The effect of echium oil or linseed oil in the diet of gestating sows on the fatty acid composition of piglets' tissues

Objectives : Polyunsaturated fatty acids (PUFA) and especially docosahexaenoic acid (DHA) are essential for the growth and development of the foetus, and dietary supplementation may be beneficial. DHA can be directly supplied from the diet through the addition of fish oil, or it may result from the conversion of dietary precursors. As fish oil becomes a scarce resource, research for sustainable alternatives is needed. This study aims to evaluate two sources of n-3 PUFA: linseed oil as a source of $-linolenic acid (ALA, C18:3n-3) and echium oil as a source of stearidonic acid (SDA, C18:4n-3). As SDA is one step further than ALA in the conversion to DHA, the hypothesis is that echium oil will yield a higher conversion to DHA than linseed oil. Materials and Methods : Two groups of sixteen sows each were fed a diet containing 1% linseed oil or 1% echium oil from day 73 of gestation and during lactation. At birth, two piglets per sow were sacrificed and blood, liver and Longissimus dorsi (LD) samples were taken for fatty acid analysis. The effect of diet was analysed by GLM using SAS 4.3. Results : The transfer of the dietary n-3 PUFA from sows to piglets differed according to the source. All tissues had a higher content of ALA when linseed oil was fed. However, when echium oil was fed only plasma and LD but not red blood cells and liver showed a higher content of SDA (and C20:4n-3). Furthermore no difference was found between linseed oil and echium oil in the amount of DHA. Conclusions : Echium oil did not result in a higher conversion to DHA than linseed oil. As echium oil contains less SDA than linseed oil contains ALA, feeding higher amounts of echium oil or richer sources of SDA should be investigated.