Plasma Glutamate Dehydrogenase Research Articles

Promotion of Pregnant Merino Ewes' Welfare with the Introduction of a Drought- and High-Temperature-Resistant Cereal into Their Diet: Analysis of Tritordeum Meadow.

Tritordeum is a new cereal resistant to drought and high temperatures, and it is a very healthy crop. The aim of this study was to compare two different diets (tritordeum meadow vs. oat meadow) for grazing pregnant ewes to determine if there was any effect on the objective physiological indicators of animal welfare. A total of 150 pregnant Merino ewes (3-5 years) were randomly divided into two groups (n = 75 each) to be fed with two different meadows, being evaluated during the spring season. Red blood cells count, haemoglobin, packed cell volume, white blood cell count, neutrophiles/lymphocytes ratio, lactate dehydrogenase, creatinine phosphokinase, aspartate aminotransferase, glucose, cortisol, total plasma proteins, albumin, globulins, albumin/globulins ratio, alkaline phosphatase, glutamate dehydrogenase, IgA, and IgG were determined. Overall, the results of this study indicate that the welfare of pregnant ewes fed with tritordeum meadow was better than that of pregnant ewes fed with oat meadow. Tritordeum meadow had a positive influence on the physiological parameters of animal welfare studied in pregnant Merino ewes. Therefore, tritordeum meadow can be considered a functional feed, as it has a beneficial effect on health beyond its basic nutritional value. Farmers are recommended to feed a cereal such as tritordeum grassland to their sheep, as it not only ensures that the animals benefit from all the nutrients, but also prevents diseases and improves their quality of life. In addition, the cereal's resistance to fungal diseases makes it suitable for use in sustainable production systems with a reduced environmental footprint.

Oral bovine serum albumin administration benefits plasma amino acid profile in blunt snout bream fed high‐fat and high‐energy diet through the TOR signaling pathway

AbstractThis study investigated the effect of oral bovine serum albumin (BSA) on plasma amino acid profile and growth performance in blunt snout bream fed high‐fat and high‐energy diets. A total of 360 fish (average weight: 45.84 ± 0.07 g) were randomly divided into three groups in four replicates and fed with the control, high‐fat diet (HFD), and high‐energy diet (HED), respectively. After 12 weeks of feeding, fish were orally administered with 10% BSA for 10 h, with the blood and liver sample obtained at 10 h. The results showed no remarkable difference (p > 0.05) in final weight, weight gain rate, feed conversion ratio, protein efficiency ratio, and daily growth rate among dietary treatments. However, fish fed HFD and HED obtained significantly higher energy and nitrogen retention content than the control. Plasma valine and histidine content were more prevalent in fish fed the control diet than in HFD and HED groups. However, BSA significantly enhanced this content with higher values observed in arginine and alanine content than in control diets at 10 h. Significantly higher liver and plasma Aspartate aminotransferase, Xanthine oxidase, and Glutamate dehydrogenase content were found in the HFD than in the control group. However, the administration of BSA at 10 h improved these parameters similar to the control. Meanwhile, protease, Lipase, aminopeptidase N, carboxypeptidase A, and Na+ K+‐ATPase were influenced significantly (p < 0.001) by sampling time, dietary treatments, and their interaction. Fish fed with the HFD and HED significantly downregulated (p < 0.05) the akt, bcat2, 4e‐bp1, s6k1, and tor expression compared to the control. However, BSA administration at 10 h improved these genes similar to the control. This study indicated that oral BSA administration could benefit plasma amino acid through the TOR signaling pathway in blunt snout bream fed high‐fat and high‐energy diets.

Evaluation of Cottonseed Meal as an Alternative to Fish Meal in Diet for Juvenile Asian Red-Tailed Catfish Hemibagrus wyckioides.

A 10-week trial was performed to investigate the effects of replacing fishmeal with cottonseed meal (CSM) on the growth rate, protein metabolism, and antioxidant response of Asian red-tailed catfish Hemibagrus wyckioides. Five isonitrogenous and isocaloric diets (C0, C8.5, C17.2, C25.7, and C34.4) were prepared to contain 0%, 8.5%, 17.2%, 25.7%, and 34.4% CSM replacing fishmeal, respectively. The weight gain, daily growth coefficient, pepsin, and intestinal amylase activities initially increased and then decreased with the raising dietary CSM levels; the highest values were observed in the C17.2 group (P < 0.05). However, feed cost exhibited the opposite trend. With the increasing dietary CSM levels, the protein efficiency ratio and intestinal trypsin activity decreased but feed conversion rate increased gradually; while no differences were observed among the C0, C8.5, and C17.2 groups (P > 0.05). Dietary CSM inclusion regardless of levels increased the plasma growth hormone level as well as hepatic aspartate aminotransferase (AST) and γ-glutamyl transpeptidase activities but decreased the plasma glutamate dehydrogenase and AST activities (P < 0.05). With the increasing dietary CSM levels, the plasma alkaline phosphatase (AKP) and hepatic superoxide dismutase activities decreased but malondialdehyde content increased gradually, while no differences were observed among the C0, C8.5, and C17.2 groups (P > 0.05). The plasma immunoglobulin M content and hepatic glutathione reductase activity initially increased but then decreased with the raising dietary CSM levels; the highest values were found in the C17.2 group. These results indicated that dietary CSM inclusion level up to 17.2% improved the growth rate, feed cost, digestive enzyme activity, and protein metabolism without compromising antioxidant capacity of H. wyckioide, whereas these parameters were depressed by further inclusion of CSM. CSM is a potentially cost-effective alternative plant protein source in diet of H. wyckioide.

SODIUM SELENITE ABROGATES THE EFFECTS OF ARSENIC TOXICITY ON ORGAN INJURY BIOMARKERS IN THE BLOOD

Heavy metals are becoming ubiquitous in our environment due to its natural abundance and anthropogenic uses. Arsenic an example of heavy metal, can cause deleterious effects in numerous organs and biochemical pathways. Use of noninvasive testing procedures had been used in diagnosis, monitoring of pathological events during treatment. In order to investigate the effects of sodium selenite on biomarkers of organ injury in arsenic-exposed rats for a period of 5 weeks, twenty-four male albino rats divided into four groups (n = 6) were exposed to sodium arsenite (SA) and sodium selenite (SS). Group I (control) received only distilled water, groups II and III were exposed to 40 ppm SA in drinking water ad libtum, in addition group III received 0.25 mg/kg bwt SS orally and group IV received 0.25 mg/kg bwt SS orally only. Activities and levels of organ-injury markers were determined in the blood using spectrophotometric method. In the SA exposed group (group II), there were significant increases (p ˂ 0.05) in the activities of plasma xanthine oxidase, lactate dehydrogenase, aldolase, glutamate dehydrogenase, NAD glycohydrolase, aspartate and alanine aminotransferases, and levels of plasma nitric oxide and hydrogen sulphide (in plasma and erythrocyte) when compared to control. Sodium selenite administration abrogated the observed effects of SA exposure by decreasing the measured biomarkers to the normal level as observed in group III and IV. In conclusion, this results suggests the use of SS is safe and non-invasive approach for the prevention of SA-induced toxicity in humans.

The Relationship between Plasma Alpha-1-Antitrypsin Polymers and Lung or Liver Function in ZZ Alpha-1-Antitrypsin-Deficient Patients.

Alpha-1-Antitrypsin (AAT) is a protein of the SERPINA1 gene. A single amino acid mutation (Lys342Glu) results in an expression of misfolded Z-AAT protein, which has a high propensity to intra- and extra-cellular polymerization. Here, we asked whether levels of circulating Z-AAT polymers are associated with the severity of lung disease, liver disease, or both. We obtained cross sectional data from the Dutch part of the Alpha1 International Registry of 52 ZZ-AAT patients who performed a pulmonary function test and donated a blood sample on the same day. From the Alpha-1 Liver Aachen Registry, we obtained a cohort of 40 ZZ-AAT patients with available data on their liver function. The levels of plasma Z-AAT polymers were determined using a LG96 monoclonal antibody-based sandwich ELISA. In a Dutch cohort, the median plasma level of Z-AAT polymers of patients diagnosed for pulmonary disease was 947.5 µg/mL (733.6–1218 µg/mL (95% CI)), which did not correlate with airflow obstruction or gas transfer value. In the Alpha-1 liver patient cohort, the median polymer level was 1245.9 µg/mL (753–2034 µg/mL (95% CI)), which correlated with plasma gamma-glutamyl transferase (GGT, rs = 0.57, p = 0.001), glutamate dehydrogenase (GLDH, rs = 0.48, p = 0.002) and triglycerides (TG, rs = 0.48, p = 0.0046). A Wilcoxon rank test showed higher Z-AAT polymer values for the liver over the lung group (p < 0.0001). These correlations support a possible link between plasma Z-AAT polymers and the liver function.

Enzymatic and fecundity evaluation of Fasciola hepatica exposed to different doses of γ- irradiation in Ethiopian sheep

The upshot of γ-irradiated Fasciola hepatica infection on the activity of plasma glutamate dehydrogenase (GLDH) and γ-glutamyl transpeptidase (GGT) was evaluated in 36 sheep infected with a single dose of 30, 60, 120, and 240 grays and those kept as negative and positive control over 17 weeks. During this period, serum and faecal samples, as well as body weight gains, were taken at weekly intervals. Furthermore, the effects of the irradiation dose (500) for oral vaccination and on the recovery of adult flukes were assessed following primary infection. Eggs were first detected in the faeces of infected sheep on week 8 post-infection. The parasite viability was severely affected by doses of γ-irradiation of 120 Gy or 240 Gy. In the aforementioned doses, relatively low numbers of mature flukes of about 60 (17.1%) and 38 (10.8%) were recovered than the control group, respectively. The sensitized lambs also showed less hepatic damage compared with the controls as indicated by lower levels of the serum enzyme glutamate dehydrogenase and γ- glutamyl transferase significant body weight loss was observed between weeks 6 and 8 post-infection followed by a steady increase of the mean weight of infected animals across time. In conclusion, vaccination of sheep with γ irradiated metacercariae of F. hepatica appeared to affect the number and development of the fluke population resulting in reduced hepatic damage during migration, reduced fecundity after patency, as measured by worm and egg counts, levels of serum glutamate dehydrogenase and γ- glutamyl transferase.

Glutamate dehydrogenase as a biomarker for mitotoxicity; insights from furosemide hepatotoxicity in the mouse.

Glutamate dehydrogenase (GLDH) is a liver-specific biomarker of hepatocellular damage currently undergoing qualification as a drug development tool. Since GLDH is located within the mitochondrial matrix, it has been hypothesized that it might also be useful in assessing mitotoxicity as an initiating event during drug-induced liver injury. According to this hypothesis, hepatocyte death that does not involve primary mitochondrial injury would result in release of intact mitochondria into circulation that could be removed by high speed centrifugation and result in lower GLDH activity measured in spun serum vs un-spun serum. A single prior study in mice has provided some support for this hypothesis. We sought to repeat and extend the findings of this study. Accordingly, mice were treated with the known mitochondrial toxicant, acetaminophen (APAP), or with furosemide (FS), a toxicant believed to cause hepatocyte death through mechanisms not involving mitotoxicity as initiating event. We measured GLDH levels in fresh plasma before and after high speed centrifugation to remove intact mitochondria. We found that both APAP and FS treatments caused substantial hepatocellular necrosis that correlated with plasma alanine aminotransferase (ALT) and GLDH elevations. The plasma GLDH activity in both the APAP- and FS- treated mice was not affected by high-speed centrifugation. Interestingly, the ratio of GLDH:ALT was 5-fold lower during FS compared to APAP hepatotoxicity. Electron microscopy confirmed that both APAP- and FS-treatments had resulted in mitochondrial injury. Mitochondria within vesicles were only observed in the FS-treated mice raising the possibility that mitophagy might account for reduced release of GLDH in the FS-treated mice. Although our results show that plasma GLDH is not clinically useful for evaluating mitotoxicity, the GLDH:ALT ratio as a measure of mitophagy needs to be further studied.

Effects of yeast fermentate supplementation on cecal microbiome, plasma biochemistry and ileal histomorphology in stressed broiler chickens

Heat stress, a common stressor in commercial poultry production, negatively affects growth and intestinal function of broiler chickens. Two experiments were conducted to evaluate the effects of a Saccharomyces cerevisiae-derived yeast fermentation product on cecal microbiome and indicators of intestinal barrier function in stressed broiler chickens. Yeast fermentate (YF) was added to the feed (1.25 kg/t) or drinking water (1.60 mL/L) for the duration of each experiment. In Exp. 1, 1-D-old male broiler chickens (N = 300 birds/treatment) were assigned to 1 of 3 treatments: stressed control (CS), stressed + YF in the feed (XS), and stressed + YF in the drinking water (AS). All birds were reared on re-used litter (d 0 to 42) and spray-vaccinated for coccidiosis (d 0). On d 18, all birds were spray-vaccinated for Newcastle/Bronchitis, then exposed to a 12 h concurrent heat stress and feed and water withdrawal. Cecal microbiome did not differ in composition or diversity between or within treatments on d 42. In Exp. 2, 1-D-old male broiler chickens (N = 40 birds/treatment) were reared to 43 d of age. Treatments included CS, XS, AS, non-stressed control (CN), non-stressed + YF in the feed (XN), and non-stressed + YF in the drinking water (AN). Stressed treatments were exposed to cyclic heat stress d 28 to 43 for 12 h/d. Blood samples collected on d 42 were used to analyze plasma chemistry, interleukin(IL)-1α, IL-8, and alpha-1-acid glycoprotein (α1-AGP); ileum samples collected on d 43 were used to assess histomorphology. Heat stress increased plasma creatine kinase (P < 0.001), uric acid (p < 0.001), sodium/potassium ratio (P < 0.001), and IL-1α (P < 0.001), but decreased alkaline phosphatase (P = 0.04), potassium (P < 0.001), IL-8 (P < 0.001), and α1-AGP (P = 0.048). Plasma glutamate dehydrogenase was higher in birds fed the control diet or YF in the feed (P < 0.001) compared to birds supplemented with YF in the drinking water. Heat stress decreased villus height (P < 0.001) and crypt depth (P < 0.001), and increased villus/crypt ratio (P < 0.001) and goblet cell density (P < 0.001). Supplementing YF in the drinking water increased villus height (P < 0.001) and crypt depth (P = 0.036) compared to supplementing YF in the feed. Adding YF to the drinking water may be an effective method to mitigate heat-stress induced changes in villus height and crypt depth during cyclic heat stress.

Effect of Yeast Fermentate Supplementation on Intestinal Health and Plasma Biochemistry in Heat-Stressed Pekin Ducks.

Simple SummaryYeast cells and cell wall components have been used to improve intestinal health in a variety of livestock. This study examines the addition of the product of yeast fermentation in feed or drinking water on intestinal morphology and blood biochemical measures in mixed-sex Pekin ducks exposed to heat stress or thermoneutral conditions. This study found that when added to the feed or drinking water, yeast fermentate increased villus length, villus/crypt ratio, and plasma uric acid concentrations. As a result, yeast fermentate may support nutrient absorption and modulate amino acid metabolism in mixed-sex Pekin ducks.One experiment was conducted to determine the effects of supplementing Saccharomyces cerevisiae-derived yeast fermentate (Diamond V Mills, Cedar Rapids, IA, USA) in the feed (XPC; 1.25 kg/metric ton feed, days 0–35) or drinking water (AviCare; 160 mL/100 L, days 0–35) on plasma biochemical and immune parameters, as well as ileal histomorphology of mixed-sex Pekin ducks grown to 35 d and exposed to cyclic heat stress (8 h/d) or thermoneutral environment (days 21–35). On the day of hatching, 144 straight run White Pekin ducks were randomly assigned to one of six treatments: stressed control (CS), stressed + XPC (XS), stressed + AviCare (AS), non-stressed control (CN), non-stressed + XPC (XN), and non-stressed + AviCare (AN). On day 33, blood samples were collected from 12 birds/treatment to assess plasma chemistry, packed cell volume, and plasma levels of interleukin (IL)-1α, IL-8, and α1-acid glycoprotein (α1-AGP). On day 34, ileum sections were collected from 12 birds/treatment to assess goblet cell density, villus length, crypt depth, and villus/crypt ratio from 6 villi per sample. Plasma phosphorus was influenced by diet (p < 0.001) and heat–diet interaction (p = 0.003), and was higher in XS than XN, and higher in AS than AN. Heat stress increased plasma glutamate dehydrogenase (GLDH) (p = 0.008). Uric acid was increased by adding yeast fermentate to the feed or drinking water (p = 0.002), but was not influenced by heat (p > 0.05). The heat–diet interaction affected plasma IL-1α (p = 0.021) and sodium (p = 0.046). Heat stress reduced villus length (p < 0.001), villus/crypt ratio (p < 0.001), and goblet cell density (p < 0.001), but did not affect crypt depth (p > 0.05). Both XPC and AviCare increased villus length (p < 0.001) and villus/crypt ratio (p < 0.001), and decreased crypt depth (p < 0.001), but did not affect goblet cell density (p > 0.05). Although adding yeast fermentate to the feed or drinking water does not appear to alleviate the effects of heat stress on goblet cell density, both routes of administration improved other measures of villus morphology and affected amino acid metabolism.

Aluminosilicate clay improves production responses and reduces inflammation during an aflatoxin challenge in lactating Holstein cows

Mitigation strategies are vital in minimizing the health and economic risks associated with dairy cattle exposure to aflatoxin (AF). The objective of this study was to determine the effects of a commercially available aluminosilicate clay in a lactation diet on production responses, blood chemistry, and liver inflammatory markers of multiparous lactating Holstein cows during an AF challenge. Sixteen multiparous lactating Holstein cows [body weight (mean ± SD) = 758 ± 76 kg; days in milk = 157 ± 43 d] were assigned to 1 of 4 treatments in a replicated 4 × 4 Latin square design with 21-d periods: no adsorbent and no AF challenge (CON), no adsorbent and an AF challenge (POS), 113 g of aluminosilicate clay top-dressed on the total mixed ration (adsorbent; FloMatrix, PMI Nutritional Additives, Arden Hills, MN) with an AF challenge (F4), or 227 g of adsorbent with an AF challenge (F8). The challenge consisted of 100 μg of AFB1/kg of dietary dry matter intake administered orally. For each period, milk was sampled 3× daily from d 14 to 21; blood, feces, and urine were sampled on d 14, 18, and 21; and liver samples were taken on d 18. Liver tissue was assessed for gene expression and histological hepatocyte inflammation. Statistical analysis was preformed using the MIXED and GLIMMIX procedures of SAS (SAS Institute Inc., Cary, NC). Fat-corrected milk (POS = 37.2, F4 = 39.2, and F8 = 38.9 kg/d) increased as concentration of adsorbent in the diet increased. There was a decrease in milk AFM1 concentration at d 18 as concentration of adsorbent in the diet increased (POS = 0.33, F4 = 0.32, and F8 = 0.27 µg/kg). There was a decrease in AFM1 concentration in urine (POS = 2.10, F4 = 1.89, and F8 = 1.78 µg/kg) and AFB1 concentration in feces (POS = 4.68, F4 = 3.44, and F8 = 3.17 µg/kg) as concentration of adsorbent in the diet increased. Cows in CON had greater concentrations of serum cholesterol (202 mg/dL) and plasma superoxide dismutase (2.8 U/mL) compared with cows in POS (196 mg/dL and 2.6 U/mL, respectively). Plasma glutamate dehydrogenase increased as concentration of adsorbent in the diet increased (POS = 37.8, F4 = 39.3, and F8 = 39.1 U/L). The expression of NFKB1 was greater in the liver of cows in POS (0.78) compared with cows in CON (0.70). The expression of MTOR was greater in the liver of cows in CON (1.19) compared with cows in POS (0.96). When compared with cows in CON, cows in POS had greater odds ratio for hepatocyte inflammation (odds ratio = 5.14). In conclusion, the adsorbent used in this study had a positive effect on milk production and hepatocyte inflammation and reduced AF transfer.

HEMATOLOGY AND PLASMA CHEMISTRY OF THE PLOUGHSHARE TORTOISE (ASTROCHELYS YNIPHORA) IN A CAPTIVE BREEDING PROGRAM.

Blood samples from 172 captive and 40 wild, healthy, juvenile and adult, ploughshare tortoises ( Astrochelys yniphora ) were analyzed to determine hematological and biochemical reference intervals. Hematological analytes included packed cell volume (PCV), white blood cell count (WBC), and WBC differential estimates. Biochemical analysis included total protein measured by photometry (TP) and by refractometry (TPr), albumin (ALB), creatine kinase (CK), aspartate aminotransferase (AST), glutamate dehydrogenase (GLDH), bile acids (BA), calcium (Ca), phosphorus (P), urea (UREA), and uric acid (UA). The jugular vein was identified as the preferred venipuncture site as subcarapacial vein venipuncture resulted in regular hemodilution. In due consideration of small sample sizes in some of the groups studied, adult tortoises had significantly higher plasma GLDH activity and TPr, TP, ALB, BA, and UREA concentrations and significantly lower AST activity and P concentration than juveniles. Captivity had a significant influence in some reference intervals, with captive adults presenting significantly higher WBC, and estimated counts of all white cell types as well as UREA and TPr than wild counterparts. Captive juveniles also showed significantly higher estimated monocyte and lower estimated eosinophil and basophil counts. Although these differences most likely reflect local environmental or dietary differences, without representing pathology or a deviation from the normal, they question the applicability of reference values from captive animals to wild animals and vice versa. Significant sex differences were only observed for PCV and UA. The reported reference intervals may serve as benchmarks for clinical assessment and conservation of this critically endangered species.

Biomarkers of Neutrophil‐Mediated Liver Injury in Patients with Alcoholic Liver Disease

Alcoholic liver disease (ALD) is a multi‐stage liver disorder associated with chronic ethanol abuse. The most serious syndrome associated with ALD is alcoholic hepatitis (AH), a type of acute‐on‐chronic liver failure that commonly occurs on a backdrop of alcoholic cirrhosis (AC). Neutrophil (PMN) accumulation in the liver is noted during AH, and is hypothesized to be a major mediator of the injury. This study was initiated to better define mechanisms of PMN mediated liver injury in human patients, using both mechanistic plasma biomarkers, and liver biopsies from AC and AH patients. We hypothesized PMN mediated ROS production exacerbated liver injury in patients with AH. Healthy volunteers, patients with clinically diagnosed AH, or abstinent AC patients were admitted to the IRB approved study, and whole blood was acquired for analysis of PMN activity and an array of mechanistic plasma biomarkers previously shown to provide insight into clinical liver injury, including cytokeratin‐18 levels, caspase‐3 activity, glutamate dehydrogenase (GDH) activity, and cytokine levels. In addition, hepatic cell death and PMN activation were measured in liver biopsies from patients with AH or AC via immunohistochemistry. Flow cytometry was used to ascertain the activation status of circulating PMNs. CD11b, a verified marker of neutrophil activation, was significantly elevated in neutrophils from AH patients, and was elevated in AC patients, but not significantly so. This was consistent with a substantial elevation in plasma IL‐8 levels, a known neutrophil chemoattractant, in the AH population. Baseline values of ROS production and phagocytic capacity were elevated in AC and AH patients, indicating low‐level basal stimulation of neutrophils. Surprisingly though, total hepatic neutrophils levels were similar in liver biopsies of AC and AH patients. Moreover, both groups stained positive for hypochlorous acid modified proteins, a gold standard histological marker for neutrophil activation, suggesting active neutrophils in both populations. Interestingly, plasma M30 levels, an apoptotic fragment of cytokeratin‐18 released during epithelial cell death, and plasma M65 levels, a necrotic fragment of cytokeratin‐18, were substantially elevated above control values, despite the fact that traditional markers of liver injury such as plasma ALT and plasma GDH were not elevated above controls, nor was there any detectable plasma caspase‐3 activity. Of note, AH patients had significantly higher plasma M65 values than AC patients, indicating increased total cell death. There was a small increase in TUNEL positive cells in AH patients (2–4 fold versus control), but this was not consistent with the dramatic elevation in M30/M65 levels (20–100 fold versus control). M30 staining of biopsies indicated only minor levels of M30 arose from the liver. In conclusion, neutrophil mediated hepatocyte cell death is likely a limited player in acute AH, although this does not preclude the possibility that neutrophil mediated ROS production contributes to the fibrotic or cirrhotic phenotype in these patients, as neutrophils are constitutively activated in the populations.Support or Funding InformationThis work was supported by a clinical pilot grant from Kansas University Medical Center. Additional support came from the “Training Program in Environmental Toxicology” T32 ES007079‐26A2 (to B.L.W.) from the National Institute of Environmental Health Sciences

Effects of a 6-wk intraduodenal supplementation with quercetin on energy metabolism and indicators of liver damage in periparturient dairy cows

Periparturient dairy cows experience metabolic challenges that result in a negative energy balance (EB) and a range of postpartum health problems. To compensate for the negative EB, cows mobilize fatty acids from adipose tissues, which can lead to fatty liver disease, a periparturient metabolic disorder. Flavonoids, such as quercetin (Q), are polyphenolic substances found in all higher plants and have hepatoprotective potential and the ability to prevent or reduce lipid accumulation in the liver. In ruminants, few studies on the metabolic effects of Q are available, and thus this study was conducted to determine whether Q has beneficial effects on EB, lipid metabolism, and hepatoprotective effects in periparturient dairy cows. Quercetin was supplemented intraduodenally to circumvent Q degradation in the rumen. Cows (n=10) with duodenal fistulas were monitored for 7wk. Beginning 3wk before expected calving, 5 cows were treated with 100mg of quercetin dihydrate per kilogram of body weight daily in a 0.9% sodium chloride solution for a total period of 6wk, whereas the control cows received only the sodium chloride solution. The plasma flavonoid levels were higher in the Q-treated cows than in the control cows. A tendency for higher postpartum (pp) than antepartum (ap) plasma flavonoid levels was observed in the Q-treated cows than in the controls, which was potentially caused by a reduced capacity to metabolize Q. However, the metabolic status of the Q-treated cows did not differ from that of the control cows. The pp increases in plasma aspartate aminotransferase and glutamate dehydrogenase activities were less in the Q-treated cows than in the control cows. The Q had no effect on energy expenditures, but from ap to pp the cows had a slight decline in respiratory quotients. Irrespective of the treatment group, the oxidation of fat peaked after calving, suggesting that the increase occurred because of an increased supply of fatty acids from lipomobilization. In conclusion, supplementation with Q resulted in lower pp plasma aminotransferase and glutamate dehydrogenase, which indicated reduced liver damage. However, the direct effects of Q on the liver and the implications for animal performance remain to be investigated.

Influence of 4-week intraduodenal supplementation of quercetin on performance, glucose metabolism, and mRNA abundance of genes related to glucose metabolism and antioxidative status in dairy cows

Quercetin has been shown to be a potent antioxidant, acts hepatoprotectively, and affects glucose and lipid metabolism in monogastrics. If this is also true in ruminants, quercetin could be beneficial in periparturient high-yielding dairy cows by ameliorating the negative effects of free radical formation and reducing the severity of liver lipidosis and ketosis. In a first attempt to evaluate effects of a long-term quercetin treatment, we intraduodenally administered twice daily 18mg of quercetin (Q)/kg of body weight to 5 late-lactation (215d in milk) dairy cows over a period of 28d. Frequent blood samples were taken before and during administration to determine plasma concentrations of flavonols and metabolites. Before and after 1 and 4wk of Q administration, glycogen and fat content as well as mRNA expression of selected genes were measured in liver biopsies. Furthermore, euglycemic, hyperinsulinemic, and hyperglycemic clamp studies were conducted before and after 2wk of Q administration. During the experiment, dry matter intake and most other zootechnical data remained unchanged. Milk protein content was increased in wk 2 and 4 of Q administration compared with basal values, whereas fat and lactose contents of milk remained unchanged. Plasma nonesterified fatty acids, γ-glutamyl transferase, cholesterol, glutamate dehydrogenase, triglyceride, and albumin concentrations, as well as liver fat and glycogen concentrations, were not affected by Q supplementation. Plasma glucose and β-hydroxybutyrate concentrations in plasma decreased and increased, respectively, under the influence of quercetin. During hyperglycemic clamp conditions, the relative increase of plasma insulin was higher after 2wk of Q administration, and a tendency for an increased rQUICKI (revised quantitative insulin sensitivity check index) was observed. The relative mRNA expression levels of selected genes related to glucose metabolism, fat metabolism, and antioxidative status were not altered after 1 or 4wk of Q supplementation. In conclusion, the effects on insulin release and sensitivity support the assumption that administration of Q could have positive effects on the metabolic adaption of high-yielding cows to early lactation. The increase of milk protein content in response to Q supplementation needs to be verified.

Circulating acylcarnitines as biomarkers of mitochondrial dysfunction after acetaminophen overdose in mice and humans

Acetaminophen (APAP) is a widely used analgesic. However, APAP overdose is hepatotoxic and is the primary cause of acute liver failure in the developed world. The mechanism of APAP-induced liver injury begins with protein binding and involves mitochondrial dysfunction and oxidative stress. Recent efforts to discover blood biomarkers of mitochondrial damage have identified increased plasma glutamate dehydrogenase activity and mitochondrial DNA concentration in APAP overdose patients. However, a problem with these markers is that they are too large to be released from cells without cell death or loss of membrane integrity. Metabolomic studies are more likely to reveal biomarkers that are useful at early time points, before injury begins. Similar to earlier work, our metabolomic studies revealed that acylcarnitines are elevated in serum from mice after treatment with toxic doses of APAP. Importantly, a comparison with furosemide demonstrated that increased serum acylcarnitines are specific for mitochondrial dysfunction. However, when we measured these compounds in plasma from humans with liver injury after APAP overdose, we could not detect any significant differences from control groups. Further experiments with mice showed that N-acetylcysteine, the antidote for APAP overdose in humans, can reduce acylcarnitine levels in serum. Altogether, our data do not support the clinical measurement of acylcarnitines in blood after APAP overdose due to the standard N-acetylcysteine treatment in patients, but strongly suggest that acylcarnitines would be useful mechanistic biomarkers in other forms of liver injury involving mitochondrial dysfunction.

Responsiveness of prehaemolytic copper poisoning in sheep from a specific pathogen-free environment to a relatively high dose of tetrathiomolybdate

Efficacy of ammonium tetrathiomolybdate (3.4 mg/kg LW, TTM3.4) was monitored in nine, specific pathogen-free sheep with mild-to-severe, prehaemolytic copper poisoning (pre-HCP). Five sheep were given three subcutaneous injections over seven...

Improved Clinicopathologic Assessments of Acute Liver Damage due to Trauma in Indian Ring-necked Parakeets (Psittacula krameri manillensis)

Increased activities of certain biochemical enzymes (alanine aminotransferase [ALT], aspartate aminotransferase [AST], lactate dehydrogenase [LDH], alkaline phosphatase [ALP]) have been associated with blunt liver injury in many species. To evaluate changes in plasma hepatic biochemical parameters in acute avian liver disease caused by trauma and to compare biochemical changes with histologic lesions in hepatic parenchyma, 30 healthy fasted Indian ring-necked parakeets (Psittacula krameri manillensis) were divided into 2 groups, and traumatic liver injury was caused by endoscopic liver biopsy (group 1) or by liver biopsy and crushing injury to the hepatic parenchyma with endoscopic forceps (group 2) in anesthetized birds. Blood samples were collected at baseline and at 12, 24, 36, 48, 60, 72, 84, 96, 108, and 120 hours in alternate groups to compare analyte values after injury with those at baseline. Results showed consistently decreased plasma ALP activity (excluding 1 time point) throughout the study, which was thought to be associated with isoflurane administration. Plasma glutamate dehydrogenase activity initially increased but rapidly declined thereafter and was attributed to acute focal hepatocellular injury. In both groups, increases in plasma AST, ALT, and LDH activities was most likely caused by muscle injury because creatine kinase activity was concurrently increased. Compared with baseline values, bile acid concentration and y-glutamyl transferase activity were not affected by liver biopsy or crush injury. Plasma sorbitol dehydrogenase activity was the most specific indicator of liver injury in both groups. Histologic changes correlated poorly with biochemical results, possibly because the small area of hepatic parenchyma that was damaged did not affect enzyme values substantially.

Hepatic effects of lung-protective pressure-controlled ventilation and a combination of high-frequency oscillatory ventilation and extracorporeal lung assist in experimental lung injury

SummaryBackgroundVentilation with high positive end-expiratory pressure (PEEP) can lead to hepatic dysfunction. The aim of this study was to investigate the hepatic effects of strategies using high airway pressures either in pressure-controlled ventilation (PCV) or in high-frequency oscillatory ventilation (HFOV) combined with an arteriovenous extracorporeal lung assist (ECLA).Material/MethodsPietrain pigs underwent induction of lung injury by saline lavage. Ventilation was continued for 24 hours either as PCV with tidal volumes of 6 ml/kg and PEEP 3 cmH2O above the lower inflection point of the pressure-volume curve or as HFOV (≥12 Hz) with a mean tracheal airway pressure 3 cmH2O above the lower inflection point combined with arteriovenous ECLA (HFOV+ECLA). Fluids and norepinephrine stabilized the circulation. The indocyanine green plasma disappearance rate, serum bilirubin, aspartate aminotransferase, alanine aminotransferase, γ-glutamyltransferase, alkaline phosphatase, glutamate dehydrogenase, lactate dehydrogenase and creatine kinase were determined repeatedly. Finally, liver neutrophils were counted and liver cell apoptosis was assessed by terminal deoxynucleotidyl transferase nick end labeling (TUNEL).ResultsAspartate aminotransferase increased in the PCV group about three-fold and in the HFOV+ECLA group five-fold (p<0.001). Correspondingly, creatine kinase increased about two-fold and four-fold, respectively (p<0.001). Lactate dehydrogenase was increased in the HFOV+ECLA group (p<0.028). The number of neutrophils infiltrating the liver tissue and the apoptotic index were low.ConclusionsHigh airway pressure PCV and HFOV with ECLA in the treatment of lavage-induced lung injury in pigs did not cause liver dysfunction or damage. The detected elevation of enzymes might be of extrahepatic origin.

Advantages of glutamate dehydrogenase as a blood biomarker of acute hepatic injury in rats.

In a recent study in rats, alanine aminotransferase (ALT), the preferred plasma biomarker of hepatocellular injury in rats, was ineffective at detecting marked hepatic necrosis produced by acetaminophen (Human and Experimental Toxicology 19, 277-83, 2000). In contrast, glutamate dehydrogenase (GLDH) was markedly elevated. Accordingly, these enzymes were comprehensively evaluated as plasma biomarkers of hepatocellular injury in rats using several other models of hepatic injury, including partial hepatectomy and exposure to methapyrilene, dexamethasone, cyproterone, isoniazid, lead nitrate, and Wyeth-14643. Other enzymes also evaluated were aspartate aminotransferase (AST), sorbitol dehydrogenase (SDH), and the hepatobiliary marker alkaline phosphatase (ALP). Compared to plasma ALT increases, plasma GLDH increases were up to 10-fold greater, up to 3-fold more persistent, and occurred at times following hepatocellular injury when plasma ALT was not increased. Plasma GLDH activity was not inhibited by the test compounds, whereas ALT was substantially inhibited by both isoniazid and lead nitrate. While plasma GLDH activity was unaffected by induction, ALT was induced by cyproterone and dexamethasone, and ALP was induced by Wyeth-14643 and partial hepatectomy. GLDH was concluded to be a more effective biomarker of acute hepatic injury than ALT, AST, SDH or ALP in the rat, based primarily on the large increase following hepatocellular injury, prolonged persistence in the blood following injury, high sensitivity for detection of injury (including pre-necrotic injury), high tissue specificity, and lower susceptibility to inhibition or induction.

Plasma aspartate aminotransferase (AST), glutamate dehydrogenase (GLDH) and gamma-glutamyl transpeptidase (GGT) activities in water buffaloes with experimental subclinical fasciolosis

The effect of chronic Fasciola hepatica infection on the activity of plasma aspartate aminotransferase (AST), glutamate dehydrogenase (GLDH) and gamma-glutamyl transpeptidase (GGT) was investigated in water buffaloes dosed daily with 60 F. hepatica metacercariae over 20 days. Experimental fluke infection caused no clinical signs but provoked an increase in plasma level of IgG directed against F. hepatica from 4 weeks after infection. There was a significant increase in plasma AST from 6 weeks post-infection. Maximal values were reached at 14 weeks and remained significantly elevated by 23 weeks. Plasma GLDH was significantly elevated from 6 to 21 weeks post-infection. Significant increases in plasma GGT occurred from 8 to 26 weeks post-infection, reaching maximal values at 15 weeks. This study shows that plasma enzyme activities may be useful in studies of fluke-induced liver damage in water buffaloes.