ASPECTS OF POSITIONAL DISTRIBUTION OF FATTY-ACIDS IN TRIACYLGLYCEROLS OF SKIN, WHITE AND DARK MUSCLE OF MACKEREL SCOMBER-SCOMBRUS IN RELATION TO HYPERTENSION

The triacylglycerols from skin, white and dark muscle of Atlantic mackerel Scomber scombrus were isolated and the distribution of fatty acids on the glycerol examined with pancreatic lipase. The dark muscle, which is the smallest dietary fat source of the three tissues, had less EPA and more DHA than the other two tissues. The EPA deficiency was located in the 2-position. The DHA was similar in both the 2- and 1,3-positions. The white muscle triacylglycerol showed a much higher proportion of DHA in the 2-position than in the 1,3-positions. The skin triacylglycerol was relatively undifferentiated in respect to distribution of EPA and DHA. Saturated acids were least in the 2-position of the white muscle triacylglycerol and highest in the 1,3-position of the same fat. Not unexpectedly, the monoethylenic fatty acids of exogenous origin were located in the 1,3-positions and the highest level was in the dark muscle triacylglycerol. The distribution of the whole of the EPA and DHA is not dissimiliar from that projected from literature on fish triacylglycerols. It is concluded that benefits attributed to a supplement of dietary mackerel, relative to herring, in certain types of hypertension follow from the total omega-3 fatty acid intake and not from any special distribution on glycerol of mackerel fatty acids.