The study compared the effects of two types of omega-3 supplements on dogs: one from plant-based flaxseed oil and the other from marine krill oil. Dogs given krill oil had a significant increase in omega-3 levels, while those given flaxseed oil saw a decrease. This suggests that marine sources of omega-3, like krill oil, are more effective for boosting omega-3 levels in dogs compared to plant-based sources like flaxseed oil.