Effects of Dietary Polyunsaturated Fat on HDL - Cholesterol, Total Cholesterol and Triglyceride in Plasma and Tissues of Adult Rats

The study was designed to observe the effects of dietary intake of three different levels of polyunsaturated to saturated fatty acid (P/S) ratio on plasma HDL - cholesterol and triglyceride in plasma and tissues of adult rats. Rats were assigned into the three diet groups, composed of protein 24%, carbohydrate 46%, and fat 30% of total caloric intake. However, the P/S ratio of fat was adjusted by using beef tallow, corn oil and perilla oil to give 0.2, 1.1 and 6.0. All groups were fed ad libitum for 4 week. Plasma cholesterol level was decreased but net significantly with increasing P/S ratio of dietary fat, and showed significant negative correlation coefficient. Plasma TG level was also decreased with increasing PUFA level of dietary fat. However, the effect of P/S ratio (6.0) was not greater than that of P/S ratio (1.1) on plasma TG concentration. This implied that high level of PUFA was not required to change plasma TG level as much in the case of HDL-cholesterol. Plasma HDL-cholesterol was significantly increased only in the group of P/S ratio 6.0 which suggested that high level of dietary PUFA was required to increase HDL level. There was a decreasing trend in the levels of total cholesterol and TG per g liver with increasing P/S ratio of dietary fat. There was no effect in the levels of TG per g skeletal muscle by P/S ratio but the level of cholesterol per unit skeletal muscle was rather increased with increased P/S ratio.