Yeung Chi Hang, Thomas. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 126-146). / Abstracts in English and Chinese. / Table of content / ACKNOWLEDGEMENT --- p.i / ABSTRACT --- p.ii / LIST OF ABBREVIATION --- p.vi / TABLE OF CONTENTS --- p.vii / Chapter Chapter1 --- General Introduction / Chapter 1.1 --- INTRODUCTION --- p.1 / Chapter 1.2 --- FORMATION OF CLA --- p.1 / Chapter 1.3 --- OCCURRENCE OF CLA IN FOODS --- p.5 / Chapter 1.4 --- PHYSIOLOGICAL EFFECTS OF CLA --- p.8 / Chapter 1.4.1 --- Anticarcinogenic Effects of CLA --- p.8 / Chapter 1.4.2 --- Antiatherogenic Effect of CLA --- p.11 / Chapter 1.4.3 --- Antioxidant Effect of CLA --- p.12 / Chapter 1.4.4 --- CLA and Immune Response --- p.13 / Chapter 1.4.5 --- CLA and Body Composition --- p.14 / Chapter Chapter2 --- Protective Effect of CLA on Copper-Induced Human LDL Oxidation / Chapter 2.1 --- INTRODUCTION --- p.17 / Chapter 2.1.1 --- Oxidative Modification of LDL and Atherosclerosis --- p.20 / Chapter 2.1.1.1 --- Understanding of LDL --- p.20 / Chapter 2.1.1.2 --- Oxidative Modification of LDL --- p.20 / Chapter 2.1.1.3 --- Role of Oxidative Modified LDL in Atherogenesis --- p.23 / Chapter 2.1.2 --- Antioxidants and Atherosclerosis --- p.25 / Chapter 2.1.3 --- Measuring TBARS Formation as an in vitro Index to Monitor LDL Oxidation --- p.26 / Chapter 2.1.4 --- CLA and Atherogenesis --- p.27 / Chapter 2.2 --- OBJECTIVE OF THE PRESENT STUDY --- p.28 / Chapter 2.3 --- MATERIALS AND METHODS --- p.29 / Chapter 2.3.1 --- Human LDL Isolation --- p.29 / Chapter 2.3.2 --- LDL Oxidation --- p.30 / Chapter 2.3.3 --- Thiobarbituric Acid Reactive Substances (TBARS) Assay --- p.30 / Chapter 2.4 --- STATISTICS --- p.31 / Chapter 2.5 --- RESULTS --- p.32 / Chapter 2.5.1 --- Inhibitory Effect of BSA on Human LDL Oxidation --- p.32 / Chapter 2.5.2 --- Pro-oxidant Effect of LA on Human LDL Oxidation --- p.32 / Chapter 2.5.3 --- Inhibitory Effect of CLA on Human LDL Oxidation --- p.32 / Chapter 2.6 --- DISCUSSION --- p.37 / Chapter 2.6.1 --- Effect ofBSA on Copper-Induced LDL Oxidation --- p.37 / Chapter 2.6.2 --- Effect of LA on Copper-Induced LDL Oxidation --- p.38 / Chapter 2.6.3 --- Protective Effect of CLA on Copper-Induced Human LDL Oxidation --- p.39 / Chapter Chapter3 --- Hypolipidemic Activity of CLA / Chapter 3.1 --- INTRODUCTION --- p.42 / Chapter 3.1.1 --- Total Cholesterol and LDL Cholesterol --- p.42 / Chapter 3.1.2 --- Triglyceride (TG) --- p.44 / Chapter 3.1.3 --- Hypolipidemic Effect of CLA --- p.45 / Chapter 3.1.4 --- Golden Syrian Hamster as an Animal Model of Cholesterol Metabolism --- p.46 / Chapter 3.2 --- OBJECTIVES OF THE PRESENT STUDY --- p.48 / Chapter 3.3 --- MATERIALS AND METHODS --- p.48 / Chapter 3.3.1 --- LA and CLA --- p.49 / Chapter 3.3.2 --- Animals --- p.49 / Chapter 3.3.3 --- Experiment1 --- p.49 / Chapter 3.3.4 --- Experiment2 --- p.51 / Chapter 3.3.5 --- "Determination of Serum TC, HDL-Cholesterol (HDL-C) and TG" --- p.54 / Chapter 3.3.6 --- Lipid analysis of Liver and Adipose Tissue --- p.54 / Chapter 3.3.6.1 --- Lipid Extraction and Separation of Different Lipid Species --- p.54 / Chapter 3.3.6.2 --- Acid-Catalyzed Methylation of Fatty Acids --- p.55 / Chapter 3.3.6.3 --- GLC Analysis of FAME --- p.55 / Chapter 3.3.7 --- Quantification of Tissue Cholesterol --- p.56 / Chapter 3.3.7.1 --- Cholesterol Extraction and Silylation --- p.56 / Chapter 3.3.7.2 --- GLC Analysis of TMS-Ether Derivative of Cholesterol --- p.56 / Chapter 3.4 --- STATISTICS --- p.57 / Chapter 3.5 --- RESULTS --- p.59 / Chapter 3.5.1 --- Body Weight and Food Intake --- p.59 / Chapter 3.5.2 --- "Effect of Dietary CLA Supplementation on Serum TG, TC and HDL-C" --- p.59 / Chapter 3.5.3 --- "Effect of Dietary CLA Supplementation on Hepatic TG, Phospholipid and Cholesterol" --- p.64 / Chapter 3.5.4 --- Effect of Dietary CLA Supplementation on Adipose Tissue TG and Cholesterol --- p.73 / Chapter 3.5.5 --- Effect of CLA Supplementation on Cholesterol Levels of Different Tissues --- p.73 / Chapter 3.6 --- DISCUSSION --- p.79 / Chapter 3.6.1 --- "Effect of CLA Supplementation on Serum TG, TC and HDL-C" --- p.79 / Chapter 3.6.2 --- "Effect of CLA Supplementation on Hepatic TG, PL and Cholesterol" --- p.81 / Chapter 3.6.3 --- Effect of CLA on Adipose Tissue TG and Cholesterol --- p.83 / Chapter 3.6.4 --- Implication of CLA Intake in Humans --- p.84 / Chapter Chapter4 --- Influences of Dietary CLA on Cholesterol Homeostasis / Chapter 4.1 --- INTRODUCTION --- p.86 / Chapter 4.2 --- NEUTRAL EFFECT OF DIETARY CLA SUPPLEMENTATION ON HMG-COA REDUCTASE ACTIVITY --- p.88 / Chapter 4.2.1 --- HMG-CoA Reductase as the Rate-Limiting Enzyme in Cholesterol Synthesis --- p.88 / Chapter 4.2.2 --- Objective of The Present Study --- p.91 / Chapter 4.2.3 --- Materials and Methods --- p.92 / Chapter 4.2.3.1 --- Preparation of Hepatic Microsome --- p.92 / Chapter 4.2.3.2 --- HMG-GoA Reductase Activity Assay --- p.92 / Chapter 4.2.4 --- Statistics --- p.93 / Chapter 4.2.5 --- Results --- p.94 / Chapter 4.2.6 --- Discussion --- p.96 / Chapter 4.3 --- DOWN-REGULATION OF THE INTESTINAL ACAT ACTIVITY BY CLA FEEDING --- p.97 / Chapter 4.3.1 --- Role of ACAT in Cholesterol Absorption --- p.97 / Chapter 4.3.2 --- Objective of The Present Study --- p.99 / Chapter 4.3.3 --- Materials and Methods --- p.100 / Chapter 4.3.3.1 --- Preparation of Intestinal Microsome --- p.100 / Chapter 4.3.3.2 --- ACAT Activity Assay --- p.100 / Chapter 4.3.4 --- Statistics --- p.101 / Chapter 4.3.5 --- Results --- p.102 / Chapter 4.3.6 --- Discussion --- p.104 / Chapter 4.4 --- ALTERATION OF FECAL EXCRETION BY DIETARY CLA --- p.105 / Chapter 4.4.1 --- Objective of The Present Study --- p.108 / Chapter 4.4.2 --- Materials and Methods --- p.109 / Chapter 4.4.2.1 --- Separation of Neutral and Acidic Sterols --- p.109 / Chapter 4.4.2.2 --- Neutral Sterol Analysis --- p.109 / Chapter 4.4.2.3 --- Acidic Sterol Analysis --- p.110 / Chapter 4.4.2.4 --- GLC Analysis of Neutral and Acidic Sterols --- p.110 / Chapter 4.4.3 --- Statistics --- p.113 / Chapter 4.4.4 --- Results --- p.114 / Chapter 4.4.4.1 --- Effect of CLA Supplementation on Fecal Output of Neutral Sterols --- p.114 / Chapter 4.4.4.2 --- Effect of CLA Supplementation on Fecal Output of Acidic Sterols --- p.114 / Chapter 4.4.5 --- Discussion --- p.118 / Chapter Chapter5 --- Conclusions --- p.123 / References --- p.126

Orientador: Cláudia Maria Bertan Membrive / Banca: Guilherme Pugliesi / Banca: Flávia Lombardi Lopes / Resumo: Mortalidade embrionária em bovinos, entre 15 e 19 dias de prenhez, pode ser promovida pela liberação de PGF2 endometrial. A síntese de PGF2 é inibida pela suplementação com compostos ricos em ácido linoléico, como a semente de girassol. Assim, objetivou-se avaliar o efeito e os mecanismos pelos quais a suplementação com semente de girassol atua na performance reprodutiva de fêmeas bovinas de corte. Hipotetizou-se que tal suplementação promove um incremento na taxa de concepção de receptoras de embriões produzidos in vitro submetidas à TETF e que tal efeito decorra de modificações na composição lipídica plasmática e endometrial, alterações na expressão de transcritos envolvidos na biossíntese de eicosanoides e/ou modificações no número e/ou morfometria das glândulas endometriais. No Experimento 1, novilhas mestiças zebuínas submetidas ao protocolo de TETF suplementadas com semente de girassol, por 22 dias a partir da remoção do dispositivo de progesterona, apresentaram maior taxa de concepção em relação ao grupo controle (55,66% vs. 36,94%; P < 0,01). No Experimento 2, vacas Nelore suplementadas com semente de girassol apresentaram maiores concentrações plasmáticas de colesterol total, LDL e HDL; modificações na composição lipídica endometrial e alterações na expressão de transcritos envolvidos na biossíntese de eicosanoides. Conclui-se que a suplementação com semente de girassol aumenta a taxa de concepção por modificar a composição lipídica plasmática e endometrial, a expressão de transcritos envolvidos na biossíntese de eicosanoides e número... ((Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Embryonic mortality in cattle, between 15 and 19 days of pregnancy, can be promoted by the release of endometrial PGF2. Synthesis of PGF2 is inhibited by supplementation with compounds rich in linoleic acid such as sunflower seed. This study aimed to evaluate the effects and the mechanisms by which supplementation with sunflower seed acts on reproductive performance of beef cows. It was hypothesized that such supplementation promotes an increase on conception rate of in vitro-produced embryos subjected to FTET; and that this effect arises from changes in plasma lipid composition and endometrial changes in the expression of transcripts involved in the biosynthesis of eicosanoids and/or changes in the number and/or endometrial gland morphology. In Experiment 1, zebu crossbred heifers submitted to the FTET protocol supplemented with sunflower seed, for 22 days from the removal of the progesterone device, showed higher conception rate in the control group (55.66% vs. 36.94% ; P < 0.01). In Experiment 2, Nelore cows supplemented with sunflower seed showed higher plasma concentrations of total cholesterol, LDL and HDL, changes in endometrial lipid composition and changes in the expression of transcripts involved in the biosynthesis of eicosanoids. It was concluded that supplementation with sunflower seeds increases the conception rate by modifying the lipid composition of the plasma and the endometrium, the expression of transcripts involved in the biosynthesis of eicosanoids and number and morphometry of the endometrial glands / Mestre

The effects of conjugated linoleic acid (CLA) on lipogenesis and preadipocyte proliferation in young pigs were evaluated in two separate experiments. The first compared dietary effects of linoleic acid, beef tallow, and CLA on composition, lipogenesis, and DNA synthesis. Eighteen pigs weaned at 17 d of age were allotted randomly to corn-based diets supplemented with 1.5% corn oil, 1.5% tallow, or 1.5% CLA. The second experiment evaluated the effects of CLA included with diets high in polyunsaturated fat or beef tallow. Twenty-four pigs weaned at 17 d of age were allotted randomly to one of four corn-based diets supplemented with: 15% corn oil, 12% corn oil + 3% CLA, 15% tallow, and 12% tallow + 3% CLA. The piglets in both trials were fed a basal diet for 7 d and their respective diet for 35 d. [U-14C]Glucose incorporation into total lipids was (experiment 1): 10.64, 11.04, 13.64; (experiment 2): 21.15, 17.54, 21.34, and 19.52 nmol/(105 cells per h) for subcutaneous (s.c.) adipose tissue from corn oil, tallow, CLA; corn oil, corn oil + CLA, tallow, and tallow + CLA-fed piglets, respectively. Tritiated thymidine incorporation into DNA was not different in s.c. adipocytes across treatment groups, but was 5,581, 2,794, 6,573, and 3,760 dpm/(105 cells per h) in s.c. stromal vascular cells from corn oil, corn oil + CLA, tallow, and tallow + CLA-fed piglets, respectively (CLA main effect p<0.034). Additionally, there was a greater proportion of s.c. adipocytes in the smaller, 180-pL cell fraction from the corn oil + CLA-fed pigs (p<0.0074). CLA in the diet increased the s.c. adipose tissue concentration of 18:0 and decreased 16:1 and 18:1 (p<0.05), suggesting depression of stearoyl-coenzyme A desaturase (SCD) enzyme activity in the CLA-fed pigs. The concentration of CLA isomers was raised only slightly in s.c. adipose tissue with the addition of CLA to the diets even though the CLA oil contained 62% CLA isomers. No effects on the growth of young pigs were observed. However, CLA caused a more saturated fatty acid composition and may suppress preadipocyte proliferation, apparent SCD activity, and lipid filling of smaller cells.

<p>The fatty acid linoleic acid has been identified as a potential mediator of atherosclerotic plaque development. Treatment of monocytes with linoleic acid leads to an increase in monocyte adhesion to endothelial cells under flow conditions; however, the mechanisms through which linoleic acid affect monocyte adhesion remain unclear. Using a combination of micropipette aspiration techniques and fluorescent microscopy, I tested the hypothesis that linoleic acid increases membrane tether formation between monocytes and endothelial cells. </p><p>Treatment of U937 monocytes with free linoleic acid or albumin-bound linoleic acid reduced the cortical tension of the monocytes. The effects of albumin-bound linoleic acid on the membrane were governed by the exchange of linoleic acid from albumin to the membrane and by the removal of fatty acids from the membrane by fatty acid binding sites on albumin. </p><p>The frequency of tether formation between U937 monocytes and TNF-α stimulated HUVECs increased following treatment with free linoleic acid or albumin-bound linoleic acid. The increase in tether frequency was not due to an increase in monocyte deformability or adhesion receptor expression. Tether extraction occurred primarily through E-selectin. Treatment with free linoleic acid increased the localization of E-selectin to clathrin-coated pits suggesting an increase in the formation of nanoclusters of E-selectin on HUVECs. The increase in tether frequency was blocked by the U73122 phospholipase C inhibitor indicating that linoleic acid increased monocyte adhesion through a phospholipase C mediated mechanism.</p><p>Treatment with free linoleic acid did not affect the threshold force for tether extraction or the effective viscosity of tethers extracted from HUVECs, but it decreased the threshold force for tether extraction from U937 monocytes and increased the effective tether viscosity. Treatment with U73122 blocked the reduction in the threshold force indicating that linoleic acid affected the regulation of the membrane adhesion energy through the hydrolysis of PIP2 by phospholipase C.</p><p>The results of the study indicated that linoleic acid promoted membrane tether formation by increasing E-selectin bond formation and reducing the adhesion energy between the U937 plasma membrane and the actin cytoskeleton through the hydrolysis of PIP2 by phospholipase C.</p> / Dissertation

The effects of conjugated linoleic acid (CLA) on lipogenesis and preadipocyte proliferation in young pigs were evaluated in two separate experiments. The first compared dietary effects of linoleic acid, beef tallow, and CLA on composition, lipogenesis, and DNA synthesis. Eighteen pigs weaned at 17 d of age were allotted randomly to corn-based diets supplemented with 1.5% corn oil, 1.5% tallow, or 1.5% CLA. The second experiment evaluated the effects of CLA included with diets high in polyunsaturated fat or beef tallow. Twenty-four pigs weaned at 17 d of age were allotted randomly to one of four corn-based diets supplemented with: 15% corn oil, 12% corn oil + 3% CLA, 15% tallow, and 12% tallow + 3% CLA. The piglets in both trials were fed a basal diet for 7 d and their respective diet for 35 d. [U-14C]Glucose incorporation into total lipids was (experiment 1): 10.64, 11.04, 13.64; (experiment 2): 21.15, 17.54, 21.34, and 19.52 nmol/(105 cells per h) for subcutaneous (s.c.) adipose tissue from corn oil, tallow, CLA; corn oil, corn oil + CLA, tallow, and tallow + CLA-fed piglets, respectively. Tritiated thymidine incorporation into DNA was not different in s.c. adipocytes across treatment groups, but was 5,581, 2,794, 6,573, and 3,760 dpm/(105 cells per h) in s.c. stromal vascular cells from corn oil, corn oil + CLA, tallow, and tallow + CLA-fed piglets, respectively (CLA main effect p<0.034). Additionally, there was a greater proportion of s.c. adipocytes in the smaller, 180-pL cell fraction from the corn oil + CLA-fed pigs (p<0.0074). CLA in the diet increased the s.c. adipose tissue concentration of 18:0 and decreased 16:1 and 18:1 (p<0.05), suggesting depression of stearoyl-coenzyme A desaturase (SCD) enzyme activity in the CLA-fed pigs. The concentration of CLA isomers was raised only slightly in s.c. adipose tissue with the addition of CLA to the diets even though the CLA oil contained 62% CLA isomers. No effects on the growth of young pigs were observed. However, CLA caused a more saturated fatty acid composition and may suppress preadipocyte proliferation, apparent SCD activity, and lipid filling of smaller cells.

Three experiments were conducted for this dissertation with the goals to; 1) determine conjugated linoleic acid (CLA) effects on net-energy balance (EBAL) and milk production parameters during periods of nutrient/energy stress, and 2) investigate temporal CLA effects on mammary lipogenic gene expression. Study one was designed to determine if abomasal CLA infusion could reduce milk fat synthesis and partition nutrients towards alternative milk components in feed restricted rotationally grazed dairy cows. Data indicate abomasally-infusing CLA reduced milk fat synthesis in nutrient restricted grazing dairy cows and improved calculated EBAL and milk protein production. Another period of transitory stress experienced by the lactating dairy cow is immediately postpartum and study two objectives were to feed rumen inert-CLA to evoke milk fat depression (MFD) and investigate production and bioenergetic parameters. Data indicated a high CLA dose (3 x greater than needed in established lactation) inhibited milk fat synthesis immediately postpartum and improved calculated EBAL in grazing dairy cows. A curvilinear relationship existed between the severity of CLA-induced MFD and milk yield response. Moderate CLA-induced MFD (<~35%) tended to increase milk yield whereas severe MFD (>~35%) diminished this response. Previous research speculated that extensive MFD might decrease Δ⁹-desaturase (stearoyl CoA desaturase; SCD) and subsequent membrane fluidity to such an extent as to adversely affect cellular functions and inhibit milk secretion, thus decreasing milk yield. However, SCD inhibition was temporally independent in the present study, offering little support for the aforementioned theory. Mammary sensitivity to CLA increased as lactation progressed and previous speculations attributed this to reduced contribution of de novo synthesised fatty acids or increased competition from circulating non-esterified fatty acids immediately postpartum. However, data indicate that de novo fatty acids and milk fat trans-10, cis-12 CLA content don’t appreciably change during early lactation, (even though MFD became more severe) offering little support for either hypothesis. Study three investigated the effects of intravenous CLA infusion on temporal expression of mammary lipogenic genes to determine if trans-10, cis-12 CLA down regulates expression of a key gene (i.e. acetyl CoA carboxylase, ACC, the rate limiting enzyme in de novo fatty acid synthesis) and reduction in other mammary lipid synthesis genes is due to lack of substrate (i.e. malonyl CoA), or an alternative indirect mechanism. Data indicated however, that mammary lipogenic genes (ACC, fatty acid synthetase and SCD) followed a similar temporal pattern, providing more support for a global regulator (i.e. sterol regulatory element binding protein-1, peroxisome proliferator-activated receptor-γ or nuclear factor- κB) rather than a specific key enzyme effect.

Conjugated linoleic acid (CLA) is predominantly found in foods of ruminant origin such as milk and processed cheese, and has gained much interest recently due to its beneficial health and biological effects on animals and humans. / The bioconversion of linoleic acid (LA) and linolenic acid (LNA) by a selected Bifidobacterium from healthy infant feces was studied. Bifidobacterium breve JKL03 had the ability to convert linolenic acid (0.2 mg/ml) to CLNA in fermentation of skim milk medium for 24 h up to a yield of 72.0% (up to 74.7% under aerobic conditions) and linoleic acid (0.2 mg/ml) into CLA by fermentation in skim milk medium for 24 h up to a yield of 23.9% (up to 28.0% under aerobic conditions). / B. breve JKL03 was also co-fermented with Lactobacillus acidophilus (NCFMRTM strain), a commonly added starter culture, to observe the resulting effects on growth during fermentation for yogurt production. Fermentation of LNA in skim milk with B. breve JKL03 and L. acidophilus (NCFM) maintained high CLNA production level. On the other hand, CLA production in the same media with both strains did not exhibit as high level as with the single B. breve. / These results are important for the advancement of knowledge on the production of CLA and CLNA in dairy products and for knowledge on the basic metabolic mechanisms for such conversion.

The objectives of this study was to examine the efficacy and safety of graded doses of c9, t11, t10, c12 CLA isomers on body composition, energy expenditure, lipid profile and hepatic biomarkers in hamsters. Male Golden Syrian hamsters (n=105) were randomized to seven treatments (control; 1, 2, 3% of c9, t11; 1, 2, 3% of t10, c12) for 28 days. Compared with control, 1% and 3% t10, c12 had lowered food intake with all three doses of t10, c12 lowering (p<0.0001) body fat mass (g). Groups fed with 1, 2, 3% t10, c12 and 3% c9, t11 treatments showed higher lean mass compared to control and other treatment groups. However, neither body weights, nor serum HDL or triglyceride levels differed across treatment groups. The 3% t10, c12 groups exhibited higher (p<0.0001) cholesterol and LDL-C levels compared to control or other treatment groups. The 2% and 3% t10, c12 groups also presented elevated ALT level (p<0.05). The present data suggest that 3% t10, c12 possess potential adverse effects on liver and posing unfavorable change in lipid profile.

The aim of this thesis was to investigate how dietary fatty acids affect the risk for cardiometabolic disease, i.e. cardiovascular disease (CVD), type 2 diabetes and obesity. The overall hypothesis was that unsaturated fatty acids and especially the predominant polyunsaturated fatty acid (PUFA) linoleic acid (LA), 18:2n-6, would decrease cardiometabolic risk compared with saturated fatty acids (SFAs), in line with current recommendations to partly replace dietary SFA with PUFA. Papers I and V were observational studies based on the community-based cohort Uppsala Longitudinal Study of Adult Men (ULSAM). Adipose tissue fatty acid composition was determined as biomarker for dietary fat intake. Studies II, III and IV were randomised short-term interventions on human volunteers, in which different dietary fats were provided to the participants. In 71-year-old men, adipose tissue LA and α-linolenic acid (18:3n-3) were associated with insulin sensitivity (euglycaemic clamp), although this association was diminished for LA after adjusting for lifestyle variables. Different SFA displayed divergent associations; only palmitic acid (16:0) was inversely associated with insulin sensitivity (Paper I). In Cox regression analyses, LA was modestly associated with decreased all-cause mortality, but not CVD mortality during 15 years follow-up (Paper V). In a 3+3-week cross-over study on 20 weight-stable volunteers with dyslipidaemia, all foods were provided. A rapeseed oil-based diet distinctly lowered low-density lipoprotein cholesterol and triglycerides compared with a dairy-fat based diet (butter, cream and fatty cheese). Insulin sensitivity or coagulation factors were not affected (Paper II). In a 10-week randomised trial on 67 abdominally obese participants, PUFA (mostly sunflower oil) decreased liver fat compared with SFA (mostly butter) under isocaloric conditions. In individuals considered highly compliant to study diets, lipoproteins were also decreased during the PUFA diet (Paper III). In a 7-week double-blind randomised trial on 41 healthy volunteers, PUFA (sunflower oil) decreased the total:HDL cholesterol ratio compared with SFA (palm oil) during moderate weight gain (1.5 kg) (Paper IV). In conclusion, LA (PUFA) intake is associated with decreased cardiometabolic risk compared with higher SFA intake, overall supporting a beneficial role of non-tropical vegetable oils in place of solid fats in preventing fatty liver and cardiometabolic disorders.

The objectives of this study was to examine the efficacy and safety of graded doses of c9, t11, t10, c12 CLA isomers on body composition, energy expenditure, lipid profile and hepatic biomarkers in hamsters. Male Golden Syrian hamsters (n=105) were randomized to seven treatments (control; 1, 2, 3% of c9, t11; 1, 2, 3% of t10, c12) for 28 days. Compared with control, 1% and 3% t10, c12 had lowered food intake with all three doses of t10, c12 lowering (p<0.0001) body fat mass (g). Groups fed with 1, 2, 3% t10, c12 and 3% c9, t11 treatments showed higher lean mass compared to control and other treatment groups. However, neither body weights, nor serum HDL or triglyceride levels differed across treatment groups. The 3% t10, c12 groups exhibited higher (p<0.0001) cholesterol and LDL-C levels compared to control or other treatment groups. The 2% and 3% t10, c12 groups also presented elevated ALT level (p<0.05). The present data suggest that 3% t10, c12 possess potential adverse effects on liver and posing unfavorable change in lipid profile.