Bio-availability and metabolism of n-3 fatty acid rich garden cress (Lepidium sativum) seed oil in albino rats

The ratio of fatty acids namely linoleic acid (LA, 18:2, n-6) and alpha linolenic acid (ALA, 18:3, n-3) in the diet plays an
important role in enrichment of ALA in tissues and further conversion to long-chain polyunsaturated fatty acids (LC-PUFA) like
eicosapentaenoic acid (EPA, 20:5, n-3) and docosahexaenoic acid (DHA, 22:6, n-3). Garden cress seed oil (GCO) is one of the
richest sources of o-3 fatty acid and contains 29–34.5% of ALA. In this study, dietary supplementation of GCO on bio-availability
and metabolism of a-linolenic acid was investigated in growing rats. Male wistar rats were fed with semi-purified diets supplemented
with 10.0% sunflower oil (SFO 10%); 2.5% GCO and 7.5% SFO (GCO 2.5%); 5% GCO and 5% SFO (GCO 5.0%); 10% GCO
(GCO 10%) for a period of 8 weeks. There was no significant difference with regard to the food intake, body weight gain and organ
weights of rats in different dietary groups. Rats fed with GCO showed significant increase in ALA levels in serum and tissues
compared to SFO fed rats. Feeding rats with 10% GCO lowered hepatic cholesterol by 12.3% and serum triglycerides by 40.4%
compared to SFO fed group. Very low density lipoprotein cholesterol (VLDL-C) and low density lipoprotein cholesterol (LDL-C)
levels decreased by 9.45% in serum of 10% GCO fed rats, while HDL remained unchanged among GCO fed rats. Adipose tissue
showed incorporation of 3.3–17.4% of ALA and correlated with incremental intake of ALA. Except in adipose tissue, the EPA,
DHA levels increased significantly in serum, liver, heart and brain tissues in GCO fed rats. A maximum level of DHA was registered
in brain (11.6%) and to lesser extent in serum and liver tissues. A significant decrease in LA and its metabolite arachidonic acid (AA)
was observed in serum and liver tissue of rats fed on GCO. Significant improvement in n-6/n-3 fatty acid ratio was observed in GCO
based diets compared to diet containing SFO. This is the first study to demonstrate that supplementation of GCO increases serum
and liver ALA, EPA, DHA and decreases LA and AA in rats. Therefore, the GCO can be considered as a potential, alternate dietary
source of ALA.