Muscle cellularity and flesh quality of wild and farmed sea bass, Dicentrarchus labrax L.

摘要

Sea bass (Dicentrarchus labrax L.) has been widely farmed in the last decade. In order to a better understanding of the final quality of this species, muscle cellularity and quality parameters of the flesh were studied on 14 specimens of wild and 11 farmed Atlantic sea bass, at approximate commercial size (weight 350 g, length 32 cm). White muscle cellularity was evaluated by means of the following parameters: number and diameter of muscle fibres, as well as the muscle fibre size distribution, throughout the total cross-section of the flesh. To ascertain the flesh quality, several physico-chemical parameters (moisture, protein, total fat, fatty acids, hydroxyproline, collagen and pH) were analyzed, and textural mechanical properties (hardness, springiness, chewiness, cohesiveness, gumminess) were determined objectively with a texturometer. Muscle cellularity was different between both groups, such that muscle fibre density was higher for wild specimens (p<0.05). Farmed sea bass showed a higher content of moisture and protein (p<0.01), and a lower flesh pH, and hydroxyproline and collagen contents (p<0.01). Despite of the fact that the total fat did not show significant differences between both populations, saturated and monounsaturated fatty acids were significantly higher in farmed than in wild sea bass, whereas wild fish showed a higher content of polyunsaturated fatty acids (p<0.05). No significant differences were found in the total content of omega -3 fatty acids between both groups. All textural properties were significantly higher in wild than in farmed fish (p<0.001), all of them show a positive and significant correlation with muscle fibre density, pH, hydroxyproline and collagen contents. Changes in these parameters determined marked differences in the flesh quality of wild and farmed sea bass, whereas no relationship was found between muscle cellularity and nutritional composition of the sea bass. According to our results, genetic factors as well as the influence of extrinsic factors such as feeding regimes and/or exercise may determine significant variations of some structural and flesh quality parameters of the sea bass..