The stability of the reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP) tests on stored horse blood

Effects of intravenous administration of ascorbic acid (vitamin C) on oxidative status in healthy adult horses

BACKGROUND

Ascorbic acid (AA) is an antioxidant that might be beneficial for adjunctive treatment of sepsis in horses. The optimal dose and effects on oxidative status are unknown.

HYPOTHESIS

Ascorbic acid administration will increase plasma AA concentrations and decrease determinants of reactive oxygen metabolites (dROM), basal and stimulant-induced intraerythrocytic reactive oxygen species (ROS) concentrations, and stimulant-induced neutrophil ROS production, and increase plasma antioxidant capacity (PAC) in a dose-dependent manner.

ANIMALS

Eight healthy horses.

METHODS

Randomized placebo-controlled crossover study. Each horse received 4 single-dose IV treatments including AA at 25, 50, and 100 mg/kg and saline (placebo) with each treatment separated by ≥1 week. Blood was collected at baseline, 2 and 6 hours for assessment of plasma dROM and PAC via photometer, intraerythrocytic ROS by flow cytometry, and stimulant-induced neutrophil ROS by a fluorometric assay. Plasma AA concentrations were measured by high-performance liquid chromatography/electrochemical detection.

RESULTS

Ascorbic acid at 100 mg/kg resulted in decreased dROM 2 hours after treatment (P = .03, 95% CI 5.51-121.2, point estimate 63.3). There was no effect of AA on basal or stimulant-induced intraerythrocytic ROS (P = .88, 95% CI -0.156 to 0.081, point estimate -0.037; P = .93, 95% CI -0.123 to 0.112, point estimate -0.006, respectively), basal or stimulant-induced neutrophil ROS (P ≥ .12, 95% CI -644.9 to 56.2, point estimate -294.4), or PAC (P ≥ .64, 95% CI -1567 to 463.4, point estimate -552.0) at any dose or timepoint. Plasma AA concentrations increased in a dose-dependent manner.

CONCLUSIONS AND CLINICAL IMPORTANCE

High-dose administration of AA might provide antioxidant benefits in horses.

Evaluation of oxidative stress in foals with Rhodococcus equi infection-induced pneumonia for the judgment of therapeutic effect

Forty-five foals with Rhodococcus equi infection and pneumonia symptoms were classified into a surviving group and a dead group. Using serum samples, the oxidative stress index (OSI) was determined at the first visit and the follow-up visit. The OSI of the surviving group was significantly lower at the follow-up than that at the first visit. No significant difference was observed between the OSI of the dead group at the first and follow-up visits. In the surviving group, treatment at the first visit mitigated inflammation and reduced OSI. However, in the dead group, poor response to the treatment provided at the first visit led to continued inflammation, and no change was observed the OSI.

Validation of a commercially available photometric analytical system for assessment of plasma oxidative status in healthy horses

Reactive oxygen species (ROS) are the end-products of physiologic functions in health. Oxidative stress occurs when endogenous antioxidants are insufficient to neutralize ROS in the system. As a result, ROS can damage DNA, RNA, proteins, lipids, and cell organelles. To obtain accurate measurements of plasma oxidative stress, levels of both oxidants and antioxidants must be measured. This study validates a commercially available, semi-quantitative, photometric analytical system that measures systemic determinants of reactive oxygen metabolites (dROM) and plasma antioxidant capacity (PAC) in stored equine plasma. The objectives of this work were: 1) to validate a photometric analytical system to quantify dROM and PAC in equine plasma; and 2) to determine expected results for these tests in healthy adult horses. We hypothesized that this system would reliably and reproducibly assess dROM and PAC in equine plasma. We observed expected, dose-dependent increases in dROM generated by adding increasing concentrations of H2O2 or ascorbic acid to equine plasma to provide samples containing a known quantity of oxidants or antioxidants respectively. Mean dROM value in healthy horses was 103.3 ±20.7 U. Carr and mean PAC was 2881.0 ± 313.9 U. Cor. This system reliably and reproducibly quantified dROM and PAC in equine plasma samples.

Effects of intravenous administration of peripheral blood-derived mesenchymal stromal cells after infusion of lipopolysaccharide in horses

BACKGROUND

A systemic and dysregulated immune response to infection contributes to morbidity and mortality associated with sepsis. Peripheral blood-derived mesenchymal stromal cells (PB-MSC) mitigate inflammation in animal models of sepsis. Allogeneic PB-MSC administered IV to horses is well-tolerated but therapeutic benefits are unknown.

HYPOTHESIS

After IV lipopolysaccharide (LPS) infusion, horses treated with PB-MSC would have less severe clinical signs, clinicopathological abnormalities, inflammatory cytokine gene expression, and oxidative stress compared to controls administered a placebo.

ANIMALS

Sixteen horses were included in this study.

METHODS

A randomized placebo-controlled experimental trial was performed. Sixteen healthy horses were assigned to 1 of 2 treatment groups (1 × 10⁹  PB-MSC or saline placebo). Treatments were administered 30 minutes after completion of LPS infusion of approximately 30 ng/kg. Clinical signs, clinicopathological variables, inflammatory cytokine gene expression, and oxidative stress markers were assessed at various time points over a 24-hour period.

RESULTS

A predictable response to IV LPS infusion was observed in all horses. At the dose administered, there was no significant effect of PB-MSC on clinical signs, clinicopathological variables, or inflammatory cytokine gene expression at any time point. Antioxidant potential was not different between treatment groups, but intracellular ROS increased over time in the placebo group. Other variables that changed over time were likely due to effects of IV LPS infusion.

CONCLUSIONS AND CLINICAL IMPORTANCE

Administration of allogeneic PB-MSC did not cause clinically detectable adverse effects in healthy horses. The dose of PB-MSC used here is unlikely to exert a beneficial effect in endotoxemic horses.

Maternal and Neonatal Evaluation of Derived Reactive Oxygen Metabolites and Biological Antioxidant Potential in Donkey Mares and Foals

Our aim was to measure the concentrations of derived reactive oxygen metabolite (d-ROMs) and biological antioxidant potential (BAP) of donkey mares and foals at delivery and to verify the protective role of the placenta against fetal oxidative stress. A total of 15 Amiata jennies with a physiological gestation length and delivery were included together with 17 foals (two twin foalings). After delivery, maternal and foal venous blood samples were collected along with blood from the artery. Circulating lactate and plasma d-ROMs and BAP were evaluated. The Wilcoxon test for paired data was applied to verify differences in d-ROMs and BAP values, while the Spearman test was used to evaluate correlations. A significantly higher d-ROMs concentration was found in jennies compared to their foals, and to the umbilical artery blood. The BAP was higher in jennies than in their foals, but no differences were observed in the umbilical artery blood. No difference was found between foals and their umbilical cord. Blood lactate was higher in foals than in their dams. Positive correlations were found between mares and umbilical cord for BAP and d-ROMs, and between mares and foals and umbilical cord for BAP. In conclusion, the placenta may be a protective factor for the fetus. As with equine foals, the antioxidant system of donkey foals does not seems to be effective at birth.

Monitoring the redox status in dairy cows by using plasma dROMs, PAT, and OSI biomarkers

The aim of this work was to determine the changes of redox indicators such as reactive oxygen metabolites (dROMs), plasma antioxidant test (PAT) and the oxidative stress index (OSI) in dairy cows at different stages of lactation using a diagnostic equipment which is suitable for in vivo oxidative stress (OS) monitoring procedures. In total, 628 dairy cows were examined in the pre-parturient period (days in milk [DIM]: -21 to -1 day; n = 117), in the calving and maternity period (DIM: 0 to 7; n = 137), in the early lactation period (DIM: 8 to 30; n = 139), and the in the peak lactation (DIM: 31 to 150; n = 235). The dROMs and OSI values were significantly different (P < 0.05) when comparing the 1st and 2nd+ lactation cows in each group. The highest mean value of dROMs was detected at the calving and maternity stage in 1st lactation cows (141 ± 25 U. Carr) and the lowest (103 ± 29 U. Carr) was found in peak lactation. The OSI developed similarly, with the highest value of 5.58 ± 0.94 in the calving and maternity period in the 1st lactation cows and the lowest value of 4.05 ± 1.21 in peak lactation and significant differences were found in many cases. Based on the results, the measurement of dROMs and OSI may be suitable for detecting oxidative stress in different lactation stages.

The impact of the oxidative status on the reproduction of cows and the calves’ health – a review

The profitability of cattle farming is largely determined by ensuring high-quality breeding animals for replacement and longevity in production. The provision of breeding animals requires adequate fertility of the cowherd and then intensive weight gain in the calf rearing period. For ensuring these demands, many management aspects must be considered. Continuous monitoring of the herd’s health status, including redox status, is essential. This review aims to provide a summary of relevant scientific data published in the last few decades regarding the role of oxidative stress (OS) in infertility of dairy cows and developmental diseases in calves, the major predisposing factors, and possible prevention.

Effects of Ultramarathon Running on Mitochondrial Function of Platelets and Oxidative Stress Parameters: A Pilot Study

Only a few studies have evaluated changes in mitochondrial function and oxidative stress associated with ultramarathon running. Invasive biopsies are needed to assess mitochondrial function of skeletal muscle, which may not be well tolerated by some individuals. Platelets (PLTs) as a metabolically highly active and homogenous cell population were suggested as a potentially valuable surrogate to investigate mitochondrial function. Thus, this study was aimed to evaluate mitochondrial function of PLTs and its association with individual race performance and markers of oxidative stress, muscle damage and renal dysfunction. Race performance and mitochondrial function (high-resolution respirometry, HRR) of PLTs using different substrates inducing ROUTINE, LEAK, N-pathway control state (Complex I linked oxidative phosphorylation; CI, OXPHOS), NS-pathway control state (CI + II linked OXPHOS and electron transfer pathway; ET), S-pathway control state (CII linked ET) as well as parameters of oxidative stress and antioxidant capacity, and markers of muscle and renal injury were assessed in eight male ultramarathon runners (26–45 years) before, immediately after and 24 h after an ultramarathon race (PRE, POST, and REC). Ultramarathon running induced an increase in LEAK O₂ flux of PLT mitochondria and slight, largely non-significant changes in the oxidant/antioxidant balance. Levels of creatine kinase (CK), lactate dehydrogenase (LDH), blood urea nitrogen, and creatinine were all significantly elevated POST and remained high in REC. There were inverse correlations between race time and N-linked substrate state PRE-POST, and changes in CK and LDH levels were significantly related to PLT mitochondrial LEAK and N-linked respiration PRE. Although race-related changes in respirometry parameters of PLT mitochondria were rather small, a somewhat more pronounced increase in the relative N-linked respiration in faster runners might suggest PLT CI as indicator of physical fitness. The higher PLT LEAK PRE and diminished increase of CK during the race may represent a prophylactic preconditioning and the slight but non-significant elevation of the antioxidant potential post-race as a protective consequence of the race-related oxidative stress and potential threat to the kidney. Our findings point toward an interrelationship between mitochondrial function of PLTs, individual fitness levels and extreme physical and metal stresses, which stimulates further research.

Efficacy of mozuku fucoidan in alternative protein-based diet to improve growth, health performance, and stress resistance of juvenile red sea bream, Pagrus major

We evaluated the efficacy of mozuku fucoidan supplementation to alternative dietary proteins used in fish meal (FM) replacement to enhance growth, immunity, and stress resistance of Pagrus major. Seven isonitrogenous (45% protein) experimental diets were formulated where diet 1 (D1) was FM-based control diet. Diets 2 to 7 were formulated by replacing 25, 50, and 75% of FM protein with soy protein isolate (SPI) protein, and each replacement level was supplemented without or with fucoidan at 0.4% for diet groups D2 (FM25), D3 (FM25Fu), D4 (FM50), D5 (FM50Fu), D6 (FM75), and D7(FM75Fu), respectively. Each diet was randomly allocated to triplicate groups of fish (4.1 g) for 56 days. Significantly higher weight gain and specific growth rate were observed in fish fed FM50Fu diet group, and it was not differed (P > 0.05) with fish fed FM25Fu diet group. FM-based control diet showed intermediate value, and it was not differed (P > 0.05) with or without fucoidan-supplemented ≤ 50% FM replacement groups and FM75Fu diet group. Significantly lower growth performances were observed in FM75 diet group. At each replacement level, fucoidan-supplemented groups showed nonsignificant improvement of feed utilization performances. Fish fed fucoidan-supplemented diets showed best condition of oxidative and freshwater stress resistance. Lysozyme activity, NBT, and peroxidase activity showed higher (P > 0.05) values in fucoidan-supplemented groups compared with the non-supplemented groups. Catalase activity was significantly lower in FM75Fu diet group. Catalase activity is significantly influenced by the interaction effects of fucoidan and FM replacement level. In conclusion, fucoidan supplementation could increase the efficiency of utilizing SPI (≥ 75%) without any adverse effects on red sea bream performance.

Delays in processing and storage of pig seminal plasma alters levels of contained antioxidants

Seminal plasma (SP) antioxidants are considered biomarkers of sperm function and fertility for AI-boars. The current protocol for their measurement implies the SP was harvested immediately after ejaculation and prompt stored at -80 °C until analysis. Such protocol may be impractical for AI-centers. This study evaluated how SP levels of antioxidants were influenced by delays in (1) SP-harvesting (0 [control], 2 or 24 h at 17 °C after ejaculate collection), in (2) SP-freezing (0 [control] or 24 h at 17 °C after SP-harvesting) or (3) the temperature of storage (-80 °C [control] or - 20 °C). The SP-antioxidants evaluated were: glutathione peroxidase [GPx], superoxide dismutase [SOD], paraoxonase-1 [PON-1], trolox equivalent antioxidant capacity [TEAC] and oxidative stress index [OSI]. A total of 120 aliquots from 10 entire ejaculates were handled in three trials. They were centrifuged (1500 g, 10 min) for harvesting SP and antioxidants were measured with an Automatic Chemistry Analyzer. A 24 h-delay in harvesting the SP led to an increase (p˂0.001) in TEAC and SOD SP-levels, and a decrease (p˂0.05) of OSI and PON-1. Similarly, a 24 h-delay to freeze the SP increased (p˂0.01) TEAC values and decreased (p˂0.01) PON-1 and GPx activity levels. Finally, storing the SP at -20 °C decreased (p˂0.001) SP-levels of TEAC, PON-1 and GPx, and increased (p˂0.01) OSI values. Strong positive relationships (p˂0.001) were found between antioxidant SP-levels in processed samples and their respective controls. In sum, handling and SP storage influence antioxidant measurements in AI-boars. Reliable levels of SP-antioxidants can only be warranted if a strict protocol for harvesting and SP storage is followed.

Effect of L-carnitine on health-related quality of life in patients with liver cirrhosis

L-carnitine (4-N-trimethylammonium-3-hydroxybutyric acid) is the physiologically active form of carnitine and is a natural compound that has been shown to exhibit antioxidant activity. L-carnitine is used as a supplementary treatment in patients with cirrhosis with hepatic encephalopathy, hyperammonemia or muscle cramps. In the present study, the effect of L-carnitine supplementation on health-related quality of life in 30 patients with cirrhosis was prospectively examined. L-carnitine (1,800 mg/day) was administered orally for 6 months. To assess the effects of L-carnitine on chronic fatigue, patients filled out a self-report questionnaire regarding their physical and mental health. The levels of total and free carnitine, and acylcarnitine were found to be significantly higher 1, 3 and 6 months after therapy initiation compared with before treatment. Serum albumin levels were significantly increased 3 and 6 months after initiation of therapy. L-carnitine supplementation significantly increased the BAP/d-ROM ratio, a marker of antioxidant status in patients with cirrhosis. Changes in serum carnitine concentrations were positively correlated with changes in serum albumin levels (R²=0.369; P=0.012), but not with changes in serum ammonia levels (R²= 0.005; P=0.78). Total and mental health scores improved significantly, and physical scores improved marginally 3 and 6 months after initiation of L-carnitine. These findings may be attributed to the enhanced serum albumin levels and oxidative stress rather than the reduced serum ammonia levels. Based on these results, it is suggested that L-carnitine can potentially alleviate chronic fatigue, along with the increased BAP/d-ROM ratio, which were involved in increased oxidative stress in patients with cirrhosis. The specific mechanisms by which L-carnitine ameliorates chronic fatigue is not fully understood and requires further investigation.

Relative Deficiency in Albumin Methionine Content is Associated With Decreased Antioxidant Capacity of Equine Plasma

Relative to other species, horses seem particularly susceptible to oxidative stress. Plasma albumin plays an important role in preventing oxidative damage, in part due to its methionine (MET) content. Equine albumin is highly unusual in that it contains no MET residues. Whether or not this causes deficient antioxidant capacity in equine plasma relative to that of other species has not yet been explored. The objective of this study was to compare the redox status of equine (no MET) to that of bovine (moderate amount of MET) plasma. Plasma was collected from healthy, nonpregnant Quarter Horse mares (n = 10) and adult, healthy, nonpregnant, dried Holstein cows (n = 15). Measures of total antioxidant capacity and oxidative stress were assessed for each plasma sample using multiple commercially available assays: total antioxidant capacity, thiol detection, thiobarbituric acid reactive substances, and advanced oxidation protein products. Plasma from horses had significantly (P < .05) lower thiol content and thiobarbituric and reactive substances and higher advanced oxidation protein products than plasma from cattle. A difference in total antioxidant capacity was not observed; however, our study was underpowered to establish a meaningful comparison. Based on these findings, the lack of MET in equine albumin appears to translate to a lower antioxidant capacity of equine plasma. Our findings are consistent with previous reports in other species that identify MET as having an important role in the antioxidant capacity of albumin. Our results also highlight the complex system of antioxidant defenses in plasma that counteract the harmful effects of oxidants.

Outcomes Assessment of Sustainable and Innovatively Simple Lifestyle Modification at the Workplace - Drinking Electrolyzed-Reduced Water (OASIS-ERW): A Randomized, Double-Blind, Placebo-Controlled Trial

Oxidative stress has been associated with many diseases as well as aging. Electrolyzed-reduced water (ERW) has been suggested to reduce oxidative stress and improve antioxidant potential. This study investigated the effects of drinking ERW on biomarkers of oxidative stress and health-related indices in healthy adults. We conducted a randomized, double-blind, placebo-controlled clinical trial on 65 participants, who were allocated into two groups. Of these, 61 received intervention (32 with ERW and 29 MW [mineral water]). All participants were instructed to drink 1.5 L/day of ERW or MW for eight weeks. Biomarkers of oxidative stress and health-related indices were assessed at baseline as well as after 4 weeks and 8 weeks of intervention. Of the primary outcome variables assessed, diacron-reactive oxygen metabolites (d-ROMs) and biological antioxidant potential showed a significant interaction between the groups and time, with d-ROMs levels significantly decreased at 8 weeks in ERW compared to those in MW. Among the secondary outcome variables, total, visceral, and subcutaneous fat mass significantly changed over time, with a significant association observed between the groups and time. Thus, daily ERW consumption may be a potential consideration for a sustainable and innovatively simple lifestyle modification at the workplace to reduce oxidative stress, increase antioxidant potential, and decrease fat mass.

An evaluation of dietary selenium nanoparticles for red sea bream (Pagrus major) aquaculture: growth, tissue bioaccumulation, and antioxidative responses

Selenium nanoparticles (Se-NPs) were added at 0, 0.5, 1, and 2 mg per kg diet to assess its effects on the performance, Se bioaccumulation, blood health, and antioxidant status of red sea bream. After 45 days, Se-NPs positively impacted the growth and feed efficiency of red sea bream especially by 1 mg per kg diet. No significant (P > 0.05) changes in survival and somatic indices were noticed among groups. Dietary Se-NPs significantly (P < 0.05) increased the protein, lipid, and Se contents in the whole body, muscle, and liver tissues, whereas decreasing the whole-body moisture content of treated groups compared with the Se-NP-free group. Using of Se-NPs at 2 mg per kg diet resulted in the highest Se content in the complete body, muscle, and liver. Significantly enhanced intestine protease activity and hematocrit levels accompanied with low cholesterol and triglyceride were observed in fish fed Se-NP-enriched diets. Fish fed on Se-NPs at 0.5, 1, and 2 mg Se-NPs per kg diet exhibited significantly higher values of biological antioxidant potential than the control group (P < 0.05). Therefore, the obtained results recommends adding 1 mg Se-NPs per kg diet to improve the growth, feed efficiency, blood health, and antioxidant defense system of red sea bream.

Markers for oxidative stress in the synovial fluid of Thoroughbred horses with carpal bone fracture

Arthritis is thought to cause oxidative stress in synovial fluid in humans, but there have been few reports in horses. To evaluate oxidative stress in synovial fluid in horses, this study used 19 horses with unilateral fracture of the carpal joint bone. Synovial fluid was collected from the carpal joint on the fracture (arthritis group) and contralateral (control group) sides. Diacron-reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP) were then measured, and the oxidative stress index (OSI) was calculated. d-ROMs and OSI of the arthritis group were significantly higher than the control group. BAP of the arthritis group was significantly lower than the control group. Thus, this study revealed that oxidative stress develops in the synovial fluid of horses during arthritis.

Fishmeal replacement by soya protein concentrate with inosine monophosphate supplementation influences growth, digestibility, immunity, blood health, and stress resistance of red sea bream, Pagrus major

We assessed the effects of fishmeal (FM) replacement by soy protein concentrate (SPC) with inosine monophosphate (IMP) supplementation on growth, digestibility, immunity, blood health, and stress resistance of red sea bream, Pagrus major. FM protein of a FM-based control diet (FM100) was replaced with 25 (FM75), 50 (FM50), 75 (FM25), and 100% (FM0) by SPC protein, and each replacement group was supplemented with 0.4% IMP to formulate five experimental diets. Each diet was randomly allocated to triplicate groups of fish (4.8 g) for 56 days. Results demonstrated that fish fed diet groups FM50 and FM75 had significantly the highest final weight, weight gain, specific growth rate, and feed intake. Meanwhile, in comparison to the control, growth performance and feed utilization did not significantly differ with the 75% FM-replaced diet group by SPC with IMP supplementation. Apparent digestibility coefficient of dry matter, protein, and lipid also followed a similar trend. All growth, feed utilization, and digestibility parameters were significantly lower in the FM0 diet group. Triglyceride level was increased (P < 0.05) with the increasing replacement level and it was significantly highest in the FM0 diet group. The fish fed diet groups FM100 and FM50 showed the best condition of oxidative and freshwater stress resistance, respectively. Meanwhile, the groups with up to 75% FM-replaced diet also showed acceptable stress resistance status. Overall, enhanced innate immune responses were observed in the entire FM replaced with IMP-supplemented diet groups in comparison to the control. Considering SGR as a model, the regression analysis determined that 71.7% FM protein could be replaced by SPC protein with IMP supplementation in diets for the growth of red sea bream.

Development of small blood volume assays for the measurement of oxidative stress markers in mammals

Measuring oxidative stress has become increasingly valuable in ecological studies, especially when different markers are measured on the same individual. However, many of the current methods lack sensitivity for analysis of low blood volume samples, which represent a challenge for longitudinal field studies of small organisms. Small blood volumes can usually only be analysed by using a single assay, therefore providing limited information on individual's oxidative profile. In this study, we used blood collected from a population of wild eastern chipmunks (Tamias striatus) and modified methods presented in the literature to improve analytical selectivity and sensitivity required for small blood volumes. Specifically, we proposed a modified malondialdehyde (MDA) analysis protocol by HPLC and also optimized both the uric acid independent ferric reducing antioxidant power (FRAP) and hypochlorous acid shock capacity (HASC) assays. Development of the three modified methods was achieved with a sensitivity and repeatability that meets standards of field ecology while allowing measurement of all three assays in duplicate using less than 60 μL of plasma. Availability of these tests using small blood volumes will provide ecologists with a more comprehensive portrait of an individual's oxidative profile and a better understanding of its determinants and interactions with the environment.

Influence of dietary inosine and vitamin C supplementation on growth, blood chemistry, oxidative stress, innate and adaptive immune responses of red sea bream, Pagrus major juvenile

Both inosine (INO) and vitamin C (l-ascorbic acid, AsA) play important roles in growth performance, feed utilization and health status of fish. Therefore, a 56 days feeding trial was conducted to determine the interactive effects of dietary INO and AsA on growth performance, oxidative status, innate and adaptive immune responses of red sea bream. Fish growth performance and fed utilization parameters were significantly affected by dietary INO supplementation but not by AsA. Fish fed diets with INO at 4 g kg^-1 diet in combination of high and low levels of AsA (3.1 g kg-1 and 9.3 g kg-1) produced the highest growth and feed utilization performances. In terms of growth and feed utilization performances no significant interaction effects were observed between INO and AsA. Dietary INO significantly influenced hematocrit, glucose and glutamyl oxaloacetic transaminase (GOT) content of red sea bream meanwhile AsA also significantly influenced hematocrit, glucose, total cholesterol, blood urea nitrogen (BUN) and glutamic-pyruvate transaminase (GPT) content of the test fish. No significant interaction effects was also observed between INO and AsA on measured hematological parameters. Reactive oxygen metabolites (d-ROMs) significantly influenced by both INO and AsA. Fish fed diet groups D1, D4 and D6 showed best oxidative stress resistance. Only INO was a significant factor on nitro-blue-tetrazolium activity (NBT) and bactericidal activity (BA). Neither INO nor AsA was a significant factor on serum catalase activity (CAT), total serum protein (TSP), peroxidase activity (PA) and lysozyme activity (LA). No significant interaction effects was observed between INO and AsA on measured innate immune parameters. Agglutination antibody titer was significantly influenced by dietary supplementation, after 15 days of vaccination but not in 21 days. In the day 15th fish and diet group D3 and D5 showed significantly higher values compared to diet groups control and D1. INO was the only significant factor of increasing agglutination antibody titer in 15 t h day. While AsA was not a significant factor on agglutination antibody titer values in day 15 t h, there was an interaction between dietary INO and AsA levels. Finally under the experimental conditions, fish fed high INO and low AsA levels (4 g kg^-1 and 0.31 g kg^-1 diet, respectively) showed best growth and feed utilization performance. Simultaneously, low level of INO and high level of AsA (2 g kg^-1 and 0.93 g kg^-1 diet, respectively) improved blood chemistry and immunological parameters. Furthermore, combined use of INO and AsA is possible to improve hemato-immunological responses of red sea bream.

Bacillus subtilis as probiotic candidate for red sea bream: Growth performance, oxidative status, and immune response traits

The effects of dietary administration of Bacillus subtilis on the growth, digestive enzyme activity, blood chemistry, oxidative status and immune response of red sea bream (Pagrus major) were evaluated in the current study. Fish fed five different levels of B. subtilis at 0 (BS0), 1 × 10⁴ (BS1), 1 × 10⁶ (BS2), 1 × 10⁸ (BS3) and 1 × 10¹⁰ (BS4) CFU kg^-1 diet for 60 days. The obtained results showed that B. subtilis supplementation significantly improved growth performance (FBW, WG and SGR), feed utilization (FI, FCE, PER and PG) and whole-body protein content when compared to the control group (P < 0.05). Furthermore, the specific activities of amylase, protease and lipase enzymes up regulated significantly upon B. subtilis incorporation in red sea bream diets (P < 0.05). No changes have been reported on blood biochemical variables except for the plasma total protein, which increased significantly in fish fed BS3 diet when compared with the control diet (P < 0.05). Hematocrit, hemoglobin and the nitro blue tetrazolium values also reported the highest values significantly in fish fed B. subtilis, especially in case of BS3 and BS4 diets (P < 0.05). Serum bactericidal activity enhanced significantly in BS2, BS3 and BS4 groups (P < 0.05), while mucus bactericidal activity showed no significant activity among tested groups (P > 0.05). Serum lysozyme activity exhibited higher values in case of BS3 and BS4 groups than BS0 group (P < 0.05), while mucus lysozyme activity increased only in BS3 group. Also, serum peroxidase activity enhanced significantly in fish fed BS2 and BS3 diets (P < 0.05), however, no activities were observed in the collected mucus. All groups reflexed high tolerance ability against oxidative stress except for BS0 and BS1 groups. Additionally, catalase activity increased significantly in all B. subtilis fed groups when compared to BS0 group (P < 0.05). Considering the obtained results, the supplementation of B. subtilis in the diet of red sea bream at 1 × 10⁸ and 1 × 10¹⁰ CFU kg^-1 diet could improve the growth, feed utilization, health condition and immune response.

Effect of prolonged submaximal exercise on serum oxidative stress biomarkers (d-ROMs, MDA, BAP) and oxidative stress index in endurance horses

Background

Oxidative stress (OS) associated with an intense exercise may have a negative influence on equine health. The aim of this study was to determine the effects of endurance races on oxidative and antioxidative status of horses by evaluating changes in reactive oxygen metabolites (d-ROMs), malondialdehyde (MDA), biological antioxidant potential (BAP) and oxidative stress index (OSI) values. The study was carried out on 53 race starts (28 individual horses) competing at different endurance races according to distance (40 and 80 km) and difficulty (easy and demanding). Blood samples were taken before and after the race.

Results

Compared to levels of OS serum biomarkers before the race, an increase in values of d-ROMs (P <  0.01), MDA (P <  0.01), and BAP (P <  0.001), and a decrease in OSI (P <  0.001) have been noted after the race. Contrary to other measured biomarkers, BAP did not show significant individual effects of horses. Horses competing at shorter races have shown a significant change in d-ROMs (P = 0.002), BAP (P <  0.001) and OSI (P = 0.004), whereas those competing at longer races in MDA (P = 0.002), BAP (P <  0.001) and OSI (P <  0.001) post-race values. Endurance racing induced changes in values of d-ROMs, BAP and OSI during both easy and demanding races.

Conclusions

Changes in all measured OS biomarkers indicate that prolonged aerobic exercise during endurance race could contribute to the imbalance between oxidants and antioxidants in horses, mainly characterised by a pronounced antioxidant response. Biological antioxidant potential was found to be the most reliable biomarker of OS in endurance horses in the present study.

Dietary substitution of fishmeal by alternative protein with guanosine monophosphate supplementation influences growth, digestibility, blood chemistry profile, immunity, and stress resistance of red sea bream, Pagrus major

We determined the effects of complete fishmeal (FM) replacement by alternative protein (soy protein concentrate, SPC) with guanosine monophosphate (GMP) supplementation on growth, digestibility, immunity, blood chemistry profile, and stress resistance of juvenile red sea bream, Pagrus major. FM protein of a FM-based control diet (FM0) was replaced with 33.3 (FM33.3), 66.6 (FM66.7), and 100% (FM100) by SPC protein, and each replacement group was supplemented with 0.4% GMP to formulate four experimental diets. Each diet was randomly allocated to triplicate groups of fish (4.8 g) for 56 days. Results demonstrated that fish fed diet group FM33.3 had the significantly highest final weight, weight gain-specific growth rate, and feed intake. Meanwhile, in comparison to control, growth performance and feed utilization did not significantly differ with 66.7% FM replacement by SPC with GMP supplementation. Apparent digestibility coefficient of protein and lipid also followed a similar trend. All growth, feed utilization, and digestibility parameters were significantly lower in FM100 diet group. Blood urea nitrogen (BUN) and triglycerides (TG) increased (P < 0.05) with increasing FM replacement level by SPC. Interestingly, total cholesterol level reduces with the increasing level of FM replacement by SPC with GMP supplementation. Fish fed FM0 diet group showed the best condition of both oxidative and freshwater stress resistance. Meanwhile, FM33.3 and FM66.7 diet groups showed acceptable conditions. Innate immune responses enhanced with the increasing FM replacement level by SPC with GMP supplementation. In conclusion, FM could be replaced ≤66.7% by SPC with GMP supplementation in diets for red sea bream without any adverse effects on fish performances.

Effects of dietary administration of guanosine monophosphate on the growth, digestibility, innate immune responses and stress resistance of juvenile red sea bream, Pagrus major

The present study explored the dietary administration effects of guanosine monophosphate (GMP) on growth, digestibility, innate immune responses and stress resistance of juvenile red sea bream, Pagrus major. A semi-purified basal diet supplemented with 0% (Control), 0.1% (GMP-0.1), 0.2% (GMP-0.2), 0.4% (GMP-0.4) and 0.8% (GMP-0.8) purified GMP to formulate five experimental diets. Each diet was randomly allocated to triplicate groups of fish (mean initial weight 3.4 g) for 56 days. The obtained results clearly indicated that, growth performance of red sea bream enhanced by dietary GMP supplementation compared to control and significantly higher final weight was found in fish fed diet group GMP-0.4. Specific growth rate (SGR) and percent weight gain (%WG) also significantly higher in diet group GMP-0.4 in compared to control and it was not differed (P > 0.05) with diet group GMP-0.8. Feed intake significantly increased with the supplementation of GMP. Feed conversion efficiency (FCE) and protein efficiency ratio (PER) also improved (P < 0.05) when fish fed the diets containing GMP and diet group GMP-0.4 showed the significantly higher value in compared to control. The Apparent digestibility coefficients (dry matter, protein and lipid) also improved by GMP supplementation and the significantly higher protein digestibility was observed in fish fed diet groups GMP-0.2, GMP-0.4 and GMP-0.8. Among the measured non specific immune parameters peroxidase activity (PA), respiratory burst activity (NBT), Bactericidal activity (BA) were significantly affected by dietary supplementation and highest value obtained in diet group GMP-0.4. Total serum protein, lysozyme activity (LA), and agglutination antibody titer also increased (P > 0.05) by GMP supplementation. In contrast, catalase activity decreased with GMP supplementation. In terms of oxidative stress GMP-0.2 showed best condition with low oxidative stress and high antioxidant level. Moreover, the fish fed GMP supplemented diets had better improvement (P < 0.05) in body protein contents, hepatosomatic index, hematocrit content and glutamyl oxaloacetic transaminase (GOT) and glutamic-pyruvate transaminase (GPT) level than the control group. Supplementation also improved (P < 0.05) freshwater stress resistances. Quadratic regression analysis of WG and LA revealed that, the optimal levels of dietary GMP were 0.45 and 0.48%, respectively, for juvenile red sea bream, which is also in line with the most of the growth performance and health parameters of the fish.

Reference range of blood biomarkers for oxidative stress in Thoroughbred racehorses (2-5 years old)

The oxidant and antioxidant equilibrium is known to play an important role in equine medicine and equine exercise physiology. There are abundant findings in this field; however, not many studies have been conducted for reference ranges of oxidative stress biomarkers in horses. This study was conducted to determine the reference values of reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP) using blood samples from 372 (191 males, 181 females) Thoroughbred racehorse aged 2 to 5 (3.43 ± 1.10 (mean ± SD)) years old. There were obvious gender differences in oxidative biomarkers, and growth/age-related changes were observed especially in females. Gender and age must be considered when interpreting obtained oxidative stress biomarkers for diagnosis of disease or fitness alterations in Thoroughbred racehorses.

Dietary effects of adenosine monophosphate to enhance growth, digestibility, innate immune responses and stress resistance of juvenile red sea bream, Pagrus major

Our study explored the dietary effects of adenosine monophosphate (AMP) to enhance growth, digestibility, innate immune responses and stress resistance of juvenile red sea bream. A semi-purified basal diet supplemented with 0% (Control), 0.1% (AMP-0.1), 0.2% (AMP-0.2), 0.4% (AMP-0.4) and 0.8% (AMP-0.8) purified AMP to formulate five experimental diets. Each diet was randomly allocated to triplicate groups of fish (mean initial weight 3.4 g) for 56 days. The results indicated that dietary AMP supplements tended to improve growth performances. One of the best ones was found in diet group AMP-0.2, followed by diet groups AMP-0.1, AMP-0.4 and AMP-0.8. The Apparent digestibility coefficients (dry matter, protein and lipid) also improved by AMP supplementation and the significantly highest dry matter digestibility was observed in diet group AMP-0.2. Fish fed diet groups AMP-0.2 and AMP-0.4 had significantly higher peroxidase and bactericidal activities than fish fed the control diet. Nitro-blue-tetrazolium (NBT) activity was found to be significantly (P < 0.05) greater in fish fed diet groups AMP-0.4 and AMP-0.8. Total serum protein, lysozyme activity and agglutination antibody titer were also increased (P > 0.05) by dietary supplementation. In contrast, catalase activity decreased with AMP supplementation. Moreover, the fish fed AMP supplemented diets had better improvement (P < 0.05) in body lipid contents, condition factor, hematocrit content and glutamyl oxaloacetic transaminase (GOT) level than the control group. Supplementation also improved both freshwater and oxidative stress resistances. Interestingly, the fish fed diet groups AMP-0.2 and AMP-0.4 showed the least oxidative stress condition. Finally it is concluded that, dietary AMP supplementation enhanced the growth, digestibility, immune response and stress resistance of red sea bream. The regression analysis revealed that a dietary AMP supplementation between 0.2 and 0.4% supported weight gain and lysozyme activity as a marker of immune functions for red sea bream, which is also inline with the most of the growth and health performance parameters of fish under present experimental conditions.

Oxidative stress markers in Thoroughbred horses after castration surgery under inhalation anesthesia

Oxidative stress has been reported to occur during surgery. It is important to reduce intraoperative oxidative stress to improve the postoperative prognosis. However, there are no reports regarding oxidative stress related to surgery in horses. In the present study, we measured pre and postsurgical diacron-reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP); the oxidative stress index (OSI) was then calculated (OSI=d-ROMs/BAP × 100). d-ROMs were not significantly different between the pre and postsurgical periods. However, BAP significantly decreased after surgery (P=0.02), and OSI significantly increased after surgery (P=0.02). Based on these results, it suggested that castration surgery under inhalation anesthesia decreases the antioxidant potential and causes oxidative stress in horses.

Systemic and respiratory oxidative stress in the pathogenesis and diagnosis of Rhodococcus equi pneumonia

REASONS FOR PERFORMING STUDY

Oxidative stress (OS) is most simply defined as an imbalance between oxidants and antioxidants. Oxidative stress has been suggested to play roles in various equine respiratory diseases and the significance of OS in the pathogenesis of Rhodococcus equi pneumonia is unknown.

OBJECTIVES

To measure and relate biomarkers of OS to lesions consistent with R. equi pneumonia.

STUDY DESIGN

Case-control study.

METHODS

Various OS biomarkers were measured from blood and exhaled breath condensate (EBC) samples collected from 26 foals between 1 and 2 months of age (n = 12 cases and n = 14 controls) on 2 Thoroughbred farms endemically affected by R. equi pneumonia. Foals were defined as cases (positive) or controls (negative) based on ultrasonographic evidence of pulmonary abscessation (>15 mm in diameter). Haematology and biochemistry testing was also performed on blood samples collected from the foals. Comparison of biomarkers and key haematological and biochemical markers of inflammation between the groups was performed using 2 sample t tests.

RESULTS

Derivatives of reactive oxygen metabolites (d-ROMs) were significantly greater in case foals than in control foals (P = 0.027) and the oxidative stress index (OSI) was higher in case foals (P = 0.014). Hydrogen peroxide (H2 O2 ) concentrations in EBC were significantly greater in case foals than in control foals (P = 0.002). Meanwhile, there were no significant differences in traditional measures of inflammation between the 2 groups.

CONCLUSIONS

Measuring OS in both blood and EBC provided useful information in the early diagnosis of R. equi pneumonia.

Responses of hematological parameters, beta-endorphin, cortisol, reactive oxygen metabolites, and biological antioxidant potential in horses participating in a traditional tournament

Several concerns have been raised over the health of animals used in equestrian games that have their origins in historical or religious events and are currently held in many countries. This study investigated physiological stress response and health status of horses participating in the Sartiglia, a historical horse tournament held in the city of Oristano, Italy, which is principally based on the attempts of masked horsemen at a gallop to run a sword through a hole in a suspended silver star. Blood samples were collected from 21 horses the day before the tournament (D0), during the tournament (D1), and the day after the tournament (D2). Samples were analyzed for complete blood count and biochemical, hormonal, and oxidative stress assays. Data were analyzed using the mixed effect model with sampling session as one of the fixed effects. On the whole, blood parameters evidenced an optimal health status of horses at D0. Significant dehydration and increase of circulating glucose, enzymes, cortisol, and β-endorphin were registered at D1 (P < 0.001) with a complete recovery of physiological values just at D2. The reactive oxygen metabolites (d-ROM), from which the prooxidant activity can be evaluated, showed an increase from D0 to D1 and D2. Concentration of biological antioxidant potential, which measured the antioxidant capacity, was characterized by the maximum level registered during the tournament and counteracted the simultaneous increase of d-ROM. It can be hypothesized that the tournament played an important role in causing high levels of oxidant markers not only because of the physical exercise represented by the gallop but also because the emotional stressors. In conclusion, the tournament caused significant changes of most parameters, which rapidly recovered to baseline values within the day after. These data will certainly be useful for a future implementation of tests in equine medicine and for the improvements of knowledge of changes of blood parameters and health of horses in similar tournaments.

Effects of ozonated autohemotherapy on the antioxidant capacity of Thoroughbred horses

The performance of horses undergoing regular intense exercise is adversely affected by oxidative stress. Thus, it is important to increase antioxidant production in horses in order to reduce oxidative stress. Ozonated autohemotherapy (OAHT) reportedly promotes antioxidant production. This study aimed to evaluate the effects of OAHT on antioxidant capacity. Ten Thoroughbred horses were used in this study. After the OAHT, we collected serum samples and measured biological antioxidant potential (BAP). We found that BAP began to increase after the OAHT and was significantly higher in the OAHT group than at 3 (P<0.01) and 7 days (P<0.05) after OAHT than in the control group at 3 and 7 days after starting collection of blood samples. Therefore, it was shown that OAHT improved the antioxidant capacity of the horses.

Effects of partial substitution of fish meal by soybean meal with or without heat-killed Lactobacillus plantarum (LP20) on growth performance, digestibility, and immune response of amberjack, Seriola dumerili juveniles

A 56-day feeding trial was conducted to evaluate the effects of supplemented diets with heat-killed Lactobacillus plantarum (HK-LP) with graded levels of soybean meal (SBM) on growth, digestibility, blood parameters, and immune response of Seriola dumerili (initial weight, 25.05 ± 0.1 g). Seven isonitrogenous and isolipidic practical diets were formulated to contain 0%, 15%, 30%, and 45% SBM, and each SBM level was supplemented with HK-LP at 0.0 and 0.1%. Fish fed diet which contains 30% SBM with HK-LP grew significantly faster than the other groups with notable feed intake and protein retention. Further, protein gain, whole body protein content, protease activity, protein, and lipid digestibility were significantly increased for all fish groups except for fish fed diet which contains 45% SBM with or without HK-LP. Interestingly, lysozyme activity was significantly enhanced in fish fed diets that contain 15% and 30% SBM with HK-LP. Hematocrit, peroxidase, and bactericidal activities revealed a significant increase in 30% SBM with HK-LP group. In addition, fish fed diets which contain 0% and 30% SBM with HK-LP showed higher tolerance against low-salinity stress compared with other groups. In conclusion, the addition of HK-LP to amberjack diets appeared to improve SBM utilization, immune response, and stress resistance.

Antioxidants and human diseases

Oxidative stress plays a pivotal role in the development of human diseases. Reactive oxygen species (ROS) that includes hydrogen peroxide, hyphochlorus acid, superoxide anion, singlet oxygen, lipid peroxides, hypochlorite and hydroxyl radical are involved in growth, differentiation, progression and death of the cell. They can react with membrane lipids, nucleic acids, proteins, enzymes and other small molecules. Low concentrations of ROS has an indispensable role in intracellular signalling and defence against pathogens, while, higher amounts of ROS play a role in number of human diseases, including arthritis, cancer, diabetes, atherosclerosis, ischemia, failures in immunity and endocrine functions. Antioxidants presumably act as safeguard against the accumulation of ROS and their elimination from the system. The aim of this review is to highlight advances in understanding of the ROS and also to summarize the detailed impact and involvement of antioxidants in selected human diseases.

Resuscitation of preterm neonates with limited versus high oxygen strategy

OBJECTIVE

To determine whether a limited oxygen strategy (LOX) versus a high oxygen strategy (HOX) during delivery room resuscitation decreases oxidative stress in preterm neonates.

METHODS

A randomized trial of neonates of 24 to 34 weeks' gestational age (GA) who received resuscitation was performed. LOX neonates received room air as the initial resuscitation gas, and fraction of inspired oxygen (Fio2) was adjusted by 10% every 30 seconds to achieve target preductal oxygen saturations (Spo2) as described by the 2010 Neonatal Resuscitation Program guidelines. HOX neonates received 100% O2 as initial resuscitation gas, and Fio2 was adjusted by 10% to keep preductal Spo2 at 85% to 94%. Total hydroperoxide (TH), biological antioxidant potential (BAP), and the oxidative balance ratio (BAP/TH) were analyzed in cord blood and the first hour of life. Secondary outcomes included delivery room interventions, respiratory support on NICU admission, and short-term morbidities.

RESULTS

Forty-four LOX (GA: 30 ± 3 weeks; birth weight: 1678 ± 634 g) and 44 HOX (GA: 30 ± 3 weeks; birth weight: 1463 ± 606 g) neonates were included. LOX decreased integrated excess oxygen (∑Fio2 × time [min]) in the delivery room compared with HOX (401 ± 151 vs 662 ± 249; P < .01). At 1 hour of life, BAP/TH was 60% higher for LOX versus HOX neonates (13 [9-16] vs 8 [6-9]) µM/U.CARR, P < .01). LOX decreased ventilator days (3 [0-64] vs 8 [0-96]; P < .05) and reduced the incidence of bronchopulmonary dysplasia (7% vs 25%; P < .05).

CONCLUSIONS

LOX is feasible and results in less oxygen exposure, lower oxidative stress, and decreased respiratory morbidities and thus is a reasonable alternative for resuscitation of preterm neonates in the delivery room.

Assessment of oxidative stress biomarkers in exhaled breath condensate and blood of Thoroughbred foals

This study reports preliminary data on systemic and local biomarkers of oxidative stress (OS) in Thoroughbred foals. Blood and exhaled breath condensate (EBC) were sampled from 13 foals on two farms. Values of reactive oxygen metabolites (d-ROMs), biological antioxidant potential (BAP), antioxidant barrier (OXY-ads), thiol antioxidant barrier (SHp) and advanced oxidation protein products (AOPPs) were determined in blood, while EBC samples were assayed for hydrogen peroxide (H(2)O(2)) levels. Systemic and local OS biomarkers did not differ between farms and gender. Increased oxidative stress index (OSI) values in a foal recovering from pneumonia and elevated H(2)O(2) in EBC coupled with low SHp and elevated AOPPs in the blood of a foal with overt upper respiratory tract disease suggested that the OS markers measured in this study may relate to the respiratory health status of foals.

Characteristics of the spin-trapping reaction of a free radical derived from AAPH: further development of the ORAC-ESR assay

The characteristics of the spin-trapping reaction in the oxygen radical absorbance capacity (ORAC)-electron spin resonance (ESR) assay were examined, focusing on the kind of spin traps. 2,2-Azobis(2-amidinopropane) dihydrochloride (AAPH) was used as a free radical initiator. The spin adducts of the AAPH-derived free radical were assigned as those of the alkoxyl radical, RO· (R=H(2)N(HN)C-C(CH(3))(2)). Among the spin traps tested, 5,5-dimethyl-1-pyrroline N-oxide (DMPO), 5,5-dimethyl-4-phenyl-1-pyrroline N-oxide (4PDMPO), 5-(2,2-dimethyl-1,3-propoxycyclophosphoryl)-5-methyl-1-pyrroline N-oxide (CYPMPO), and 5-diethoxyphosphoryl-5-methyl-1-pyrroline N-oxide (DEPMPO) were applicable to the ORAC-ESR assay. Optimal formation of spin-trapped radical adduct was observed with 1 mM AAPH, 10 mM spin trap, and 5 s UV irradiation. The calibration curve (the Stern-Volmer's plot) for each spin trap showed good linearity, and their slopes, k (SB)/k (ST), were estimated to be 87.7±2.3, 267±15, 228±9, and 213±16 for DMPO, 4PDMPO, CYPMPO, and DEPMPO, respectively. Though the k (SB)/k (ST) values for selected biosubstances varied with various spin traps, their ratios to Trolox (the relative ORAC values) were almost the same for all spin traps tested. The ORAC-ESR assay also had a very good reproducibility. The ORAC-ESR assay was conducted under stoichiometric experimental conditions. The present results demonstrate the superiority of the ORAC-ESR assay.

Interplay between plasma oxidative status, cortisol and coping styles in wild alpine marmots, Marmota marmota

Variation in how individuals cope behaviourally and physiologically with stressors is widespread and can have a significant impact on life-history traits and fitness. Individual coping styles are characterised by differential behavioural and adrenocortical reactivity to various challenges. As stress hormones can affect the production of reactive chemical species and the antioxidant status, individuals with different coping styles may differ also in oxidative status. Field studies on wild mammalian populations are few in number and none so far has simultaneously tested the relationship between coping style, adrenocortical reactivity and oxidative status in the same individuals. We measured individual variation in coping styles along a proactive-reactive continuum together with variation in baseline and stress-induced plasma oxidative damage, plasma non-enzymatic antioxidant capacity and cortisol in wild alpine marmots, Marmota marmota. Confirmatory path analysis revealed that different coping styles are accompanied by different baseline and stress-induced plasma oxidative statuses. Our findings also highlight the potential role of cortisol as a mediator of such differences.

Relationship between oxidative stress and the success of artificial insemination in dairy cows in a pasture-based system

This study was designed to evaluate whether the outcome of artificial insemination (AI) was affected by the metabolic and oxidative status of dairy cows. Seventy-nine inseminations in 40 cows, were classified, on the basis of blood progesterone (P4) and pregnancy-associated glycoprotein (PAG) concentrations and clinical confirmation of pregnancy into, three categories: (1) positive (AI+, resulted in pregnancy, n=26; 33%), (2) negative (AI-, did not result in pregnancy, n=49; 62%), and (3) embryonic mortality (EM, n=4; 5%). Reactive oxygen metabolites, biological antioxidant potential, oxidative stress index, body condition score, glucose, total proteins, albumin, urea, non-esterified fatty acids (NEFAs), cholesterol, triglycerides, haptoglobin and advanced oxidative protein products (AOPPs) were measured on the day of AI (day 0), and 30 and 42 days later. Cows with EM had lower BCS scores (2.5) than AI+ (2.8) and AI- (2.9) cows (P<0.05). During the post-partum period, body condition score (BCS) increased and NEFAs decreased (P<0.05) suggesting a recovery from the negative energy balance (NEB). The only significant differences found were that the mean concentration of AOPPs was higher and that of albumin lower in EM cows than in AI+ and AI- (P<0.05) animals. Plasma concentration of reactive oxygen metabolites and biological antioxidant potential were not related to AI outcome. Further studies are required to confirm this finding and to clarify the role of oxidative status on cows' fertility.

Biomarkers of oxidative stress in ruminant medicine

The study of oxidative stress is a relatively young field of research in ruminant medicine. Oxidative stress results from increased exposure to or production of oxidants, or from decreased dietary intake, de novo synthesis or increased turnover of antioxidants. The understanding of the role of oxidants and antioxidants in physiological and pathological conditions is rapidly increasing. Oxidative stress is an active field of research in veterinary medicine and has been implicated in numerous disease processes including sepsis, mastitis, acidosis, ketosis, enteritis, pneumonia, respiratory, and joint diseases. Compared to human medicine, only a limited number of conditions have been investigated in regard to the effects of oxidative stress in ruminants. Studies in cattle have been sporadic and mainly with mastitis, pneumonia, and retained placenta. More recently, studies have been focused on metabolic diseases that affect dairy cows during the peripartum period. Numerous and rapidly evolving methodologies for evaluating oxidative stress are available to researchers and clinicians, each with their own distinct advantages and disadvantages. Differences in models and methodologies make it difficult to make meaningful comparisons, even for studies that seem quite similar superficially. With this in mind, it is the goal of this review to discuss the advantages and shortfalls of different methodologies commonly used to measure oxidative stress and damage in ruminants. Clarity of understanding of the pathophysiology of oxidative stress in ruminants will allow the design of specific antioxidant therapies. Future research should focus on the establishment of a reference panel of biomarker of oxidative stress to be used in ruminant medicine. To help accelerate practical applications, we propose the development of an oxidative stress index as an approach in ruminant and veterinary medicine.

Effects of Yerba Mate (Ilex paraguariensis) supplementation on the productive performance of dairy cows during mid-lactation

Yerba Mate (Ilex paraguariensis), a tea known for its high antioxidant content, was fed (250 g/cow.day) to 8 of 16 Holstein cows for 6 weeks to assess its effect on their performance. Cows were weighed and blood samples were taken on Weeks 0, 3 and 6. Blood samples were centrifuged and plasma was analysed for reactive oxygen metabolites, biological antioxidant potential, advanced oxidation protein products and non-esterified fatty acids. Cows were milked two times daily and milk yields were recorded daily for individual cows. On Weeks 0 and 6, individual milk samples were collected from two consecutive milkings, composited, and analysed for somatic cell counts, fat and true protein concentrations. Plasma concentrations of reactive oxygen metabolites, biological antioxidant potential and non-esterified fatty acids were not affected by Yerba Mate supplementation. Similarly, no effect of Yerba Mate supplementation was noted on milk fat and protein content and on somatic cell counts. This study indicates that supplementation of dairy cows’ diet with Yerba Mate during mid lactation seems to improve milk yield when cows are fed with maize silage; however, even if the effect on milk yield was significant it was quite small and needs to be validated with further studies. Cows’ oxidative status was not affected by Yerba Mate supplementation indicating that the effect of Yerba Mate on their productive performances is not mediated by changes in redox status.