Two groups of rats were fed on diets with protein from a marine specie holothuria (Holothuria forskali) or casein (for the control group) during 16 days with the aim of assessing the nutritional value of the holothuria protein. Several serum lipid levels were also determined. The results of the nutritive parameters indicate that except for True Digestibility (which did not differ significantly between the two groups) all other indicators were significantly lower for the holothuria fed group. HDL-cholesterol level was significantly higher in the holothuria fed group, while triglyceride level was lower.