Qualité de la chair des lignées de truite arc-en-ciel après sept générations de sélection sur la teneur en lipides musculaires

National audience; Flesh lipid content is a determinant of fillet quality that could be controlled by selective breeding. Two lines of rainbow trouts divergently selected for lipid content, a lean muscle line (L) and a fat muscle line (F), were assessed for raw, cooked, and smoked fillet quality parameters. Fish from the L line gave consistently lower values than those from the F line for all adiposity parameters (fat-meter value, muscle lipid and dry matter content). Raw fillet from L fish gave lower values of lightness, redness and yellowness. However, cooked fillets differed only for yellowness whereas smoked fillets differed for both redness and yellowness but not for lightness. Mechanical resistance of fillets was also affected by selection. Fillets from L fish were firmer at slaughter time and two days post-mortem, as were the smoked fillets. However, no difference in textural parameters was measured between cooked fillets from the two lines. Histological measurement of white muscle fiber size revealed that M fish had much smaller fiber than G fish.