iirc all omega3 in non-plants comes from their diet of plants. Similarly we make Omega3 eggs, by feeding them lots of omega 3. Someday we may have omega3 pepperoni pizza by feeding the cows a GMO corn that makes omega3. The more the consumer demands, the more industry will shift to provide, but sometimes it's a comedy. We wanted pasture chickens w/ omega 3 from grass, we got caged birds w/ flaxseed supplements.
Or feeding cows what they "naturally" graze on, namely, grass. Grass-fed beef has substantially more omega-3s than the grain-fed beef we eat today.
Even we humans have a ton more omega-6 in our tissues than we did before, largely because of our diets. In 1961, we ate diets of 5.8% omega-6s, and our adipose tissue concentrations of n-6 were 9%. Today, Americans eat around 9% of their energy as n6 fats, and they are 23%+ of our fat tissue!
