THE EFFECT OF DIETARY-CHANGES ON PLASMA-LIPIDS AND LIPOPROTEINS OF 6 LABRADOR RETRIEVERS

Six healthy, spayed female Labrador Retrievers (aged 55 to 11 years), kept under controlled conditions of exercise and housing, were fed a d iet of 15 per cent fat, 24 per cent carbohydrate and 33 per cent prote in for two weeks before and between each of three test diets, of diffe ring fat to carbohydrate ratios (A 13:44, B 20:33, C 25:26 fat:carbohy drate gm per cent dry weight) given in a predetermined order for four weeks each. Fasting plasma lipoproteins and total fatty acids were mea sured weekly. In the fourth week of each test period post-prandial pla sma lipoproteins were measured; Diets B and C increased total (P<0.001 ) and LDL cholesterol (P<0.05) whilst diet A increased HDL triglycerid e (P<0.05). Eicosapentaenoic acid (C20:5) increased on diets B and C, and oleic acid (C18:1) on diet A. Post-prandial hypertriglyceridaemia occurred on all diets. Chylomicron clearance was slower on higher fat diets. Relatively small dietary changes produced significant alteratio ns of plasma lipids, lipoproteins and chylomicron clearance.