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Igor Babiak - One of the best experts 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.

  • maternal gene expression in Atlantic Halibut hippoglossus hippoglossus l and its relation to egg quality
    BMC Research Notes, 2010
    Co-Authors: Maren Mommens, Sylvie Bolla, Jorge M O Fernandes, Teshome Tilahun Bizuayehu, Ian A Johnston, Igor Babiak
    Abstract:

    Background The commercial production of Atlantic Halibut (Hippoglossus hippoglossus L.) suffers from a major bottleneck due to the low success of producing juveniles for on-growing. Atlantic Halibut females are routinely hand-stripped and incorrect timing of stripping can result in low quality eggs due to post-ovulatory aging. Post-ovulatory aging leads to compositional changes in eggs that include maternally provided proteins and RNAs. There have been few studies of the maternally provided mRNA transcripts that control early development in commercially important fish species. The present study aimed to study maternal gene expression in Atlantic Halibut and its relation to egg quality parameters including blastomere symmetry and hatching success.

  • selection of suitable reference genes for real time pcr studies of Atlantic Halibut development
    Comparative Biochemistry and Physiology B, 2008
    Co-Authors: Jorge M O Fernandes, Igor Babiak, Maren Mommens, Ørjan Hagen, Christel Solberg
    Abstract:

    Gene expression studies are fundamental to understand the molecular basis of severe malformations in fish development, particularly under aquaculture conditions. Real-time PCR (qPCR) is the most accurate method of quantifying gene expression, provided that suitable endogenous controls are used to normalize the data. To date, no reference genes have been validated for developmental gene expression studies in Atlantic Halibut (Hippoglossus hippoglossus). We have determined the expression profiles of 6 candidate reference genes (Actb, Eef2, Fau, Gapdh, Tubb2 and 18S rRNA) in 6 embryonic and 5 larval stages of Atlantic Halibut development. There were significant changes in expression levels throughout development, which stress the importance and complexity of finding appropriate reference genes. The three software applications (BestKeeper, geNorm and NormFinder) used to evaluate the stability of potential reference genes produced comparable results. Tubb2 and Actb were the most stable genes across the different developmental stages, whereas 18S rRNA and Gapdh were the most variable genes and thus inappropriate to use as reference genes. According to geNorm and NormFinder, the best two-gene normalization factors corresponded to the geometric average of Tubb2/Actb and Tbb2/Fau, respectively. We believe that either of these normalization factors can be used for future developmental gene expression studies in Atlantic Halibut.

Thor Magne Jonassen - One of the best experts 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 - One of the best experts 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, Deborah J Martinrobichaud, Joanne Power
    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.

Susan E Douglas - One of the best experts on this subject based on the ideXlab platform.

  • A nutrigenomic analysis of intestinal response to partial soybean meal replacement in diets for juvenile Atlantic Halibut, Hippoglossus hippoglossus, L.
    Aquaculture, 2020
    Co-Authors: Harry M. Murray, Robert M. Flight, Santosh P Lall, Rajesh Rajaselvam, Lee Anne Boutilier, Brian Blanchard, Stefanie Colombo, Vindhya Mohindra, Susan E Douglas
    Abstract:

    Aquaculture feeds for carnivorous finfish species have been dependent upon the use of fish meal as the major source of dietary protein; however, the increasing demands upon the finite quantity of this high-quality protein source requires that feeds become increasingly comprised of alternative plant and/or animal protein. Soybean meal has been has been used to partially replace fish meal in the diets of several fish but it is known to cause enteritis in Atlantic salmon, Salmo salar. We have compared two groups of juvenile (207.2 \ub1 6.6 g) Atlantic Halibut, Hippoglossus hippoglossus, L., fed diets containing fish meal (FM; control) or 30% soybean meal (SBM; experimental) as a protein source for 3 weeks. No detectable difference in feed intake or palatability was evident with the SBM diet relative to the FM diet. Histological examination of the distal intestine was performed to examine leukocyte infiltration of the lamina propria and other changes in morphology commonly observed with soybean-induced enteritis of salmonids. No significant difference was found between fish fed the FM and SBM diets. Global gene expression profiling performed using a high-density oligonucleotide microarray containing 9260 unique features, printed in quadruplicate, from Atlantic Halibut revealed subtle underlying changes in the expression of several immune genes and genes involved in muscle formation, lipid transport, xenobiotic detoxification, digestion and intermediary metabolism. These results indicate that SBM can be used successfully as a replacement for animal protein in diet for juvenile Atlantic Halibut, although long-term effects on the immune system may ensue. Crown Copyright \ua9 2009.Peer reviewed: YesNRC publication: Ye

  • a nutrigenomic analysis of intestinal response to partial soybean meal replacement in diets for juvenile Atlantic Halibut hippoglossus hippoglossus l
    Aquaculture, 2010
    Co-Authors: Harry M. Murray, Robert M. Flight, Santosh P Lall, Rajesh Rajaselvam, Lee Anne Boutilier, Brian Blanchard, Stefanie Colombo, Vindhya Mohindra, Susan E Douglas
    Abstract:

    Abstract Aquaculture feeds for carnivorous finfish species have been dependent upon the use of fish meal as the major source of dietary protein; however, the increasing demands upon the finite quantity of this high-quality protein source requires that feeds become increasingly comprised of alternative plant and/or animal protein. Soybean meal has been has been used to partially replace fish meal in the diets of several fish but it is known to cause enteritis in Atlantic salmon, Salmo salar . We have compared two groups of juvenile (207.2 ± 6.6 g) Atlantic Halibut, Hippoglossus hippoglossus , L., fed diets containing fish meal (FM; control) or 30% soybean meal (SBM; experimental) as a protein source for 3 weeks. No detectable difference in feed intake or palatability was evident with the SBM diet relative to the FM diet. Histological examination of the distal intestine was performed to examine leukocyte infiltration of the lamina propria and other changes in morphology commonly observed with soybean-induced enteritis of salmonids. No significant difference was found between fish fed the FM and SBM diets. Global gene expression profiling performed using a high-density oligonucleotide microarray containing 9260 unique features, printed in quadruplicate, from Atlantic Halibut revealed subtle underlying changes in the expression of several immune genes and genes involved in muscle formation, lipid transport, xenobiotic detoxification, digestion and intermediary metabolism. These results indicate that SBM can be used successfully as a replacement for animal protein in diet for juvenile Atlantic Halibut, although long-term effects on the immune system may ensue.

  • comprehensive est analysis of Atlantic Halibut hippoglossus hippoglossus a commercially relevant aquaculture species
    BMC Genomics, 2007
    Co-Authors: Susan E Douglas, Leah C Knickle, Jennifer Kimball, Michael Reith
    Abstract:

    Background An essential first step in the genomic characterisation of a new species, in this case Atlantic Halibut (Hippoglossus hippoglossus), is the generation of EST information. This forms the basis for subsequent microarray design, SNP detection and the placement of novel markers on genetic linkage maps.

Harald B Tvedt - One of the best experts on this subject based on the ideXlab platform.

  • Gynogenesis and sex determination in Atlantic Halibut (Hippoglossus hippoglossus)
    Aquaculture, 2020
    Co-Authors: Harald B Tvedt, Tillmann J Benfey, Deborah J Martin-robichaud, Colin Mcgowan, Michael Reith
    Abstract:

    Gynogenesis refers to a process of uniparental inheritance whereby the resulting offspring retain only maternal DNA. It has been used to identify sex-determining mechanisms in fish and to produce all-female populations for aquaculture. The objective of this study was to develop a protocol for the production of gynogenetic Atlantic Halibut for both these purposes. Various milt concentrations (1:20, 1:40 and 1:80 dilutions in seminal plasma) and UV doses (0\u20131382 mJ/cm2) were tested for providing genetically inactivated, yet motile, spermatozoa for the production of gynogenetic haploids. Spermatozoon motility, assessed both as duration of swimming and percentage of motile spermatozoa, declined with increasing UV dose. Haploidy in developing embryos was determined either visually (\u2018haploid syndrome\u2019) or by genetic analysis using microsatellite DNA. The optimum milt treatment for the production of haploids was 1:80 dilution followed by a UV exposure of 65 mJ/cm2. Retention of the second polar body for the production of gynogenetic diploids was achieved by exposing newly activated eggs (15 min post-activation at 5\u20136 \uc2\ub0C) to hydrostatic pressure of 8500 psi for 5 min. These treatments were combined to produce a population of gynogenetic diploids that was subsequently demonstrated to be comprised solely of females, thereby demonstrating that female is the homogametic sex in this species. It should therefore be possible to produce all-female populations of Atlantic Halibut for commercial culture through gynogenesis or by crossing hormonally masculinized genotypic females to normal females.Peer reviewed: YesNRC publication: Ye

  • gynogenesis and sex determination in Atlantic Halibut hippoglossus hippoglossus
    Aquaculture, 2006
    Co-Authors: Tillmann J Benfey, Harald B Tvedt, Deborah J Martinrobichaud, Colin Mcgowan, Michael Reith
    Abstract:

    Abstract Gynogenesis refers to a process of uniparental inheritance whereby the resulting offspring retain only maternal DNA. It has been used to identify sex-determining mechanisms in fish and to produce all-female populations for aquaculture. The objective of this study was to develop a protocol for the production of gynogenetic Atlantic Halibut for both these purposes. Various milt concentrations (1:20, 1:40 and 1:80 dilutions in seminal plasma) and UV doses (0–1382 mJ/cm 2 ) were tested for providing genetically inactivated, yet motile, spermatozoa for the production of gynogenetic haploids. Spermatozoon motility, assessed both as duration of swimming and percentage of motile spermatozoa, declined with increasing UV dose. Haploidy in developing embryos was determined either visually (‘haploid syndrome’) or by genetic analysis using microsatellite DNA. The optimum milt treatment for the production of haploids was 1:80 dilution followed by a UV exposure of 65 mJ/cm 2 . Retention of the second polar body for the production of gynogenetic diploids was achieved by exposing newly activated eggs (15 min post-activation at 5–6 °C) to hydrostatic pressure of 8500 psi for 5 min. These treatments were combined to produce a population of gynogenetic diploids that was subsequently demonstrated to be comprised solely of females, thereby demonstrating that female is the homogametic sex in this species. It should therefore be possible to produce all-female populations of Atlantic Halibut for commercial culture through gynogenesis or by crossing hormonally masculinized genotypic females to normal females.

  • 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, Deborah J Martinrobichaud, Joanne Power
    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.