LIPOPROTEIN METABOLISM IN THE PRERUMINANT CALF - EFFECT OF A HIGH-FATDIET SUPPLEMENTED WITH L-METHIONINE

The effects of dietary lipid and L-Met supplementation on plasma lipid s and lipoproteins were investigated in 16-wk-old preruminant calves. Four calves received the basal milk diet (2.0 g of lipid/kg of BW per meal) for 8 d followed by the same diet supplemented with L-Met (2.6 g /kg of dietary DM) for 5 d. Similarly, seven calves received successiv ely the basal diet supplemented with cream (2.7 g of lipid/kg of BW pe r meal) and the same diet supplemented with L-Met. The diet with cream induced higher triglyceridemia than the basal diet because of a marke d increase in chylomicra and in very low density lipoproteins, which s uggested stimulation of intestinal lipoprotein secretion. Moreover, th is lipid-enriched diet stimulated the formation of very light high den sity lipoproteins to the detriment of heavy high density lipoproteins. These particles, the bovine counterpart of mammalian high density lip oproteins of type 1, were distributed within the density range of low density lipoproteins. Addition of L-Met in the diets increased plasma concentrations of chylomicra and very low density lipoproteins, sugges ting direct stimulation of the intestinal secretion of both of these l ipoproteins and of the hepatic very low density lipoproteins. No effec t of L-Met was observed on the concentrations and the physicochemical properties of low and light high density lipoproteins.