Commercial fish diets often contain high levels of carbohydrates, even though fish have a limited capacity to utilise them and to clear a high glucose load from their system. Therefore, special attention has been given to investigating the physiological responses of fish to carbohydrate-rich feeds. The project GLUCOSE USE IN FISH (Carbohydrate utilization by the working muscle of rainbow trout) investigated the use of carbohydrate-rich diets in pejerrey, South American fish species with great potential for aquaculture. The study's aim was to explore the metabolic responses of pejerrey to high-carbohydrate feed by investigating how they regulate glucose homeostasis. Researchers explored metabolic changes in O. bonariensis in response to dietary conditions. This included the regulation of glucose transporters at transcriptional level in target tissues. Studies have shown that exercise can increase carbohydrate utilisation in rainbow trout and brown trout. Therefore, the team hypothesised that sustained exercise can be used to enhance carbohydrate expenditure in pejerrey. Researchers investigated the ability of fish to increase their natural capacity to clear and utilise plasma glucose by contracting muscle. Therefore, researchers studied the cellular and molecular mechanisms regulating the GLUT-1 and -4 glucose transporters in red and white muscles. Changes in patterns of gene expression were examined using a microarray platform and key biochemical parameters were measured in rainbow trout after four weeks of sustained swimming. These results are expected to help scientists understand how glucose is regulated. The knowledge resulting from GLUCOSE USE IN FISH can be transferred to European companies. This will lead to more efficient and environmentally friendly feeding practices in the rapidly growing and economically important aquaculture sector.
Fish, carbohydrate feed, pejerrey, metabolic response, glucose, rainbow trout