The amount of omega 3 listed in a dog kibble isn't really dependent on the protein source. The manufacturers can add it in a variety of ways through fish or oils. Omega 3s are heat and air sensitive; so a lot of it is destroyed in the kibble cooking process. That's why I always supplement with salmon oil and vitamin E no matter what kibble I'm feeding. The CN Herring and Sweet Potato lists a 1.5% of omega 3 so I might not supplement quite as much as I would with a formula like EVO which has 0.5% omega 3.