Lipoprotein Metabolism in the Preruminant Calf: Effect of a High Fat Diet Supplemented with L-Methionine

Abstract

The effects of dietary lipid and L-Met supplementation on plasma lipids 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 successively the basal diet supplemented with cream (2.7 g of lipid/kg of BW per meal) and the same diet supplemented with L-Met. The diet with cream induced higher triglyceridemia than the basal diet because of a marked increase in chylomicra and in very low density lipoproteins, which suggested stimulation of intestinal lipoprotein secretion. Moreover, this lipid-enriched diet stimulated the formation of very light high density lipoproteins to the detriment of heavy high density lipoproteins. These particles, the bovine counterpart of mammalian high density lipoproteins 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, suggesting direct stimulation of the intestinal secretion of both of these lipoproteins and of the hepatic very low density lipoproteins. No effect of L-Met was observed on the concentrations and the physicochemical properties of low and light high density lipoproteins.

Lipids and lipoproteins in blood serum of calves receiving Yea-Sacc¹⁰²⁶ dietary supplement

“…This is confirmed by other authors (Jenkins et al, 1988;Auboiron et al, 1994;Leplaix-Charlat et al, 1996). VLDL and LDL underwent more considerable changes.…”

“…VLDL and LDL underwent more considerable changes. When the calves were fed colostrum and whole milk, VLDL was the main transporting fraction of TG, which explains why the level of VLDL was then the highest (Auboiron et al, 1994(Auboiron et al, , 1995 and the concentrations of LDL and TG in this fraction, the lowest. When the diet was changed, the percentage of LDL increased in all of the calves, whereas that of VLDL declined, an observation that is confirmed by Jenkins et al (1998).…”

“…According to other authors, the lipid profile, secretion and composition of lipoproteins in calves are modified by the age of animals, amount and type of ingested fat and fodder additives (Jenkins et al, 1988;Auboiron et al, 1994Auboiron et al, ,1995LeplaixCharlat et al, 1996). The effect of biological supplements on the metabolism of lipids in calves has not been investigated to date.…”

Effects of dietary fat and L-methionine on the hepatic metabolism of very low density lipoproteins in the preruminant calf, Bos spp

“…This might result from an insufficient dose of L -methionine as compared to the high level of fat intake or from a possible competition between liver and intestine for Lmethionine uptake. Indeed, recent studies of chylomicron metabolism in methionine-supplemented diet in the preruminant calf (Auboiron et al, 1994) show that L -methionine leads to a marked increase in plasma levels of chylomicrons in peripheral blood, indicating possible stimulation of the secretion of this TG-rich lipoprotein by the intestine.…”

“…However, feeding MHAs to dairy cows during early lactation did not increase the hepatic secretion of triglycerides (Pullen et al, 1989). This lack of effect might be explained by premature bacterial degradation of MHAs during the passage of the digestive contents in the rumen (Patterson and Kung, 1988 (Auboiron et al, 1994).…”