Beneficial effects of plant sterols/stanols-containing milk powder on lipid metabolism in hamsters

Abstract

The effect of plant sterols/stanols-containing milk powder (phytosterol milk powder, PSMP, containing 2.78% phytosterols mixture) on lipid metabolism in hamsters was investigated. One hundred male 7-week-old Golden Syrian hamsters were given free access to regular rodent chow and water for 1 week to acclimatize. Four extremely (10%) over- and underweight hamsters were eliminated. Sixteen hamsters were killed and examined for plasma and liver lipid compositions to establish the baseline. The remaining hamster were randomly divided into 5 groups, each group of hamsters had statistically similar average body weight, but fed with different experimental diets for 4 weeks. All 5 groups of hamsters were fed with high fat, high cholesterol diet containing different ingredients. Regular rodent chow diet was supplemented with 0.5% (w/w) cholesterol and corn/coconut oil mixture (corn oil/coconut oil = 1:1) to raise the final fat content to 15% (w/w) (Group 1 - control group). Group 2 was the positive control (PC) group, which was fed with diet containing 0.72% (w/w) phytosterols (consisted of 75% β-sitosterol and 10% campesterol). Groups 3-5 were the experimental groups, of which 12.95, 25.90 or 64.75% (w/w) PSMP 1x, 2x and 5x PSMP groups) was added to the diet and the phytosterol mixture contents in these diets were 0.36, 0.72 and 1.8% (w/w), respectively. At the end of 4-week feeding period, hamsters were killed and the plasma and hepatic lipid compositions together with the fecal neutral sterol content were determined. No adverse effects of PSMP on growth and health condition in hamsters were found in this experiment. At the highest feeding dose of PSMP (64.75%, w/w), hamsters had the highest body weight gain and the lowest plasma and liver lipid contents. PSMP showed significant effects on lowering the concentrations of plasma total cholesterol and low density lipoprotein cholesterol. It could also lower the atherogenic index (LDL-C/HDL-C), hepatic lipid levels and relative liver weight while raising the fecal cholesterol and phytosterols excretion in the hyperlipidemic hamsters.