Effects of dietary fat and L-methionine on the hepatic metabolism of very low density lipoproteins in the preruminant calf, Bos spp.
The effects of triglycerides (TG) from tallow (1.21 and 2.13 g TG/kg of body weight (BW) per meal, diets R and B respectively) and from tallow plus cream (2.50 g TG/kg of BW per meal, diet L) with or without L-methionine (2.6 g/kg dry matter) on hepatic apparent secretion of very low density lipoproteins (VLDL) were investigated in 3 groups of 4 preruminant calves fitted with chronic catheters and with electromagnetic blood-flow probes implanted in their hepatic vessels. Increasing TG concentrations stimulated the apparent VLDL secretion by the liver (1.02, -0.36 and -1.51 mg VLDL mass/min per kg of BW in diets L, B and R, respectively). L-Methionine increased this secretion when associated with the lipid-restricted (diet R; 0.25 and -1.51 mg VLDL/min per kg of BW) and basal (diet B; 0.35 and -0.36 mg VLDL/min per kg of BW) diets (non-significant). However, the VLDL apparent secretion decreased with the lipid-enriched diet (diet L), which suggests an insufficient dose of L-methionine compared with the level of TG intake, and a possible competition between liver and intestine for utilization of L-methionine for the synthesis of TG-rich lipoproteins.
Auboiron
S
S
INRA-Theix, unité de recherches Métabolismes énergétique et lipidique, Saint-Genès-Champanelle, France.
Durand
D
D
Robert
J C
JC
Chapman
M J
MJ
Bauchart
D
D
D000818:Animals; D001835:Body Weight; D002417:Cattle / Q000254:growth & development / Q000378:metabolism*; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology*; D005223:Fats; D008079:Lipoproteins, VLDL / Q000097:blood / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008715:Methionine / Q000008:administration & dosage / Q000494:pharmacology*; D008892:Milk; D012417:Rumen / Q000254:growth & development; D014280:Triglycerides / Q000494:pharmacology
D004041:Dietary Fats; D005223:Fats; D008079:Lipoproteins, VLDL; D014280:Triglycerides; C013698:tallow; D008715:Methionine