Dietary fish protein modulates high density lipoprotein cholesterol and lipoprotein lipase activity in rabbits

To explore the pathways by which fish protein feeding influences HDL metabolism, postheparin plasma lipoprotein lipase and hepatic triglyceride lipase activities were measured in rabbits fed fish protein or soybean protein combined with corn oil or coconut oil in a 2 x 2 factorial arrangement. In addition to greater serum total and LDL-cholesterol concentrations, the elevated HDL cholesterol concentration caused by feeding fish protein, compared with soybean protein, was accompanied by lower VLDL triglycerides and parallel higher lipoprotein lipase activity in fish protein-fed rabbits. These results suggest an enhanced assembly of circulating HDL through promoted lipoprotein lipase activity in rabbits fed fish protein. Moreover, dietary proteins and lipids interacted with one another to alter HDL triglycerides and liver cholesterol concentrations. Diet-induced changes in lipoprotein lipase activity were, however, not related to insulinemia, which was unaltered by purified diet feeding. The present results suggest that fish protein may affect HDL metabolism through the modulation of lipoprotein lipase activity in rabbits.