FATTY-ACID COMPOSITION OF THE TOTAL, NEUTRAL AND PHOSPHOLIPIDS OF POND-RAISED BRAZILIAN PIARACTUS-MESOPOTAMICUS

Seven sample lots of farmed Piaractus mesopotamicus, fed a set diet, c ollected at different times during the year were analysed. The total l ipids (11 +/- 3% fresh weight, muscle) consisted of 94% neutral lipids and 5% phospholipids. Sixty-seven fatty acids and dimethylacetals wer e detected in the total lipids, the principal acids being 18:1 omega 9 +/- omega 7 (41.0 +/- 1.7%), 16:0 (24.2 +/- 1.2%), 18.2 omega 6 (9.1 +/- 0.5%), 16:1 omega 7 (8.9 +/- 0.7%), 18:0 (7.7 +/- 0.5%) and 14:0 ( 3.2 +/- 0.5%). The neutral lipids exhibited a similar profile. The pho spholipids had a higher proportion of polyunsaturated fatty acids, the major components being 18:1 omega 9 +/- omega 7 (17.5 +/- 1.8%), 16:0 (16.7 +/- 2.0%), 20:4 omega 6 (11.6 +/- 1.3%), 22:6 omega 3 (11.0 +/- 1.3%), 18:2 omega 6 (9.1 +/- 0.7%), 18:0 (8.9 +/- 1.1%), 22:5 omega 6 (5.8 +/- 0.7%). No definite trend was seen in relation to season (wat er temperature, 7-26 degrees C). The fish samples analysed were poor i n omega 3 fatty acids, which appeared to reflect the low omega 3 fatty acid content of the diet.