the effect of dietary protein source on plasma lipids and lipoproteins in male and female wistar rats

the purpose of this study was to investigate the effect of feeding dietary soy protein and soy protein supplemented with methionine on lipids and lipoproteins content of blood in wistar rats. sixteen male and 16 female wistar rats with the initial live weight of 116 ± 6.3 and 115.8 ± 6.8 grams respectively, were fed by the isocaloric and isonitrogenous diets containing casein (20%), soy protein (28%), soy protein (27%) supplemented with methionine (0.3%) and soy protein (14%) plus casein (10%) for 8 weeks. soy-methionine fed animals performed higher average live weight gain in comparison with the other groups (p<0.05). female rats showed higher serum triglyceride and lower ldl- cholesterol in comparison with male rats (p<0.05). casein fed rats had higher serum cholesterol concentration than soy-casein and soy-methionine groups (p<0.05). according to the metabolic responses of rats to experimental diets, it was concluded that soy-methionine and soy-casein diets were more effective in reducing total and ldl-cholesterol compared to casein or soy diets in male and female wistar rats.