender development. A temperature study was conducted to examine the effect of temperature on the sex differentiation in farmed Atlantic halibut. Sexually undifferentiated larvae were exposed to 7°C, 10°C, or 13°C during gonadal differentiation. Temperature effects on the transcription rate of the aromatase genes cyp19a (ovary type) and cyp19b (brain type) and the ESR genes esr1 and esr2 were examined by quantitative real-time PCR. With increasing temperatures, both cyp19a mRNA levels and the female incidence showed a decreasing trend, thus strongly indicating a relation between the expression of cyp19a and morphological ovary differentiation. In contrast to cyp19a, the levels of cyp19b, esr1, and esr2 mRNA strongly increased in all temperature groups throughout the study period, and did not show obvious temperature-related expression patterns. The present data provide evidence that posthatching temperature exposure significantly affects the expression of cyp19a mRNA during the developmental period and that high temperature possibly influences genetic sex determination in Atlantic halibut. Though, the female incidence never exceeded 50%, suggesting that only the homogametic (XX) female is thermolabile. So whereas temperature treatment is not likely suitable for direct feminization in halibut, the possibility for high-temperature production of XX neomales for broodstock to obtain all-female offspring by crossing with XX females is suggested. Mol. Reprod. Dev. 73: 1481,1490, 2006. © 2006 Wiley-Liss, Inc. [source] Effects of protein hydrolysate in weaning diets for Atlantic cod (Gadus morhua L.) and Atlantic halibut (Hippoglossus hippoglossus L.)AQUACULTURE NUTRITION, Issue 2 2009A. KVÅLE Abstract The study aims to test whether predigested dietary protein enhances the utilization of formulated diets at weaning, and also whether it stimulates intestinal maturation. In this study, Atlantic cod [Gadus morhua L.; 41 days posthatch (dph)] and Atlantic halibut [Hippoglossus hippoglossus L.; 63 days postfirst feeding (dpff)] were weaned onto diets with graded levels of protein hydrolysate. By increasing the inclusion of dietary protein as hydrolysate from 0 to 400 g kg,1, cod increased the rate of survival from 7 ± 1% to 18 ± 2% (82 dph; regression, P = 4*10,7). In halibut, the survival rate decreased from 57 ± 9% to 22 ± 7% as the inclusion of protein in the form of hydrolysate increased from 0 to 450 g kg,1 (119 dpff; regression, P = 8*10,5). Growth was not affected in any of the species. Results in specific activities of the intestinal enzymes leucine aminopeptidase (LAP) and alkaline phospatase (AP) supported the results in survival in halibut and partly also in cod, by showing increased activities in groups with increased survival (anova, P < 0.05). The lower optimal level of hydrolysed protein in halibut than in cod is suggested mainly because of a slower feeding practice in halibut, which allows more extensive nutrient leaching before ingestion. [source] The problem of meeting dietary protein requirements in intensive aquaculture of marine fish larvae, with emphasis on Atlantic halibut (Hippoglossus hippoglossus L.)AQUACULTURE NUTRITION, Issue 3 2007A. KVÅLE Abstract Atlantic halibut (Hippoglossus hippoglossus) achieve a mature gastrointestinal tract approximately 2 months after first feeding (12 °C). The immature digestion may be the reason that compound diets fail to sustain growth and survival in first feeding halibut larvae and in larvae of other marine fish species. On the other hand, larvae fed with live feeds are capable of extraction of sufficient quantities of nutrients to sustain high growth rates. A lower availability of the protein in formulated diets compared with live prey is considered to be an important reason for the low performance of formulated diets. One approach to increase dietary protein availability is supplementation of pre-digested proteins. Experiments using tube fed individual larvae show that halibut larvae are able to utilize hydrolysed protein more efficiently than intact protein. However, Atlantic halibut in culture did not respond well to dietary supplementation of hydrolysed protein, in contrast to some other species. One reason may be extensive leaching of pre-hydrolysed proteins from the microparticulate feed. Atlantic halibut are slow feeders and may thus suffer more from nutrient leaching than species eating more rapidly. Feed formulation techniques affect dietary protein leaching, and in this paper, different techniques and their impact on feed properties are described. Microbound diets are most widely used in larval rearing, but show high rates of nutrient leaching. Lipid-based capsules seem to have the best potential to prevent leaching, however, they are not able to deliver a complete diet. The high need for improvements in larval feed formulation techniques are clearly stated, and some suggestions are given. Among these are production of complex particles, where small lipid-based capsules or liposomes containing the low molecular weight water-soluble nutrients are embedded. In such feed particles the water-soluble molecules are protected from leaching. Techniques for delivery of water-soluble nutrients that are needed in large quantities, i.e. free amino acids or hydrolysed and water-soluble protein, remain to be developed. [source] Iodine enrichment of Artemia and enhanced levels of iodine in Atlantic halibut larvae (Hippoglossus hippoglossus L.) fed the enriched ArtemiaAQUACULTURE NUTRITION, Issue 2 2006M. MOREN Abstract Flatfish metamorphosis is initiated by the actions of thyroid hormones (TH) and iodine is an essential part of these hormones. Hence, an iodine deficiency may lead to insufficient levels of TH and incomplete metamorphosis. In this study, different iodine sources for enrichment of Artemia were evaluated and the levels of iodine obtained in Artemia were within the range of 60,350 ,g g,1 found in copepods. Larval Atlantic halibut was fed Artemia enriched with either normal DC-DHA Selco or DC-DHA Selco (commercial enrichments) supplemented with iodine from days 9 to 60 postfirst feeding. There was no significant difference in growth, mortality or metamorphic development between the groups. The analyses showed that we were able to enrich Artemia with iodine. Further, the larvae-fed iodine-enriched Artemia had higher whole body iodine concentration compared to larvae-fed Artemia without iodine enrichment. [source] Distribution of ,-tocopherol in fillets of turbot (Scophthalmus maximus) and Atlantic halibut (Hippoglossus hippoglossus), following dietary ,-tocopheryl acetate supplementationAQUACULTURE NUTRITION, Issue 2 2004N. Ruff Abstract The present study investigated the distribution of , -tocopherol (vitamin E) in fillets of turbot (Scophthalmus maximus) and Atlantic halibut (Hippoglossus hippoglossus). Turbot and Atlantic halibut were fed commercial diets, supplemented with different levels of , -tocopheryl acetate at the dietary target levels of 100, 500 and 1000 mg , -tocopheryl acetate kg,1 diet. The actual levels were 72, 547 and 969 for turbot, while halibut received 189, 613 and 875 mg , -tocopheryl acetate kg,1 diet. Turbot were fed the diets for 24 weeks, while Atlantic halibut were fed for 20 weeks prior to slaughter. At the end of the feeding periods fish had reached a final weight of around 1 kg. Fish were slaughtered and filleted. From the four fillets obtained per fish, 22 samples were taken from designated areas and analysed for their , -tocopherol content. The average concentrations of , -tocopherol incorporated in turbot and Atlantic halibut increased with increasing levels of , -tocopheryl acetate in the diet. Atlantic halibut had significantly (P < 0.05) more , -tocopherol in positions 2/II and 1/I than in position 9/IX. Turbot had significantly (P < 0.05) more , -tocopherol in position 2/II than in positions 1/I, 4/IV and 11/XI. By mapping , -tocopherol concentrations in fish fillets, a high degree of quality prediction may be established. Moreover, this study may help scientists in their choice of sampling position, when investigating if , -tocopheryl acetate supplementation resulted in successful , -tocopherol incorporation. [source] Long-term effect of photoperiod manipulation on growth, maturation and flesh quality in Atlantic halibutAQUACULTURE RESEARCH, Issue 11 2009Albert K Imsland Abstract The aim of this study was to investigate the effect of continuous light at different stages during the production cycle of Atlantic halibut Hippoglossus hippoglossus L. on growth, age at first maturity, endocrine parameters and flesh quality. A group of juvenile halibut [mean (SD), initial weight 191.3 g (44.7)] was reared in indoor tanks under ambient temperature conditions for 38 months until harvesting (mean final weight, 4.6 kg). The entire photoperiod experiment was divided into four phases, where the fish in each phase were exposed to either natural photoperiod (62°33,N) or continuous light (L). Thus, the following five photoperiod combinations were tested: (a) Control group (NNNN), (b) Group 2A (NLNN), (c) Group 2B (NNLN), (d) Group 2C (NNNL) and (e) Production group (LNNN). Exposure to continuous light stimulated growth, and the final mean weights of Groups 2A and 2B were 23% and 11% higher than those of the Control group (NNNN). The final plasma 11-ketotestosteron levels were lower in Groups 2A (2.94 ng mL,1) and 2B (2.46 ng mL,1) compared with the Control (5.29 ng mL,1), Group 2C (5.09 ng mL,1) and the Production group (4.78 ng mL,1) during spring 2007 (age 4 years), indicating higher age at first maturity in Groups 2A and 2B. Photoperiod regime had only a minor, and transient, effect on flesh-quality traits of the fish, whereas a significant seasonal effect was seen with a tendency towards increased gaping, lower pH, lower hardness and lower shear force in July compared with December and March. [source] Feed intake, growth and nutrient utilization in Atlantic halibut (Hippoglossus hippoglossus) fed diets containing a bacterial protein mealAQUACULTURE RESEARCH, Issue 4 2007Turid Synnøve Aas Abstract Triplicate groups of Atlantic halibut were fed diets containing 0%, 9% or 18% of a bacterial protein meal (BPM) produced from natural gas in a 9-week trial. Growth rates, relative feed intake, feed efficiency ratio and retention of all indispensable amino acids were significantly lower in fish fed the 18% BPM diets than in those fed the 0% and 9% BPM diets. There were no significant treatment effects on urea levels in plasma, liver or muscle, or in uric acid levels in plasma. The hepatosomatic index was lowest in fish fed the 18% BPM diet. Although the concentration of copper, an element abundant in BPM, increased in the liver as dietary BPM level increased, the total copper content in liver decreased. Fish fed the 0% and 9% BPM diets had a higher degree of supranuclear vacuolization of pyloric caeca and mid-intestine epithelia compared with fish fed the 18% BPM diet. In conclusion, the halibut fed the 9% BPM diet performed equally well as the control group regarding growth, feed intake and feed efficiency ratio, whereas performance was reduced in the fish fed the 18% BPM diet. [source] Biological and technical evaluation of the potential of marine and anadromous fish species for cold-water maricultureAQUACULTURE RESEARCH, Issue 2 2002N R Le François Abstract Concern about the overexploitation of wild aquatic resources, the slow recovery of the groundfish fisheries and the need to encourage the diversification of the mariculture industry of the province of Quebec (Canada) all provided strong incentive to explore the potential of a wide selection of marine and anadromous fish species for cold-water mariculture. Starting from a list of over 45 indigenous fish species of potential commercial interest, a biotechnical review was initiated. Technical sheets for each species were produced and aquaculture-based selection criteria covering three aquaculture approaches of development (complete life cycle, on-growing and stock enhancement) were examined. Species were ranked according to their degree of suitability for the given biological parameters. The final classification analysis within the complete life cycle production strategy positioned the Atlantic wolffish as the top candidate species (91%) followed by the spotted wolffish and Arctic charr (87%). Growth rate, optimal growth temperature, duration of the weaning period, minimal lethal temperature, larval size and feed requirements were the determining criteria. The on-growing scenario final results ranked Arctic charr first (84%) followed by Atlantic cod (79%) and Atlantic halibut (74%) mostly owing to their growth rate at low temperature and optimal growth temperature criteria. Stock enhancement programmes should concentrate their efforts on the striped bass (56%), the haddock (54%) and the Atlantic sturgeon (34%) based on their growth rate, fishery status, landing price and the availability of impact studies. [source] Successful early weaning of Atlantic halibut (Hippoglossus hippoglossus L.) in small shallow raceway systemsAQUACULTURE RESEARCH, Issue 3 2001T Næss Abstract Small raceways were used in a weaning experiment with Atlantic halibut (Hippoglossus hippoglossus L.) larvae. The size of the tanks was 1.0 × 0.4 m with a 1- to 2-cm water level. Duplicate larval groups were transferred to the raceways from circular first feeding tanks at 0.07, 0.10 and 0.16 g wet weight, while recommended weaning size of this species is 0.2,0.3 g. During the first 7 days of weaning, Artemia was used as a food supplement in combination with the formulated dry feed. Thereafter only dry feed was used. The dry feed used in this experiment was produced by a special heat technique. The 0.07, 0.10 and 0.16 g larval groups were evaluated after 31, 25 and 17 days respectively (same date) The corresponding average survival was 81.4%, 78.0% and 96.6% and the specific daily growth rate was 3.18%, 3.17% and 2.38% respectively. In the Artemia control group, a survival rate of 96.0% and a growth rate of 5.28% was achieved. To evaluate the weaning success, the groups were followed in a 22-day post-weaning period on a commercial dry diet. Higher growth rates, 5.8,6.9%, were then obtained in all experimental groups, except control. The survival here averaged approximately 80% in the three experimental groups, but showed some differences between replicates. One hundred per cent survival was achieved during weaning in the former Artemia group. From the start of weaning to the end of the post-weaning period, the survival rates averaged 64% for the 0.07 and 0.10 g groups, approximately 80% for the 0.16 g group and 96% in the Artemia control group. Higher variance (CV) through the experiment and highest growth of the 75% quartiles of the fish groups compared with the 50% and 25%, indicated suppressed growth of the smaller fish. The successful weaning at these small sizes considerably reduced the live food period. Based on the present knowledge of the energetic demands of this species, it is calculated that weaning at 0.07 g compared with 0.25 g will reduce the amount of Artemia needed by at least 60%. No differences in pigmentation or degree of completed eye migration were detected between groups, indicating that this is determined at earlier developmental stages. [source] Temperature effects on sex determination and ontogenetic gene expression of the aromatases cyp19a and cyp19b, and the estrogen receptors esr1 and esr2 in atlantic halibut (Hippoglossus hippoglossus)MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 12 2006Solveig van Nes Abstract The aromatase (CYP19) and estrogen receptor (ESR) play important roles in the molecular mechanism of sex determination and differentiation of lower vertebrates. Several studies have proven these mechanisms to be temperature sensitive, which can influence the direction of phenotypic gender development. A temperature study was conducted to examine the effect of temperature on the sex differentiation in farmed Atlantic halibut. Sexually undifferentiated larvae were exposed to 7°C, 10°C, or 13°C during gonadal differentiation. Temperature effects on the transcription rate of the aromatase genes cyp19a (ovary type) and cyp19b (brain type) and the ESR genes esr1 and esr2 were examined by quantitative real-time PCR. With increasing temperatures, both cyp19a mRNA levels and the female incidence showed a decreasing trend, thus strongly indicating a relation between the expression of cyp19a and morphological ovary differentiation. In contrast to cyp19a, the levels of cyp19b, esr1, and esr2 mRNA strongly increased in all temperature groups throughout the study period, and did not show obvious temperature-related expression patterns. The present data provide evidence that posthatching temperature exposure significantly affects the expression of cyp19a mRNA during the developmental period and that high temperature possibly influences genetic sex determination in Atlantic halibut. Though, the female incidence never exceeded 50%, suggesting that only the homogametic (XX) female is thermolabile. So whereas temperature treatment is not likely suitable for direct feminization in halibut, the possibility for high-temperature production of XX neomales for broodstock to obtain all-female offspring by crossing with XX females is suggested. Mol. Reprod. Dev. 73: 1481,1490, 2006. © 2006 Wiley-Liss, Inc. [source] | ||||||||||