397 zyxwvuts Atherosclerosis, 2G (1977) 397-403 @ Elsevier/North-Holland Scientific Publishers, Ltd. EXPERIMENTAL ATHEROSCLEROSIS IN RABBITS FED CHOLESTEROL-FREE DIETS Part 7. Interaction of Animal or Vegetable Protein With Fiber DAVID KRITCHEVSKY, SHIRLEY A. TEPPER, DOROTHY E. WILLIAMS and JON A. STORY The W istar Institute of Anatomy and Biology, 36th Street at Spruce, Philadelphia, 19104 (U.S.A.) (By invitation, received November, 1976) Pa. Summary Rabbits were maintained for 10 months on a semipurified, cholesterol-free atherogenic regimen. All diets contained sucrqse (40%) and hydrogenated coconut oil (14%). The protein (25%) was either casein or soya protein and the fiber (15%) was either wheat straw, alfalfa, or cellulose. Within either protein group the order for induction of cholesteremia was cellulose = wheat straw > alfalfa. For atherogenesis, the effect was cellulose > wheat straw > alfalfa. Soya-wheat straw or soya--cellulose diets were less cholesteremic and athero- genie than their casein counterparts. When alfalfa was the fiber, the two types of protein were almost equivalent. Our results show that casein may be more cholesteremic and atherogenic than soya protein under certain conditions (cellulose or wheat straw as fiber) but the addition of alfalfa to the diet renders the two proteins equivalent. Key words: Alfalfa - Casein - Cellulose -Experimental atherosclerosis - Fiber - Rab- bits - Semipurified diet -Soya protein - W heat straw Introduction Our work with the semipurified, cholesterol-free atherogenic diet introduced by Lambert et al. [l] and Malmros and Wigand [2] has shown that the athero- zyxwvutsr This zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Paper is dedicated to Professor F.G. Schettler on the occasion of his sixthieth birthday. Supported, in Part. by a grant (HL 03299) and a Research Career Award (HL 0734) from the National Heart, Lung and Blood Institute and by grants-in-aids from the National Dairy Council and the National Livestock and Meat Board.