Abstract

The present study was undertaken to measure the effects of dietary tyrosine added to rat diet on serum cholesterol levels in the rat. A total of twenty Wistar strain albino rats were fed with different doses of tyrosine enriched diets containing 0.8 g/100 g, 1.0 g/100 g and 1.2 g/100 g. After 3 weeks of experimental feeding, there was significant increase (p<0.05) in total postprandial serum cholesterol of rats fed with graded of tyrosine when compared with the normal control. Same trend was followed in the week 2 of the same feeding pattern. The effects of dietary tyrosine supplementation on cholesterol levels of the high density lipoprotein (HDL) fraction were comparable, but not all significant on the week 3 treatment. However, there was significant decrease (p<0.05) in week 2 of rats fed with the different graded doses of the tyrosine meal when compared with the normal control group. In addition, significant increase was also observed in the low density lipoprotein (LDL) as compared to the control after week 2 and 3 of tyrosine meal treatment. These results revealed that tyrosine supplementation in a physiological amount may increase cholesterol levels in the rat when added to diet, with a slow release of tyrosine during digestion.

Key words: Dietary tyrosine, total cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL).