Chub and horse mackerel from the Southern Adriatic Sea as sources of n-3 PUFA.

Objective - To ascertain the extent to which the flesh from chub mackerel (Scomber japonicus) and horse mackerel (Trachurus trachurus) caught off the Apulia coast (Southern Italy) could contribute to meet human requirements for n-3 polyunsaturated fatty acids (n-3 PUFA). Methodology - Two batches per species, 40 fish each, were harvested in the coastal waters of the Gulf of Manfredonia (Southern Adriatic Sea). Chub mackerel (CMK) were caught in February and in October 2005 (overall average weight +/- standard error = 99.0 +/- 2.50 g and 397 +/- 4.14 g, respectively), whereas horse mackerel (HMK) were caught in July 2005 and March 2006 (overall average weight +/- s.e. = 305 +/- 6.90 g and 297 +/- 4.27 g, respectively). Within each batch 20 fish were filleted, the raw skinned fillets of each fish being paired and individually analysed in duplicate for lipids (chloroform-methanol extraction), and fatty acid composition (% fatty acid methyl esters) and content (mg/100 g edible portion) by capillary gas chromatography. The remaining 20 fish per batch were thoroughly cooked on an electric open-hearth grill and the flesh from the paired fillets of each fish individually analysed for the same nutrients. Summary of the main results - Fall CMK, either raw or cooked, were fattier than winter ones (overall mean, o.m. = 4.31 vs. 2.02%, P<0.001). Saturated fatty acid (SFA) percentage was slightly increased by cooking (o.m. 25.81 vs. 26.93%, P<0.01), but it did not seem to be influenced by catch season. This very effect was the only significant one as to monounsaturated fatty acid (MUFA) and PUFA percentages: fall CMK were richer in MUFA compared with winter fish (o.m. 20.06 vs. 13.60%, P<0.001), whereas they had a lower content of PUFA (o.m. 47.10 vs. 53.76%, P<0.001), both of the n-6 (o.m. 5.06 vs. 6.67, P<0.001) and n-3 families (o.m. 40.45 vs. 45.40%, P<0.001). Being fattier, though, fall CMK had a far higher content of n-3 PUFA. With an average content of 1322 mg/100 g edible portion (range 803 – 1960 mg/100 g), a 100-g serving of grilled flesh was able to cover 82% of daily n-3 PUFA requirement for an adult male, reaching a maximum of 120% daily requirement for an adult female. Summer HMK, either raw or cooked, were fattier than winter ones (o.m. 6.23 vs. 4.55%, P<0.001). SFA percentage was slightly decreased by cooking (o.m. 29.16 vs. 27.46%, P<0.001), catch season still having no significant effect on this group of fatty acids as already observed for CMK. Other groups of fatty acids, namely MUFA, n-3 PUFA and PUFA on the whole, behaved quite differently in this species, being affected by both state (raw-cooked) and catch season. The highest n-3 PUFA content was found in the grilled flesh of summer HMK, with an average content of 1936 mg/100 g edible portion (range 1328 – 2973 mg/100 g), high enough to exceed by far the daily requirements of an adult male.