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Atlantic Halibut

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Igor Babiak – 1st expert on this subject based on the ideXlab platform

  • sex biased mirna expression in Atlantic Halibut hippoglossus hippoglossus brain and gonads
    Sexual Development, 2012
    Co-Authors: Teshome Tilahun Bizuayehu, Jorge M O Fernandes, Joanna Babiak, Birgitta Norberg, Steinar Johansen, Igor Babiak

    Abstract:

    The role of miRNA in fish sexual development is not elucidated yet. We profiled miRNAs in gonads and brains of Atlantic Halibut using SOLiD sequencing technology. We found tissue- and sexually dimorph

  • Induced sex reversal using an aromatase inhibitor, Fadrozole, in Atlantic Halibut (Hippoglossus hippoglossus L.)
    Aquaculture, 2012
    Co-Authors: Joanna Babiak, Igor Babiak, Torstein Harboe, Trine Haugen, Birgitta Norberg

    Abstract:

    Abstract Production of all-female Atlantic Halibut ( Hippoglossus hippoglossus L.) is desirable for the industry because of sexual growth dimorphism existing in this species. The first step towards establishing monosex all-female cohorts is to produce sex-reversed females (neo-males). The objective of this study was to test the efficiency of an aromatase inhibitor, Fadrozole, to induce masculinisation in Atlantic Halibut. Three doses of Fadrozole were tested: 100, 500 and 700 mg/kg of feed, applied for 42–60 days to weaned Halibut fry of 26–30 mm TL. All tested doses proved to be efficient, resulting in the development of testes in up to 97% of examined individuals. Seventeen-α-methyltestosterone (MT) was used as a positive control. MT-treated fish were all males. No abnormalities in the development of gonads were observed in any of the groups. Analysis of 11-ketotestosterone (11KT) blood plasma levels showed that most of individuals in the experimental groups had 11KT levels typical for males while controls had 11KT levels typical for males or females.

  • differential expression patterns of conserved mirnas and isomirs during Atlantic Halibut development
    BMC Genomics, 2012
    Co-Authors: Teshome Tilahun Bizuayehu, Jorge M O Fernandes, Steinar Johansen, Carlos Fredrico Ceccon Lanes, Tomasz Furmanek, Bard Ove Karlsen, Igor Babiak

    Abstract:

    MicroRNAs (miRNAs) play a major role in animal ontogenesis. Size variants of miRNAs, isomiRs, are observed along with the main miRNA types, but their origin and possible biological role are uncovered yet. Developmental profiles of miRNAs have been reported in few fish species only and, to our knowledge, differential expressions of isomiRs have not yet been shown during fish development. Atlantic Halibut, Hippoglossus hippoglossus L., undergoes dramatic metamorphosis during early development from symmetrical pelagic larval stage to unsymmetrical flatfish. No data exist on role of miRNAs in Halibut metamorphosis. miRNA profiling using SOLiD deep sequencing technology revealed a total of 199 conserved, one novel antisense, and one miRNA* mature form. Digital expression profiles of selected miRNAs were validated using reverse transcription quantitative PCR. We found developmental transition-specific miRNA expression. Expression of some miRNA* exceeded the guide strand miRNA. We revealed that nucleotide truncations and/or additions at the 3′ end of mature miRNAs resulted in size variants showing differential expression patterns during the development in a number of miRNA families. We confirmed the presence of isomiRs by cloning and Sanger sequencing. Also, we found inverse relationship between expression levels of sense/antisense miRNAs during Halibut development. Developmental transitions during early development of Atlantic Halibut are associated with expression of certain miRNA types. IsomiRs are abundant and often show differential expression during the development.

Thor Magne Jonassen – 2nd expert on this subject based on the ideXlab platform

  • Intraspecific differences in physiological efficiency of juvenile Atlantic Halibut Hippoglossus hippoglossus L.
    Journal of The World Aquaculture Society, 2007
    Co-Authors: Albert K. Imsland, Thor Magne Jonassen, Sigurd O. Stefansson, Shusaku Kadowaki, Marl H. G. Berntssen

    Abstract:

    We compared growth efficiency, feeding consumption, metabolism, excretion, and energy allocation in populations of juvenile Atlantic Halibut from Norway, Iceland, and Canada reared at low (8 C), medium (12 C, 15 C) and high (18 C) experimental temperatures. Our findings show that protein utilization and energy allocation in juvenile Atlantic Halibut varies among different populations, as the Norwegian population displayed the highest protein efficiency ratio, protein production value, and energy conversion efficiency compared to the Canadian population, while the Icelandic population showed overall intermediate growth performance. The results do not conform to a simple thermal adaptation model but might represent an example of: 1) local adaptation of fish populations; or 2) countergradient variation where shorter growing season at higher latitudes is compensated with higher physiological efficiency. These findings have implications for Halibut culture, particularly in selection work focusing on growth performance.

  • regulation of growth in turbot scophthalmus maximus rafinesque and Atlantic Halibut hippoglossus hippoglossus l aspects of environment genotype interactions
    Reviews in Fish Biology and Fisheries, 2001
    Co-Authors: Albert K. Imsland, Thor Magne Jonassen

    Abstract:

    This review is aimed atelucidating the mechanisms that regulate growthin cultured juvenile Atlantic Halibut (Hippoglossus hippoglossus) and turbot (Scophthalmus maximus) by evaluating thesignificance of environmental factors(temperature, photoperiod) and the interactionsbetween them. In addition, we examine growthproperties in three populations of juvenileHalibut and turbot in order to elucidate anygeographical differences in growth and growthefficiency in these species. Both temperatureand photoperiod have a significant andpersistent effect on growth rate in bothspecies. Temperature tolerance, demonstrated bya wide temperature range supporting maximalgrowth, increased with size. Fish subjected tocontinuous light exhibited faster growth thanthose experiencing a natural photoperiod or aconstant short day. Moreover, when thephotoperiod increased naturally with day-lengthor when fish were abruptly switched from beingreared on short-day conditions to continuouslight, a subsequent increase in growth rate wasobserved. This growth enhancing effect ofextended photoperiods was more apparent in ashort time scale in Atlantic Halibut than inturbot, but both species show significantlong-term effects of extended photoperiods.

  • Regulation of growth in turbot (Scophthalmus maximus Rafinesque) and Atlantic Halibut (Hippoglossus hippoglossus L.): aspects of environment × genotype interactions
    Reviews in Fish Biology and Fisheries, 2001
    Co-Authors: Albert K. Imsland, Thor Magne Jonassen

    Abstract:

    This review is aimed atelucidating the mechanisms that regulate growthin cultured juvenile Atlantic Halibut (Hippoglossus hippoglossus) and turbot (Scophthalmus maximus) by evaluating thesignificance of environmental factors(temperature, photoperiod) and the interactionsbetween them. In addition, we examine growthproperties in three populations of juvenileHalibut and turbot in order to elucidate anygeographical differences in growth and growthefficiency in these species. Both temperatureand photoperiod have a significant andpersistent effect on growth rate in bothspecies. Temperature tolerance, demonstrated bya wide temperature range supporting maximalgrowth, increased with size. Fish subjected tocontinuous light exhibited faster growth thanthose experiencing a natural photoperiod or aconstant short day. Moreover, when thephotoperiod increased naturally with day-lengthor when fish were abruptly switched from beingreared on short-day conditions to continuouslight, a subsequent increase in growth rate wasobserved. This growth enhancing effect ofextended photoperiods was more apparent in ashort time scale in Atlantic Halibut than inturbot, but both species show significantlong-term effects of extended photoperiods.

Joanne Power – 3rd expert on this subject based on the ideXlab platform

  • the relationship between sperm density spermatocrit sperm motility and fertilization success in Atlantic Halibut hippoglossus hippoglossus
    Aquaculture, 2001
    Co-Authors: Tillmann J Benfey, Harald B Tvedt, Joanne Power, Deborah J Martinrobichaud

    Abstract:

    Abstract The commercialization of Atlantic Halibut, Hippoglossus hippoglossus , aquaculture has been hampered by a failure to obtain consistently high fertilization rates. The principal goal of this research was to determine the optimum sperm density for successful fertilization of Atlantic Halibut eggs. Sperm densities ranged from 2×10 11 to 6×10 11 spermatozoa/ml at 23% and 99% spermatocrit, respectively, for 36 milt samples collected from 17 males. Regression analysis showed a significant positive linear relationship between sperm density and spermatocrit, supporting the use of spermatocrit as a rapid estimator of sperm density in this species. There was no relationship between sperm density and sperm motility (defined as time elapsed from activation until 8 to 9.4×10 5 spermatozoa/egg, respectively.