HEPATIC TRIACYLGLYCEROL REGULATION IN RATS FED FUNCTIONAL MILK FAT AT HIGH FAT LEVELS

GERSTNER, CAROLINA; LAVANDERA, JIMENA; GONZALEZ, MARCELA; SAIN, JULIANA; ANTONACCI, LILIANA; GAGLIOSTRO, GERARDO; BERNAL, CLAUDIO

Posadas-Misiones

Congreso; 56 th INTERNATIONAL CONFERENCE ON THE BIOSCIENCES LIPIDS (ICBL); 2015

High intake of Milk Fat (MF) has been associated with lipid alterations andcardiovascular disease risk. However, unsaturated fatty acid supplementation todairy cow diets might decrease the saturated fatty acids (SFA) and increase theConjugated Linoleic Acids (CLA) and t11-18:1 contents of MF leading to afunctional milk fat (FMF) with potential health benefits on lipid regulation. Sincesteatosis and other hepatic lipid alterations have been associated with highintake of fats in humans and in experimental animals, the aim of this study wasto investigate some biochemical mechanisms involved in the liver triacylglycerol(TAG) regulation of rats fed MF and FMF diets at 7 and 30%. Male Wistar rats (¡Ö100g) were fed (60d)diets based on MF, FMF or control (C) fat, at 7 or 30% (w/w) of fat levels. TAGlevels, TAG secretion rate (TAGSR), regulatory key enzyme activities and theexpression of some transcription factors and enzymes involved in TAG modulationin liver were determined. Hepatic TAG contents were (mmol/g);C7:29.12¡À1.91a,b; C30:48.14¡À2.35c; MF7:23.84¡À1.37a;MF30:35.32¡À2.69b; FMF7:22.91¡À1.36a; FMF30:33.22¡À3.15a.Increased hepatic TAG content in C30 (vs.C7) rats was associated with anincreased SREBP-1c gene expression (+48%), as well as FAS (105%) and ACC (135%)activities. FMF30 (vs.C7) decreased the SREBP-1a (-33%) and CPT-Ia (-56%) mRNAexpressions, increased SREBP-1c (29%), FAS (90%) and SCD1 (55%) mRNAexpressions, raised the FAS (296%) and ACC (63%) activities and elevated the hepaticTAGSR (25%). While MF30 (vs. C7) did not increase the hepatic TAGSR, but also modifiedthe lipogenesis/ b-oxidation equilibrium. MF30 decreased the CPT-Ia(-31%) mRNA expression, increased the FAS (86%) and SCD1 (250%) mRNAexpressions, reduced the CPT-Ia activity (-50%), elevated the FAS (110%) andACC (58%) activities. In conclusion, although high fat diets increased theequilibrium lipogenesis/b-oxidation, FMF at high-fat levels prevented thehepatic TAG accretion by increasing the TAG-SR.