Effect of two different protein/fat ratios of the diet on meagre (Argyrosomus regius) traits.

摘要

The aim of this study was to evaluate the effect of 2 diets with different protein/fat ratios (P/F; diet A: P/F 2.26; diet B: P/F 3.36) on the chemical composition, fatty acid profile and some somatic indices of meagre (Argyrosomus regius). The trial was carried out in 2 groups raised in 2 different sea cages during 15 months. At the end of the production cycle, biometric measures as well as chemical-nutritional analysis of the fillets were conducted on 25 fish per group. Diet A, with a lower P/F, furnished animals with higher percentages of mesenteric fat (0.48 vs. 0.41%; P<0.01) and fillet yield (51.21 vs. 48.12; P<0.01). Moreover, the fillets obtained with the diet A showed higher percentage of fat (3.60 vs. 2.41%; P<0.01), lower moisture (74.10 vs. 75.42%; P<0.01), lower losses of water under pressure (16.73 vs. 20.20%; P<0.01) and after 48 h of refrigeration (3.08 vs 4.23%; P<0.01). The fatty acid profile of fillets was affected by the diet. Diet A resulted to a higher level of saturated fatty acids (26.44 vs. 23.17% of total lipid; P<0.01) and a lower percentage of polyunsaturated fatty acids (31.56 vs. 36.08%; P<0.01) in the fillet, mainly due to the lower content of linoleic acid (13.63 vs. 19.77%; P<0.01). The atherogenic (AI) and thrombogenic (TI) indices, which were very low in group B (AI=0.48 vs. 0.60, P<0.01; TI=0.33 vs. 0.37, P<0.01), together with the low lipid content of meat in both groups, confirmed the very high nutritional quality of meagre fillets.