Effects of β-carotene on lipid metabolism in rats fed with or without cholesterol

The purpose of this study was to investigate the effect of β-carotene on lipid metabolism in rats fed with or without cholesterol. Forty male adult Wistar rats were randomly divided into four groups in a 2 X 2 factorial design according to 1% cholesterol (with or without) and 0.2% β-carotene (with or without). Half of rats of each group were killed after three- or six-week feeding, then liver and-artery blood were collected. Items analyzed included serum total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL- C), liver total cholesterol, and liver triglyceride. Retinol and β-carotene in serum and liver were analyzed by HPLC. The results showed that cholesterol-fed groups had significantly higher liver total cholesterol concentrations after three-week feeding and higher serum total cholesterol concentrations after six-week feeding, especially in the non-β-carotene-fed group. Cholesterol-fed groups had lower serum HDL-C concentrations after three-week feeding, but there was no difference in the LDL-C concentration. After six-week feeding, HDL-C concentration was still lower in rats fed cholesterol but no β-carotene whereas LDL-C concentration rose significantly. Rats fed cholesterol and β-carotene had no such condition and the HDL-C concentration rose significantly. Cholesterol feeding made the liver TG concentration higher after three-week feeding, but there was no difference in the serum TG concentration after either three- or six-week feeding. β-Carotene feeding showed lower liver TG concentration and higher serum TG concentration after three-week feeding, but no difference in serum TG concentration between β-carotene-fed and non-β-carotene-fed groups after six-week feeding. Cholesterol feeding made the liver retinol concentration lower whereas β-carotene feeding made the liver retinol concentration higher but had no effect on the serum retinol concentration. The serum β-carotene concentration was decreased whereas the liver β-carotene concentration was not affected due to cholesterol feeding.