Objective
The objective of the project is to develop a new index of age in crustaceans using the marine decapod crustacean, Nephrops norvegicus, as the model species. The project aims to demonstrate a correlation between the quantity of the age pigment lipofuscin deposited in brain tissue and the metabolic age of individuals reared under known regimes of temperature and calorific intake. The final phase of the project will attempt to age a wild population of Nephrops using the model developed for captive animals.
The pigment content of wild caught Nephrops is related to size indicating a probable relation with age. Pigment accumulation is being monitored in a Nephrops sample which were caught in the Irish Sea presumed age 2 and now being maintained in the laboratory. This was necessary because of the difficulties encountered in rearing Nephrops juveniles in large numbers. Nevertheless a sample of reared juveniles is also available. In culture Homarus the pigment has accumulated linearly with age in animals ranging from 6 months to 16 months. The pigment content of these animals is approximately 12 times lower than that of wild caught commercial sized animals.
3 phases are envisaged as follows.
Phase 1 is the demonstration of morphological lipofuscin in Nephrops. This phase develops the technique for quantifying the amount of morphological lipofuscin in histological sections of brain tissue and makes a preliminary assessment of the potential of this method for ageing of Nephrops taken from the wild. Tissue sections will be viewed under fluorescence microscope and quantified by image analysis either directly or from fluorescence micrographs. A preliminary assessment of the potential of the method for ageing individuals will be carried out by quantifying the amount of lipofuscin in wild caught animals of widely different sizes (and presumed ages).
Phase 2 is the establishment of a correlation between lipofuscin and age in reared animals. To establish a definite correlation between the amount of lipofuscin in sectioned tissue and age of Nephrops, animals will be reared from the larval stages to 3 years of age. Lipofuscin accumulation in these animals will be monitored at 3 month intervals. Because lipofuscin accumulates as a function of physiological, rather than chronological, age the effects of different temperature regimes and diet and calorific intake on metabolic rates (and accumulating physiological age) will be determined. Separate temperature regimes that simulate annual environmental temperature cycles experienced by the Irish Sea population and by a warm water population in the Mediterranean will be applied to different groups of animals. Gut physiology research (enzyme range, activity, energetics) will allow the development of optimum diets for Nephrops which are essential for a successful long term rearing programme. Metabolic rates of ind viduals will be measured under different temperature and calorific intake to determine the effects of these parameters on lipofuscin deposition.
Phase 3 is the use of the lipofuscin age index on wild populations. The correlation between lipofuscin and age developed in phase 2 will be used to determine the age of wild individuals from the Irish Sea. This will involve streamlining the techniques for handling large samples so that the actual age structure of the population can be determined. The age structure determined by analysis of length frequency data and by the use of lipofuscin will be compared.
Fields of science (EuroSciVoc)
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CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
- natural sciencesphysical sciencesopticsmicroscopy
- medical and health scienceshealth sciencesnutrition
- medical and health sciencesbasic medicinephysiology
- natural sciencesbiological sciencesbiochemistrybiomoleculesproteinsenzymes
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Dublin 2
Ireland