Embryonic fatty acid metabolism in diabetic pregnancy: the difference between embryoblasts and trophoblasts.

During the first days of development the preimplantation embryo is supplied with nutrients from the surrounding milieu. Maternal diabetes mellitus affects the uterine microenvironment, leading to a metabolic adaptation processes in the embryo. We analysed embryonic fatty acid (FA) profiles and expression of processing genes in rabbit blastocysts, separately in embryoblasts (EBs) and trophoblasts (TBs), to determine the potential consequences of maternal diabetes mellitus on intracellular FA metabolism. Insulin-dependent diabetes was induced by alloxan in female rabbits. On Day 6 post coitum, FA profiles in blastocysts (EB, TB and blastocoel fluid) and maternal blood were analysed by gas chromatography. The expression levels of molecules involved in FA elongation (fatty acid elongases, ELOVLs) and desaturation (fatty acid desaturases, FADSs) were measured in EB and TB. Maternal diabetes mellitus influenced the FA profile in maternal plasma and blastocysts. Independent from metabolic changes, rabbit blastocysts contained a higher level of saturated fatty acids (SFAs) and a lower level of polyunsaturated fatty acids (PUFAs) compared to the FA profile of the maternal plasma. Furthermore, the FA profile was altered in the EB and TB, differently. While SFAs (palmitic and stearic acid) were elevated in EB of diabetic rabbits, PUFAs, such as docosahexaenoic acid, were decreased. In contrast, in the TB, lower levels of SFAs and higher levels of oleic acid were observed. EB and TB specific alterations in gene expression were found for ELOVLs and FADSs, key enzymes for FA elongation and desaturation. In conclusion, maternal diabetes mellitus alters embryonic FA metabolism differently in EB and TB, indicating a lineage-specific metabolic adaptive response.

On the relevance of technical variation due to building pools in microarray experiments.

BACKGROUND: Pooled samples are frequently used in experiments measuring gene expression. In this method, RNA from different individuals sharing the same experimental conditions and explanatory variables is blended and their concentrations are jointly measured. As a matter of principle, individuals are represented in equal shares in each pool. However, some degree of disproportionality may arise from the limits of technical precision. As a consequence a special kind of technical error occurs, which can be modelled by a respective variance component. Previously published theory - allowing for variable pool sizes - has been applied to four microarray gene expression data sets from different species in order to assess the practical relevance of this type of technical error in terms of significance and size of this variance component. RESULTS: The number of transcripts with a significant variance component due to imperfect blending was found to be 4329 (23 %) in mouse data and 7093 (49 %) in honey bees, but only 6 in rats and none whatsoever in human data. These results correspond to a false discovery rate of 5 % in each data set. The number of transcripts found to be differentially expressed between treatments was always higher when the blending error variance was neglected. Simulations clearly indicated overly-optimistic (anti-conservative) test results in terms of false discovery rates whenever this source of variability was not represented in the model. CONCLUSIONS: Imperfect equality of shares when blending RNA from different individuals into joint pools of variable size is a source of technical variation with relevance for experimental design, practice at the laboratory bench and data analysis. Its potentially adverse effects, incorrect identification of differentially expressed transcripts and overly-optimistic significance tests, can be fully avoided, however, by the sound application of recently established theory and models for data analysis.

Impact of dietary protein level and source of polyunsaturated fatty acids on lipid metabolism-related protein expression and fatty acid concentrations in porcine tissues.

The study assessed the effects of reduced protein (RPD) vs high protein diet (HPD) in combination with n-3/n-6 PUFA-containing plant oils [linseed oil (LO)/sunflower seed oil (SO)] supplementation on lipid metabolism-related protein expression and fatty acid concentrations in porcine tissues. Forty male Landrace pigs (castrates) were allocated into four groups fed diets different in dietary protein and PUFA level and one control group. SCD-1 protein expression in pig muscle, back fat, and liver was not affected by diet. The protein expression of precursor (pSREBP-1c) and active nuclear form of SREBP-1c (mSREBP-1c) in muscle and back fat was affected by diet, however not in liver of pigs. In contrast, the expression of ACC and FAS expression was significantly affected by diet only in the liver. The fatty acid concentrations in muscle, liver, and back fat resulted in higher n-3 PUFA concentrations of LO groups compared to the SO groups.

Fatty acid profiles and adipogenic gene expression of various fat depots in Japanese Black and Holstein steers.

Objective of the study was to assess the breed effect on fatty acid (FA) composition of different adipose tissues and on mRNA expression of genes involved in adipogenesis and fat metabolism. Japanese Black (JB) and Holstein (HS) steers were kept under equivalent conditions with high energy intake resulting in large differences in intramuscular fat (IMF) accumulation in longissimus muscle (LM). The relative FA composition of muscle, intermuscular fat, visceral fat, and perirenal fat was comparable between JB and HS steers. Circulating fatty acids were also similar in both breeds. Most relevant breed effects were identified in IMF, underlining the uniqueness of this adipose tissue site. JB steers had more monounsaturated FA and less saturated FA. Perilipin 1 and adipose differentiation-related protein (ADFP) mRNA levels were higher in IMF of JB. The results suggest advanced maturity of IMF cells in JB and altered local conditions in muscle influencing IMF accumulation and composition.

Higher body fatness in intrauterine growth retarded juvenile pigs is associated with lower fat and higher carbohydrate oxidation during ad libitum and restricted feeding.

PURPOSE: A thrifty energy metabolism has been suggested in intrauterine growth restricted (IUGR) offspring. We characterized energy metabolism and substrate oxidation patterns in IUGR pigs in response to food restriction (FR) and refeeding (RFD). METHODS: Female pigs with low (L; 1.1 kg; n = 20) or normal birth weight (N; 1.5 kg; n = 24) were fed ad libitum after weaning. Half of L and N pigs were food restricted (R; LR, NR) from days 80 to 100 (57% of ad libitum) and refeed from days 101 to 131, while the remaining pigs were fed ad libitum (control, C). Using indirect calorimetry, carbohydrate and fat oxidation (COX, FOX), energy expenditure (EE) and balance (EB), resting metabolic rate (RMR) [all related to kg body weight(0.62) (BW)] and RQ were determined at 4 days before (day 76) and after (day 83) beginning of FR, 4 days before (day 97) and after (day 104) end of FR and 25 days after beginning of RFD (day 125). Body fat and muscle weights were determined at day 131. RESULTS: In spite of higher relative food intake (FI), BW was lower in L pigs. In L pigs, physical activity was lower at age 76 and 83 days compared to N pigs. IUGR did not affect EE or RMR, but resulted in higher COX and lower FOX, causing greater and earlier onset of fat deposition. During FR, EE and RMR of R pigs dropped below that of C pigs, and BW gain was delayed by 30% irrespective of birth weight. In response to FR, COX decreased and FOX increased. During FR, in LR pigs FOX was ~50% of that in NR pigs. After 4 days, but not 25 days of RFD, EB and fat synthesis were higher in pigs previously subjected to FR, indicating early catch-up fat. In R pigs, BW and the abdominal fat proportion were lower at 131 days. CONCLUSIONS: Differences in food intake and substrate oxidation pattern, but not in EE and RMR, between L and N pigs were reflected in higher body fat proportions but lower body and muscle weights in L pigs. Refeeding following FR was initially associated with increased FI, a more positive EB and a more intense stimulation of fat synthesis which did not persist after 25 days of refeeding.

Distribution of conjugated linoleic acid (CLA) isomers and other fatty acids in polar and neutral fractions of milk from cows fed different lipid supplements / Distribución de isómeros de ácido linoléico conjugado (CLA) y ácidos grasos en las fracciones neutra y polar de la leche de vacas alimentadas con diferentes suplementos lipídicos / Distribuição de isômeros do acido linoleico conjugado (CLA) e outros ácidos graxos nas frações polares e neutras no leite de vacas alimentadas com diferentes suplementos lipídicos

Background: milk fatty acid composition has become very important for consumers due to the positive relationship that has been found between some fatty acids and human health. In recent years, content and fatty acid composition in the different fractions of milk lipids has also become important due to reported potential technological and sensory implications. Objective: the aim of this study was to evaluate the effect of dietary supplementation with several lipid supplements on the proportion of neutral (triglycerides) and polar lipids (phospholipids) of milk fat, alterations of the fatty acid composition and Conjugated Linolenic Acid isomers (CLA) of total milk lipids. Methods: 18 first lactation German Holstein cows were assigned to three dietary treatments for 10 weeks as follows: Rumen-stable fractionated palm fat, linseed oil plus algae, and sunflower oil plus algae. Results: dietary polyunsaturated fat supplements increased the proportion of phospholipids and decreased triglycerides in milk fat compared to Rumen-stable fractionated palm fat. Long chain polyunsaturated fatty acids were preferentially deposited into phospholipids. Diet effect was more pronounced in triglycerides than in phospholipids. Plant oil/algae supplemented diets induced lower proportions of total saturated fatty acids and higher proportions of total unsaturated fatty acids in triglycerides. Conclusions: linseed oil plus algae feeding generated the best results in reference to fatty acids related to human health. Sunflower oil plus algae caused accumulation of CLAtrans-10,cis-12, CLAtrans-7,cis-9, CLAtrans-7,trans-9 and CLAtrans-10,trans-12 and decrease of CLAtrans-9,trans-11 in total milk fat, whereas linseed oil plus algae increased CLAtrans-12,trans-14, CLAtrans-11,trans-13, and CLAtrans-11,cis-13 deposition compared to rumen-stable fractionated palm fat.

Antecedentes: la composición de ácidos grasos de la leche ha tomado gran importancia para los consumidores a causa de la relación positiva que se ha encontrado entre algunos ácidos grasos y la salud humana. En los últimos años, el contenido y composición de ácidos grasos en las diferentes fracciones de los lípidos de la leche también ha tomado importancia debido a las posibles implicaciones tecnológicas y sensoriales que se han reportado. Objetivo: el objetivo del presente estudio fue evaluar los cambios en la proporción de lípidos neutros (triglicéridos) y lípidos polares (fosfolípidos) y alteraciones de la composición de ácidos grasos e isómeros del Ácido Linoléico Conjugado (CLA) del total de lípidos de la leche como resultado de la suplementación dietaria con diferentes suplementos lipídicos. Métodos: 18 vacas Holstein Alemán de primera lactancia fueron asignadas a tres tratamientos dietarios durante 10 semanas, así: grasa de palma fraccionada y estable al rumen, aceite de lino más alga, y aceite de girasol más alga. Resultados: la suplementación con ácidos grasos poliinsaturados incrementó la proporción de fosfolípidos y disminuyó la de triglicéridos en la grasa de la leche comparado con grasa de palma fraccionada y estable al rumen. Los ácidos grasos poliinsaturados de cadena larga fueron preferencialmente depositados en los fosfolípidos. El efecto de la dieta fue más pronunciado en los triglicéridos que en los fosfolípidos. Las dietas suplementadas con aceite vegetal y alga indujeron a menores proporciones de ácidos grasos saturados y mayores proporciones de ácidos grasos insaturados en los triglicéridos. Conclusiones: la suplementación con aceite de lino más alga generó los mejores resultados respecto a la composición de ácidos grasos relacionados con la salud humana. El aceite de girasol más alga causó una acumulación de isomeros CLAtrans-10,cis-12, CLAtrans-7,cis-9, CLAtrans- 7,trans-9 y CLAtrans-10,trans-12 y disminuyó CLAtrans-9,trans-11 en la grasa total de la leche mientras que el aceite de lino más alga incrementó CLAtrans-12,trans-14, CLAtrans-11,trans-13, y CLAtrans-11,cis-13 comparado con la grasa de palma fraccionada y estable al rumen.

Antecedentes: a composição de ácidos graxos do leite tem-se tornado muito importante para os consumidores devido à relação positiva encontrada entre alguns ácidos graxos e a saúde humana. Nos últimos anos, o conteúdo e composição dos ácidos graxos nas diferentes frações lipídicas no leite também se tornaram importantes devido às consequências tecnológicas e sensoriais que tem sido reportada recentemente. Objetivo: realizou-se um estudo para avaliar as mudanças na proporção de lipídios neutros (triglicerídeos) e polares (fosfolipídios) na gordura do leite e as alterações da composição dos ácidos graxos e os isômeros do Ácido Linoleico Conjugado (CLA) no total dos lipídeos do leite como resultado da suplementação na dieta com diferentes suplementos lipídeos. Métodos: 18 vacas Holandesas na Alemanha, todas de primeira lactação foram avaliadas em três tratamentos com regimes alimentares diferentes durante 10 semanas, assim: óleo de palma fracionada e estável no rúmen, óleo de linhaça mais algas e óleo de girassol mais algas. Resultados: a suplementação com ácidos graxos poli-insaturados incrementou a proporção de fosfolipídios e diminuiu a proporção de triglicerídeos na gordura do leite, comparado com o óleo de palma fracionada e estável no rúmen. Os ácidos graxos poliinsaturados de cadeia longa foram preferencialmente depositados nos fosfolipídios. O efeito da dieta foi mais pronunciado nos triglicerídeos que nos fosfolipídios. As dietas que foram suplementadas com óleo vegetal mais algas reduziram a proporção de ácidos graxos saturados, e aumentaram a proporção de ácidos graxos insaturados nos triglicerídeos. Conclusões: a suplementação com óleo de linhaça mais alga gerou os melhores resultados respeito à composição dos ácidos graxos relacionados com a saúde humana. O óleo de girassol mais alga causaram uma acumulação de CLAtrans-10, cis-12, CLAtrans-7, cis-9, CLAtrans-7, trans-9 e CLAtrans-10, trans-12 e diminuiu CLAtrans-9, trans-11 na gordura total do leite, enquanto que óleo de linhaça mais alga aumentou a deposição de CLAtrans-12, trans-14, CLAtrans-11, trans-13, e CLAtrans-11, cis-13, em comparação com o óleo de palma fracionada e estável no rúmen.

High-fat diets rich in ω-3 or ω-6 polyunsaturated fatty acids have distinct effects on lipid profiles and lipid peroxidation in mice selected for either high body weight or leanness.

OBJECTIVE: The aim of the study is to determine the response of muscle lipid peroxidation and the fatty-acid profile of three groups of mice-high body weight (DU6) obesity-prone mice, high treadmill performance (DUhTP) lean mice, and unselected control mice (DUK) fed high-fat diets (HFDs) rich in ω-3 or ω-6 polyunsaturated fatty acids (PUFA). METHODS: The isocaloric HFDs were enriched with either ω-3 PUFA (27% fish oil, ω-3 HFD) or ω-6 PUFA (27% sunflower oil, ω-6 HFD), and the control group was fed standard chow (7.2% fat). Statistical calculations were done with procedure GLM of SAS. RESULTS: As expected, the ω-3 and ω-6 PUFA-rich HFDs showed significant effects on fatty-acid concentrations of skeletal muscle in all three lines of mice compared with the standard chow. The investigations of muscle lipid peroxidation revealed that the ω-3 PUFA-rich HFD caused the highest lipid peroxidation values in muscle of lean DUhTP mice and unselected control DUK mice. However, lower lipid peroxidation levels were observed in the obesity-prone DU6 mice. In contrast, the ω-6 PUFA-rich HFD did not influence lipid peroxidation in muscle of any of the different lines of mice. The present study suggests that a higher overall antioxidant capacity in the muscle tissue of obesity-prone DU6 mice may lead to lower levels of reactive oxygen species formation by ω-3 PUFA-rich HFDs in comparison with lean DUhTP mice. CONCLUSION: These studies raise the possibility that obesity per se may be protective against oxidative damage when high ω-3 PUFA diets are used.

Dietary PUFA Intervention Affects Fatty Acid- and Micronutrient Profiles of Beef and Related Beef Products.

The study investigated the dietary impact of 18:3n-3 vs. 18:2n-6 on fatty acid- and micronutrient concentration of beef muscle and the extent of diet- and processing-induced changes of lipid- and micronutrient concentrations of beef products made thereof (German Corned beef (GCB), tea sausage spread (TSS), scalded sausage (SS)). Beef and beef products were obtained from German Holstein bulls which either received a control diet consisting of maize silage and concentrate with soybean meal (41%), or an experimental diet of grass silage and concentrate plus rapeseed cake (12%) and linseed oil (3%). The study revealed that upon an 18:3n-3 vs. 18:2n-6 intervention the amounts of 18:3n-3, EPA and Σn-3 LC-PUFA were significantly increased by 2.6, 2.3 and 1.7 fold, respectively. Experimental diet significantly increased ß-carotene contents, and the γ-tocopherol contents were decreased. During beef processing, n-3 PUFA from beef were found to be product-specifically transferred into the corresponding beef products. 18:3n-3 and Σn-3 LC-PUFA contents were found to be 1.4 and 1.5 times higher in GCB from grass silage- than maize silage-fed bulls. The trace element contents in GCB (iron, copper, zinc, selenium) were not affected by the diet; however γ-tocopherol contents were decreased by experimental diet. In conclusion, dietary n-3 PUFA were completely transferred into beef products unaffected by beef processing conditions.

How selected tissues of lactating holstein cows respond to dietary polyunsaturated fatty acid supplementation.

The effect of a 10-week supplementation with polyunsaturated fatty acids [via sunflower oil/DHA-rich algae (SUNA) or linseed oil/DHA-rich algae (LINA) enriched diets] versus saturated fatty acids (SAT) of lactating German Holstein dairy cows in mid-lactation on expression patterns of lipid metabolism-associated genes and gene products in hepatic, longissimus muscle and subcutaneous/perirenal/omental adipose tissue was assessed. Most pronounced transcriptomic responses to dietary PUFA were obtained in hepatic [down-regulated ACACA (FC = 0.83, SUNA; FC = 0.86, LINA), FADS1 (FC = 0.60, SUNA; FC = 0.72, LINA), FADS2 (FC = 0.64, SUNA; FC = 0.79, LINA), FASN (FC = 0.64, SUNA; FC = 0.72, LINA), SCD (FC = 0.37, SUNA; FC = 0.47, LINA) and SREBF1 (FC = 0.79, SUNA, LINA) expression] and omental adipose [up-regulated ACACA (FC = 1.58, SUNA; FC = 1.22, LINA), ADFP (FC = 1.33, SUNA; FC = 1.32, LINA), CEBPA (FC = 1.75, SUNA; FC = 1.40, LINA), FASN (FC = 1.57, SUNA; FC = 1.21, LINA), LPL (FC = 1.50, SUNA; FC = 1.20, LINA), PPARG (FC = 1.36, SUNA; FC = 1.12, LINA), SCD (FC = 1.41, SUNA; FC = 1.17, LINA) and SREBF1 (FC = 1.56, SUNA; FC = 1.18, LINA) expression] tissue. Interestingly, gene/gene product associations were comparatively low in hepatic and omental adipose tissue compared with longissimus muscle, perirenal adipose and subcutaneous adipose tissue, indicating matches only in regard to minor concentrations of SCD product 18:1c9, FADS1 product 20:4n-6 and FADS2 product 18:3n-6 in hepatic tissue, and higher concentrations of ACACA and FASN gene products 12:0 and 14:0 and SCD product 18:2c9,t11 in omental adipose tissue. Whereas all analyzed tissues accumulated dietary PUFA and their ruminally generated biohydrogenation products, tissue-divergent preferences for certain fatty acids were identified. This descriptive study reports tissue-divergent effects of dietary PUFA and outlines the significance of a PUFA intervention with regard to dairy cows' nutritional management.

Different dietary protein and PUFA interventions alter the fatty acid concentrations, but not the meat quality, of porcine muscle.

The present study investigated the effect of a reduced protein diet in combination with different vegetable oils (sunflower seed oil or linseed oil) on carcass traits, meat quality and fatty acid profile in porcine muscle. Forty male Landrace pigs were allocated into four experimental groups (each n = 8) and one control group (n = 8) at a live weight of approximately 60 kg. The pigs were fed ad libitum from 60 kg to 100 kg live weight and restricted to 2.8 kg/day until they reached 120 kg. In contrast to other studies, the intramuscular fat content (IMF) did not increase in animals of groups fed a reduced protein diet and vegetable oils. The IMF ranged between 1.2% and 1.4%. The growth performance and meat quality of the longissimus muscle was not affected by the diet, but the average daily gain (ADG) and drip loss were affected. The muscle fatty acid concentrations were significantly affected by the diet, resulting in higher n-3 FA concentrations up to 113 mg/100 g muscle and lower n-6/n-3 PUFA ratio for pigs fed linseed oil-containing high- and reduced protein diets, compared to sunflower seed oil-containing diets.

Dietary fatty acid intervention of lactating cows simultaneously affects lipid profiles of meat and milk.

BACKGROUND: The present study investigated tissue-specific responses of muscle and mammary gland to a 10 week intervention of German Holstein cows (n = 18) with three different dietary fat supplements (saturated fat; linseed oil or sunflower oil plus docosahexaenoic acid-rich algae) by analysing fatty acid profiles and quality parameters of meat and milk. RESULTS: Plant oil/algae intervention affected neither fat content nor quality parameters of meat but decreased fat content and saturated fatty acid amounts of milk. Linseed oil/algae intervention caused significantly higher concentrations of C18:3n-3 (meat, 1.0 g per 100 g; milk, 1.2 g per 100 g) and C22:6n-3 (meat, 0.3 g per 100 g; milk, 0.14 g per 100 g). Sunflower oil/algae intervention increased n-6 fatty acid contents in milk (4.0 g per 100 g) but not in meat. Elevated amounts of C18:1trans isomers and C18:1trans-11 were found in meat and especially in milk of plant oil/algae-fed cows. C18:1cis-9 amounts were found to be increased in milk but decreased in meat after plant oil/algae intervention. CONCLUSION: The present study demonstrated that dietary fatty acid manipulation substantially shifted the fatty acid profiles of milk and to a lesser extent of meat, whereas meat quality traits were not affected. Indications of tissue-specific responses of mammary gland and muscle were identified.

Dietary n-3 PUFA affect lipid metabolism and tissue function-related genes in bovine muscle.

Gene expression profiles of bovine longissimus muscle as affected by dietary n-3 v. n-6 fatty acid (FA) intervention were analysed by microarray pre-screening of >3000 muscle biology/meat quality-related genes as well as subsequent quantitative RT-PCR gene expression validation of genes encoding lipogenesis-related transcription factors (CCAAT/enhancer-binding protein ß, sterol regulatory element-binding transcription factor 1), key-lipogenic enzymes (acetyl-CoA carboxylase α (ACACA), fatty acid synthase (FASN), stearoyl-CoA desaturase (SCD)), lipid storage-associated proteins (adipose differentiation-related protein (ADFP)) and muscle biology-related proteins (cholinergic receptor, nicotinic, α1, farnesyl diphosphate farnesyl transferase 1, sema domain 3C (SEMA3C)). Down-regulation of ACACA (P = 0·00), FASN (P = 0·09) and SCD (P = 0·02) gene expression upon an n-3 FA intervention directly corresponded to reduced SFA, MUFA and total FA concentrations in longissimus muscle, whereas changes in ADFP (P = 0·00) and SEMA3C (P = 0·05) gene expression indicated improved muscle function via enhanced energy metabolism, vasculogenesis, innervation and mediator synthesis. The present study highlights the significance of dietary n-3 FA intervention on muscle development, maintenance and function, which are relevant for meat quality tailoring of bovine tissues and modulating animal production-relevant physiological processes.

Metabolic responses to high-fat diets rich in n-3 or n-6 long-chain polyunsaturated fatty acids in mice selected for either high body weight or leanness explain different health outcomes.

BACKGROUND: Increasing evidence suggests that diets high in polyunsaturated fatty acids (PUFA) confer health benefits by improving insulin sensitivity and lipid metabolism in liver, muscle and adipose tissue. METHODS: The present study investigates metabolic responses in two different lines of mice either selected for high body weight (DU6) leading to rapid obesity development, or selected for high treadmill performance (DUhTP) leading to a lean phenotype. At 29 days of age the mice were fed standard chow (7.2% fat, 25.7% protein), or a high-fat diet rich in n-3 PUFA (n-3 HFD, 27.7% fat, 19% protein) or a high-fat diet rich in n-6 PUFA (n-6 HFD, 27.7% fat, 18.6% protein) for 8 weeks. The aim of the study was to determine the effect of these PUFA-rich high-fat diets on the fatty acid profile and on the protein expression of key components of insulin signalling pathways. RESULTS: Plasma concentrations of leptin and insulin were higher in DU6 in comparison with DUhTP mice. The high-fat diets stimulated a strong increase in leptin levels and body fat only in DU6 mice. Muscle and liver fatty acid composition were clearly changed by dietary lipid composition. In both lines of mice n-3 HFD feeding significantly reduced the hepatic insulin receptor ß protein concentration which may explain decreased insulin action in liver. In contrast, protein kinase C ζ expression increased strongly in abdominal fat of n-3 HFD fed DUhTP mice, indicating enhanced insulin sensitivity in adipose tissue. CONCLUSIONS: A diet high in n-3 PUFA may facilitate a shift from fuel deposition in liver to fuel storage as fat in adipose tissue in mice. Tissue specific changes in insulin sensitivity may describe, at least in part, the health improving properties of dietary n-3 PUFA. However, important genotype-diet interactions may explain why such diets have little effect in some population groups.

Trans-18:1 and CLA isomers in rumen and duodenal digesta of bulls fed n-3 and n-6 PUFA-based diets.

The aim of the study was to investigate the effect of n-6 PUFA (maize silage/grass silage, soybean meal and soybean oil, control) and n-3 PUFA (grass silage, rapeseed cake and rapeseed oil, experiment) based diets on the occurrence of rumen- and duodenal digesta trans-C18:1 and CLA isomers of German Simmental bulls. The results based on rumen and duodenal digesta samples immediately taken from the bulls just after slaughter. The diet affected the occurrence of individual trans-C18:1 and CLA isomers in the rumen and duodenal digesta in different ways. The isomer trans-11,cis-13 CLA was detected as the most abundant isomer in the rumen of n-3 PUFA based diet fed bulls compared to n-6 PUFA based diet fed bulls. The trans-7,cis-9 CLA isomer was not detected in the rumen samples of bulls fed both diets, however abundant trans-7,cis-9 CLA was identified and quantified in the duodenum digesta. Both the concentration of the sum of trans-18:1 fatty acids and individual isomers in the rumen were not affected by the diet, except trans-16-18:1. The concentration of trans-16-18:1 was significantly decreased in the rumen of n-3 PUFA supplemented-fed bulls compared to n-6 PUFA supplemented-fed bulls.

Antioxidant enzyme activities and antioxidant capacity in longissimus muscle from bulls fed diets rich in polyunsaturated fatty acids.

The effect of a treatment diet composed of grass silage and concentrate including rapeseed (with/without feeding restriction) was compared with a control diet of maize silage/grass silage (70:30) and concentrate including soybean, on the antioxidant enzyme activities of fresh longissimus muscle from German Simmental bulls. Additionally, the effect of diet on antioxidant capacity (AOC) of hydrophilic and lipophilic antioxidants was evaluated in fresh and stored beef muscle using the FRAP-ferric reducing ability and TEAC - Trolox-equivalent antioxidant capacity assays at different reaction times. Catalase and superoxide dismutase activities were significantly higher in the treatment diet groups, and glutathione peroxidase activity was not different. AOC was not affected by the diet. However, storage affected the values of FRAP and TEAC assays, and the results were time-depending. 30min were found like a minimum reaction time for both assays. Generally, AOC values of the hydrophilic antioxidants were significantly higher than lipophilic values.

Effect of dietary n-3 and n-6 PUFA on lipid composition of different tissues of German Holstein bulls and the fate of bioactive fatty acids during processing.

The present study investigated the effects of dietary linolenic acid (ALA) versus linoleic acid (LA) on meat quality, fatty acid composition, and stearoyl-CoA desaturase (SCD) activity in longissimus muscle (MLD) and subcutaneous adipose tissue (SAT) of German Holstein bulls and the transfer of beneficial n-3 fatty acids into German corned beef sausages (GCB). Feeding LA- and ALA-enriched diets increased essential fatty acids in MLD and SAT. The ALA-supplemented diet decreased significantly the SCD activity in MLD and SAT, resulting in a reduced relative concentration of oleic acid in muscle. The relative proportion of CLAcis-9,trans-11 analyzed by HPLC was not different between groups in either tissue. GCB were produced by using the lean meat of bulls. Beef products of bulls fed the ALA-supplemented diet were rich in ALA and n-3 LC PUFA. Most importantly, there was no loss of n-3 fatty acids during processing under production conditions. Conclusively, the n-6/n-3 fatty acid ratio was beneficially low.

Relationship between lipid peroxidation and antioxidant status in the muscle of German Holstein bulls Fed n-3 and n-6 PUFA-enriched diets.

This study evaluated the influence of different n-3 and n-6 PUFA-enriched diets on the relationship between lipid peroxidation and antioxidant status by analyzing fatty acids (FA), lipid peroxidation, antioxidant capacity (AOC), antioxidant enzymes, trace elements, and fat-soluble vitamins in the longissimus muscle. Diet caused significant changes in muscle FA composition, leading to accumulation of beneficial n-3 FA. beta-Carotene and catalase activity were significantly elevated in muscle of the n-3 PUFA-enriched diet group compared to the n-6 PUFA-enriched diet group. Lipid peroxidation was higher in muscle of the n-3 PUFA-enriched diet group after 15 min of reaction time. There was no significant effect of diet on AOC, but it increased with reaction time. The present results suggest that the antioxidant defense in muscle of the n-3 PUFA-enriched diet group could balance reactive substances under low oxidative conditions. However, the antioxidant capacity was not sufficient under abundant accumulation of reactive substances.

Assessment of the antioxidant potential of selected plant extracts--in vitro and in vivo experiments on pork.

The antioxidant potential of selected plant extracts was assessed in vitro and in vivo experiments on pork. In the in vitro experiment, the anti-oxidative capacity of ethanol-water extract of Melissa officinalis (MW), ethanol-propylene-glycol extracts of M. officinalis (MP), Origanum vulgaris (O) and Salvia officinalis (S) at different dilutions was analysed. Furthermore a 2% essential oil concentrate was added to Origanum (OSi) and Salvia (SSi). In the two in vivo experiments in total 104 Slovak White Meaty pigs were fed with plant extracts (MW and O) at different doses with/without additional vitamin E. In the in vitro experiment Melissa (MW) showed a higher antioxidant potential compared to Origanum and Salvia assessed by TEAC assay. Addition of essential oil to Origanum improved substantially the anti-oxidative capacity. In the in vivo experiment the highest muscle anti-oxidative effect was obtained by feeding 60 ml Origanum. Small improvement in muscle antioxidant potential was observed by feeding Melissa or Origanum in combination with vitamin E. By feeding 10 ml Melissa, Origanum or Salvia the meat quality parameters such as pH(1) and pH(24), drip loss and shear force was not affected. After 5 days storage of meat the redness value was positively affected.

Vaccenic acid and cis-9,trans-11 CLA in the rumen and different tissues of pasture- and concentrate-fed beef cattle.

The objective of present study was the comparison of trans-11 18:1 (VA) and cis-9,trans-11 CLA concentrations in the rumen and different tissues in beef cattle, and to examine the diet and breed effects on the compound concentration and deposition. Sixty-four German Holstein and German Simmental bulls were randomly assigned to two dietary treatments, based on concentrate or pasture. The concentration of cis-9,trans-11 CLA and VA in rumen, duodenal digesta and different tissues was determined by gas chromatography. The results showed that pasture relative to concentrate feeding significantly increased the concentration of VA in duodenal digesta, plasma and erythrocyte phospholipids. Pasture-based feeding resulted in a significant enrichment of cis-9,trans-11 CLA in plasma lipids and erythrocyte phospholipids, but not in rumen and duodenal digesta, compared to concentrate-fed diet. Diet did not affect the cis-9,trans-11 CLA concentrations (mg/100 g fresh tissue) in semitendinosus muscle and subcutaneous fat. There was a breed effect on the deposition of cis-9,trans-11 CLA in longissimus muscle with lower concentration in pasture-fed German Simmental bulls compared to concentrate-fed bulls. However, pasture feeding significantly increased both, the VA and cis-9,trans-11 CLA concentrations in liver and heart tissues. Both diet and breed effects on Delta(9)-desaturase index was observed in muscle and subcutaneous fat tissues. There was a linear relationship between the concentration of VA and cis-9,trans-11 CLA and the coefficients of determination (R (2)) varied between 0.29 and 0.87 from rumen to the different tissues.

Comparison of different methylation methods for the analysis of conjugated linoleic acid isomers by silver ion HPLC in beef lipids.

Four different methods for the methylation of conjugated linoleic acid isomers (CLA) in ruminant lipids were compared by silver ion (Ag+) HPLC. The combination of base-catalyzed methods followed by an acid-catalyzed method with BF3/MeOH was tested under different temperatures (room temperature and at 60 degrees C), along with based-catalyzed methylation with NaOCH3 and methylation with BF3/MeOH after saponification with NaOH. The comparison among these four methods was done on muscle and adipose tissue samples from bulls. The repeatability theta of the combined base- and acid-catalyzed methylation (NaOCH3/BF3) at ambient temperature for 20 min and at 60 degrees C for 10 min was most suitable for the quantitative Ag+-HPLC analysis of CLA isomers. At 60 degrees C the combined methods supplied the highest concentrations of most CLA isomers. The base-catalyzed methylation and the saponification followed by BF3/MeOH methylation for 5 min generated significantly lower concentrations for most CLA isomers compared to the combined methods.