You may have heard or read this through advertising channels: `Are plants the new cows?’. This widely used slogan by a major consumer goods supplier from the Benelux responds to the current trend of eating more plant based food or becoming flexitarian. This trend also seems to slumber in feeds. For E.F.S., being a salmon oil/fish oil supplier, the question arises: ”Can salmon oil/fish oil be substituted by vegetable oils?”

The concise scientific answer is `no’.

Fatty acids

Plants naturally contain only one omega-3 fatty acid, i.e. alpha-linolenic acid (ALA: C 18:3). Fish on the other hand extract several omega-3 fatty acids from feed, including some essential fatty acids such as eicosapentaenoic acid(EPA: C 20:5) and docosahexaenoic (DHA: C 22:6), which algae and plankton produce by means of photosynthesis. This leads the formed omega-3 that has been formed further down the food chain. By eating fish humans also become part of this chain. For centuries fish has been eaten to promote good health (fish on Friday), including filets, but of course also the well-known cod liver oil.

Nowadays eating meat/fish is under intense scrutiny and is also mentioned in the climate agreement. The food sector suggests we can get sufficient nutrients, including omega-3, from plant products. One of the assertions made is ‘Are plants the new cows?’. It overlooks the fact that vegetable oils only contain the omega-3 fatty acid alphalinolenic acid and not EPA and DHA. Now it happens to be the case that humans and animals are able convert alphalinolenic acid into EPA and DHA, but various studies show that conversion into the essential fatty acids is very limited. Hussein et al. (2005) have shown that ALA can only form 0.3% EPA and <0.01% DHA.

Exactly EPA and DHA are the polyunsaturated fatty acids that offer many health benefits. In the current human and animal dietary pattern the omega-3:omega-6 ratio is out of balance. An optimal ratio is 1:5, however often this ratio is over 1:10. This leads to an rise in inflammatory reactions, reduced fertility, and an increased risk of cardiovascular diseases and skin problems. Recent field research by E.F.S. shows that the use of 1% E.F.S. Scottish fish oil in sow feed generates an average number of 1.2 piglets born alive per litter (2018).

Therefore it can be stated that fish and fish oil are not fully interchangeable with plants and vegetable oils. For health purposes it remains important to consume fish products as a source of omega-3.


The additional question that arises when mulling over the assertion `are plants the new cows.’ is: `Is the substitution of fish oil by vegetable oil a sustainable alternative?’.

As a result  of overfishing in the past and insufficient availability of wild fish many farmed fish are produced and consumed today. By the introduction of current systems and certifications (such as MSC and ASC) fisheries have been regulated in a responsible and more sustainable manner. Also fish farming under strictly controlled conditions is very efficient, among others due to a very low feed conversion.

In the past fisheries would dump viscera at sea, which had and still has a negative effect on the environment. Current legislation includes the provision that viscera need to be landed. E.F.S.’s suppliers convert these viscera into a highquality oil and protein.

In doing so a waste stream from the food sector is processed in the feed sector and thus a contribution is made to sustainable and healthy livestock farming.