Subcutaneous Adipose Tissue Fatty Acid Research Articles

Adipose tissue fatty acids suggest spatial and temporal dietary differences in great cormorants of the Baltic Sea area

AbstractIncreased numbers of great cormorants (Phalacrocorax carbo) in the Baltic Sea may have local impacts on fisheries and salmonid hatcheries. We studied spatial and temporal variability in cormorant diet, and potential consumption of hatchery salmonids, by analysing knee subcutaneous adipose tissue fatty acids (FA) of specimens (N = 77) collected along Swedish and Finnish coasts in different seasons during 2013–2017. The FA profiles of the subspecies sinensis and carbo were similar, with large individual variation. The proportion of C18 polyunsaturated FAs (PUFAs) was the largest in the north, whereas the proportion of C20–22 monounsaturated FAs (MUFAs) increased towards the south, reflecting diminishing freshwater and increasing marine food web characteristics towards the south. As an exception, the C20–22 MUFA percentage was high in sinensis collected in June 2017 from the northern Baltic Sea. The source of C20–22 MUFAs was probably hatchery salmonids, raised on ocean fish hatchery feed and released 10 days before, near the cormorant capture site. The FA profiles of northern and southern cormorants differed from each other both in early and late summer samples, suggesting spatially different diets. The largest individual variation was found in 22:1n-11, characteristic of ocean zooplanktivorous fish, and likely originating from Atlantic wild or Baltic Sea hatchery-reared fish. This study shows that adipose tissue FA profiles can be used as proxies for seabird diet monitoring and indicators of predation on hatchery-reared fish. Obtaining quantitative estimates on the proportions of dietary fish species requires future feeding experiments, allowing calibration between the FA compositions and diet.

Exercise Training Alters Red Blood Cell Fatty Acid Desaturase Indices and Adipose Tissue Fatty Acid Profile in African Women with Obesity.

This study assessed the changes in red blood cell total phospholipid (RBC-TPL) and subcutaneous adipose tissue (SAT) fatty acid (FA) composition in response to 12 weeks of exercise training in South African women with obesity and the associations with changes in cardiometabolic risk factors. Previously sedentary women were randomized into control (n = 15) or exercise (n = 20) groups. RBC-TPL and SAT FA profiles, SAT gene expression, systemic inflammatory markers, liver fat, and insulin sensitivity (SI ) were measured before and after the intervention. Compared with control, exercise training induced decreases in RBC-TPL dihomo-γ-linolenic acid content and stearoyl-CoA desaturase-1 and increased delta-5 desaturase-estimated activity (P < 0.05). In the combined group, these changes correlated with changes in circulating leptin and TNFα (P < 0.05), as well as lower liver fat (P < 0.01). Exercise training decreased saturated FA (lauric and myristic acids) and increased polyunsaturated FA (eicosadienoic and adrenic acids) (P < 0.05) in abdominal SAT, whereas γ-linolenic acid decreased (P < 0.01) in gluteal SAT. These changes in RBC-TPL and SAT FA compositions were not associated with changes in SAT gene expression and SI . Exercise training alters RBC-TPL desaturase activities, which correlate with lower liver fat and systemic inflammation but not with the improvement of SI .

Effects of dietary fat sources on the intramuscular and subcutaneous adipose tissue fatty acid composition, and consumer acceptability of lamb.

Lamb diets can alter the fatty acid (FA) profile of muscle and adipose tissue, which may affect the sensory quality and consumer acceptability of the meat. In this study, lambs received one of four pre-slaughter diets: a barley / maize / soya-based concentrate (C), supplemented with a saturated fat source (Megalac®) (SAT), or supplemented with protected linseed oil (PLO); or a by-product (citrus pulp / distillers' grain / soya-based) diet (BPR). Intramuscular FAs and adipose tissue branched-chain FAs were measured and consumer evaluation (hedonic liking and attribute intensity) was undertaken with cooked lamb. Compared to the other diets, the BPR diet resulted in a higher muscle concentration and a greater proportion of C18:2n-6, and greater proportions of conjugated linoleic acid (c9,t11-C18:2) and n-6 polyunsaturated FAs (PUFA), whereas the PLO diet resulted in higher muscle proportions of C18:0 and saturated FAs, higher concentrations of C18:3n-3 and n-3 PUFA, and a lower n-6 to n-3 ratio. The consumer acceptability of lamb was not affected by the pre-slaughter diets. Changes in the FA profile of lamb muscle and adipose tissue through the inclusion of sources of saturated fat, protected linseed oil, or by-products in the pre-slaughter diet did not result in consumer detection of significant effects on the acceptability of the cooked meat. © 2020 Society of Chemical Industry.

FADS1 genotype is distinguished by human subcutaneous adipose tissue fatty acids, but not inflammatory gene expression

Single nucleotide polymorphisms (SNPs) in FADS1/FADS2 genes are associated with changes in serum and tissue polyunsaturated fatty acid (PUFA) content. PUFA regulate inflammatory signaling pathways in adipose tissue; however, the effect of SNPs in FADS1/FADS2 on adipose tissue inflammation is equivocal. The present study examined if SNPs in FADS1/FADS2 modify human subcutaneous adipose tissue (SAT) fatty acid profiles and the expression of genes associated with inflammation/immune function, lipid metabolism, and cellular differentiation. SAT fatty acids and the expression of 117 genes were measured in 174 men and women from the DiOGenes Study using gas chromatography and qRT-PCR, respectively. Associations between fatty acids, gene expression, and SNPs in FADS1/FADS2 were investigated by linear regression and multivariate analysis. Four SNPs (rs174537, rs174546, rs174556, rs174601) in FADS1/FADS2 were significantly associated with SAT fatty acids. All SNPs were in high linkage disequilibrium with the commonly reported rs174537 SNP in FADS1. Minor allele carriers for rs174537 (GT+TT) had reduced 20:4n-6 (p = 1.74E-5), lower delta-5 desaturase enzyme activity (p = 2.09E-9), and lower FADS1 gene expression (p = 0.03) compared to major GG carriers. Multivariate analysis revealed that 20:4n-6 and 20:3n-6 explained ~19% of the variance between rs174537 genotypes, while gene expression explained <7%. Receiver operating characteristic (ROC) curves indicated that rs174537 genotype can be distinguished with SAT fatty acids (AUC = 0.842), but not gene expression (AUC = 0.627). No differences in SAT inflammatory gene expression were observed between rs174537 genotypes. SAT 20:3n-6 levels were positively correlated with the expression of several inflammatory genes, and inversely correlated with FADS1 expression. This study showed that FADS1 genotype is distinguished by SAT fatty acid profiles, but not inflammatory gene expression.

460 Effect of Different Fatty Acid Profiles in the Maternal and Finishing Diet on Subcutaneous Adipose Tissue Fatty Acid Profile and Gene Expression.

460 Effect of Different Fatty Acid Profiles in the Maternal and Finishing Diet on Subcutaneous Adipose Tissue Fatty Acid Profile and Gene Expression.

The role of visceral and subcutaneous adipose tissue fatty acid composition in liver pathophysiology associated with NAFLD

Visceral adiposity is associated with type-2-diabetes, inflammation, dyslipidemia and non-alcoholic fatty liver disease (NAFLD), whereas subcutaneous adiposity is not. We hypothesized that the link between visceral adiposity and liver pathophysiology involves inherent or diet-derived differences between visceral and subcutaneous adipose tissue to store and mobilize saturated fatty acids. The goal of the present study was to characterize the fatty acid composition of adipose tissue triglyceride and portal vein fatty acids in relation to indices of liver dysregulation. For 8 weeks rats had free access to control (CON; 12.9% corn/safflower oil; 3.6 Kcal/g), high saturated fat (SAT; 45.2% cocoa butter; 4.5 Kcal/g) or high polyunsaturated fat (PUFA; 45.2% safflower oil; 4.5 Kcal/g) diets. Outcome measures included glucose tolerance, visceral and subcutaneous adipose tissue triglyceride, liver phospholipids and plasma (portal and systemic) free fatty acid composition, indices of inflammation and endoplasmic reticulum stress in the liver and adipose tissue depots and circulating adipo/cytokines. Hepatic triglycerides were significantly increased in both high fat diet groups compared to control and were significantly higher in PUFA compared to SAT. Although glucose tolerance was not different among diet groups, SAT increased markers of inflammation and ER stress in the liver and both adipose tissue depots. Fatty acid composition did not differ among adipose depots or portal blood in any dietary group. Overall, these data suggest that diets enriched in saturated fatty acids are associated with liver inflammation, ER stress and injury, but that any link between visceral adipose tissue and these liver indices does not involve selective changes to fatty acid composition in this depot or the portal vein.

Increasing concentrations of wheat dry distillers’ grains with solubles in iso-nitrogenous finishing diets reduce lamb performance

It was hypothesized that the inclusion of wheat dry distillers’ grains with solubles (WDDGS) up to 470g/kg dry matter (DM), fed to lambs in iso-nitrogenous diets, would neither affect growth performance, nor subcutaneous adipose tissue fatty acid composition. Thus, this study aimed to assess the effects of increasing concentrations of WDDGS in iso-nitrogenous diets on in vitro fermentation, in sacco degradation, growth performance and fatty acid profiles of adipose tissue in lambs. Increasing concentrations of WDDGS (100, 300 and 470g/kg dry matter (DM)) were achieved by replacing soybean meal, alfalfa hay and soybean hulls. In vitro fermentation of the diets was conducted to measure fermentation variables and CH4 production. In situ digestion kinetics of DM, crude protein (CP), and neutral detergent fiber (NDF) of the treatment diets were evaluated using three ruminally cannulated cows. Additionally, 60 lambs were used to determine the effect of WDDGS on growth performance and fatty acid profiles of subcutaneous tail fat. In the in sacco study, WDDGS increased (P=0.03) DM, CP and NDF effective degradability and reduced (P<0.01) rumen undegradable protein. In the in vitro incubations, CH4 production (mg/gDMD) increased (P=0.05) in the 470g/kg WDDGS group. In the growth trial, increasing WDDGS in the diet linearly reduced DMI (P=0.02), ADG (P<0.01) and hot carcass weight (P<0.01). Linear increases in trans-10 octadecenoic acid (P=0.02) and linear decrease in oleic acid (P<0.01) resulted in a linear reduction of total monounsaturated fatty acids (MUFA; P=0.02) yet, linoleic acid was linearly increased (P<0.01). In summary, increasing concentrations of WDDGS in iso-nitrogenous diets fed to lambs decreased animal performance and negatively affected the fatty acid profile of adipose tissue.

Epicardial and subcutaneous adipose tissue Fatty acids profiles in diabetic and non-diabetic patients candidate for coronary artery bypass graft.

We have recently shown that in high cholesterol-fed rabbits, the sensitivity of epicardial adipose tissue to changes in dietary fat is higher than that of subcutaneous adipose tissue. Although the effects of diabetes on epicardial adipose tissue thickness have been studied, the influence of diabetes on profile of epicardial free fatty acids (FFAs) has not been studied. The aim of this study is to investigate the effect of diabetes on the FFAs composition in serum and in the subcutaneous and epicardial adipose tissues in patients undergoing coronary artery bypass graft (CABG). Forty non-diabetic and twenty eight diabetic patients candidate for CABG with >75% stenosis participated in this study. Fasting blood sugar (FBS) and lipid profiles were assayed by auto analyzer. Phospholipids and non-estrified FFA of serum and the fatty acids profile of epicardial and subcutaneous adipose tissues were determined using gas chromatography method. In the phospholipid fraction of diabetic patients' serum, the percentage of 16:0, 18:3n-9, 18:2n-6 and monounsaturated fatty acids (MUFAs) was lower than the corresponding values of the non-diabetics; whereas, 18:0 value was higher. A 100% increase in the amount of 18:0 and 35% decrease in the level of 18:1n-11 was observed in the diabetic patients' subcutaneous adipose tissue. In epicardial adipose tissue, the increase of 18:0 and conjugated linolenic acid (CLA) and decrease of 18:1n-11, w3 (20:5n-3) and 22:6n-3 were significant; but, the contents of arachidonic acid and its precursor linoleic acid were not affected by diabetes. The fatty acids' profile of epicardial and subcutaneous adipose tissues is not equally affected by diabetes. The significant decrease of 16:0 and w3 fatty acids and increase of trans and conjugated fatty acids in epicardial adipose tissue in the diabetic patients may worsen the formation of atheroma in the related arteries.

Subcutaneous adipose tissue fatty acid desaturation in adults with and without rare adipose disorders

BackgroundElevated stearoyl-CoA desaturase activity has been described in obese states, with an increased desaturation index (DI) suggesting enhanced lipogenesis. Differences in the DI among various phenotypes of abnormal adiposity have not been studied. Abnormal accumulation of subcutaneous adipose tissue occurs in rare adipose disorders (RADs) including Dercum's disease (DD), multiple symmetric lipomatosis (MSL), and familial multiple lipomatosis (FML). Examining the DI in subcutaneous fat of people with DD, MSL and FML may provide information on adipose tissue fatty acid metabolism in these disorders. The aims of this pilot study were: 1) to determine if differences in adipose tissue DIs are present among RADs, and 2) to determine if the DIs correlate to clinical or biochemical parameters.MethodsSubcutaneous adipose tissue was obtained from human participants with DD (n = 6), MSL (n = 5), FML (n = 8) and obese Controls (n = 6). Fatty acid composition was determined by gas chromatography/mass spectrometry. The DIs (palmitoleic/palmitic, oleic/stearic, vaccenic/stearic ratios) were calculated from the gas chromatogram peak intensities. SCD1 gene expression was determined. Spearman's correlations between the DIs and available clinical or biochemical data were performed.ResultsIn DD subjects, the vaccenic/stearic index was lower (p < 0.05) in comparison to Controls. Percent of total of the saturated fatty acid myristic acid was higher in DD compared with Controls and FML. Percent of monounsaturated vaccenic acid in DD trended lower when compared with Controls, and was decreased in comparison to FML. In MSL, total percent of the polyunsaturated fatty acids was significantly lower than in the Control group (p < 0.05). In the total cohort of subjects, the palmitoleic/palmitic and oleic/stearic DIs positively correlated with age, BMI, and percent body fat.ConclusionsThe positive associations between the DIs and measures of adiposity (BMI and percent body fat) support increased desaturase activity in obesity. The lower vaccenic/stearic DI in DD SAT compared with Controls suggests presence of other factors involved in fat accumulation in addition to lifestyle. Other mechanisms driving fat accumulation in DD such as inflammation or lymphatic dysfunction should be investigated.

The effect of maternal linseed supplementation and/or lamb linseed supplementation on muscle and subcutaneous adipose tissue fatty acid composition of indoor lambs

Eighty eight lambs were used in a 2×2 factorial arrangement 1) to investigate the effect of maternal dietary linseed supplementation and/or lamb linseed supplemented concentrate on growth performance, carcass fat quality and fatty acid (FA) composition of muscle and dorsal adipose tissue of indoor lambs 2) to study the relationships between subcutaneous fat quality and FA composition. Feeding linseed to ewes increased C18:3 n-3 (ALA) proportion in milk and therefore the ALA supply to suckling lambs. However, ALA and n-3 polyunsaturated FA (n-3 PUFA) proportions in lamb tissues were not affected. Feeding linseed to lambs during the post-weaning period significantly increased the proportions of ALA and n-3 PUFA in tissues. Softer and more colored fat was associated with a decrease in even medium-chain saturated FA and increases in odd and methyl FA proportions but not with ALA proportion in subcutaneous adipose tissue.

Influence of a High Cholesterol Regime on Epicardial and Subcutaneous Adipose Tissue Fatty Acids Profile in Rabbits

We have shown that the fatty acid profile of epicardial adipose tissue (EAT) in patients with obstructed coronary vessels is different from that of the subcutaneous adipose tissue (SAT). The diversity and amount of fatty acids in the adipose tissue can be affected by the component of the lipids in diet. As a result, this study investigated the influence of a high cholesterol regime on EAT and subcutaneous adipose tissue fatty acids profile in rabbits. Sixteen New Zealand white rabbits were randomly divided into two equal groups. The control group received a normal standard diet, whereas the test group was fed with the high cholesterol regime for 2 months. At the end of this period, the rabbits were anesthetized, 1-5 mg of EAT and SAT were removed, and their fatty acids content was determined. The high cholesterol regime caused a significant increase in low-density lipoprotein (LDL) and triglycerides levels and a marked decrease in high-density lipoprotein (HDL) concentration. After 2 months, in the EAT, fatty acids 16:0 and 18:1t and saturated fatty acid (SFA) showed a significant increase (P<0.05), whereas, fatty acids 12:0, 18:1, 18:2, and 18:3, monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), ω3, and ω6 had a significant decrease (P<0.05). In SAT, fatty acids 18:3, 20:4, 22:6, MUFA, and ω3 decreased and PUFA, SFA, and ω6 significantly increased (P<0.05). Consumption of a high cholesterol regime for 2 months resulted in a significant increase in atherogenic fatty acids and a decrease in antiatherogenic ones in the EAT. EAT is very sensitive to lipid changes of the regime comparing to SAT.

Cardiovascular disease risk factors and dietary habits of farmers from Crete 45 years after the first description of the Mediterranean diet

Farmers from Crete as first studied within the framework of the Seven Countries Study, were historically known for holding the title of the 'gold standard' of health status globally and had a very low prevalence of both cardiovascular disease (CVD) and cancer. Taking the above into account we evaluated the changes in CVD risk factors among farmers in Crete, Greece and compared our findings with data from the 1960s. Cross-sectional. Five hundred and two farmers (18-79 years old) from the Valley of Messara in Crete were randomly selected and examined in 2005. Complete clinical, biochemical, dietetic, anthropometrical and lifestyle CVD risk factors were assessed, matched and compared with published data from the 1960s. In comparison with 45 years ago, present day male farmers from Crete were found to have a 30% higher BMI (29.8 vs. 22.9 kg/m, P<0.001) and a 16% higher total cholesterol level (239.6 vs. 206.9 mg/dl, P<0.001) and also a not so favourable daily dietary intake (increase in meat and saturated fat and decrease in fruit, P<0.001, respectively), while a significant reduction in systolic blood pressure and energy intake was noticed. In regards to changes in subcutaneous adipose tissue fatty acid composition, a decrease in monounsaturated (P<0.001) and an increase in saturated fatty acids (P<0.001) was also found elucidating the temporal change in dietary habits. The population's lack of adherence to the Mediterranean diet, have led to the fact that currently farmers from Crete are likely to be at a higher risk for developing CVD in comparison with earlier generations.

Relation between degree of obesity and site-specific adipose tissue fatty acid composition in a Mediterranean population

Objective Obesity itself could be a key factor determining fatty acid (FA) composition of adipose tissue (AT). A Mediterranean diet influences this relationship. However, a relation between different overweight and obesity levels (including morbidly obese subjects) and AT FA pattern has not been fully established. The objective of the present study was to analyze potential differences in AT FA composition attending to degree of obesity in patients who follow a Mediterranean dietary pattern. Methods Our study comprises 60 patients classified as overweight, obese, or morbidly obese (20 subjects in each group). Dietary composition was assessed by a 7-d record, and visceral and subcutaneous AT FAs were analyzed by gas chromatography. Cardiometabolic risk-related parameters were also assessed. Results Our results showed that dietary habits were similar among groups, although palmitic intake was higher and palmitoleic intake was lower in the morbidly obese group. Concerning AT, we observed significant differences in the visceral depot. Concretely, both total monounsaturated FA ( P = 0.039) and palmitoleic acid ( P = 0.008) were higher in overweight subjects. Most differences were found in the subcutaneous tissue. Among them, n-9 and total monounsaturated FA ( P < 0.001) were significantly higher again in overweight subjects, while 22:6 n-3 was higher in morbidly obese subjects. Subcutaneous adipose dihommo-γ-linolenic content and dietary palmitic and palmitoleic acids were independent predictors of body mass index. Conclusions We confirm the relationship between degree of obesity and dietary and AT FA composition in this Mediterranean population. Despite a similar dietary pattern among groups, overweight and morbidly obese patients have a less detrimental FA profile than obese patients, probably due to differences in adipose tissue metabolism.

Relative validity of fatty acid intakes from an FFQ compared with subcutaneous adipose tissue fatty acids

Relative validity of fatty acid intakes from an FFQ compared with subcutaneous adipose tissue fatty acids

Effect of Feeding Regime on Fatty Acid Composition of Longissimus dorsi Muscle and Subcutaneous Adipose Tissue of Akkaraman Lambs

Summary In this study, effect of feeding regime on fatty acid composition including conjugated linoleic acid (CLA) of Longissimus dorsi muscle and subcutaneous adipose tissue from lambs were investigated. From same flock, forty-five male Akkaraman suckling lambs, the most common lamb breeds in Turkey, were fed mainly maternal milk from birth to weaning and then were divided into three groups (only maternal milk-fed group, pasture-fed group and concentrate-fed group) at three months of age with an average live weight of 25 kg. Longissimus dorsi muscle from pasture fed-lambs contained significantly more total CLA, n-3 and n-3/n-6 ratio than other groups. In addition, pasture-fed lambs contained significantly more total saturated fatty acid (SFA), CLA, n-3 and n-3/n-6 ratio compared concentrate fed-lambs in subcutaneous adipose tissue. In conclusion, intramuscular muscle and subcutaneous adipose tissue fatty acid composition of lamb can be improved by pasture in the feeding regime.

A reduced protein diet induces stearoyl-CoA desaturase protein expression in pig muscle but not in subcutaneous adipose tissue: relationship with intramuscular lipid formation

A reduced protein diet (RPD) is known to increase the level of intramuscular lipid in pig meat with a smaller effect on the amount of subcutaneous adipose tissue. This might be due to tissue-specific activation of the expression of lipogenic enzymes by the RPD. The present study investigated the effect of a RPD, containing palm kernel oil, soyabean oil or palm oil on the activity and expression of one of the major lipogenic enzymes, stearoyl-CoA desaturase (SCD) and on the level of total lipids and the fatty acid composition of muscle and subcutaneous adipose tissue in pigs. The RPD significantly increased SCD protein expression and activity in muscle but not in subcutaneous adipose tissue. The level of MUFA and total fatty acids in muscle was also elevated when the RPD was fed, with only small changes in subcutaneous adipose tissue. A positive significant correlation between SCD protein expression and total fatty acids in muscle was found. The results suggest that an increase in intramuscular but not subcutaneous adipose tissue fatty acids under the influence of a RPD is related to tissue-specific activation of SCD expression. It is suggested that the SCD isoform spectra in pig subcutaneous adipose tissue and muscle might be different.

Adipose fatty acid composition and the risk of serious ventricular arrhythmias in acute myocardial infarction

The relation between subcutaneous adipose tissue fatty acid composition and serious ventricular arrhythmias during acute myocardial infarction was studied in 2 groups of patients. In group 1 (n = 42), studied retrospectively, patients with ventricular fibrillation or tachycardia had a higher concentration of long-chain saturated fatty acids than those without (32.5 ± 0.8% vs 29.7 ± 0.4% [mean ± standard error of the mean], p < 0.01). In a prospective study, patients with arrhythmias (n = 106) had higher levels of long-chain saturated fatty acids (32.1 ± 0.5% vs 30.7 ± 0.4%, p < 0.05) and of stearic acid (4.9 ± 0.2% vs 4.4 ± 0.1%, p < 0.02) and a lower concentration of palmitoleic acid (7.3 ± 0.3% vs 8.1 ± 0.2%, p < 0.005). When peak plasma creatine kinase concentrations were included with the individual fatty acid levels in a multiple logistic regression, only creatine kinase correlated significantly with ventricular arrhythmias (p < 0.01). Thus, saturated fatty acids in cardiac membranes may lead to greater vulnerability to ventricular arrhythmias, although infarct size is the only statistically significant predictor after multiple regression analysis.

Dietary Fat, Adipose Tissue Composition, and the Development of Carcinoma of the Colon&lt;xref ref-type="fn" rid="FN1"&gt;2&lt;/xref&gt;

Dietary fat and plasma lipids have been implicated in the development of carcinoma of the colon. Because of the difficulties in obtaining accurate dietary histories, subcutaneous adipose tissue fatty acids were analyzed to compare fat intake in 3 groups of patients undergoing colonoscopy: patients with carcinoma of the colon (n = 53; average age, 64 yr; 47% male), patients with neoplastic polyps (n = 34; age 63 yr; 71% male), and patients with normal findings (controls; n = 68; age 58 yr; 40% male). The groups were similar with regard to body mass index and coffee and egg consumption. One-way analysis of variance of the plasma total cholesterol, triglycerides, high-density lipoprotein cholesterol, 9 adipose fatty acids, groups of polyunsaturated fatty acids (vegetable origin), saturated fatty acids (animal origin), or the ratio of polyunsaturated to saturated fatty acids did not show any significant differences across the 3 groups. The quality of dietary fat does not appear to be associated with the development of carcinoma of the colon or of neoplastic polyps in this population.

Effects of Intravenous Infusions of Glucose, Lactate, Propionate or Acetate on the Induction of Lipogenesis in Bovine Adipose Tissue

Crossbred steers (seven to nine per treatment) fed a pelleted alfalfa hay diet were biopsied (preinfusion) to obtain subcutaneous adipose tissue (SAT). Five days later a continuous intravenous infusion was begun of either 0.9% NaCl, glucose (2.75 moles/day), DL-lactate (5.5 moles/day of L-lactate), propionate (5.5 moles/day) or acetate (8.25 moles/day); after infusion for 14 days, a second biopsy sample of SAT was obtained. Glucose and DL-lactate infusion increased acetyl-CoA carboxylase activity about 12-fold compared to preinfusion activity of 5.3 +/- 4.2 nmoles/minute/g of wet weight. Glucose infusion induced activities of fatty acid synthetase (2.6 fold) and NADP+-malate dehydrogenase (7-fold) relative to preinfusion activities of 26.8 +/- 5.2 and 30.3 +/- 15.5 nmoles/minute/g of wet weight, respectively. Glucose, DL-lactate and propionate infusion increased NADP-isocitrate dehydrogenase activity 20-30% compared to preinfusion activity. Activity of NAD-malate dehydrogenase was not altered by any infusion treatment (P > 0.05). Activity of ATP-citrate lyase was decreased 48% by lactate infusion. Glucose, lactate and propionate infusion increased the rates of lactate and glucose incorporation into fatty acids in SAT incubated in vitro three to fourfold over preinfusion incorporation rates. Increased availability of glucose or gluconeogenic precursors may be responsible for induction of lipogenesis in steers fed high concentrate diets.