Gene expression of free fatty acids-sensing G protein-coupled receptors in beef cattle

Many physiological functions are regulated by free fatty acids (FFA). Recently, the discovery of FFA-specific G protein-coupled receptors (FFARs) has added to the complexity of their actions at the cellular level. The study of FFAR in cattle is still in its earliest stages focusing mainly on dairy cows. In this study, we set out to map the expression of genes encoding FFARs in 6 tissues of beef cattle. We also investigated the potential effect of dietary forage nature on FFAR gene expression. To this end, 16 purebred Charolais bulls were fed a grass silage ration or a maize silage ration (n = 8/group) with a forage/concentrate ratio close to 60:40 for 196 d. The animals were then slaughtered at 485 ± 42 d and liver, spleen, ileum, rectum, perirenal adipose tissue (PRAT), and Longissimus Thoracis muscle were collected. FFAR gene expression was determined by real-time quantitative PCR. Our results showed that of the five FFARs investigated, FFAR1, FFAR2, FFAR3, and GPR84 are expressed (Ct < 30) in all six tissues, whereas FFAR4 was only expressed (Ct < 30) in PRAT, ileum, and rectum. In addition, our results showed that the nature of the forage, i.e., grass silage or maize silage, had no effect on the relative abundance of FFAR in any of the tissues studied (P value > 0.05). Taken together, these results open new perspectives for studying the physiological role of these receptors in beef cattle, particularly in nutrient partitioning during growth.

Phytosterols activating nuclear receptors are involving in steroid hormone-dependent cancers: Myth or fact?

Nuclear receptors (NRs) represent intracellular proteins that function as a signaling network of transcriptional factors to control genes in response to a variety of environmental, dietary, and hormonal stimulations or serve as orphan receptors lacking a recognized ligand. They also play an essential role in normal development, metabolism, cell growth, cell division, physiology, reproduction, and homeostasis and function as biological markers for tumor subclassification and as targets for hormone therapy. NRs, including steroid hormone receptors (SHRs), have been studied as tools to examine the fundamentals of transcriptional regulation within the development of mammals and human physiology, in addition to their links to disturbances. In this regard, it is widely recognized that aberrant NR signaling is responsible for the pathological growth of hormone-dependent tumors in response to SHRs dysregulation and consequently represents a potential therapeutic candidate in a range of diseases, as in the case of prostate cancer and breast cancer. On the other hand, phytosterols are a group of plant-derived compounds that act directly as ligands for NRs and have proven their efficacy in the management of diabetes, heart diseases, and cancers. However, these plants are not suggested in cases of hormone-dependent cancer since a certain group of plants contains molecules with a chemical structure similar to that of estrogens, which are known as phytoestrogens or estrogen-like compounds, such as lignans, coumestans, and isoflavones. Therefore, it remains an open and controversial debate regarding whether consuming a phytosterol-rich diet and adopting a vegetarian lifestyle like the Mediterranean diet may increase the risk of developing steroid hormone-dependent cancers by constitutively activating SHRs and thereby leading to tumor transformation. Overall, the purpose of this review is to better understand the relevant mechanistic pathways and explore epidemiological investigations in order to establish that phytosterols may contribute to the activation of NRs as cancer drivers in hormone-dependent cancers.

Genomic Analysis of Visceral Fat Accumulation in Holstein Cows

Visceral fat is related to important metabolic processes, including insulin sensitivity and lipid mobilization. The goal of this study was to identify individual genes, pathways, and molecular processes implicated in visceral fat deposition in dairy cows. Data from 172 genotyped Holstein cows classified at slaughterhouse as having low (n = 77; omental fold <5 mm in thickness and minimum fat deposition in omentum) or high (n = 95; omental fold ≥20 mm in thickness and marked fat deposition in omentum) omental fat were analyzed. The identification of regions with significant additive and non-additive genetic effects was performed using a two-step mixed model-based approach. Genomic scans were followed by gene-set analyses in order to reveal the genetic mechanisms controlling abdominal obesity. The association mapping revealed four regions located on BTA19, BTA20 and BTA24 with significant additive effects. These regions harbor genes, such as SMAD7, ANKRD55, and the HOXB family, that are implicated in lipolysis and insulin tolerance. Three regions located on BTA1, BTA13, and BTA24 showed marked non-additive effects. These regions harbor genes MRAP, MIS18A, PRNP and TSHZ1, that are directly implicated in adipocyte differentiation, lipid metabolism, and insulin sensitivity. The gene-set analysis revealed functional terms related to cell arrangement, cell metabolism, cell proliferation, cell signaling, immune response, lipid metabolism, and membrane permeability, among other functions. We further evaluated the genetic link between visceral fat and two metabolic disorders, ketosis, and displaced abomasum. For this, we analyzed 28k records of incidence of metabolic disorders from 14k cows across lactations using a single-step genomic BLUP approach. Notably, the region on BTA20 significantly associated with visceral fat deposition was also associated with the incidence of displaced abomasum. Overall, our findings suggest that visceral fat deposition in dairy cows is controlled by both additive and non-additive effects. We detected at least one region with marked pleiotropic effects affecting both visceral fat accumulation and displaced abomasum.

Circadian Gene PER2 Silencing Downregulates PPARG and SREBF1 and Suppresses Lipid Synthesis in Bovine Mammary Epithelial Cells

Simple Summary

The present study was constructed to determine the effects of the core circadian clock gene, Period 2 (PER2), on lipid synthesis in bovine mammary epithelial cells (BMECs). Data revealed that PER2-regulated genes were involved in fatty acid de novo synthesis, desaturation, TAG accumulation, and lipid droplet secretion in primary BMECs, partly by inhibiting PPARG and SREBF1. Our overall data suggests that PER2 in bovine mammary cells plays a role in regulating milk fat synthesis directly, or via the activation of the transcription regulators PPARG and SREBF1. This study provides molecular evidence underscoring a link between the circadian clock and lipid metabolism in bovines.

Abstract

PER2, a circadian clock gene, is associated with mammary gland development and lipid synthesis in rodents, partly via regulating peroxisome proliferator-activated receptor gamma (PPARG). Whether such a type of molecular link existed in bovines was unclear. We hypothesized that PER2 was associated with lipid metabolism and regulated cell cycles and apoptosis in bovine mammary epithelial cells (BMECs). To test this hypothesis, BMECs isolated from three mid-lactation (average 110 d postpartum) cows were used. The transient transfection of small interfering RNA (siRNA) was used to inhibit PER2 transcription in primary BMECs. The silencing of PER2 led to lower concentrations of cellular lipid droplets and triacylglycerol along with the downregulation of lipogenic-related genes such as ACACA, FASN, LPIN1, and SCD, suggesting an overall inhibition of lipogenesis and desaturation. The downregulation of PPARG and SREBF1 in response to PER2 silencing underscored the importance of circadian clock signaling and the transcriptional regulation of lipogenesis. Although the proliferation of BMECs was not influenced by PER2 silencing, the number of cells in the G2/GM phase was upregulated. PER2 silencing did not affect cell apoptosis. Overall, the data provided evidence that PER2 participated in the coordination of mammary lipid metabolism and was potentially a component of the control of lipid droplets and TAG synthesis in ruminant mammary cells. The present data suggested that such an effect could occur through direct effects on transcriptional regulators.

Multifaceted role of one-carbon metabolism on immunometabolic control and growth during pregnancy, lactation and the neonatal period in dairy cattle

Dairy cattle undergo dramatic metabolic, endocrine, physiologic and immune changes during the peripartal period largely due to combined increases in energy requirements for fetal growth and development, milk production, and decreased dry matter intake. The negative nutrient balance that develops results in body fat mobilization, subsequently leading to triacylglycerol (TAG) accumulation in the liver along with reductions in liver function, immune dysfunction and a state of inflammation and oxidative stress. Mobilization of muscle and gluconeogenesis are also enhanced, while intake of vitamins and minerals is decreased, contributing to metabolic and immune dysfunction and oxidative stress. Enhancing post-ruminal supply of methyl donors is one approach that may improve immunometabolism and production synergistically in peripartal cows. At the cellular level, methyl donors (e.g. methionine, choline, betaine and folic acid) interact through one-carbon metabolism to modulate metabolism, immune responses and epigenetic events. By modulating those pathways, methyl donors may help increase the export of very low-density lipoproteins to reduce liver TAG and contribute to antioxidant synthesis to alleviate oxidative stress. Thus, altering one-carbon metabolism through methyl donor supplementation is a viable option to modulate immunometabolism during the peripartal period. This review explores available data on the regulation of one-carbon metabolism pathways in dairy cows in the context of enzyme regulation, cellular sensors and signaling mechanisms that might respond to increased dietary supply of specific methyl donors. Effects of methyl donors beyond the one-carbon metabolism pathways, including production performance, immune cell function, mechanistic target or rapamycin signaling, and fatty acid oxidation will also be highlighted. Furthermore, the effects of body condition and feeding system (total mixed ration vs. pasture) on one-carbon metabolism pathways are explored. Potential effects of methyl donor supply during the pepartum period on dairy calf growth and development also are discussed. Lastly, practical nutritional recommendations related to methyl donor metabolism during the peripartal period are presented. Nutritional management during the peripartal period is a fertile area of research, hence, underscoring the importance for developing a systems understanding of the potential immunometabolic role that dietary methyl donors play during this period to promote health and performance.

Molecular networks of insulin signaling and amino acid metabolism in subcutaneous adipose tissue are altered by body condition in periparturient Holstein cows

Peripartal cows mobilize not only body fat but also body protein to satisfy their energy requirements. The objective of this study was to determine the effect of prepartum BCS on blood biomarkers related to energy and nitrogen metabolism, and mRNA and protein abundance associated with AA metabolism and insulin signaling in subcutaneous adipose tissue (SAT) in peripartal cows. Twenty-two multiparous Holstein cows were retrospectively classified into a high BCS (HBCS; n = 11, BCS ≥ 3.5) or normal BCS (NBCS; n = 11, BCS ≤ 3.17) group at d 28 before expected parturition. Cows were fed the same diet as a total mixed ration before parturition and were fed the same lactation diet postpartum. Blood samples collected at -10, 7, 15, and 30 d relative to parturition were used for analyses of biomarkers associated with energy and nitrogen metabolism. Biopsies of SAT harvested at -15, 7, and 30 d relative to parturition were used for mRNA (real time-PCR) and protein abundance (Western blotting) assays. Data were subjected to ANOVA using the MIXED procedure of SAS (v. 9.4; SAS Institute Inc., Cary, NC), with P ≤ 0.05 being the threshold for significance. Cows in HBCS had greater overall plasma nonesterified fatty acid concentrations, due to marked increases at 7 and 15 d postpartum. This response was similar (BCS × Day effect) to protein abundance of phosphorylated (p) protein kinase B (p-AKT), the insulin-induced glucose transporter (SLC2A4), and the sodium-coupled neutral AA transporter (SLC38A1). Abundance of these proteins was lower at -15 d compared with NBCS cows, and either increased (SLC2A4, SLC38A1) or did not change (p-AKT) at 7 d postpartum in HBCS. Unlike protein abundance, however, overall mRNA abundances of the high-affinity cationic (SLC7A1), proton-coupled (SLC36A1), and sodium-coupled amino acid transporters (SLC38A2) were greater in HBCS than NBCS cows, due to upregulation in the postpartum phase. Those responses were similar to protein abundance of p-mTOR, which increased (BCS × Day effect) at 7 d in HBCS compared with NBCS cows. mRNA abundance of argininosuccinate lyase (ASL) and arginase 1 (ARG1) also was greater overall in HBCS cows. Together, these responses suggested impaired insulin signaling, coupled with greater postpartum AA transport rate and urea cycle activity in SAT of HBCS cows. An in vitro study using adipocyte and macrophage cocultures stimulated with various concentrations of fatty acids could provide some insights into the role of immune cells in modulating adipose tissue immunometabolic status, including insulin resistance and AA metabolism.

Long-term effects of prior diets, dietary transition and pregnancy on adipose gene expression in dairy heifers

Adipose tissue is highly involved in whole-body metabolism and is the main site for lipid synthesis, storage and mobilization in ruminants. Therefore, knowledge about adipose tissue responses to different diets is important, especially in growing heifers as the feeding regimes of replacement heifers affect their future success as dairy cows. However, at gene expression level such knowledge is limited. As part of a larger feed trial, adipose tissue biopsies from 24 Norwegian Red heifers were collected at 12 months of age (12MO) and at month seven of gestation (PREG) and analyzed by next-generation mRNA sequencing. Between these two sampling points, all heifers had gone through a successful conception and a feed change from four dietary treatments of high or low energy (HE/LE) and protein (HP/LP) content (treatments LPHE, HPHE, LPLE and HPLE) to a low-energy, low-protein pregnancy feed given to all animals. Gene expression differences between different feed treatments at 12MO are described in an earlier publication from our group. The main objectives of this study were to investigate the long-term effects of diets differing in protein and energy density level on gene expression in adipose tissue of growing replacement dairy heifers. To achieve this, we examined the post-treatment effects between the treatment groups at month seven of gestation; 6 months after the termination of experimental feeding, and the long-term gene expression changes occurring in the adipose tissue between 12MO and PREG. Post-treatment group comparisons showed evidence of long-term effects of dietary treatment on adipose gene expression. Differences between protein treatments were smaller than between energy treatments. Adipose gene expression changes from 12MO to PREG were much larger for the HE than the LE treatments and seemed to mostly be explained by the characteristics of the diet change. 97 genes displayed a unidirectional expression change for all groups from 12MO to PREG, and are considered to be treatment-independent, possibly caused by pregnancy or increased age. This study provides candidate genes and key regulators for further studies on pregnancy preservation (TGFB1, CFD) and metabolic regulation and efficiency (PI3K, RICTOR, MAP4K4,) in dairy cattle.

Far-off and close-up feeding levels affect immunological performance in grazing dairy cows during the transition period

During the peripartum period, dairy cows often have signs of inflammation. Various stresses, including infectious and metabolic diseases, have been discussed as causative for this inflammation. In this study, expression profiles for 17 immune markers were measured in whole blood preparations from 78 dairy cows over a time frame starting 1 wk before calving to 4 wk after calving. Additionally, the effects of far-off and close-up feeding on immune function of dairy cows during the peripartum period were investigated. Cows were assigned to 1 of 2 feeding levels in late lactation to achieve a low and high BCS at the time of dry-off (approximately 4.25 and 5.0 on a 10-point scale). Following dry-off, both herds were managed to achieve a BCS of 5.0 one month before calving; this involved controlled feeding (i.e., maintenance) and over-feeding of ME during the far-off dry period. Within each far-off feeding-level treatment, cows were offered 65, 90, or 120% of their precalving ME requirements for 3 wk precalving in a 2 × 3 factorial arrangement. Analysis of gene expression profiles from blood cells revealed effects of time indicating that the transition cow's immune system counteracts the peripartum inflammation, whereas later postcalving it becomes activated to provide protection against postpartum infections. Far-off feeding affected (P < 0.05) the expression of 2 of the investigated genes at calving. Interleukin-6 (IL-6) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression in unstimulated, peripheral leukocytes were lower (P < 0.05) in animals from the Far-Off_Over-fed group compared with the Far-Off_Control-fed group. Close-up feeding had several effects on gene expression, indicating that immune function in Feed120 animals was distinct from the Feed90 and Feed65. In conclusion, feeding management precalving becomes an important intervention to ensure immunocompetence at and after calving.

RNA-seq analysis of bovine adipose tissue in heifers fed diets differing in energy and protein content

Adipose tissue is no longer considered a mere energy reserve, but a metabolically and hormonally active organ strongly associated with the regulation of whole-body metabolism. Knowledge of adipose metabolic regulatory function is of great importance in cattle management, as it affects the efficiency and manner with which an animal converts feedstuff to milk, meat and fat. However, the molecular mechanisms regulating metabolism in bovine adipose tissue are still not fully elucidated. The emergence of next-generation sequencing technologies has facilitated the analysis of metabolic function and regulation at the global gene expression level. The aim of this study was to investigate the effect of diets differing in protein and energy density level on gene expression in adipose tissue of growing replacement dairy heifers using next-generation RNA sequencing (RNAseq). Norwegian Red heifers were fed either a high- or low-protein concentrate (HP/LP) and a high- or low-energy roughage (HE/LE) diet from 3 months of age until confirmed pregnancy to give four treatments (viz, HPHE, HPLE, LPHE, LPLE) with different growth profiles. Subcutaneous adipose tissue sampled at 12 months of age was analyzed for gene expression differences using RNAseq. The largest difference in gene expression was found between LPHE and LPLE heifers, for which 1092 genes were significantly differentially expressed, representing an up-regulation of mitochondrial function, lipid, carbohydrate and amino acid metabolism as well as changes in the antioxidant system in adipose tissue of LPHE heifers. Differences between HPHE and HPLE heifers were much smaller, and dominated by genes representing NAD biosynthesis, as was the significantly differentially expressed genes (DEG) common to both HE-LE contrasts. Differences between HP and LP groups within each energy treatment were minimal. This study emphasizes the importance of transcriptional regulation of adipose tissue energy metabolism, and identifies candidate genes for further studies on early-stage obesity and glucose load in dairy cattle.

The contribution of hormone sensitive lipase to adipose tissue lipolysis and its regulation by insulin in periparturient dairy cows

Hormone sensitive lipase (HSL) activation is part of the metabolic adaptations to the negative energy balance common to the mammalian periparturient period. This study determined HSL contribution to adipose tissue (AT) lipolysis and how insulin regulates its activity in periparturient dairy cows. Subcutaneous AT (SCAT) samples were collected at 11 d prepartum (dry) and 11 (fresh) and 24 d (lactation) postpartum. Basal and stimulated lipolysis (ISO) responses were determined using explant cultures. HSL contribution to lipolysis was assessed using an HSL inhibitor (CAY). Basal lipolysis was higher in SCAT at dry compared with fresh. CAY inhibited basal lipolysis negligibly at dry, but at fresh and lactation it reduced basal lipolysis by 36.1 ± 4.51% and 43.1 ± 4.83%, respectively. Insulin inhibited lipolysis more pronouncedly in dry compared to fresh. Results demonstrate that HSL contribution to basal lipolysis is negligible prepartum. However, HSL is a major driver of SCAT lipolytic responses postpartum. Lower basal lipolysis postpartum suggests that reduced lipogenesis is an important contributor to fatty acid release from SCAT. Loss of adipocyte sensitivity to the antilipolytic action of insulin develops in the early lactation period and supports a state of insulin resistance in AT of cows during the first month postpartum.

Dietary energy level affects adipose depot mass but does not impair in vitro subcutaneous adipose tissue response to short-term insulin and tumor necrosis factor-α challenge in nonlactating, nonpregnant Holstein cows

We assessed effects of overfeeding energy to nonlactating and nonpregnant Holstein cows during a length of time similar to a typical dry period on body lipid storage and the abundance of genes related to insulin signaling, inflammation, and ubiquitination in subcutaneous adipose tissue (SAT) in vitro challenged with insulin and recombinant bovine tumor necrosis factor-α. Fourteen cows were randomly assigned to either a high-energy (OVE; net energy for lactation = 1.60 Mcal/kg of dry matter; n = 7) or control (CON; net energy for lactation = 1.30 Mcal/kg of dry matter; n = 7) diet for 6 wk. Immediately after slaughter, liver, kidneys, and mammary gland were separated and weighed. The adipose tissue mass in the omental, mesenteric, and perirenal depots was dissected and weighed. Subcutaneous adipose tissue was collected from the tail-head region and was used as follows: control, bovine insulin (INS) at 1 µmol/L, tumor necrosis factor-α at 5 ng/mL (TNF), and their combination. Despite a lack of difference in final body condition score, OVE cows had greater energy intake and were heavier than CON cows. Furthermore, overfeeding led to greater mass of mesenteric and perirenal adipose, liver, and mammary gland. Overall, SAT incubated with INS had an upregulation of insulin receptor (INSR), interleukin-10 (IL10), small ubiquitin-like modifier 3 (SUMO3), and ubiquitin conjugating enzyme E2I (UBC9), whereas TNF upregulated peroxisome proliferator-activated receptor gamma (PPARG), diacylglycerol O-acyltransferase 2 (DGAT2), interleukin-6 (IL6), nuclear factor kappa B subunit 1 (NFKB1), small ubiquitin-like modifier 2 (SUMO2), and UBC9. Regardless of in vitro treatment, feeding OVE upregulated PPARG, fatty acid synthase (FASN), and insulin induced gene 1 (INSIG1). Abundance of PPARG was greater in SAT of OVE cows cultured individually with INS and TNF. The interaction between diet and in vitro treatment revealed that sterol regulatory element binding transcription factor 1 (SREBF1) had greater abundance in SAT from the CON group in response to culture with INS, whereas SAT from OVE cows had greater SREBF1 abundance in response to culture with TNF. The mRNA abundance of IL6 and NFKB1 was greater in response to TNF treatment and overall in CON cows. Furthermore, SAT from these cows had greater IL10 abundance when cultured with INS and TNF. Overall, data highlighted that overfeeding energy increases adipose tissue mass in part by stimulating transcription of key genes associated with insulin signaling, adipogenesis, and lipogenesis. Because SAT thickness or mass was not measured, the lack of effect of overfeeding on body condition score limits its use to predict overall body lipid storage. An overt inflammatory response in SAT after a 6-wk period of over-consumption of energy could not be discerned.

Fatty and hydroxycarboxylic acid receptors: The missing link of immune response and metabolism in cattle

Fatty and hydroxycarboxylic acids are one of the main intermediates of energy metabolism in ruminants and critical in the milk production of cattle. High production demands on a dairy farm can induce nutritional imbalances and metabolism disorders, which have been widely associated with the onset of sterile inflammatory processes and increased susceptibility to infections. The literature suggests that short-chain fatty acids (SCFA), long-chain fatty acids (LCFA) and hydroxycarboxylic acids are relevant modulators of the host innate inflammatory response. For instance, increased SCFA and lactate levels are associated with subacute ruminal acidosis (SARA) and the activation of pro-inflammatory processes mediated by diverse leukocyte and vascular endothelial cells. As such, free LCFA and the ketone body β-hydroxybutyrate are significantly increased in the plasma 1-2 weeks postpartum, coinciding with the time period in which cows are more susceptible to acquiring infectious diseases that the host innate immune system should actively oppose. Today, many of these pro-inflammatory responses can be related to the activation of specific G protein-coupled receptors, including GPR41/FFA3 and GPR43/FFA2 for SCFA; GPR40/FFA1 and GPR120/FFA4 for LCFA, GPR109A/HCA2 for ketone body β-hydroxybutyrate, and GPR81/HCA₁ for lactate, all expressed in different bovine tissues. The activation of these receptors modulates the release of intracellular granules [e.g., metalloproteinase-9 (MMP-9) and lactoferrin], radical oxygen species (ROS) production, chemotaxis, and the production of relevant pro-inflammatory mediators. The article aimed to review the role of natural ligands and receptors and the resulting impact on the host innate immune reaction of cattle and, further, to address the most recent evidence supporting a potential connection to metabolic disorders.

Transcriptional changes in mesenteric and subcutaneous adipose tissue from Holstein cows in response to plane of dietary energy

Background

Dairy cows can readily overconsume dietary energy during most of the prepartum period, often leading to higher prepartal concentrations of insulin and glucose and excessive body fat deposition. The end result of these physiologic changes is greater adipose tissue lipolysis post-partum coupled with excessive hepatic lipid accumulation and compromised health. Although transcriptional regulation of the adipose response to energy availability is well established in non-ruminants, such regulation in cow adipose tissue depots remains poorly characterized.

Results

Effects of ad-libitum access to high [HIGH; 1.62 Mcal/kg of dry matter (DM)] or adequate (CON; 1.35 Mcal/kg of DM) dietary energy for 8 wk on mesenteric (MAT) and subcutaneous (SAT) adipose tissue transcript profiles were assessed in non-pregnant non-lactating Holstein dairy cows using a 13,000-sequence annotated bovine oligonucleotide microarray. Statistical analysis revealed 409 and 310 differentially expressed genes (DEG) due to tissue and diet. Bioinformatics analysis was conducted using the Dynamic Impact Approach (DIA) with the KEGG pathway database. Compared with SAT, MAT had more active biological processes related to adipose tissue accumulation (adiponectin secretion) and signs of pro-inflammatory processes due to adipose tissue expansion and macrophage infiltration (generation of ceramides). Feeding the HIGH diet led to changes in mRNA expression of genes associated with cell hypertrophy (regucalcin), activation of adipogenesis (phospholipid phosphatase 1), insulin signaling activation (neuraminidase 1) and angiogenesis (semaphorin 4G, plexin B1). Further, inflammation due to HIGH was underscored by mRNA expression changes associated with oxidative stress response (coenzyme Q3, methyltransferase), ceramide synthesis (N-acylsphingosine amidohydrolase 1), and insulin signaling (interferon regulatory factor 1, phosphoinositide-3-kinase regulatory subunit 1, retinoic acid receptor alpha). Activation of ribosome in cows fed HIGH indicated the existence of greater adipocyte growth rate (M-phase phosphoprotein 10, NMD3 ribosome export adaptor).

Conclusions

The data indicate that long-term ad-libitum access to a higher-energy diet led to transcriptional changes in adipose tissue that stimulated hypertrophy and the activity of pathways associated with a slight but chronic inflammatory response. Further studies would be helpful in determining the extent to which mRNA results also occur at the protein level.

Metabolic and Endocrine Role of Adipose Tissue During Lactation

The adipose tissue serves an essential role for survival and reproduction in mammals, especially females. It serves primarily as an energy storage organ and is directly linked to the reproductive success of mammals. In wild animals, adipose tissue function is linked to seasonality of the food supply to support fetal growth and milk production. Adipose tissue depots in ruminants and non-ruminants can secrete many signal molecules (adipokines) that act as hormones and as pro- and anti-inflammatory cytokines. The visceral adipose tissue especially appears to be more endocrinologically active than other adipose depots. The endocrine function is important for the overall long-term regulation of energy metabolism and plays an important role in the adaptation to lactation in many mammalian species, including humans. Furthermore, endocrine signals from adipose tissue depots contribute to fertility modulation, immune function, and inflammatory response. Energy homeostasis is modulated by changes in feed intake, insulin sensitivity, and energy expenditure, processes that can be influenced by adipokines in the brain and in peripheral tissues.

Regulation of lipid metabolism in adipose depots of fat-tailed and thin-tailed lambs during negative and positive energy balances

This study aimed to evaluate the effects of negative and positive energy balances on gene expression of regulators and enzymes controlling lipogenesis and lipolysis in muscle and adipose depots of fat-tailed and thin-tailed lambs. Lambs were slaughtered during neutral, negative and positive energy balances for sample collection. Real time q-PCR was conducted to measure the gene expression. Expression of PPARγ was increased in response to positive energy balance regardless of genotype and type of tissue (P<0.04). Expression of SREBF1 was reduced in response to negative and positive energy balances in fat-tailed lambs, whereas in thin-tailed lambs, downregulated SREBF1 was restored during positive energy balance (P<0.01). Enhancement in FABP4 expression in response to negative and positive energy balances was respectively higher in thin-tailed and fat-tailed lambs affected by interaction of genotype and energy balance (P<0.11). In thin-tailed lambs, the enhanced FABP4 expression in response to negative energy balance was considerably higher in mesenteric adipose depot, whereas in fat-tailed lambs, positive energy balance induced enhancement in FABP4 expression was considerably higher in fat-tail adipose depot. The results demonstrate that transcription regulation of lipogenesis and lipolysis during negative and positive energy balances occurs differently in fat-tailed and thin-tailed lambs. Thin-tailed and fat-tailed lambs are respectively more responsive to negative and positive energy balances and mesenteric and fat-tail adipose depots respectively in thin-tailed and fat-tailed lambs are the main adipose depots responsible for higher responsiveness of thin-tailed and fat-tailed lambs to negative and positive energy balances.

Polychlorinated Biphenyl 153 in Lipid Medium Modulates Differentiation of Human Adipocytes

Emerging evidence indicates that polychlorinated biphenyls (PCBs) are involved in the development of diabetes mellitus in the obese. The purpose of this study was to determine mechanisms by which PCB 153 (2,2′,4,4′,5,5′-hexachloro-biphenyl) could influence diet-induced obesity and insulin resistance during adipogenesis. Lineage of h-ADMSCs was differentiated either as control (differentiation medium only), or with lipid vehicle modeling high fat nutrition (NuTRIflex) or lipid free vehicle (dimethylsulfoxide) for 28 days with or without PCB 153 daily co-exposure (in three concentrations 0.1, 1, and 10 µM). Gene expression analyses were performed using RT-qPCR at days 4, 10, 21, 24, 28; protein levels Akt and phosphorylated Akt (Phospho-Akt) by Western blot at days 4, and 21. PCB 153 treatment of h-ADMSCs only in lipid vehicle was associated with down regulation of key master genes of adipogenesis: PPARγ, SREBP-1, PPARGC1B, and PLIN2 during the whole process of differentiation; and with increased Akt and decreased Phospho-Akt protein level at day 21. We have shown that PCB 153, in concentration 0.1 µM, has a potential in lipid rich environment to modulate differentiation of adipocytes. Because European and U.S. adults have been exposed to PCB 153, this particular nutrient-toxicant interaction potentially impacts human obesity and insulin sensitivity.

Supplemental Smartamine M in higher-energy diets during the prepartal period improves hepatic biomarkers of health and oxidative status in Holstein cows

Background

Feeding higher-energy prepartum is a common practice in the dairy industry. However, recent data underscore how it could reduce performance, deepen negative energy balance, and augment inflammation and oxidative stress in fresh cows. We tested the effectiveness of rumen-protected methionine in preventing the negative effect of feeding a higher-energy prepartum. Multiparous Holstein cows were fed a control lower-energy diet (CON, 1.24 Mcal/kg DM; high-straw) during the whole dry period (~50 d), or were switched to a higher-energy (OVE, 1.54 Mcal/kg DM), or OVE plus Smartamine M (OVE + SM; Adisseo NA) during the last 21 d before calving. Afterwards cows received the same lactation diet (1.75 Mcal/kg DM). Smartamine M was top-dressed on the OVE diet (0.07% of DM) from -21 through 30 d in milk (DIM). Liver samples were obtained via percutaneous biopsy at -10, 7 and 21 DIM. Expression of genes associated with energy and lipid metabolism, hepatokines, methionine cycle, antioxidant capacity and inflammation was measured.

Results

Postpartal dry matter intake, milk yield, and energy-corrected milk were higher in CON and OVE + SM compared with OVE. Furthermore, milk protein and fat percentages were greater in OVE + SM compared with CON and OVE. Expression of the gluconeogenic gene PCK1 and the lipid-metabolism transcription regulator PPARA was again greater with CON and OVE + SM compared with OVE. Expression of the lipoprotein synthesis enzyme MTTP was lower in OVE + SM than CON or OVE. Similarly, the hepatokine FGF21, which correlates with severity of negative energy balance, was increased postpartum only in OVE compared to the other two groups. These results indicate greater liver metabolism and functions to support a greater production in OVE + SM. At 7 DIM, the enzyme GSR involved in the synthesis of glutathione tended to be upregulated in OVE than CON-fed cows, suggesting a greater antioxidant demand in overfed cows. Feeding OVE + SM resulted in lower similar expression of GSR compared with CON. Expression of the methionine cycle enzymes SAHH and MTR, both of which help synthesize methionine endogenously, was greater prepartum in OVE + SM compared with both CON and OVE, and at 7 DIM for CON and OVE + SM compared with OVE, suggesting greater Met availability. It is noteworthy that DNMT3A, which utilizes S-adenosylmethionine generated in the methionine cycle, was greater in OVE and OVE + SM indicating higher-energy diets might enhance DNA methylation, thus, Met utilization.

Conclusions

Data indicate that supplemental Smartamine M was able to compensate for the negative effect of prepartal energy-overfeeding by alleviating the demand for intracellular antioxidants, thus, contributing to the increase in production. Moreover Smartamine M improved hepatic lipid and glucose metabolism, leading to greater liver function and better overall health.

Electronic supplementary material

The online version of this article (doi:10.1186/s40104-017-0147-7) contains supplementary material, which is available to authorized users.

Far-off and close-up dry matter intake modulate indicators of immunometabolic adaptations to lactation in subcutaneous adipose tissue of pasture-based transition dairy cows

The common practice of increasing dietary energy density during the close-up dry period (last ∼3 wk prepartum) has been recently associated with a higher incidence of metabolic disorders after calving. Despite these reports, over-feeding of metabolizable energy (ME) during the far-off, nonlactating period is a common management policy aimed at achieving optimum calving body condition score (BCS) in pasture-based systems, as cows are generally thinner than total mixed ration cows at the end of lactation. Our hypothesis was that both far-off and close-up overfeeding influence the peripartum adipose tissue changes associated with energy balance and inflammatory state. Sixty mid-lactation, grazing dairy cows of mixed age and breed were randomly allocated to 1 of 2 groups that were managed through late lactation to achieve a low and high BCS (approximately 4.25 and 5.0 on a 10-point scale) at dry-off. The low BCS cows were then overfed ME to ensure that they achieved the same BCS as the higher BCS group by calving. Within each rate of BCS gain treatment, cows were offered 65, 90, or 120% of their pre-calving ME requirements for 3 wk pre-calving in a 2 × 3 factorial arrangement of treatments (i.e., 10 cows/treatment). Subcutaneous adipose tissue was collected via biopsy at -1, 1, and 4 wk relative to parturition. Quantitative PCR was used to measure mRNA and microRNA expression of targets related to adipogenesis and inflammation. Cows overfed in the far-off period had increased expression of miR-143 and miR-378 prepartum (-1 wk) indicating greater adipogenesis, consistent with their rapid gain in BCS following dry-off. Furthermore, the lower postpartum expression of IL6, TNF, TLR4, TLR9, and miR-145, and a higher abundance of miR-99a indicated lower body fat mobilization in early lactation in the same group. In the close-up period, feeding either 65 or 120% of ME requirements caused changes in FASN, IL1B, IL6R, TLR9, and the microRNA miR-143, miR-155, and miR-378. Their respective expression patterns indicate a tentative negative-feedback mechanism in metabolically compromised, feed-restricted cows, and a possible immune-related stimulation of lipolysis in apparently static adipocytes in overfed cows. Data from cows fed 90% of ME requirements indicate the existence of a balance between lipolytic (inflammatory-related) and anti-lipolytic signals, to prime the mobilization machinery in light of imminent lactation. Overall, results indicate that far-off dry cow nutrition influences peripartum adipose tissue metabolism, with neither strategy negatively affecting the physiological adaptation to lactation. Furthermore, to ensure a favorable transition, cows should be subjected to a small feed restriction in the close-up period, irrespective of far-off nutritional management.

Invited review: nutrient-sensing receptors for free fatty acids and hydroxycarboxylic acids in farm animals

Data on nutrient sensing by free fatty acid receptors (FFAR1, FFAR2, FFAR3, FFAR4) and hydroxycarboxylic acid receptors (HCAR1, HCAR2) are increasing for human or rodent models. Both receptor families link intestinal fermentation by the microbiota and energy metabolism with cellular responses. Therefore, this finding provides a link that is independent of the only function of the fermentation products as energy substrates. For example, these reactions are associated with insulin secretion, regulation of lipolysis, adipose tissue differentiation and innate immune responses. In farm animals, the available data on both receptor families from the intestine and other tissues increase. However, currently, the data are primarily linked with the distribution of receptor messenger RNAs (mRNAs) and more rarely with proteins. Functional data on the importance of these receptors in farm animal species is not abundant and is often associated with the immune system. In certain farm animal species, the receptors were cloned and ligand binding was characterised. In chicken, only one FFAR2 was recently identified using genome analysis, which is contradictory to a study using an FFAR1 small interfering RNA. The chicken FFAR2 is composed of more than 20 paralogs. No data on HCAR1 or HCAR2 exist in this species. Currently, in pigs, most available data are on the mRNA distribution within intestine. However, no FFAR1 expression has been shown in this organ to date. In addition to FFAR2, an orthologue (FFAR2-like) with the highest abundance in intestine has been reported. The data on HCAR1 and HCAR2 in pigs is scarce. In ruminants, most of the currently available information on receptor distribution is linked to mRNA data and shows the expression, for example, in mammary gland and adipose tissue. However, some protein data on FFAR2 and FFAR1 protein has been reported and functional data availability is slowly increasing. The receptor mRNAs of HCAR1 and HCAR2 are expressed in bovine. The HCAR2 protein has been demonstrated in certain tissues, such as liver and fat. Because of the physiological importance of both receptor families in human life science, more studies that analyse the physiological significance of both receptor families in animal science may be performed within the next several years.

Prepartum body condition score and plane of nutrition affect the hepatic transcriptome during the transition period in grazing dairy cows

Background

A transcriptomic approach was used to evaluate potential interactions between prepartum body condition score (BCS) and feeding management in the weeks before calving on hepatic metabolism during the periparturient period.

Methods

Thirty-two mid-lactation grazing dairy cows of mixed age and breed were randomly allocated to one of four treatment groups in a 2 × 2 factorial arrangement: two prepartum BCS categories [4.0 (thin, BCS4) and 5.0 (optimal, BCS5); based on a 10-point scale], and two levels of energy intake during the 3 weeks preceding calving (75 and 125 % of estimated requirements). Liver samples were obtained at −7, 7, and 28 d relative to parturition and subsequent RNA was hybridized to the Agilent 44 K Bovine (V2) Microarray chip. The Dynamic Impact Approach was used for pathway analysis, and Ingenuity Pathway Analysis was used for gene network analysis.

Results

The greater number of differentially expressed genes in BCS4 cows in response to prepartum feed allowance (1071 vs 310, over the entire transition period) indicates that these animals were more responsive to prepartum nutrition management than optimally-conditioned cows. However, independent of prepartum BCS, pathway analysis revealed that prepartal feeding level had a marked effect on carbohydrate, amino acid, lipid, and glycan metabolism. Altered carbohydrate and amino acid metabolism suggest a greater and more prolonged negative energy balance postpartum in BCS5 cows overfed prepartum. This is supported by opposite effects of prepartum feeding in BCS4 compared with BCS5 cows in pathways encompassing amino acid, vitamin, and co-factor metabolism. The prepartum feed restriction ameliorates the metabolic adaptation to the onset of lactation in BCS5 cows, while detrimentally affecting BCS4 cows, which seem to better adapt when overfed. Alterations in the glycosaminoglycans synthesis pathway support this idea, indicating better hepatic health status in feed-restricted BCS5 and overfed BCS4 cows. Furthermore, IPA network analysis suggests liver damage in feed-restricted thin cows, likely due to metabolic overload.

Conclusion

Overall, the data support the hypothesis that overfeeding in late-pregnancy should be limited to underconditioned cows, while cows with optimal degree of body condition should be maintained on an energy-restricted diet.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-3191-3) contains supplementary material, which is available to authorized users.

Deriving Gene Networks from SNP Associated with Triacylglycerol and Phospholipid Fatty Acid Fractions from Ribeyes of Angus Cattle

The fatty acid profile of beef is a complex trait that can benefit from gene-interaction network analysis to understand relationships among loci that contribute to phenotypic variation. Phenotypic measures of fatty acid profile from triacylglycerol and phospholipid fractions of longissimus muscle, pedigree information, and Illumina 54 k bovine SNP genotypes were utilized to derive an annotated gene network associated with fatty acid composition in 1,833 Angus beef cattle. The Bayes-B statistical model was utilized to perform a genome wide association study to estimate associations between 54 k SNP genotypes and 39 individual fatty acid phenotypes within each fraction. Posterior means of the effects were estimated for each of the 54 k SNP and for the collective effects of all the SNP in every 1-Mb genomic window in terms of the proportion of genetic variance explained by the window. Windows that explained the largest proportions of genetic variance for individual lipids were found in the triacylglycerol fraction. There was almost no overlap in the genomic regions explaining variance between the triacylglycerol and phospholipid fractions. Partial correlations were used to identify correlated regions of the genome for the set of largest 1 Mb windows that explained up to 35% genetic variation in either fatty acid fraction. SNP were allocated to windows based on the bovine UMD3.1 assembly. Gene network clusters were generated utilizing a partial correlation and information theory algorithm. Results were used in conjunction with network scoring and visualization software to analyze correlated SNP across 39 fatty acid phenotypes to identify SNP of significance. Significant pathways implicated in fatty acid metabolism through GO term enrichment analysis included homeostasis of number of cells, homeostatic process, coenzyme/cofactor activity, and immunoglobulin. These results suggest different metabolic pathways regulate the development of different types of lipids found in bovine muscle tissues. Network analysis using partial correlations and annotation of significant SNPs can yield information about the genetic architecture of complex traits.

Insulin signaling, inflammation, and lipolysis in subcutaneous adipose tissue of transition dairy cows either overfed energy during the prepartum period or fed a controlled-energy diet

Adipose tissue mobilization is a hallmark of the transition period in dairy cows. Cows overfed energy during the dry period have higher concentrations of nonesterified fatty acids (NEFA) and β-hydroxybutyrate (BHB) compared with cows fed a controlled-energy diet prepartum. The reason for an increase in blood NEFA concentrations at the level of adipose tissue in cows overfed energy has not been fully elucidated. One hypothesis is that cows with high BHB concentrations suffer from adipose tissue-specific insulin resistance, leading to higher rates of adipose tissue mobilization in the postpartum period. To test this hypothesis, subcutaneous adipose tissue biopsies of cows overfed energy in excess of predicted requirements by 50% in the dry period, and that had high concentrations of blood BHB postpartum (group H; n=12), were used. Findings were compared with results of biopsies from cows fed a controlled-energy diet and with low BHB concentrations postpartum (group C; n=12) to create the biggest contrast in BHB concentrations. Subcutaneous adipose tissue biopsies were obtained before and 60 min after an intravenous glucose challenge (0.25 g/kg of glucose) at 28 and 10 d before expected calving as well as on d 4 and 21 postpartum. Phosphorylation of protein kinase B, extracellular signal-regulated kinase, and hormone-sensitive lipase was determined before and after glucose infusion by Western blot. Western blot was also used to assess the baseline protein abundance of peroxisome proliferator-activated receptor gamma and insulin receptor β-subunit. In addition, gene expression of fatty acid synthase, adiponectin, monocyte chemoattractant protein 1, and tumor necrosis factor α was determined by real-time quantitative reverse-transcription PCR. Backfat thickness was determined in the thurl area by ultrasonography. Cows in group H showed a greater degree of lipogenesis prepartum, but no differences were found in lipolytic enzyme activity postpartum compared with cows in group C. Baseline plasma insulin concentrations were decreased and serum NEFA concentrations increased postpartum in group H. Insulin signaling through protein kinase B, quantity of insulin receptor, markers of inflammation, and peroxisome proliferator-activated receptor gamma in adipose tissue were not different between the groups, but expression of adiponectin was increased in adipose tissue of cows in group H during the immediate peripartum period. In conclusion, differences in serum concentrations of NEFA between cows overfed energy prepartum and high blood concentrations of BHB are likely due to greater negative energy balance postpartum reflected in lower circulating concentrations of glucose and insulin and an increase in the total amount of mobilized adipose tissue mass rather than due to changes in adipose tissue insulin signaling.

Prepartum feeding level and body condition score affect immunological performance in grazing dairy cows during the transition period

Precalving feeding level affects dry matter intake, postcalving energy balance, the risk of hepatic lipidosis and metabolic disease, and gene expression in liver and adipose tissue. These coincide with a higher risk of disease postpartum and, very likely, a failure to reach optimum production as well as reproductive targets. Current interpretation of the available evidence suggest that metabolic stressors affect the immune system of transition dairy cows and lead to reduced immunocompetence. The objective of the current study was to investigate the effect of precalving body condition score (BCS) and level of feeding on immunocompetence during the peripartum period. Twenty-three weeks before calving, 78 cows were allocated randomly to 1 of 6 treatment groups (n=13) in a 2 × 3 factorial arrangement: 2 precalving BCS categories (4.0 and 5.0, based on a 10-point scale) and 3 levels of energy intake during the 3 wk preceding calving (75, 100, and 125% of estimated requirements). Blood was sampled precalving and at 1, 2 and 4 wk after calving. Cells were analyzed by flow cytometry and quantitative real-time PCR. The numbers of T helper lymphocytes (CD4+), cytotoxic T lymphocytes (CD8+), natural killer cells (CD335+), and γδ T lymphocytes (WC1+) as well as their activation status [IL-2 receptor (CD25)+ cells] were highly variable between animals, but there was no evident effect of BCS, feeding level, or time. All groups presented with an increase in expression of cytokines in unstimulated blood cells in the week after calving, although this was significant only for IFNG in the BCS 4.0 group. Analysis of in vitro-stimulated cells allowed 2 general observations: (1) cows with high energy intake precalving (125%) had increased cytokine expression precalving, and (2) all cows had increased cytokine expression in the week after calving. The present study provides evidence that prepartum feed management can affect immunocompetence during the transition period. Considering the current results, optimally conditioned animals might benefit from a restricted precalving diet, whereas underconditioned cows can be fed to requirements.

Maternal Plane of Nutrition During Late-Gestation and Weaning Age Alter Steer Calf Longissimus Muscle Adipogenic MicroRNA and Target Gene Expression

The main objective was to evaluate if different planes of maternal nutrition during late gestation and weaning age alter microRNA (miRNA) and target gene expression in offspring longissimus muscle (LM). Early (EW) and normal weaned (NW) Angus × Simmental calves (n = 30) born to cows that were grazing endophyte-infected tall fescue and red clover pastures with no supplement [low plane of nutrition (LPN)], or supplemented with 2.3 and 9.1 kg of dried distiller's grains with solubles and soy hulls [medium and high plane of nutrition (MPN, HPN), respectively] during the last 105 ± 11 days of gestation were used. Biopsies of LM were harvested at 78 (early weaning), 187 (normal weaning) and 354 days of age. Results indicate a role of pro-adipogenic miRNA in the control of adipogenesis in LM of NW-MPN steers between 78 and 187 days of age through upregulation of (1) miR-103 which inhibits CAV1, a protein that destabilizes INSR and leads to insulin resistance; (2) miR-143 which inhibits DLK1, a protein that inhibits adipocyte differentiation; and (3) miR-21 which impairs TGFBR2-induced inhibition of adipocyte differentiation. Among the studied anti-adipogenic miRNA, cow plane of nutrition resulted in downregulation of miR-34a expression in MPN steers compared with HPN and LPN at 78 days of age. Data for miR-34a provided a potential sign of epigenetic regulation of LM in beef offspring due to the cow plane of nutrition during late gestation.

Body condition score and plane of nutrition prepartum affect adipose tissue transcriptome regulators of metabolism and inflammation in grazing dairy cows during the transition period

Recent studies demonstrating a higher incidence of metabolic disorders after calving have challenged the management practice of increasing dietary energy density during the last ~3 wk prepartum. Despite our knowledge at the whole-animal level, the tissue-level mechanisms that are altered in response to feeding management prepartum remain unclear. Our hypothesis was that prepartum body condition score (BCS), in combination with feeding management, plays a central role in the peripartum changes associated with energy balance and inflammatory state. Twenty-eight mid-lactation grazing dairy cows of mixed age and breed were randomly allocated to 1 of 4 treatment groups in a 2 × 2 factorial arrangement: 2 prepartum BCS categories (4.0 and 5.0, based on a 10-point scale; BCS4, BCS5) obtained via differential feeding management during late-lactation, and 2 levels of energy intake during the 3 wk preceding calving (75 and 125% of estimated requirements). Subcutaneous adipose tissue was harvested via biopsy at -1, 1, and 4 wk relative to parturition. Quantitative polymerase chain reaction was used to measure mRNA and microRNA (miRNA) expression of targets related to fatty acid metabolism (lipogenesis, lipolysis), adipokine synthesis, and inflammation. Both prepartum BCS and feeding management had a significant effect on mRNA and miRNA expression throughout the peripartum period. Overfed BCS5 cows had the greatest prepartum expression of fatty acid synthase (FASN) and an overall greater expression of leptin (LEP); BCS5 was also associated with greater overall adiponectin (ADIPOQ) and peroxisome proliferator-activated receptor gamma (PPARG), whereas overfeeding upregulated expression of proadipogenic miRNA. Higher postpartum expression of chemokine ligand 5 (CCL5) and the cytokines interleukin 6 (IL6) and tumor necrosis factor (TNF) was detected in overfed BCS5 cows. Feed-restricted BCS4 cows had the highest overall interleukin 1 (IL1B) expression. Prepartum feed restriction resulted in greater chemokine ligand 2 (CCL2) expression. Overall, changes in mRNA expression were consistent with the expression pattern of inflammation-related miRNA. These data shed light on molecular mechanisms underlying the effect of prepartum BCS and feeding management on metabolic and inflammatory status of adipose tissue during the peripartum period. Data support the use of a controlled feed restriction prepartum in optimally conditioned cows, as well as the use of a higher level of dietary energy in under-conditioned cows.

Effects of precalving body condition score and prepartum feeding level on production, reproduction, and health parameters in pasture-based transition dairy cows

Precalving feeding level alters postcalving energy balance, dry matter intake, the liver and adipose tissue transcriptome, hepatic lipidosis, and the risk of metabolic diseases in both high-production cows consuming total mixed rations and moderate-production cows grazing pasture. We hypothesized that the reported benefits of a controlled restriction before calving are dependent on precalving body condition score (BCS): low BCS animals would not benefit from reduced feeding levels precalving, but high BCS cows would have metabolic and immunomodulatory profiles indicative of an improved health status. One hundred sixty-one days before calving, 150 cows were allocated randomly to 1 of 6 treatment groups (n = 25) in a 2 × 3 factorial arrangement: 2 precalving BCS categories (4.0 and 5.0; based on a 10-point scale: BCS4 and BCS5, respectively) and 3 levels of energy intake during the 3 wk preceding calving (75, 100, and 125% of estimated requirements). Cows in the BCS4 and BCS5 groups were managed through late lactation to ensure that target calving BCS was achieved at dry off. Cows were then fed to maintain this BCS target until 3 wk before expected calving date, at which point they were managed within their allotted precalving energy intake treatments by offering different allowances of fresh pasture/cow per day. Milk production, body weight, and BCS were measured weekly; blood was sampled weekly before and after calving and on d 0, 1, 2, 3, and 4 relative to calving. Aspirated plasma was assayed for nonesterified fatty acids, β-hydroxybutyrate, total protein, albumin, cholesterol, haptoglobin, IL-1β, IL-6, total antioxidant capacity, and reactive oxygen species. Liver was sampled wk 1, 2, and 4 postcalving for triacylglycerol analysis. Results confirm that precalving BCS and precalving feeding level have both independent and interdependent effects on production and health characteristics of transition dairy cows. Irrespective of precalving BCS, a controlled restriction precalving reduced the net release of nonesterified fatty acids from adipose tissue postpartum and increased plasma calcium concentrations, reducing the risk of milk fever. Fatter cows produced more milk but lost more BCS postcalving and had greater blood β-hydroxybutyrate concentrations and increased hepatic lipidosis. In comparison, after calving, indicators of reduced immune competence were accentuated in BCS4 cows subjected to a feed restriction before calving, probably increasing the risk of infectious diseases. It would appear from these results that optimally conditioned cows will benefit from a short-term (2-3 wk) controlled feed restriction (75-90% of requirements), whereas cows in less than optimal condition should be fed to requirements before calving.

Immune system, inflammation and nutrition in dairy cattle

Good health is essential for good performance and the welfare of dairy cows, and nutrition is an important component of good health. Health is influenced by the interaction between the innate adaptive components of the immune system and other factors, such as the local and systemic inflammatory response, which can sometimes be more harmful than useful. Therefore, for dairy cows, particularly those in the periparturient period, it is important to avoid, or reduce as much as possible, any kind of infectious, parasitic or metabolic disease and the associated inflammation. Such inflammation can impair cow performance by lowering milk yield, dry matter intake, fertility and energy efficiency, and can reduce liver function. Good nutrition is essential in maintaining a functional immune system, while also avoiding other causes of inflammation, such as tissue damage, and digestive and metabolic syndrome-related disorders. Provision of appropriate nutrients, such as antioxidants, omega-3 polyunsaturated fatty acids, conjugated linoleic acid and vitamin D can have anti-inflammatory effects. In the future, ways to reduce inflammation while maintaining a good immune defence must be developed and the susceptibility of the cow to diseases and inflammation evaluated. Ideally, we would be able to selectively breed for cows with a lower susceptibility to both diseases and inflammation.

Inflammation- and lipid metabolism-related gene network expression in visceral and subcutaneous adipose depots of Holstein cows

This experiment was conducted to determine the effects of energy overfeeding on gene expression in mesenteric (MAT), omental (OAT), and subcutaneous (SAT) adipose tissue (AT) from nonpregnant and nonlactating Holstein cows. Eighteen cows were randomly assigned to either a controlled energy [LE, net energy for lactation (NE(L)) = 1.35 Mcal/kg of dry matter (DM)] or moderate energy-overfed group (HE, NE(L) = 1.62 Mcal/kg of DM) for 8 wk. Cows were then euthanized and subsamples of MAT, OAT, and SAT were harvested for transcript profiling via quantitative PCR of 34 genes involved in lipogenesis, triacylglycerol (TAG) synthesis, lactate signaling, hepatokine signaling, lipolysis, transcription regulation, and inflammation. The interaction of dietary energy and adipose depot was not significant for any gene analyzed except LPL, which indicated a consistent response to diet. Expression of ACACA and FASN was greater in SAT than MAT, whereas expression of SCD and ADFP were greatest in SAT, intermediate in OAT, and lowest in MAT. However, the 2 visceral depots had greater expression of THRSP, ACLY, LPL, FABP4, GPAM, and LPIN1 compared with SAT. The transcription factor SREBF1 was more highly expressed in MAT and SAT than in OAT. The expression of PNPLA2 was greater in visceral AT sites than in SAT, but other lipolysis-related genes were not differentially expressed among AT depots. Visceral AT depots had greater expression of LEP, ADIPOQ, and SAA3 compared with SAT. Moreover, MAT had greater expression than SAT of proinflammatory cytokines (IL1B and IL6), IL6 receptor (IL6R), and chemokines (CCL2 and CCL5). However, TNF expression was greatest in SAT, lowest in OAT, and intermediate in MAT. Overall, results indicated that visceral AT might be more active in uptake of preformed long-chain fatty acids than SAT, whereas de novo fatty acid synthesis could make a greater contribution to the intracellular pool of fatty acids in SAT than in visceral AT. The visceral AT compared with SAT seem to have a greater capacity for expression (and potentially for secretion) of proinflammatory cytokines; thus, excessive accumulation of visceral lipid due to a long-term overfeeding energy may be detrimental to liver function and overall health of dairy cows, particularly during the transition period.