Effect of squalene, tocotrienols and alpha-tocopherol supplementations in the diet on serum and liver lipids in the hamster

The short-term effect of dietary squalene (SQ) tocotrienols (T3) and alpha-tocopherol (T) on serum and liver cholesterol levels was investigated in the hamster. Our results show that dietary squalene (0.1%) lowered serum total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) levels as compared with the control palm oil triacylglycerol (POTG) group; however, only the difference between serum TC levels of the two groups was significant (P<0.05). In the presence of 162 ppm of tocotrienols or 72 ppm of alpha-tocopherol the serum TC and LDL-C levels of squalene-fed hamsters were further lowered (P<0.01) as compared with that of the POTG and POTG-SQ groups; the HDL-C level appeared unaffected. As for the serum TAG level, the effect of squalene, tocotrienols and alpha-tocopherol were inconsistent. The liver total lipids of the squalene-fed (POTG-SQ), squalene and T3-fed (POTG-SQ-T3) and squalene and alpha-tocopherol-fed (POTG-SQ-T) hamsters were significantly increased as compared to that of the POTG group. This increase in total lipids was due to significant increases in TC and Cholesterol ester (CE) levels in the liver of the treated groups as compared with the control group (POTG). Liver TAG level was not affected consistently in treated groups. Our results show that short-term low-level (0.1%) squalene feeding lowered serum cholesterol levels by increasing cholesterol ester accumulation in the liver. Tocotrienols and alpha-tocopherol enhanced the serum cholesterol-lowering effect of dietary squalene without increasing further the cholesterol ester accumulation activity in the liver of the hamster. Copyright (C) 1997 Elsevier Science Inc.