Oxidative Stress In Dairy Cows Research Articles

Regulation of cholesterol metabolism during high fatty acid–induced lipid deposition in calf hepatocytes

Cholesterol in the circulation is partly driven by changes in feed intake, but aspects of cholesterol metabolism during development of fatty liver are not well known. The objective of this study was to investigate mechanisms of cholesterol metabolism in calf hepatocytes challenged with high concentrations of fatty acids (FA). To address mechanistic insights regarding cholesterol metabolism, liver samples were collected from healthy control dairy cows (n = 6; 7-13 d in milk) and cows with fatty liver (n = 6; 7-11 d in milk). In vitro, hepatocytes isolated from 3 healthy female calves (1 d old) were challenged with or without a mix of 1.2 mM FA to induce metabolic stress. In addition, hepatocytes were processed with 10 µmol/L of the cholesterol synthesis inhibitor simvastatin or 6 µmol/L of the cholesterol intracellular transport inhibitor U18666A with or without the 1.2 mM FA mix. To evaluate the role of cholesterol addition, hepatocytes were treated with 0.147 mg/mL methyl-β-cyclodextrin (MβCD + FA) or 0.147 mg/mL MβCD with or without 10 and 100 µmol/L cholesterol before incubation with FA (CHO10 + FA and CHO100 + FA). In vivo data from liver biopsies were analyzed by 2-tailed unpaired Student's t-test. Data from in vitro calf hepatocytes were analyzed by one-way ANOVA. Compared with healthy cows, blood plasma total cholesterol and plasma low-density lipoprotein cholesterol content in cows with fatty liver was markedly lower, whereas the hepatic total cholesterol content did not differ. In contrast, compared with healthy controls, the triacylglycerol content in the liver and the content of FA, β-hydroxybutyrate, and aspartate aminotransferase in the plasma of cows with fatty liver were greater. The results revealed that both fatty liver in vivo and challenge of calf hepatocytes with 1.2 mM FA in vitro led to greater mRNA and protein abundance of sterol regulatory element binding transcription factor 1 (SREBF1) and fatty acid synthase (FASN). In contrast, mRNA and protein abundance of sterol regulatory element binding transcription factor 2 (SREBF2), acyl coenzyme A-cholesterol acyltransferase, and ATP-binding cassette subfamily A member 1 (ABCA1) were lower. Compared with the FA group, the cholesterol synthesis inhibitor simvastatin led to greater protein abundance of microsomal triglyceride transfer protein and mRNA abundance of SREBF2, 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), ACAT2, and lower ABCA1 and FASN protein abundance. In contrast, compared with the FA group, the cholesterol intracellular transport inhibitor U18666A + FA led to greater total cholesterol concentration and greater protein and mRNA abundance of FASN. Compared with the MβCD + FA group, the addition of 10 µmol/L cholesterol led to greater concentration of cholesteryl ester and excretion of apolipoprotein B100, and greater protein and mRNA abundance of ABCA1 and microsomal triglyceride transfer protein, and lower concentration of malondialdehyde. Overall, a reduction in cholesterol synthesis promoted FA metabolism in hepatocytes likely to relieve the oxidative stress caused by the high FA load. The data suggest that maintenance of normal cholesterol synthesis promotes very low-density lipoprotein excretion and can reduce lipid accumulation and oxidative stress in dairy cows that experience fatty liver.

Abomasal infusion of essential fatty acids and conjugated linoleic acid during late pregnancy and early lactation affects immunohematological and oxidative stress markers in dairy cows

Oxidative stress and inflammation, as natural parts of metabolic adaptations during the transition from late gestation to early lactation, are critical indicators of dairy cows' metabolic health. This study was designed to investigate the effects of abomasal infusion of essential fatty acids (EFA), particularly α-linolenic acid, and conjugated linoleic acid (CLA) on plasma, erythrocyte, and liver markers of oxidative stress in dairy cows during the transition period. Rumen-cannulated German Holstein cows (n = 38) in their second lactation (11,101 ± 1,118 kg milk/305 d, mean ± standard deviation) were abomasally infused with one of the following treatments from d -63 antepartum until d 63 postpartum (PP): CTRL (n = 9; 76 g/d coconut oil); EFA (n = 9; 78 g/d linseed plus 4 g/d safflower oil); CLA (n = 10; isomers cis-9,trans-11 and trans-10,cis-12 CLA; 38 g/d); and EFA+CLA (n = 10; 120 g/d). Hematological parameters as well as markers of oxidative status were measured in plasma, erythrocytes, and liver before and after calving. Immunohematological parameters, including erythrocyte number, hematocrit, hemoglobin, mean corpuscular hemoglobin, leukocytes, and basophils, were affected by time, and their peak levels were observed on the day after calving. The oxidative stress markers glutathione peroxidase 1 and reactive oxygen metabolites in plasma and erythrocytes were both affected by time, exhibiting the highest levels on d 1 PP, whereas β-carotene, retinol, and tocopherol were at their lowest levels at the same time. Immunohematological parameters were only marginally affected by fatty acid treatment in a time-dependent manner. As such, lymphocyte and atypical lymphocyte counts were both significantly highest in the groups that received EFA at d 1 PP. Moreover, EFA supplementation increased the mean corpuscular volume and showed a trend for induction of mean corpuscular hemoglobin compared with the CLA group during the transition period. The PP mean thrombocyte volume was higher in the EFA than in the CLA group (except for d 28) and both EFA and CLA reduced number of thrombocytes and thrombocrit at distinct time points. Hepatic mRNA abundance of markers related to oxidative status, including glutathione peroxidase (GPX-1) and catalase (CAT), was lower (P < 0.05) in EFA-treated than non-EFA-treated cows at d 28 PP. Dairy cows at the onset of lactation were characterized by induced markers of both oxidative stress and inflammation. Supplementing EFA and CLA had minor and time-dependent effects on markers of oxidative stress in plasma, erythrocytes, and liver. A comparison of EFA supplementation with CLA or CTRL showed higher immunohematological response at d 1 PP and lower hepatic antioxidant levels by d 28 PP. Supplementation with EFA+CLA had only a minor effect on oxidative markers, which were more similar to those with the EFA treatment. Altogether, despite the time-dependent differences, the current findings show only minor effects of EFA and CLA supplementation in the prevention of early lactation-induced oxidative stress.

The hindgut microbiome contributes to host oxidative stress in postpartum dairy cows by affecting glutathione synthesis process

BackgroundDairy cows are susceptible to postpartum systemic oxidative stress (OS), which leads to significant production loss and metabolic disorders. The gut microbiota has been linked to host health and stress levels. However, to what extent the gut microbiota is associated with postpartum OS remains unknown. In this study, the contribution of the fecal microbiota to postpartum systemic OS and its underlying mechanisms were investigated by integrating 16S rRNA gene sequencing, metagenomics, and metabolomics in postpartum dairy cattle and by transplanting fecal microbiota from cattle to mice.ResultsA strong link was found between fecal microbial composition and postpartum OS, with an explainability of 43.1%. A total of 17 significantly differential bacterial genera and 19 species were identified between cows with high (HOS) and low OS (LOS). Among them, 9 genera and 16 species showed significant negative correlations with OS, and Marasmitruncus and Ruminococcus_sp._CAG:724 had the strongest correlations. The microbial functional analysis showed that the fecal microbial metabolism of glutamine, glutamate, glycine, and cysteine involved in glutathione synthesis was lower in HOS cows. Moreover, 58 significantly different metabolites were identified between HOS and LOS cows, and of these metabolites, 19 were produced from microbiota or cometabolism of microbiota and host. Furthermore, these microbial metabolites were enriched in the metabolism of glutamine, glutamate, glycine, and cysteine. The mice gavaged with HOS fecal microbiota had significantly higher OS and lower plasma glutathione peroxidase and glutathione content than those orally administered saline or LOS fecal microbiota.ConclusionsIntegrated results suggest that the fecal microbiota is responsible for OS and that lower glutathione production plays a causative role in HOS. These findings provide novel insights into the mechanisms of postpartum OS and potential regulatory strategies to alleviate OS in dairy cows.7tQg4Y_kMTvQ-DRCXBSguhVideo

Biological Health Markers Associated with Oxidative Stress in Dairy Cows during Lactation Period

This review aims to summarize and present different biological health markers in dairy cows during the lactation period. Biochemical health markers provide an indicator of how foreign chemical substances, whether external or internal, affect the animal's health. To understand the relationship between dairy cow health issues and oxidative stress, various biomarkers of oxidative stress must be investigated. Biochemical and hematological factors play a significant role in determining the biological health markers of animals. A variety of biochemical parameters are dependent on various factors, including the animal's breed, its age, its development, its pregnancy status, and its production status. When assessing the health of cattle, a blood test is conducted to determine the blood chemistry. To diagnose diseases in dairy animals, the blood biochemistry is necessary to determine the cause of many physiological, metabolic, and pathological problems. Observing blood alterations during pregnancy and at peak lactation may determine what factors lift oxidative stress in cows due to disturbances in feed intake and metabolic processes.

Meloxicam inhibited oxidative stress and inflammatory response of LPS-stimulated bovine endometrial epithelial cells through Nrf2 and NF-κB pathways

Meloxicam is a selective cyclooxygenase-2 inhibitor and has been widely used in combination with antibiotics to alleviate uterine inflammation and provide analgesia in postpartum cows. Studies have shown that meloxicam has antioxidant and anti-inflammatory effects. However, the link between meloxicam and uterine inflammation and oxidative stress in dairy cows has not been studied. The purpose of this study was to research the effects of meloxicam (0.5 or 5 μM) on oxidative stress and inflammatory response of primary bovine endometrial epithelial cells (BEEC) stimulated by Escherichia coli lipopolysaccharide (1 μg/mL LPS). As a result, LPS stimulated the production of oxidative stress markers and the expression of inflammatory factors, accompanied by a decrease in the activity and the gene transcription of antioxidant enzymes. Co-treatment of meloxicam and LPS reduced the content of oxidative stress markers and the mRNA levels of the pro-inflammatory genes, and improved antioxidant enzyme activities and the corresponding gene expression as compared with the cells treated with LPS alone. Meloxicam attenuated the inhibitory effect of the Nrf2 pathway and the phosphorylation levels of p65 and IκBα caused by LPS. In conclusion, meloxicam alone had no effect on BEEC, but prevented oxidative stress and inflammatory response in LPS-stimulated BEEC.

Circulating and endometrial cell oxidative stress in dairy cows diagnosed with metritis

Dairy cows diagnosed with metritis may experience a greater degree of oxidative stress (OS) and a deficit in the antioxidative capacity compared to healthy cows. We aimed to assess circulating OS markers and endometrial cell mitochondrial function, intracellular reactive oxygen species (ROS) production, and mean endometrial nuclear cell area in postpartum cows diagnosed with metritis or as healthy. From an initial pool of 121 Holstein cows, we retrospectively selected 34 cows and balanced for metritis (n = 17) or healthy (n = 17). Metritis was defined as an enlarged uterus with red-brown watery or thick off-white purulent discharge occurring within 21 days postpartum. Cows with no signs of clinical disease (including dystocia or retained placenta) were referred to as healthy. Blood samples for serum reactive oxygen metabolites (d-ROM), antioxidants (OXY), and oxidative status index (OSI) tests, evaluated via photometric determination of plasma thiols, were performed at 7, 14, 21, 28, and 35 days postpartum. Furthermore, from the initial pool, a random subset of 5 cows diagnosed with metritis and 6 diagnosed as healthy we collected (at the same time points as for the blood samples) endometrial cytology samples using the cytobrush technique. From the uterine samples, we evaluated the endometrial cell mitochondrial function, intracellular ROS levels, and the endometrial cell nuclear area using MitoTracker Orange, dichlorodihydrofluorescein diacetate, and Hoechst 33258, respectively. Mixed linear regression models, accounting for repeated measurements, were fitted to assess the effect of metritis versus healthy on circulating and endometrial cell OS parameters and endometrial cell size. The effect of days postpartum and its interaction with uterine health status were forced into each model. Serum concentrations of d-ROMs and OSI were greater in metritis at 7, 14, and 35 days postpartum than in healthy cows. Interestingly, the mean endometrial cell nuclear area was lower in metritis than healthy cows at 14 and 21 days postpartum. We found no differences between metritis and healthy for endometrial cell mitochondrial function and intracellular ROS production. In conclusion, cows diagnosed with metritis experienced greater systemic OS levels than healthy cows, but their OS was not higher in the uterine milieu.

Serum ANGPTL4 and FGF2, energy-related blood biochemicals, cytokine responses and oxidative stress in dairy cows with subclinical ketosis

In this study, it was aimed to investigate the serum levels of ANGPTL4, FGF21, IL-1β, IL-6, SOD, MDA, and serum biochemical and hematological parameters in cows with subclinical ketosis. The mean serum β-hydroxybutyric acid (BHB) level was 1.37 ± 0.04 mmol/L in 10 dairy cows aged 3-5 years that were &amp;lt;21 days postpartum and diagnosed with subclinical ketosis. The mean serum BHB level was 0.40 ± 0.08 mmol/L in 10 healthy dairy cows in the same period and in the same age range. An increase in serum AST (P&amp;lt;0.001) and a decrease in serum albumin levels (P&amp;lt;0.05) indicated altered liver functions. An increase in serum non-esterified fatty acid (P&amp;lt;0.001) and decreases in serum HDL, triglyceride, and total cholesterol levels (P&amp;lt;0.05) were interpreted as indicators of increased metabolic pathology risk due to negative energy balance. Increases in serum ANGPTL4, FGF2, IL-1β, IL-6, and MDA (P&amp;lt;0.001) and SOD levels (P&amp;lt;0.05) were evaluated as indicators of the development of effective metabolic, inflammatory, and oxidative stress.It was concluded that significant increases in serum ANGPTL4, FGF2, IL-1β, IL-6, and MDA and SOD levels in dairy cows with subclinical ketosis were associated with negative energy balance, effective cytokine responses, and oxidative stress.

Effects of clinoptilolite on heavy metal levels in milk, proinflammatory cytokine responses (IL-1β and IL-6) and oxidative stress in dairy cows.

The effects of clinoptilolite on milk copper (Cu), lead (Pb), zinc (Zn), cadmium (Cd) and iron (Fe) concentrations, proinflammatory cytokine responses, oxidative stress status, whole blood cell counts and liver and kidney functions were investigated in dairy cows exhibiting no signs of any kind of toxicity. Clinoptilolite was added to the feed at a dose of 200 mg kg-1 body weight in the clinoptilolite-treated group (n = 14), but was not added to the feed in the control group (n = 7). In the milk samples (n = 21) collected before the experiment, the Cu, Pb, Zn, Cd and Fe values were 0.021 ± 0.020, 0.104 ± 0.01, 3.42 ± 0.32, <0.000, 0.56 ± 0.34 ppm, respectively. At the end of the experiment (30th day), among the elements measured in milk samples collected from the clinoptilolite-treated group, only the Pb value (0.076 ± 0.01) was lower than the 0-day value of the clinoptilolite-treated group (0.104 ± 0.01) and the 30th-day value of the control group (0.105 ± 0.01) was found to be statistically lower. Changes determined at the end of clinoptilolite application in serum superoxide dismutase (SOD), malondialdehyde (MDA), albumin, glucose, urea and urine creatinine/urine total protein (uCr/uTP) values, which were interpreted as the effect of lead exposure before the trial, were evaluated as the positive effect of clinoptilolite. It was concluded that the addition of clinoptilolite to the feed in dairy cows caused a significant decrease in the amount of Pb in milk, and positive changes in the parameters related to oxidative stress in serum and in parameters related to renal function.

Effect of Copper and Zinc Supplementation on Antioxidants and Biochemical Status of Osmanabadi Goats

Background: Copper and zinc in animal diets significantly impact livestock productivity. Zinc is not stored in the body and must be supplemented regularly to maintain optimal immuno-physiological function in animals. Many factors restrict the bioavailability of zinc and its absorption in the intestine. Cu deficiency is common in feed ingredients. Feeding copper levels in the diet is also essential for immune system optimization since copper inhibits the development of metabolic and oxidative stress in dairy cows. Methods: Experimental animals (n=18) were equally divided into three groups with an average body weight 29 kg. T0 was control group with basal diet, T1 group supplemented with copper sulphate (100 mg/goat/day + Basal diet) and T2 group supplemented with zinc oxide (40 mg/goat/day + Basal diet) for 90 days. Blood samples were collected at fortnight intervals and estimated using standard protocols. Result: Total antioxidant capacity (TAC) Superoxide dismutase (SOD) and Catalase were significantly higher in zinc supplemented group followed by copper supplemented group. Thiobarbituric acid reactive substances (TBARS) were significantly lower in the zinc and copper supplemented groups compared to control group. Glucose concentration showed no significant change. Total cholesterol was significantly lower in the copper supplemented group. Total proteins, albumin and triglycerides were significantly higher in the zinc supplemented group than in other groups.

Supplementation with N-carbamoylglutamate during the transition period improves the function of neutrophils and reduces inflammation and oxidative stress in dairy cows

The aim of this study was to investigate the effects of N-carbamoylglutamate (NCG) supplementation during the transition period on the functions of blood polymorphonuclear neutrophils (PMN), inflammation, and oxidative stress in dairy cows. Thirty multiparous Chinese Holstein dairy cows at wk 4 before parturition were blocked into 2 groups by parity, body weight, and milk yield of previous lactation, and randomly allocated to 2 dietary treatments of basal diet supplemented without (control, n = 15) or with 20 g/d per cow of NCG (NCG, n = 15). The supplementation was carried out from d -21 to 21 relative to calving. Health incidents (mastitis, retained placenta, and lameness) were recorded, and blood samples were collected at d -21, -7, 0 (the calving date), 7, and 21 relative to parturition and analyzed for variables related to inflammation and oxidative stress. In addition, whole blood was collected at d 7 to isolate PMN and used for analysis of the expression of functional genes and from d -21 to 21 for determination of weekly hematological parameters. The number of lymphocytes was greater at d 7 in the blood of NCG cows. The plasma level of malondialdehyde was lower in the NCG group, and blood reactive oxygen species were lower at d 7, whereas total antioxidant capacity tended to be greater in the NCG group and glutathione peroxidase tended to be higher at d 21 in cows fed NCG, suggesting that NCG supplementation improved antioxidation in cows. In addition, the concentration of serum amyloid A was lower in NCG-fed animals during the postpartum stage. Blood concentrations of IL6 and tumor necrosis factor-α were lower and tended to be lower in NCG-fed animals at d 7, respectively. Meanwhile, the concentrations of IL6 tended to be lower in NCG-fed animals at d 21. Furthermore, the expression of S100A9 and MMP9 in the PMN was lower and tended to be lower, respectively, whereas the expression of ITGB2, XBP1 tended to be higher and expression of CLEC6A was higher in NCG-fed cows. Overall, our results indicated that supplementation with NCG during the transition period showed the beneficial effects on animal health, by improving PMN functions and alleviating inflammation status and oxidative stress in dairy cows.

The Link Between 15-F2t-Isoprostane Activity and Acute Bovine Endothelial Inflammation Remains Elusive.

Modern dairy cattle suffer from increased incidence and severity of mastitis during major physiological transitions of the lactation cycle. Oxidative stress, a condition resulting from inadequate antioxidant defense against reactive oxygen and nitrogen species, is a major underlying component of mastitis pathophysiology. Isoprostanes (IsoP) are molecules derived from cellular lipid membranes upon non-enzymatic interaction with reactive species during inflammation, and are regarded as highly sensitive and specific biomarkers of oxidative stress. Changes in IsoP concentrations have been noted during major physiological transitions and diseases such as coliform mastitis in dairy cattle. However, the biological role of IsoP during oxidative stress in dairy cows has not been well-elucidated. Therefore, this study aimed to characterize the impacts of IsoP on oxidative stress outcomes in a bovine model of acute endothelial inflammation. Bovine aortic endothelial cells (BAEC; n = 4) were stimulated with 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) or lipopolysaccharide (LPS) with or without 15-F2t-IsoP to determine how IsoP influence oxidative stress outcomes. Our endothelial inflammation model showed relatively decreased reactive metabolites and increased barrier integrity in cells treated with both the agonist and IsoP compared to agonist treatment alone. However, IsoP do not appear to affect oxidative stress outcomes during acute inflammation. Understanding the effect of IsoP on BAEC is an early step in elucidating how IsoP impact dairy cows during times of oxidative stress in the context of acute clinical mastitis. Future studies should define the optimal dosing and treatment timing of IsoP to maximize their cytoprotective potential during acute inflammation.

Application of an optimized and validated LC–MS/MS method for the quantification of free 3-nitrotyrosine in plasma, urine and liver tissue of lactating dairy cows

In dairy cows, the high energy demand and oxygen requirements during the transition period could increase oxidative stress (OS), impairing the challenging metabolic adaptation needed during this period. Also, OS and health could be affected by some environmental conditions such as heat stress. In this sense, 3-nytrotyrosine (3-NT) has been described as a biomarker of OS. Therefore, the aim of this study was to develop and validate a fast, reliable method for the accurate determination of free 3-NT in blood, urine and liver samples by liquid chromatography–tandem mass spectrometry (LC-MS/MS). To this end, during the transition period, 3-NT concentrations were analyzed in samples from dairy cows grouped according to different environmental conditions: cows that gave birth during winter (winter group, WG; n = 18) and cows that gave birth during spring (spring group, SG; n = 18). Additionally, other plasma parameters such as β-hydroxybutyrate acid (BHBA) and glucose concentrations and liver triacylglycerol (TAG) content and aspartate transaminase activity were exhaustively studied. Samples were collected at 21 (±3) days before the expected calving date, and at 7 (±3) and 21 (±3) days after calving. The analysis of the samples involved a purification step by solid-phase extraction. The method developed was validated in terms of linearity, specificity, precision, accuracy, recovery, matrix effect, dilution and analyte stability. The lower limit of quantification of the method was 1.02 ng/mL for plasma, 0.24 mg/L for urine and 0.05 mg/kg for liver tissue. Coefficients of variation for the concentrations tested were < 15% and accuracy was within 85–115%. 3-NT concentration was higher in cows of the SG than in those of the WG in the three matrices evaluated. BHBA and glucose concentrations were higher and lower, respectively, in cows of the SG. BHBA concentration was particularly higher in cows of the SG on day 21 postpartum. Liver TAG content and aspartate transaminase activity were also higher in cows of the SG on the postpartum days. These results suggest that the methodology developed and validated by LC-MS/MS for the quantification of 3-NT in different fluids and liver tissue could be a very useful parameter to evaluate OS in dairy cows during the transition period.

Green Tea Polyphenols Alleviate Hydrogen Peroxide-Induced Oxidative Stress, Inflammation, and Apoptosis in Bovine Mammary Epithelial Cells by Activating ERK1/2-NFE2L2-HMOX1 Pathways.

Oxidative stress (OS) is one of the main limiting factors affecting the length of lactation and milk quality in dairy cows. For high-producing dairy cows, the OS of mammary glands is a serious problem. Green tea polyphenols (GTP), found mainly in tea, are a combination of many phenols. GTP have a good effect on antioxidation, inflammation resistance, obesity, fat cell metabolism improvement, and lowering of blood lipid. Therefore, we studied the role of GTP on OS in dairy cows and further investigated whether GTP alleviates oxidative damage of bovine mammary epithelial cells (BMECs) induced by hydrogen peroxide (H2O2) and its underlying molecular mechanism. In this study, 500 μM of H2O2 for 12 h incubation was chosen as the condition of the OS model of BMECs. In addition, the present results found that treatment with GTP alleviated the oxidative damage induced by H2O2 [the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) were significantly increased, and the contents of malondialdehyde (MDA), 8-isoprostaglandin (8-iso-PG), 8-oxo-deoxyguanosine (8-OHdG), and protein carbonyl (PC) and caspase-3 and caspase-9 activities were significantly reduced]. These effects are related to the activation of the erythrocyte-derived nuclear factor 2-like protein 2 (NFE2L2) signaling pathway and the inactivation of the caspase/Bcl-2 apoptotic pathway. When NFE2L2 short interfering RNA (siRNA) was used to downregulate the expression of NFE2L2 in cultured BMECs, NFE2L2-siRNA transfection abolished the protective effect of GTP on H2O2-induced intracellular reactive oxygen species (ROS) accumulation and apoptosis. In addition, the mitogen-activated protein kinase (MAPK) inhibition test further proved that GTP relieved H2O2-induced oxidative damage by activating the NFE2L2 signaling pathway, which was achieved by activating the extracellular-regulated kinase 1/2 (ERK1/2) signaling pathway. Overall, the results indicate that GTP has a beneficial effect on the redox balance of BMECs. In addition, GTP might be a latent antioxidant in vivo, which can be administered to ruminants during stressful periods such as the perinatal period.

Oxidative Stress in Dairy Cows: Insights into the Mechanistic Mode of Actions and Mitigating Strategies.

This review examines several molecular mechanisms underpinning oxidative stress in ruminants and their effects on blood and milk oxidative traits. We also investigate strategies to alleviate or repair oxidative damages by improving animal immune functions using novel feed additives. Microbial pathogenic cells, feeding management, and body condition score were some of the studied factors, inducing oxidative stress in ruminants. The predominance of Streptococcus spp. (24.22%), Acinetobacter spp. (21.37%), Romboutsia spp. (4.99%), Turicibacter spp., (2.64%), Stenotrophomonas spp. (2.33%), and Enterococcus spp. (1.86%) was found in the microbiome of mastitis cows with a decrease of d-mannose and increase of xanthine:guanine ratio when Streptococcus increased. Diversity of energy sources favoring the growth of Fusobacterium make it a keystone taxon contributing to metritis. Ruminal volatile fatty acids rose with high-concentrate diets that decreased the ruminal pH, causing a lysis of rumen microbes and release of endotoxins. Moreover, lipopolysaccharide (LPS) concentration, malondialdehyde (MDA), and superoxide dismutase (SOD) activities increased in high concentrate cows accompanied by a reduction of total antioxidant capacity (T-AOC), glutathione peroxidase (GPx), and catalase (CAT) activity. In addition, albumin and paraoxonase concentrations were inversely related to oxidative stress and contributed to the protection of low-density and high-density lipoproteins against lipid peroxidation, protein carbonyl, and lactoperoxidase. High concentrate diets increased the expression of MAPK pro-inflammatory genes and decreased the expression of antioxidant genes and proteins in mammary epithelial tissues. The expression levels of NrF2, NQO1, MT1E, UGT1A1, MGST3, and MT1A were downregulated, whereas NF-kB was upregulated with a high-grain or high concentrate diet. Amino-acids, vitamins, trace elements, and plant extracts have shown promising results through enhancing immune functions and repairing damaged cells exposed to oxidative stress. Further studies comparing the long-term effect of synthetic feed additives and natural plant additives on animal health and physiology remain to be investigated.

Heat stress modulates polymorphonuclear cell response in early pregnancy cows: I. interferon pathway and oxidative stress.

One of the major causes of early pregnancy loss is heat stress. In ruminants, interferon tau (IFNT) is the embryo signal to the mother. Once the interferon signaling pathway is activated, it drives gene expression for interferon-stimulated genes (ISGs) and alters neutrophils responses. The aim of the present study was to evaluate interferon (IFN) pathway, ISGs and gene expression in polymorphonuclear leukocytes (PMN) and oxidative stress in dairy cows under heat stress. Pregnant cows had their estrous cycle synchronized and randomly assigned to a comfort or heat stress group. Blood samples were collected at artificial insemination (AI) and on Days 10, 14 and 18 following AI. Pregnant cows were pregnancy checked by ultrasound on Day 30 and confirmed on Day 60 post-AI. Results are presented as mean ± SEM. The corpus luteum (CL) diameter was not different between groups of pregnant cows; concentration of progesterone of pregnant cows on Day 18 following AI was greater in comfort group compared to heat stressed group. Comfort pregnant cows had higher expression of all analyzed genes from interferon pathway, except for IFNAR1, on both Days 14 and 18. Conversely, heat stressed cows did not show altered expression of IFNT pathway genes and ISGs between Days 10, 14, and 18 after AI. The oxidative stress, determined as malondialdehyde (MDA) levels, was greater in heat stress group on Days 10, 14 and 18, independent of pregnancy status. Heat stress negatively influences expression of ISGs, IFN pathway gene expression in neutrophils, and oxidative stress. Our data suggest that lower conception rates in cows under heat stress are multifactorial, with the association of interferon pathway activation and the unbalanced oxidative stress being main contributing factors.

In vitro–In vivo Hybrid Approach for Studying Modulation of NRF2 in Immortalized Bovine Mammary Cells

Nuclear factor erythroid 2-related factor 2 (NRF2) plays a key role in the response to oxidative stress. Diets containing known NRF2 modulators could be used to minimize oxidative stress in dairy cows. Currently, studies evaluating the activity of NRF2 in bovine have used the classical in vitro approach using synthetic media, which is very different than in vivo conditions. Furthermore, studies carried out in vivo cannot capture the short-term and dynamic response of NRF2. Thus, there is a need to develop new approaches to study NRF2 modulation. The aim of the present study was to establish an in vitro–in vivo hybrid system to investigate activation of NRF2 in bovine cells that can serve as an intermediate model with results closer to what is expected in vivo. To accomplish the aim, we used a combination of a gene reporter assay in immortalized bovine mammary cells, synthetic NRF2 modulators, and blood serum from periparturient cows. Synthetic agonist tert-butylhydroquinone and sulforaphane confirmed to be effective activators of bovine NRF2 with acute and large effect at 30 and 5 μM, respectively, with null response after the above doses due to cytotoxicity. When the agonists were added to blood serum the response was more linear with maximum activation of NRF2 at 100 and 30 μM, respectively, and the cytotoxicity was prevented. High concentration of albumin in blood serum plays an important role in such an effect. Brusatol (100 nM) was observed to be an effective NRF2 inhibitor while also displaying general protein synthesis inhibition and cytotoxicity when added to synthetic media. A consistent inhibition of NRF2 was observed when brusatol was added to the blood serum but the cytotoxicity was reduced. The synthetic inhibitor ML385 had no effect on modulation of bovine NRF2. Hydrogen peroxide activates NRF2 in bovine mammary cells starting from 100 μM; however, strong cytotoxicity was detected starting at 250 μM when cells were cultivated in the synthetic media, while blood serum prevented cytotoxicity. Overall, our data indicated that the use of synthetic media can be misleading in the study of NRF2 in bovine and the use of blood serum appears necessary.

Determination of thiol/disulphide homeostasis as a new indicator of oxidative stress in dairy cows with subclinical endometritis

The objective of this study was to determine thiol/disulphide homeostasis (TDH) in infertile cows with subclinical endometritis (SCE). Endometrial cytological samples were collected using a cytobrush to diagnose SCE in 36 infertile cows. According to the results of the cytology examination, those with acute endometritis were classified as Group I (n = 20) and those with chronic endometritis were classified as Group II (n = 16). A control group was formed of heifers as Group III (n = 20). Blood samples were taken from each group on the day of diagnosis (day 0) to analyse TDH. In the cytology examination, both the Giemsa method and immunocytochemical staining were applied to determine chronic inflammation and activity status. In 55.55% (20/36) of the infertile cows with cytological endometritis, the inflammation was determined to be active, and in 44.44% (16/36) it had become chronic. The native thiol and total thiol levels were found to be statistically significantly lower in the acute (206.54 ± 8.30 μmol/L; 227.11 ± 9.30 μmol/L) and chronic SCE cases (225.15 ± 11.89 μmol/L; 247.96 ± 10.80 μmol/L) compared to the heathy control group (308.47 ± 13.59 μmol/L; 336.83 ± 15.5 μmol/L respectively) (P&lt;0.001). Disulphide levels, disulphide/total thiol, native thiol/total thiol and disulphide/native thiol ratios were similar in all the groups (P&gt;0.05). The diagnostic accuracy of native thiol, which can be used in the diagnosis of SCE, was 92.8%, that of total thiol was 89.3% and that of disulphide was 64.3% according to the ROC curve analysis. These results demonstrate that TDH is a reliable and sensitive indicator of oxidative stress in cow SCE, and that abnormal TDH might play a role in SCE pathogenic mechanisms. This is the first study to evaluate thiol/disulphide homeostasis in dairy cows with SCE as a new indicator of oxidative stress.

Green tea polyphenols supplementation alters immunometabolism and oxidative stress in dairy cows with hyperketonemia

Peripartal cows often experience negative energy balance, and are therefore prone to suffering from metabolic diseases such as hyperketonemia, which causes financial losses in dairy farms. This study aimed to investigate the effect of green tea polyphenol (GTP) supplementation during the periparturient period on production performance, oxidative stress and immunometabolism in dairy cows with hyperketonemia. One hundred Holstein cows were assigned to GTP (0.2 g/kg DM; n = 50) or control (without GTP; n = 50) group based on body weight, previous milk yield, and parity on d 15 before expected parturition. Subsequently, 10 cows with hyperketonemia were selected from each group, according to blood β-hydroxybutyric acid (BHBA) concentration between 1.2 and 2.9 mmol/L from 2 to 3 d postpartum. All cows were fed a close-up diet and a lactation diet with or without GTP supply from 15 d prepartum until 30 d postpartum. Milk and blood samples were obtained from 20 cows selected with hyperketonemia on 10, 20, and 30 d postpartum. Compared with control cows, greater milk yield and lower somatic cell count were observed in GTP cows. The GTP group had lower concentrations of BHBA, free fatty acids, cholesterol, triglyceride, reactive oxygen species, malondialdehyde, and hydrogen peroxide, greater concentrations of glucose, lower activities of aspartate aminotransferase, alanine aminotransferase, and glutamyl transpeptidase, alongside greater activities of superoxide dismutase, glutathione peroxidase, and total antioxidant capacity. Additionally, GTP supplementation up-regulated concentrations of interleukin-6 and interleukin-10, but down-regulated concentrations of tumor necrosis factor-α, interleukin-1β, interleukin-2, interleukin-8, and interferon-γ in plasma. Greater concentrations of plasma immunoglobulin G were also detected in the GTP group. Overall, the data suggested that GTP supplementation from 15 d prepartum to 30 d postpartum improved the milk yield and health status in cows with hyperketonemia during early lactation.

Butyrate alleviates oxidative stress by regulating NRF2 nuclear accumulation and H3K9/14 acetylation via GPR109A in bovine mammary epithelial cells and mammary glands

Oxidative stress consistently affects lactation length and quality in dairy cows. Oxidative stress in the mammary gland of high-yielding dairy cows is a serious problem. Therefore, we studied the role of butyrate in dairy cow oxidative stress and further elucidated the mechanism of the antioxidative action of mammary epithelial cells in dairy cows. Oxidative stress and activated GPR109A were present in high-yielding dairy cows. Then, bovine mammary epithelial cells (BMECs) were isolated, and oxidative stress-related protein expression was measured, confirming that sodium butyrate (NaB) exerted antioxidant effects through GPR109A, NRF2 and H3K9/14 acetylation. To further study the antioxidative mechanism of butyrate in dairy cows, we also confirmed that butyrate promoted NRF2 nuclear accumulation and H3K9/14 acetylation through the AMPK signaling pathway by western blotting. Additionally, we preliminarily clarified the interaction between NRF2 and H3K9/14 acetylation by Co-IP and ChIP. Butyrate activated the AMPK signaling pathway through GPR109A to promote NRF2 nuclear accumulation and H3K9/14 acetylation, subsequently exerting antioxidant effects through the synergistic functions of these two processes. Then, we studied the effect of butyrate on oxidative stress in dairy cows in vivo, and the results were consistent with those in vitro. Therefore, butyrate played an antioxidant and antiapoptotic role through the GPR109A/AMPK/NRF2 signaling pathway, while H3K9/14 acetylation could promote NRF2 transcription and enhance the antioxidant capacity of BMECs.

Evaluation of Oxidative Stress in Dairy Cows with Left Displacement of Abomasum.

Simple SummaryThe present study evaluated oxidative and antioxidant status in dairy cows with Left Displacement of the Abomasum (LDA), an economically important postpartum disease in cattle. The oxidant capacity of plasma measured with a test fo reactive oxygen metabolites, the d-ROMs test, was significantly higher and the plasma biological antioxidant potential (BAP), measured with the BAP test was lower in the LDA group compared with the control group. Oxidative status was assessed using an arbitrary index obtained from the ratio between d-ROMs and BAP and the results showed that cows with LDA experience an imbalance between oxidants and antioxidants.Left Displacement of the Abomasum (LDA) is a condition that occurs in high-producing postpartum dairy cows and it causes economic losses. Studies performed in the last decade indicate that adult dairy cows experience oxidative stress. Increasing interest in the role of oxidative status in ruminant medicine has emphasized the need to develop reliable methods to assess it. A few studies have evaluated the relationship between LDA and oxidative status, mostly through the determination of single parameters of oxidation and the determination of antioxidant status separately, with contrasting results. The aim of this study was to assess the oxidative status by the measurement of Reactive Oxygen Metabolites with d-ROMs and Biological Antioxidant Potential BAP and the calculation of the Oxidative Status index in 74 multiparous dairy cows with LDA. Each case was matched with a control herdmate. The amount of free oxygen radicals in plasma samples was determined using the d-ROMs test, the concentration of antioxidants was measured using the BAP test and the Oxidative Status index was also calculated. The concentration of d-ROMs was significantly higher in the study group compared to the control group (179 ± 37.7 U CARR and 158 ± 23.0 U CARR, respectively), while the concentration of BAP was significantly lower in the study group than in the control group (2156 ± 98.1 µmol/L vs. 2558 ± 108.5 µmol/L). The Oxidative Status index value was significantly higher in cows with LDA than in healthy cows (8.3 ± 1.51 vs. 6.2 ± 0.76). The results of this study indicated that an inbalance between oxidants and antioxidants occurred in cattle with LDA.