Lower Plasmatic Levels of Saturated Fatty Acids and a Characteristic Fatty Acid Composition in the Ovary Could Contribute to the High-Fertility Phenotype in Dummerstorf Superfertile Mice.

In recent decades, fertility traits in humans as well as in farm animals have decreased worldwide. As such, it is imperative to know more about the genetics and physiology of increased or high fertility. However, most of the current animal models with reproductive phenotypes describe lower fertility or even infertility (around 99%). The "Dummerstorf high-fertility lines" (FL1 and FL2) are two unique mouse lines selected for higher reproductive performances, more specifically for higher number of pups per litter. We recently described how those superfertile mice managed to increase their reproductive phenotype by doubling the ovulation rate and consequently the litter size compared to the unselected mice of the same founder population. FLs show an unusual estrous cycle length and atypical levels of hormones that link reproduction and metabolism, such as insulin in FL1 and leptin in FL2. Moreover, we described that their higher ovulation rate is mostly due to a higher quality of their oocytes rather than their sheer quantity, as they are characterized by a higher quantity of high-quality oocytes in antral follicles, but the quantity of follicles per ovary is not dissimilar compared to the control. In the present study, we aimed to analyze the lipid composition of the fertility lines from plasma to the gonads, as they can connect the higher reproductive performances with their metabolic atypicalities. As such, we analyzed the fat content of FLs and fatty acid composition in plasma, liver, fat, oocytes of different quality, and granulosa cells. We demonstrated that those mice show higher body weight and increased body fat content, but at the same time, they manage to decrease the lipid content in the ovarian fat compared to the abdominal fat, which could contribute to explaining their ovarian quality. In addition, we illustrate the differences in fatty acid composition in those tissues, especially a lower level of saturated fatty acids in plasma and a different lipid microenvironment of the ovary. Our ongoing and future research may be informative for farm animal biology as well as human reproductive medicine, mostly with cases that present characteristics of lower fertility that could be reversed following the way-of-managing of Dummerstorf high-fertility lines.

Reduced lipolysis in lipoma phenocopies lipid accumulation in obesity.

BACKGROUND: Elucidation of lipid metabolism and accumulation mechanisms is of paramount importance to understanding obesity and unveiling therapeutic targets. In vitro cell models have been extensively used for these purposes, yet, they do not entirely reflect the in vivo setup. Conventional lipomas, characterized by the presence of mature adipocytes and increased adipogenesis, could overcome the drawbacks of cell cultures. Also, they have the unique advantage of easily accessible matched controls in the form of subcutaneous adipose tissue (SAT) from the same individual. We aimed to determine whether lipomas are a good model to understand lipid accumulation. METHODS: We histologically compared lipomas and control SAT, followed by assessment of the lipidome using high-resolution 1H NMR spectroscopy and ESI-IT mass spectrometry. RNA-sequencing was used to obtain the transcriptome of lipomas and the matched SAT. RESULTS: We found a significant increase of small-size (maximal axis < 70 µm) and very big (maximal axis > 150 µm) adipocytes within lipomas. This suggests both enhanced adipocyte proliferation and increased lipid accumulation. We further show that there is no significant change in the lipid composition compared to matched SAT. To better delineate the pathophysiology of lipid accumulation, we considered two groups with different genetic backgrounds: (1) lipomas with HMGA2 fusions and (2) without gene fusions. To reduce the search space for genes that are relevant for lipid pathophysiology, we focused on the overlapping differentially expressed (DE) genes between the two groups. Gene Ontology analysis revealed that DE genes are enriched in pathways related to lipid accumulation. CONCLUSIONS: We show that the common shared lipid accumulation mechanism in lipoma is a reduction in lipolysis, with most gene dysregulations leading to a reduced cAMP in the adipocyte. Superficial lipomas could thus be used as a model for lipid accumulation through altered lipolysis as found in obese patients.

The repertoire of Adhesion G protein-coupled receptors in adipocytes and their functional relevance.

BACKGROUND: G protein-coupled receptors (GPCR) are well-characterized regulators of a plethora of physiological functions among them the modulation of adipogenesis and adipocyte function. The class of Adhesion GPCR (aGPCR) and their role in adipose tissue, however, is poorly studied. With respect to the demand for novel targets in obesity treatment, we present a comprehensive study on the expression and function of this enigmatic GPCR class during adipogenesis and in mature adipocytes. METHODS: The expression of all aGPCR representatives was determined by reanalyzing RNA-Seq data and by performing qPCR in different mouse and human adipose tissues under low- and high-fat conditions. The impact of aGPCR expression on adipocyte differentiation and lipid accumulation was studied by siRNA-mediated knockdown of all expressed members of this receptor class. The biological characteristics and function of mature adipocytes lacking selected aGPCR were analyzed by mass spectrometry and biochemical methods (lipolysis, glucose uptake, adiponectin secretion). RESULTS: More than ten aGPCR are significantly expressed in visceral and subcutaneous adipose tissues and several aGPCR are differentially regulated under high-caloric conditions in human and mouse. Receptor knockdown of six receptors resulted in an impaired adipogenesis indicating their expression is essential for proper adipogenesis. The altered lipid composition was studied in more detail for two representatives, ADGRG2/GPR64 and ADGRG6/GPR126. While GPR126 is mainly involved in adipocyte differentiation, GPR64 has an additional role in mature adipocytes by regulating metabolic processes. CONCLUSIONS: Adhesion GPCR are significantly involved in qualitative and quantitative adipocyte lipid accumulation and can control lipolysis. Factors driving adipocyte formation and function are governed by signaling pathways induced by aGPCR yielding these receptors potential targets for treating obesity.

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.

Differences in the lipid patterns during maturation of 3T3-L1 adipocytes investigated by thin-layer chromatography, gas chromatography, and mass spectrometric approaches.

Populations of industrialized countries have registered a dramatically increasing prevalence in obesity for many years. Despite continuous research, mechanisms involved in the storage and utilization of chemical energy in adipocytes are still under investigation. Adipocytes have the task to store excessive energy in the form of triacylglycerols (TG) and it is already well-known that the fatty acyl composition of TG is largely determined by the composition of the diet. In contrast to TG, the composition of adipocyte phospholipids was less comprehensively investigated. In this study, the compositions of the most abundant phospholipid classes of 3T3-L1 undifferentiated (preadipocytes) and differentiated cells (adipocytes) were determined. The lipid fractions were isolated by normal phase high-performance thin-layer chromatography and subsequently analyzed by electrospray ionization mass spectrometry. Additionally, the fatty acyl (FA) compositions were determined by gas chromatography. The positions of the FA residues were additionally confirmed by phospholipase A2 digestion. The advantages and disadvantages of the different analytical approaches will be discussed. It will be shown that undifferentiated 3T3-L1 and mature adipocytes differ extremely regarding their compositions. This goes along with an increase in odd-chain fatty acids. Graphical abstract.

Relationship between the fatty acid profile of hair and energy availability of lactating primiparous cows.

We hypothesised that a relationship would exist between hair fatty acids, especially C12:0, C14:0 and C16:0, and parameters of energy metabolism such as energy intake, energy mobilisation, and energy requirement for maintenance and milk performance. For this study, 11 primiparous German Holstein cows were available from which hair samples at weeks 6 and 8 of lactation were analysed. The average body weight of these animals was 558 ± 27 kg at calving and milk yield at 100-days in milk was 3,537 ± 529 kg. Feed intake and milk yield were measured daily. Body weight and back fat thickness were measured at calving and in weeks 2, 4, and 8 of lactation. Energy balance and energy utilisation were calculated until week 6 of lactation. Spearman's correlation coefficients were found to be significantly positive for the relationship between the percentage of C12:0 and C14:0 fatty acids in the hair in lactation week 8 and energy intake in weeks 5 and 6 (0.62 < r < 0.65, P < 0.05). If the animals are grouped according to their energy utilisation between weeks 1 and 6 into two groups higher (n = 6) or lower (n = 5) than the median, animals of the high energy utilising group had a higher energy intake. These animals had also higher percentages of the C12:0 fatty acid in their hair fat (week 6: 4.9% vs. 3.1%, P < 0.05; week 8: 4.3% vs. 2.9%, P = 0.05). Our hypothesis is supported, and this study justifies further investigation of the content of medium-chain fatty acids in hair samples as biomarkers for the metabolic status of a cow during early lactation.

Effects of long-term microalgae supplementation on muscle microstructure, meat quality and fatty acid composition in growing pigs.

We investigated the effects of long-term microalgae supplementation (7% in a piglet diet and 5% in a fattening diet) on muscle microstructure and meat quality, including fatty acid composition in female Landrace pigs (n = 31). The major effects were muscle-specific increases in n-3 and n-6 polyunsaturated fatty acids (PUFA) concentrations, resulting in increased accumulation of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Carcass traits and meat quality of longissimus thoracis muscle were not affected by the microalgae diet with the exception of reduced drip loss (p = 0.01) and increased protein proportion (p = 0.04). In addition, the microalgae diet resulted in a shift to a more oxidative myofibre type composition in semitendinosus but not longissimus thoracis muscle. In conclusion, microalgae supplementation offers a unique opportunity to enhance essential n-3 PUFA contents in pig meat. The results support small but coordinated changes in skeletal muscle phenotypic appearance and functionality.

Dose response of rumen-protected conjugated linoleic acid supplementation to fattening bulls and heifers on growth, and carcass and meat quality.

We investigated the influence of rumen-protected conjugated linoleic acid (rpCLA) on growth performances, and carcass and meat quality traits in beef. Twenty-four young bulls and 30 heifers obtained from double-muscled beef sires and dairy cows were fed a low-protein ration (110 g/kg DM of crude protein) supplemented with 0, 8 or 80 g/d of a commercial rpCLA product. The animals were monthly weighed and scored for body muscularity and fatness. Blood samples were collected after 140 days on feed. Animals were slaughtered when they reached average in vivo fatness scores of around 2.5 (heifers) and 2.0 (bulls) points respectively. At slaughter, carcasses, various organs and parts of the gastrointestinal tract were weighed; the 5th rib was dissected and its tissue and muscle chemical composition was determined. The rpCLA had little influence on growth performance but decreased the blood urea content by 28% (p < 0.01). The rpCLA × sex interactions for daily gain (p < 0.05), conformation scores (p < 0.01), and blood creatinine content (p < 0.05) suggest that males were more responsive to rpCLA than females when fed a low-protein ration, probably because of the metabolic protein-sparing effect of CLA. Only slight differences were observed in carcass weight and quality at slaughter. The results indicate that the response of beef cattle to rpCLA is dependent on sex or on their propensity for lean and fat accretion. It is also possible that counteracting feedback mechanisms compensate for the influence of rpCLA administration over the course of growth.

Feed-efficient pigs exhibit molecular patterns allowing a timely circulation of hormones and nutrients.

Feed efficiency (FE) is a measure of the rate between feed intake and body weight gain and is subject to constant progress in pigs, based on extensive performance tests and analyses of physiological parameters. However, endocrine regulatory circuits that comprise the sensation and perception of intrinsic requirements and appropriate systemic responses have not yet been fully elucidated. It is hypothesized that the gut-brain axis, which is a network of hierarchical anterior regulatory tissues, contributes largely to variations in FE. Therefore, full-sib pigs with extreme residual feed intake values were assigned to experimental groups of high and low FE. Relevant hormones, minerals, and metabolites including fatty acid profiles were analyzed in serum to assess postprandial conditions. Transcriptome profiles were deduced from intestinal (duodenum, jejunum, ileum) and neuroendocrine tissues (hypothalamus). Serum analyses of feed-efficient animals showed an increased content of the incretin GIP, calcium, magnesium, ß-hydroxybutyric acid, and fat compared with low-FE pigs. Complementary expression profiles in intestinal tissues indicate a modulated permeability and host-microbe interaction in FE-divergent pigs. Transcriptomic analyses of the hypothalamus showed that differences between the FE groups in appetite and satiety regulation are less pronounced. However, hypothalamic abundance of transcripts like ADCY7, LHCGR, and SLC2A7 and molecular signatures in local and systemic tissue sites indicate that increased allocation and circulation of energy equivalents, minerals, and hormones are promoted in feed-efficient animals. Overall, patterns of gastrointestinal hormones and gene expression profiles identified host-microbiota interaction, intestinal permeability, feed intake regulation, and energy expenditure as potential mechanisms affecting FE in pigs.

Sea Buckthorn Pomace Supplementation in the Diet of Growing Pigs-Effects on Fatty Acid Metabolism, HPA Activity and Immune Status.

There is evidence that sea buckthorn, as a source of n-3 polyunsaturated fatty acids (n-3 PUFA), possesses health-enhancing properties and may modulate neuroendocrine and immune functions. In the present study, we investigated the effect of sea buckthorn pomace (SBP) supplementation in the diet of growing German Landrace pigs on fatty acids in the blood and hypothalamus, peripheral immune parameters and mRNA expression of corticotropin-releasing hormone (CRH), mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) in the hypothalamus and spleen. Pigs were fed diets supplemented with 12% of dried SBP or 0% SBP (control group) over an intervention period of eight weeks. The fatty acid profiles in blood plasma were significantly affected by SBP supplementation only for C18:2n-6 and n-6/n-3 PUFA ratio compared with the control group. SBP supplementation did not significantly affect the fatty acid concentrations in the hypothalamus. Furthermore, there were no significant differences in mRNA expression of CRH, MR and GR in the hypothalamus or of GR mRNA expression in the spleen. Concerning the immune status, the plasma IgG levels tended to be higher in SBP pigs, whereas the leukocyte distribution, mitogen-stimulated lymphocyte proliferation, and serum IgM levels remained unchanged. In conclusion, the SBP supplementation of the diet only caused moderate effects on fatty acid metabolism, but no significant effects on hypothalamic-pituitary-adrenal (HPA) activity and immunity in growing pigs. It seems that a beneficial effect of dietary n-3 PUFA on health and welfare is more likely to be expected during stressful situations.

Strategies towards Improved Feed Efficiency in Pigs Comprise Molecular Shifts in Hepatic Lipid and Carbohydrate Metabolism.

Due to the central role of liver tissue in partitioning and metabolizing of nutrients, molecular liver-specific alterations are of considerable interest to characterize an efficient conversion and usage of feed in livestock. To deduce tissue-specific and systemic effects on nutrient metabolism and feed efficiency (FE) twenty-four animals with extreme phenotypes regarding residual feed intake (RFI) were analyzed. Transcriptome and fatty acid profiles of liver tissue were complemented with measurements on blood parameters and thyroid hormone levels. Based on 803 differentially-abundant probe sets between low- and high-FE animals, canonical pathways like integrin signaling and lipid and carbohydrate metabolism, were shown to be affected. Molecular alterations of lipid metabolism show a pattern of a reduced hepatic usage of fatty acids in high-FE animals. Complementary analyses at the systemic level exclusively pointed to increased circulating triglycerides which were, however, accompanied by considerably lower concentrations of saturated and polyunsaturated fatty acids in the liver of high-FE pigs. These results are in accordance with altered muscle-to-fat ratios usually ascribed to FE animals. It is concluded that strategies to improve FE might favor a metabolic shift from energy storage towards energy utilization and mobilization.

Nutrition-dependent changes of mouse adipose tissue compositions monitored by NMR, MS, and chromatographic methods.

Many diseases nowadays are assumed to be genetically determined. Therefore, many knockout mouse models have been established and are widely used. Unfortunately, nutrition (in particular the fat content of food) is often neglected in studies on these disease models. In this study the effects of nutrition on the lipid (triacylglycerol, TAG) compositions of different mouse adipose tissues were investigated. Mice were subjected to different diets [high fat (HF) vs. standard diet (SD)] and different adipose tissue samples (brown, visceral, and subcutaneous fat) were isolated after 12 weeks. Subsequent to lipid extraction, the organic extracts were analyzed by mass spectrometry (MALDI and ESI), high-resolution (1)H and (31)P NMR spectroscopy, high-performance thin-layer chromatography (HPTLC), and gas chromatography (GC). In adipose tissue of mice fed with HF diet, (a) decreased double bond contents and (b) decreased fatty acyl chain lengths of tissue TAGs were observed; this trend could be concomitantly monitored by all methods used. However, the adipose tissue still contained significant amounts of slightly unsaturated fatty acyl residues (18:1). Thus, a certain double bond content seems necessary to maintain the properties of adipose tissues.

Evaluation of a commercial enzymatic test kit regarding the quantitative analysis of different free fatty acids.

The quantitative determination of the total free fatty acids (FFAs) is an important analytical task because FFAs exhibit important physiological effects and are also relevant in many other fields, for instance, in food research. Our aim was to investigate whether a commercially available enzymatic test kit developed for the determination of FFAs in human serum is also suitable to determine different physiological and nonphysiological FFAs and to which extent the impact on the sensitivities (i.e., the accuracy by which a given FFA can be determined) differ. It will be shown that the chain length as well as the double bond content has a significant impact on the sensitivity by which a given FFA can be determined. For instance, palmitic acid (16:0) is determined with an approximately 20 times higher sensitivity in comparison to docosahexaenoic acid (22:6n-3). All data were obtained by measuring the concentrations of the FFAs by gas chromatography, and selected FFAs were also determined in a complex matrix of human serum. It is concluded that this kit is not useful if major alterations of the FFA composition of a complex mixture are expected because the individual FFAs are not detected with the same sensitivities: the concentrations of polyunsaturated FFA determined by this kit are wrong.

Yolk Fatty Acid Content, Lipid Health Indices, and Oxidative Stability in Eggs of Slow-Growing Sasso Chickens Fed on Flaxseed Supplemented with Plant Polyphenol Extracts.

Previous attempts to increase the level of flaxseed in hens' diet for the production of n-3 polyunsaturated fatty acids (n-3 PUFAs)-enriched eggs have been commonly associated with undesirable effects on production efficiency, lipid health indices, and oxidative stability of eggs, requiring adequate research attention. This study investigated the effects of feeding a moderate level of flaxseed (FS) and plant polyphenol extracts (PPEs) on fatty acid content, oxidative stability, and lipid health indices in eggs of slow-growing Sasso T451A laying hens. One hundred and five hens were assigned to five groups (seven replicates of three) and fed on FS (75 g flaxseed and no antioxidants), VE8 (75 g flaxseed and 800 mg vitamin E), TS8 (75 g flaxseed and 800 mg Thymus schimperi), DA8 (75 g flaxseed and 800 mg Dodonaea angustifolia), and CD8 (75 g flaxseed and 800 mg Curcuma domestica) extract per kg diets. The egg yolk content of eicosapentaenoic acid (EPA, C20:5 n-3) in the DA8, TS8, and CD8 diets and docosahexaenoic acid (DHA, C22:6 n-3) in TS8 and CD8 diets significantly (p < 0.05) increased compared with the FS diet. The FS diet significantly increased the malondialdehyde (MDA) content in egg yolks, whereas the TS8 diet decreased it by 67% (p < 0.05). Little difference was observed in yolk fatty acid content between cooked and raw eggs. Production of n-3 PUFA-enriched eggs with favorable lipid health indices was possible through inclusion of PPEs extracted from local plant species grown in Ethiopia and a moderate dose of flaxseed in the diet of laying hens.

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.

Are n-3 PUFAs from Microalgae Incorporated into Membrane and Storage Lipids in Pig Muscle Tissues?-A Lipidomic Approach.

For the study of molecular mechanisms of to lipid transport and storage in relation to dietary effects, lipidomics has been rarely used in farm animal research. A feeding study with pigs (German Landrace sows) and supplementation of microalgae (Schizochytrium sp.) was conducted. The animals were allocated to the control group (n = 15) and the microalgae group (n = 16). Shotgun lipidomics was applied. This study enabled us to identify and quantify 336 lipid species from 15 different lipid classes in pig skeletal muscle tissues. The distribution of the lipid classes was significantly altered by microalgae supplementation, and ether lipids of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidic acid (PA) were significantly decreased. The total concentration of triacylglycerides (TAGs) was not affected. TAGs with high degree of unsaturation (TAG 56:7, TAG 56:6, TAG 54:6) were increased in the microalgae group, and major abundant species like TAG 52:2 and TAG 52:1 were not affected by the diet. Our results confirmed that dietary DHA and EPA are incorporated into storage and membrane lipids of pig muscles, which further led to systemic changes in the lipidome composition.

Maternal Conjugated Linoleic Acid Supply in Combination With or Without Essential Fatty Acids During Late Pregnancy and Early Lactation: Investigations on Physico-Chemical Characteristics of the Jejunal Content and Jejunal Microbiota in Neonatal Calves.

Conjugated linoleic acids (CLAs) modulate the fatty acid composition in dairy cow milk, which represents the most important nutrient source of neonatal calves. In turn, dietary fatty acids are known to influence the gut microbiota. The current preliminary study investigated effects of a maternal fatty acid supplementation (MFAS) during transition period with coconut oil (CON, control), CLA (Lutalin®), or CLA + EFA (Lutalin® + essential fatty acids-linseed oil; safflower oil) on physico-chemical characteristics of jejunal content and microbiota of 5-day-old calves. MFAS of CLA + EFA increased α-linolenic, eicosapentaenoic, docosapentaenoic, and n-3 fatty acid proportions in jejunum compared to the other groups (P < 0.05). Proportions of n-6 and polyunsaturated fatty acids increased by MFAS of CLA + EFA compared to CON (P < 0.05). Most abundant phyla in the jejunum were Proteobacteria, Firmicutes, and Bacteroidota. CLA + EFA decreased the relative abundance of Diplorickettsiales (Proteobacteria) compared to CON and CLA (P < 0.05). CLA calves showed a lower abundance of Enterobacterales (Proteobacteria) compared to CON calves (P = 0.001). The abundance of Veillonellales-Selenomonadales and RF39 (Firmicutes) decreased in CLA + EFA calves compared to CON calves (P < 0.05). Bacteroidales (Bacteroidota) decreased in CLA + EFA calves compared to CLA calves (P < 0.05). The relative abundance of Cyanobacteria and Euryarchaeota decreased and the abundance of Chloroflexi increased in CLA + EFA calves compared to CON and CLA calves (P < 0.05). MFAS alters the fatty acid composition and microbial milieu in the intestinal content of neonatal calves due to their ability to modulate colostral fatty acid composition of dams.

Insights into molecular pathways and fatty acid membrane composition during the temperature stress response in the murine C2C12 cell model.

Daily and seasonal temperature fluctuations are inevitable due to climate change, which highlights the importance of studying the detrimental effects of temperature fluctuations on the health, productivity, and product quality of farm animals. Muscle membrane composition and the molecular signals are vital for muscle cell differentiation and muscle growth, but their response to temperature stress is not well characterized. Temperature changes can lead to modification of membrane components of the cell, which may affect its surroundings and intracellular signaling pathways. Using C2C12 myoblast cells as a model of skeletal muscle development, this study was designed to investigate the effects of high temperature (39 °C and 41 °C) and low temperature (35 °C) on molecular pathways in the cells as well as the cell membrane fatty acid composition. Our results show that several genes were differentially expressed in C2C12 cells cultured under heat or cold stress, and these genes were enriched important KEGG pathways including PI3K-Akt signaling pathway, lysosome and HIF- signaling pathway, Wnt signaling pathway and AMPK signaling pathway. Our analysis further reveals that several membrane transporters and genes involved in lipid metabolism and fatty acid elongation were also differentially expressed in C2C12 cells cultured under high or low temperature. Additionally, temperature stress shifts the fatty acid composition in the cell membranes, including the proportion of saturated, monounsaturated and polyunsaturated fatty acids. This study revealed an interference between fatty acid composition in the membranes and changing molecular pathways including lipid metabolism and fatty acids elongation mediated under thermal stress. These findings will reinforce a better understanding of the adaptive mechanisms in skeletal muscle under temperature stress.

Lipidomic specializations of honeybee (Apis mellifera) castes and ethotypes.

Honeybees of the same colony combine a near-homogeneous genetic background with a high level of phenotypic plasticity, making them ideal models for functional lipidomics. The only external lipid source of the colony is pollen, a diet rich in polyunsaturated fatty acids (PUFA). It has been suggested that differences in exposure to pollen-derived PUFA could partly explain differences in longevity between honeybee castes. We here investigated whether the membrane composition of honeybees plays roles in the physiological adaptation to tasks of individuals within the colony. Membranes of cell heaters, a group of workers producing heat from their flight muscles to uphold brood nest temperature, were compared to those of different types of non-heaters. We found that the lipidomic profiles of these groups fall into clearly different "lipotypes", characterized by chain length and saturation of phospholipid-bound fatty acyl residues. The nutritional exposure to PUFA during early adult life and pupal development at the lower edge of the natural range of brood nest temperature both suppressed the expression of the cell heater-"lipotype". Because cardiolipins (CL) are the lipid class most clearly differentiating honeybee phenotypes, and CL plays central roles in mitochondrial function, dysfunction and aging, our findings could help to understand these processes in other animals and humans. Taken together, the lipidome analysis of different life stages of workers, fertile queens, and drones lead to the hypothesis that honeybee "lipotypes" might represent adaptations to different energetic profiles and the likelihood of exposure to low temperatures.

Association between Fatty Acid Composition in Hair and Energy Availability during Early Lactation in Simmental and German Holstein Cows.

This study examined (1) if fatty acids in bovine hair are influenced by dietary energy levels and (2) if the relationship between energy availability and fatty acids in hair persists across breeds and farms. Sixty-two and 59 Fleckvieh (Simmental), and 55 German Holstein cows from three farms, respectively, were fed two levels of energy concentration of roughage (6.1 and 6.5 MJ net energy for lactation/kg dry matter) and two levels of concentrate supply (150 and 250 g/kg energy-corrected milk). The average body weight was 727 kg (Simmental) and 668 kg (Holstein). The average lactation number was 3.1. Hair samples were taken in lactation weeks 4 and 8. In Simmental cows, a lower energy deficit due to a relatively higher energy intake from high energy concentration of the roughage was associated with higher C18:2n-6 and C18:3n-3 contents in hair at week 8. In cows from all three farms, higher energy intake between lactation weeks 2 and 6 correlated with higher content of C18:2n-6 in hair samples taken in lactation weeks 4 and 8. No correlation was found for C12:0. These results provide the first evidence that increased energy intake increases the contents of C18:2n-6 in hair.