U.S.-Japan Cooperative Science: Sources, Acquisition and Use of Algal Lipids by Herbivorous Fishes

Northern Arizona University, Flagstaff AZ

Investigators

Abstract

9981677 Montgomery This award supports a two year collaborative research project between Professor Linn Montgomery of Northern Arizona University in Flagstaff and Professor Heisuke Nakagawa of Hiroshima University in Japan. The researchers will be undertaking a study of the sources, acquisition, and use of algal lipids by herbivorouos fishes. In spite of multiple important functions served by lipids (fats and oils), nutritional studies of herbivorous animals tend to focus on either provision of energy through digestion of carbohydrates or on acquisition of protein required for growth. Lipids constitute a large fraction of biological membranes, served as efficient energy-storage molecules, "spare" protein for growth and enzyme synthesis (rather than protein being degraded to meet energy demands). They even reduce the overall cost of digesting and processing food, relative to protein-rich diets, because they are easy to digest and metabolize. The researchers will test various hypotheses in a single geographic area and oceanographic system (the Japanese islands). In addition, most studies of lipid composition of fish tissues focus on muscle and frequently provide no information about seasonal changes. This research would compare lipid composition in transport (plasma), storage (fat depots), metabolizing (liver) and other tissues (muscle, nerve), and would do so in both summer and winter to detect likely maximum differences. Finally, the collaborators will survey subsistence and commercial fishers to identify herbivorous fish taken and document any general or seasonal preferences which might relate to lipid quality or quantity. The project brings together the efforts of two laboratories that have complementary expertise and research capabilities. Results of the research will assess, in a preliminary way, how variation in lipid composition among species, seasons or geographic locations may be reflected in differential use of these fishes for food among local subsistence or small-scale commercial fisheries. Results will also have implications for dietary recommendations for humans, particularly those relating to intake of various long-chain polyunsaturated fatty acids known to affect cardiovascular disease, certain cancers, and other health conditions. This research advances international human resources through the participation of a postdoc and graduate student. Through the exchange of ideas and technology, this project will broaden our base of basic knowledge and promote international understanding and cooperation. The researchers plan to publish results of the research in scientific journals and on their web page (HTTP://www2.nau.edu/~wim).