In a study on rats that directly compared krill oil and fish oil supplementation, krill oil reduced liver triglyceride levels significantly more.
Scientists looked at three groups of rats -- one group that consumed a control diet, one group that had its diet supplemented with 2.5 percent krill oil, and a final group that was given 2.5 percent fish oil in its diet. Both krill oil and fish oil significantly inhibited the activity of enzymes that metabolize fat in the liver, but the krill oil had a more pronounced effect.
Emax Health reports:
"According to the study's authors, 'these data suggest a higher potency of krill oil in decreasing hepatic lipogenesis [production of fat by the liver] when compared to fish oil at relatively short periods of dietary treatment.' Experts do not know why krill oil seems to have this effect, although some suggest the body can better absorb and utilize krill, or that krill may have a different ratio of the two main omega-3 fatty acids."