1.1Sources

Euphausiacea (commonly called 'Krill', which refers to the entire Euphausiacea family but can come from the atlantic or pacific in which the species are referred to as superba and pacifica, respectively) is a family of small sea creature (crustacean) which confers some dietary eicosapentanoic acid (EPA) and docosahexaenoic acid (DHA), the two fatty acids that are the active components of Krill Oil and can increase plasma levels of EPA and DHA. Krill tends to have similar DHA content to oily fish with a slightly higher EPA content (per weight basis).The krill itself does have a respectable and bioavailable protein content (11.9-15.4% total animal weight; lipids consist of 0.5-3.6% total weight and 12-50% dry weight), but the oil itself is not a protein supplement due to processing most amino acids out of the oil; nutritionally, krill is similar to shrimp.

What tends to make krill unique from fish oil is the collection of fatty acids in the form of phospholipids rather than triglycerides, which is a phenomena that separates crustacean animals from fish in general;while crustaceans have been reported to have up to 65% of total fatty acids bound as phospholipids krill has been quantified in the 28-58% range.

1.2Composition

Krill oil fatty acids tend to be diacylglycerides (two fatty acids bound to a glycerol molecule) rather than triglycerides, and due to binding to a phosphatidic acid group at the final binding site the structure is a phospholipid in nature.

Fish oil supplementation tends to be triglycerides while Lovaza (brand name) are ethyl esters.

1.3Properties

Freezing of krill appears to reduce the phospholipid content by up to 15% after 30 days of storage following freezing with about half of the phospholipids being destroyed after 7 months.

Due to the astaxanthin content, the fatty acids in krill oil appear to be more resistant to oxidation as astaxanthin appears to be destroyed sacrificially.