Abstract
Most fish are characterized by a limited efficiency to use carbohydrates, however, the exact mechanism of glucose intolerance in teleost fish is still unclear. The purpose of this study was to determine the effects of many different kinds of natural bio-materials on insulin resistance in fish white muscle. Sixteen bio-materials were administered orally at the amount of 100 mg/kg BW/day except lactoferrin （LF ; 200 mg/kg BW/day） to goldfish （Carassius auratus） for 3 weeks, and the ability to improve insulin sensitivity was examined individually. On week 3, the rate of 2-deoxy-D-glucose （2DG） uptake in the white muscle was measured. The rate in the goldfish muscle was less than one-sixth of those in mammals such as mice and rats, that is, an extremely high insulin resistance in fish muscle was found. Oral administration of a wild plant mineral mixture, seaweed mineral mixture, red ginseng and inositol improved markedly the insulin sensitivity in trunk muscle of fish. These findings suggest that the administration of these bio-materials induces a greater potential to utilize dietary carbohydrates as an energy source to spare protein. Consequently, the costs to aquaculture diets may be substantially reduced and moreover may lead to a solution of the global protein supply shortage.
