Muscle development, growth and flesh quality
Christel Solberg (PhD, Professor), Ian A. Johnston (PhD, Professor II), Marit Bjørnevik (PhD, Associate Professor), Jialin Bai (PhD, NRC Research Fellow), Grete Lysfjord(Assistant Professor), Ørjan Hagen (PhD student) and Chris Johnsen (Master student).
Muscle growth and flesh quality. The density of muscle fibres and the concentration of collagen pyridinoline crosslinks affect texture and gaping. Muscle fibre recruitment and the post-translation modification of muscle collagen farmed halibut are investigated in collaboration with Aga Marine AS at Dønna. The aim is to quantify the number, types and distribution of muscle fibres, collagen concentration, the amount of pyridinoline crosslinks (using a sensitive HPLC method) and proteoytic enzymes activities in a complete seasonal cycle in 2-sea winter fish. Biological traits are being correlated with flesh quality parameters including texture (measured with a TA XT2 Texture Analyser) colour, water holding capacity, pH and chemical composition determined by NIR-spectroscopy. This work has been supported by MABIT “Optimal production of farmed halibut”.
We are also benchmarking the quality characteristics of farmed and wild halibut and Atlantic cod (Gadus morhua). The later work is supported by a sub-contract from the EU VIth Framework Integrated Research Project, SEAFOODplus.
In cooperation with the local industry as Codfarmers and GIFAS, the effect of different feed, feeding regimes, light treatment, maturation and starvation on the growth and quality on cod are investigated over the whole production cycle, from approx. 200 g to 4 kg. The effect on the fatty acids and the proximate composition in the liver is also investigated. These projects are supported by the feed industry and Innovation Norway.
In cooperation with Follalaks the effect of different smoltproduction, season and feeding regimes on the muscle growth and flesh quality in Atlantic salmon is investigated over the whole production cycle from release to seawater to slaughter at approx. 4kg. Together with GIFAS, the effect of different feeding regimes, as feeding to satiation and 15% reduced feeding on the growth, muscle fibre distribution, texture, colour and chemical composition is investigated at 2 and 4 kg Atlantic salmon. These projects are supported by the feed industry and Innovation Norway.
Molecular Biology and Genomics. Our current focus is on the development of a molecular tool kit for investigating normal and abnormal growth performance and flesh quality in Atlantic halibut (Hippoglossus hippoglossus).Genes that can be used as phenotypic markers of tissue stem cells for muscle, bone, connective tissue and adipocytes are being characterised using homology cloning and DNA walking techniques. In addition, full-length cDNA libraries have been constructed in p-Bluescript II SK+XR vector (Stratagene) from the isolated trunks of 1 d-old yolk-sac larvae and the fast myotomal muscle of juvenile halibut. Expressed Sequence Tags (ESTs) from these libraries can be viewed at (http://www.st-andrews.ac.uk/~fmrg ). Genes of particular interest are currently being characterised including Spindilin protein involved in cellcycle control and derived from maternal mRNA, two markers of osteoblasts (osteonectin and muscoskeletal embryonic nuclear protein), cathepsin B involved in protein degradation and hairy-related 4, a bHLH protein of the Hairy-E(Sp1) family that directs the development of primary neurones. We are also making polyclonal and monoclonal antibodies of selected biomarker proteins as a future community resource. This work is done in collaboration with “Fish muscle research group”, Gatty Marine Laboratory, St. Andrews University, Scotland. This work is supported by grant from the Research Council of Norway (159594/S40) and by the MABIT program (AF0024).
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