Exercise training combined with a high-fat diet improves the flesh flavour, texture and nutrition of gibel carp (Carassius auratus gibelio)

•A high-fat diet (HFD) increased muscle fat content but reduced flesh hardness.•Exercise training (ET) improved texture but reduced flavour amino acid contents.•Feeding a HFD restored flavour amino acid contents in fish flesh during ET.•ET combined with a HFD improved the flavour, nutritional value and aroma of flesh. To meet the consumer demand for high-quality flesh sources, this study investigated the impacts of exercise training (ET) combined with a high-fat diet (HFD) on flesh quality. The results showed that HFD increased muscular fat content but reduced hardness, flexibility and adhesiveness. ET decreased fat content but increased flesh water holding capacity, hardness and stickiness. In terms of flavour, ET decreased the umami and sweet amino acid contents, which were restored when concomitantly feeding the HFD. Metabolomics further revealed that ET and HFD mainly affect the alanine, aspartate and glutamate metabolism, the citrate cycle and purine metabolism. The E-nose and volatile metabolomics analysis demonstrated that the combination of ET and HFD improved the aroma of flesh by enhancing the content of key flavour compounds within flesh such as hexadecenoic acid, ethyl ester and methyl stearate. This research provides a new strategy for improving the flesh quality of cultured fish.