Biomedical subjects

W G Bottje

Publications and source records attributed to W G Bottje.

At least 19 recordsLinked to original sources

PubMed2002

Heart and breast muscle mitochondrial dysfunction in pulmonary hypertension syndrome in broilers (Gallus domesticus).

This study was conducted to determine function and defects in electron transport in muscle mitochondria of meat chickens (broilers) with pulmonary hypertension syndrome (PHS). The respiratory control ratio (RCR, indicative of respiratory chain coupling) was higher in the control than in PHS breast and heart muscle mitochondria, but there were no differences in the ADP/O (an index of oxidative phosphorylation). Sequential additions of ADP improved the RCR in the control breast muscle mitochondria and the ADP/O in PHS breast and heart muscle mitochondria. Basal hydrogen peroxide production, (an indicator of electron leak), was higher in PHS breast and heart muscle mitochondria than in controls and differences in electron leak in PHS mitochondria were magnified by inhibiting electron transport at Complex I and III (cyt b(562)). Complex I activity was lower in PHS heart mitochondria but there was no difference in Complex II activity. Thus, compared to controls, PHS mitochondria exhibited site-specific defects in electron transport within Complex I and III that could contribute to lower respiratory chain coupling. Additionally, it appears that healthy broilers may exhibit higher basal levels of electron leak compared to other avian species. Together, these findings provide insight into inefficient cellular use of oxygen that may contribute to the development of PHS in broilers.

Animals↗

PubMed2002

Antioxidant enzyme activities and mitochondrial fatty acids in pulmonary hypertension syndrome (PHS) in broilers.

Major objectives of this study were to assess antioxidant protection and fatty acid profile in lung mitochondria and whole liver in broilers with pulmonary hypertension syndrome [(PHS; with and without high dietary vitamin E (VE)] (Experiment 1) and in broilers that did not develop PHS but were genetically selected (S) or not selected (NS) for resistance to PHS (Experiment 2). In Experiment 1, lung mitochondrial glutathione peroxidase (GSH-Px) activity was elevated in broilers with PHS compared to controls, broilers fed high VE, and broilers fed high VE with PHS (VE-PHS), but there were no differences in GSH reductase (GSH-Rd) among groups. In liver tissue, GSH-Px was also elevated by PHS but was lower in VE and VE-PHS groups than in controls. There were no differences in liver GSH-Rd, superoxide dismutase (SOD), or gamma-glutamylcysteine synthetase (gamma-GCS) activities with the exception that gamma-GCS was higher in the VE-PHS group than in the other groups. In Experiment 2, S lung mitochondria exhibited lower GSH-Px and higher GSH-Rd compared to NS broilers. In the liver, there were no differences in GSH-Px, GSH-Rd, or gamma-GCS, but SOD was lower in S compared to the NS broilers. High VE increased the percentage of saturated fatty acids and decreased the percentage of unsaturated fatty acids in lung mitochondria in Experiment 1; there were no differences in fatty acid content between S and NS mitochondria in Experiment 2. Thus, it appears that GSH recycling enzyme activities are affected by PHS and high VE presumably in response to differences in oxidative stress and that genetic resistance to PHS is associated with an inherently better capability to metabolize oxidants in lung mitochondria. The increase in saturation of lung mitochondrial fatty acids with high dietary VE would presumably make them more resistant to oxidative stress and, thus, reduce the level of PHS-induced oxidative stress.

Animals↗

PubMed2001

Uptake of DL-2-hydroxy-4-methylthio-butanoic acid (DL-HMB) in the broiler liver in vivo.

The methionine source DL-2-hydroxy-4methylthio-butanoic acid (DL-HMB; Alimet feed supplement) is widely used in the poultry industry. The purpose of this study was to determine the capacity of the broiler liver to remove DL-HMB from the circulation. Cannulae were implanted in the carotid artery and hepatic and hepatic portal veins in anesthetized male broilers (3.33 +/- 0.13 kg BW). In Experiment 1, birds (n = 5) were infused with DL-HMB solutions (diluted in saline, pH 7.2 to 7.4) into the hepatic portal vein at rates ranging from 4.4 to 22 mg/min per kg BW, whereas in Experiment 2, birds (n = 6) were infused with DL-HMB at rates ranging from 2.2 to 4.4 mg/min per kg BW. Plasma samples from each vessel were obtained before and after each 10-min DL-HMB infusion period with a 10-min clearance period allowed between each DL-HMB infusion. Regression analysis revealed a highly significant correlation in the amount of DL-HMB entering the liver via afferent vessels (afferent DL-HMB) and DL-HMB removed by the liver (y = 0.86(x) - 173, r2 = 0.98). The slope of this regression indicates that 86% of DL-HMB entering in afferent blood (i.e. from both the hepatic artery and hepatic portal vein) was removed or that the liver apparently metabolized 86% of the DL-HMB that entered the liver. The results indicate that the broiler liver has the capacity to remove DL-HMB from the circulation far in excess of that needed to metabolize DL-HMB that would enter the liver following gastrointestinal absorption in birds fed a conventional poultry diet. In addition, present results implicate the liver as a major site of removal from circulation and further metabolism of DL-HMB in chickens.

Animal Feed↗

PubMed2001

Electron transport chain defect and inefficient respiration may underlie pulmonary hypertension syndrome (ascites)-associated mitochondrial dysfunction in broilers.

By using a series of chemical inhibitors of mitochondrial respiration, a site-specific defect in the electron transport chain was identified in mitochondria obtained from broilers with pulmonary hypertension syndrome (PHS; ascites). Located at the succinate:ubiquinone oxido-reductase (Complex II:CoQ) interface, this defect would allow electrons to leak from the respiratory chain and consume oxygen by forming reactive oxygen species at a greater rate than in control mitochondria. Lower levels of the primary antioxidants, alpha- and beta-tocopherol, and glutathione (GSH) in PHS mitochondria confirmed the presence of oxidative stress. Respiration studies of PHS liver mitochondria also revealed disease-associated decreases in the respiratory control ratio (RCR, an index of electron transport chain coupling). Differences in the RCR as well as the adenosine diphosphate (ADP) to O ratio (an index of oxidative phosphorylation) between control and PHS mitochondria were accentuated by sequential additions of ADP to isolated mitochondria. In a second experiment, similar improvements in functional indices following sequential additions of ADP and responses to respiratory chain inhibitors were observed in liver mitochondria isolated from Single Comb White Leghorn (SCWL) males (resistant to PHS) similar to that observed in control broiler mitochondria in Experiment 1. The combined results indicate the presence of a site-specific defect at either Complex II, ubiquinone, or both in liver mitochondria obtained from broilers with PHS that may be responsible for the oxidative stress and mitochondrial dysfunction observed in this costly metabolic disease.

Adenosine Diphosphate↗

PubMed2001

Lung mitochondrial dysfunction in pulmonary hypertension syndrome. I. Site-specific defects in the electron transport chain.

The main objectives of this study were to determine a) site-specific defects in the electron transport chain of lung mitochondria of broilers with pulmonary hypertension syndrome (PHS), b) if these defects are attenuated by high dietary vitamin E, and c) if these defects have a genetic basis. In Experiment 1, lung mitochondria were isolated from broilers with and without PHS fed diets containing 15 IU and 100 IU dl-alpha-tocopherol acetate/kg (VE); the four treatments were control, VE, PHS, and VE-PHS, respectively. Hydrogen peroxide (H2O2) generation in isolated lung mitochondria was monitored by dichlorofluorosein (DCF) fluorescence in response to chemicals that inhibit electron flow at specific sites on the electron transport chain using a 96-well microplate with Cytoflour (excitation/emission 480/530 nm). Basal H2O2 production was higher in PHS than in control mitochondria. Differences in H2O2 production between control and PHS were magnified by inhibition of Complexes I and III (Coenzyme Q) of the respiratory chain in mitochondria. Functional defects in PHS mitochondria were attenuated by high dietary VE. In Experiment 2, basal H2O2 production and that following inhibition of Complexes I and III were lower in lung mitochondria isolated from broilers selected for genetic resistance to PHS than in nonselected birds in the base population. The results of this study indicate that site-specific defects in Complexes I and III may underlie lung mitochondrial dysfunction in broilers with PHS, that these defects are attenuated by high dietary vitamin E, and that these defects may be related to genetic predisposition to PHS.

Animals↗

PubMed2001

Lung mitochondrial dysfunction in pulmonary hypertension syndrome. II. Oxidative stress and inability to improve function with repeated additions of adenosine diphosphate.

The major objective of this study was to examine lung mitochondrial dysfunction and antioxidants in pulmonary hypertension syndrome (PHS) in broilers. Lung mitochondria were obtained from broilers fed diets containing 15 IU (control) and 100 IU dl-alpha-tocopherol acetate, i.e., vitamin E (VE)/kg with and without PHS; the four treatment groups were control, VE, PHS, and VE-PHS, respectively (Experiment 1), or from healthy broilers genetically selected or not selected for resistance to PHS (Experiment 2). Mitochondrial function was assessed with sequential additions of adenosine diphosphate (ADP) to mimic a repeated demand for energy. Compared to controls, PHS mitochondria in Experiment 1 exhibited mitochondrial dysfunction [lower respiratory control (RCR) and ADP:O ratios and an inability to improve function with repeated energy demand] and oxidative stress [lower alpha-tocopherol and reduced glutathione (GSH) and higher oxidized glutathione levels (GSSG)]. High dietary alpha-tocopherol had no effect on lung mitochondrial function in healthy broilers (VE vs. controls) but attenuated dysfunction in VE-PHS mitochondria. In Experiment 2, there were no differences in selected and nonselected mitochondrial function following a single addition of ADP, but nonselected mitochondria exhibited lower RCR and ADP:O values with repeated energy demand. Higher GSSG levels were also observed in nonselected lung. The results indicate that lung mitochondrial dysfunction present in broilers with PHS was associated with oxidative stress and may be attenuated by high dietary vitamin E. Furthermore, genetic resistance to PHS was associated with more efficient oxidative phosphorylation in lung mitochondria and an inherently lower degree of oxidative stress.

Adenosine Diphosphate↗

PubMed2000

Hepatic and extra-hepatic stimulation of glutathione release into plasma by norepinephrine in vivo.

Studies were conducted to determine the effect of norepinephrine (NE) on reduced glutathione (GSH) and oxidized glutathione (GSSG) export from hepatic and extra-hepatic tissues in vivo. Anesthetized Single Comb White Leghorn (SCWL) males were implanted with cannulae in the carotid artery, hepatic vein (HV) and hepatic portal veins (PV), and the left bile duct. In Experiment 1, GSH and GSSG in hepatic and portal venous plasma and bile were determined prior to, during, and following two 20-min infusions of NE (2 and 10 microg/min per kg BW) into the hepatic PV. The lower NE infusion rate increased hepatic venous GSH (indicative of increased GSH export into liver sinusoids) without affecting systemic or hepatic vascular pressures; however, it had no affect on portal venous GSH. The higher NE infusion rate increased GSH in the HV and hepatic PV (indicative of extra hepatic export of glutathione) as well as systemic pressure, hepatic and portal venous pressures, and the transhepatic pressure gradient. Biliary secretion of GSH and GSSG was unaffected by either rate of NE infusion in Experiment 1. In Experiment 2, pretreatment of birds with phentolamine, an alpha-adrenergic receptor blocker (alpha-block), abolished sinusoidal export GSH as well as the ability of NE to stimulate GSH release from hepatic and extra-hepatic tissue. Although HV and PV pressures were lower in alpha-block birds compared with controls, there were no differences in the transhepatic pressure gradient between groups. Plasma GSSG was below the limits of detection in Experiments 1 and 2. The combined results of Experiments 1 and 2 indicate that hepatic export of GSH was independent of changes in systemic or hepatic vascular pressures or changes in the transhepatic pressure gradient. The results of these studies are the first to demonstrate that export of GSH into plasma in vivo is mediated by an alpha-receptor-mediated mechanism in hepatic and extra-hepatic tissues. The findings may be particularly important with regard to antioxidant homeostasis of animals during periods of stress.

Animals↗

PubMed2000

Biliary glutathione secretion in male single comb white leghorn chickens after inhibition of gamma-glutamyl transpeptidase.

The amount of hepatic export of glutathione into bile and the importance of gamma-glutamyl transpeptidase (gammaGT) activity for catabolizing glutathione in the bile duct, have not been reported previously for domestic fowl. Therefore, the primary objective of this study was to establish baseline values of biliary glutathione, and a secondary objective was to investigate the effect of acivicin (AT-125; a gammaGT inhibitor) on biliary glutathione in the chicken. Cannulae were placed in the carotid artery (to measure blood pressure) and into the left bile duct of anesthetized male Single Comb White Leghorn (SCWL) chickens (n = 5; 17 to 18 wk). The right bile duct was clamped between the liver and gall bladder. Bile samples were collected at 15-min intervals into microcentrifuge tubes (on ice) containing serine borate and iodoacetic acid to prevent glutathione oxidation. After two samples were obtained to establish baseline values, retrograde infusion of AT-125 (30 microLmol/kg BW) was given to inhibit gammaGT activity in the biliary tree. Systemic blood pressure of the birds remained above 100 mm Hg throughout each experiment (90 to 120 min). Bile flow did not change significantly during the experiment and ranged between 0.15+/-0.03 and 0.20+/-0.07 mL/15 min per kg BW. Baseline biliary secretion values of reduced glutathione (GSH), oxidized glutathione (GSSG), and total glutathione (TGSH) were 4.6, 5.9, and 17 nmol/min per kg BW. After AT-125 infusion, biliary GSH levels increased from 15 to 31 nmol/min per kg BW, indicating that considerable gammaGT-mediated catabolism of GSH occurred in the biliary tree of SCWL males. These results indicate that considerable turnover of GSH in the livers of domestic chickens is due to biliary excretion and that substantial recovery of GSH occurs through activity of gammaGT in the biliary tree.

Animals↗

PubMed1999

Evidence of mitochondrial dysfunction in broilers with pulmonary hypertension syndrome (Ascites): effect of t-butyl hydroperoxide on hepatic mitochondrial function, glutathione, and related thiols.

The purpose of this study was to assess mitochondrial function and glutathione (a mitochondrial antioxidant) in response to oxidative stress in mitochondria in vitro obtained from broilers with and without pulmonary hypertension syndrome (PHS). Liver mitochondria from Control and PHS broilers were incubated with 0, 1, and 5-mM tertiary-butyl hydroperoxide (tBH). Indices of mitochondrial function [the respiratory control ratio (RCR) and the adenosine diphosphate to oxygen ratio (ADP:O)], and levels of mitochondrial and extra-mitochondrial reduced (GSH) and oxidized (GSSG) glutathione, cysteine, cystine, glutamate and cysteinyl-glycine were determined following tBH treatment. Lower RCR and ADP:O values were observed in PHS mitochondria than in controls. Whereas control mitochondria remained coupled (RCR > 2.0), only 3 PHS preparations remained coupled after 60 min of incubation with 5 mM tBH, indicating a greater susceptibility to oxidative stress in PHS mitochondria. The lower RCR in PHS mitochondria was due to increased oxygen consumption during State IV respiration. Oxidative stress following tBH treatment (decreased GSH and increased GSSG) was observed, but there were no differences in GSH or GSSG between control and PHS mitochondria. The PHS mitochondria did exhibit elevated mitochondrial and extramitochondrial cystine than controls, however. The results indicate that PHS mitochondria do not lack antioxidant protection from GSH, but lower RCR and ADP:O ratios in PHS mitochondria indicate a dysfunction that may contribute to the pathophysiology of this metabolic disease in broilers.

Adenosine Diphosphate↗

PubMed1999

Venous blood pressure in broilers during acute inhalation of five percent carbon dioxide or unilateral pulmonary artery occlusion.

We evaluated the hypothesis that venous congestion (increased venous volume), as reflected by venous hypertension (increased venous pressure), can arise when the right ventricle is unable to elevate the pulmonary arterial pressure sufficiently to propel the cardiac output through an anatomically inadequate or inappropriately constricted pulmonary vasculature. Changes in venous pressure were evaluated in clinically healthy broilers during modest increases in pulmonary vascular resistance induced by inhalation of 5% CO2 and during large increases in pulmonary vascular resistance accomplished by acutely tightening a snare around one pulmonary artery. Inhalation of 5% CO2 induced a pronounced respiratory acidosis, as reflected by increases the partial pressure of CO2 and the hydrogen ion concentration in arterial blood. Inhalation of 5% CO2 also increased pulmonary arterial pressure by approximately 3 mm Hg and increased venous pressure by approximately 1 mm Hg when compared with the pre-inhalation venous pressure. Tightening the pulmonary artery snare increased the pulmonary arterial pressure by approximately 10 mm Hg, and this degree of pulmonary hypertension was sustained until the snare was released. When compared with the pre- and post-snare intervals, tightening of the pulmonary artery snare induced a sustained increase in venous pressure of > or = 1 mm Hg. Veins have highly compliant walls that permit an approximate doubling in volume with only small (4 to 6 mm Hg) increases in central venous pressure. Presumably the apparently modest 1 mm Hg increase in venous pressure measured after CO2 inhalation or unilateral pulmonary artery occlusion reflects a large increase in venous volume and, thus, substantial venous congestion. These observations support the hypothesis that increases in pulmonary vascular resistance can initiate increases in venous pressure by challenging the capacity of the right ventricle to propel all of the returning venous blood through the lungs. Central venous congestion predisposes broilers to the onset of cirrhosis and ascites by impeding the outflow of hepatic venous blood and increasing the hydrostatic pressure within hepatic sinusoids.

Acidosis, Respiratory↗

PubMed1999

Thromboxane mimics the pulmonary but not systemic vascular responses to bolus HCl injections in broiler chickens.

Bolus i.v. injections of 1.2 N HCl elicit a rapid but transient pulmonary vasoconstriction in broiler chickens. In mammals, the pulmonary vasoconstrictive response to bolus acid injection depends on increased synthesis of thromboxane A2; however, the vascular responsiveness of domestic fowl to thromboxane previously had not been evaluated. In the present study, we tested the hypothesis that, if HCl triggers pulmonary vasoconstriction by stimulating thromboxane A2 synthesis in broilers, then bolus i.v. injections of the potent thromboxane A2 mimetic U44069 (9,11-dideoxy-9alpha,11alpha-epoxy-methanoprostaglandin++ + F2alpha; 1 micromol/mL; 0.5 mL injected volume) should trigger hemodynamic responses similar to those elicited by HCl (1.2 N; 1.5 mL injected volume). Both HCl and the thromboxane mimetic elicited twofold or greater increases in pulmonary vascular resistance, which in turn increased pulmonary arterial pressure by 50% despite concurrent reductions in cardiac output. The reductions in cardiac output were associated with reductions in stroke volume but not heart rate. The thromboxane mimetic also increased the total peripheral resistance, which minimized the reduction in mean systemic arterial pressure associated with the decrease in cardiac output. In contrast, HCl injections did not increase total peripheral resistance; consequently, the reduction in cardiac output caused the mean systemic arterial pressure to decrease by 30 mm Hg. Mannitol (2.5%; 1.5 mL) was injected i.v. as a volume control, and had no influence on any of the variables. This study provides the first direct evidence that thromboxane is a potent pulmonary vasoconstrictor in broilers, and provides support for the hypothesis that thromboxane mediates the pulmonary vasoconstrictive response to bolus i.v. injections of HCl. The differential response of the systemic vasculature to the thromboxane mimetic and HCl may indicate that cardiopulmonary responses to HCl injections are not mediated solely via thromboxane production. Alternatively, a direct dilatory effect of elevated hydrogen ion concentrations on the systemic vasculature may have counteracted any tendency for simultaneously evolved endogenous thromboxane to elicit systemic vasoconstriction.

Animals↗

PubMed1998

CD4, CD8 and TCR defined T-cell subsets in thymus and spleen of 2- and 7-week old commercial broiler chickens.

To better understand immune development and function in meat-type chickens (broilers), the proportions of T-cells expressing CD4, CD8, and T-cell receptors (TCR) in the thymus and spleen were determined by three-color fluorescence and flow cytometry in 2- and 7-week old broilers raised in commercial growing conditions. Broiler thymocytes consisted of single-(CD4+CD8- and CD4-CD8+) and double-(CD4+CD8+) positive subpopulations. Within these CD4+ and/or CD8+ thymocyte populations, all types of TCR (y delta, V beta 1 alpha beta, and V beta 2 alpha beta) could be identified. In the thymus, percentages of CD4+CD8- cells increased, CD4-CD8+ cells remained unchanged, and CD4+CD8+ cells decreased between 2 and 7 weeks of age. In the spleen, in addition to single-positive lymphocytes, double-positive populations were identified, expressing either y delta or alpha beta TCR. The percentage of CD4+CD8- splenocytes decreased, and the percentages of both CD4-CD8+ and CD4+CD8+ splenocytes increased between 2 and 7 weeks of age. Age-associated shifts in TCR usage (the proportion of cells expressing a certain type of TCR) were observed in the single-positive, but not in the double-positive, T-cell populations of both thymus and spleen. This multiparameter cell population analysis in broilers demonstrates thymic and splenic T-cell subsets similar to those previously described in layers. Differences in the proportions among T-cell subsets between 2- and 7-week old broilers likely reflect a more competent immune system in the older birds.

Aging↗

PubMed1998

Hepatic export of glutathione and uptake of constituent amino acids, glutamate and cysteine, in broilers in vivo.

This study was conducted to document the glutathione (GSH) cycle (interorgan circulation of GSH) in broilers in vivo. Two experiments were conducted on 36 anesthetized male broilers (n = 6 per treatment) implanted with cannulae in the carotid artery, hepatic portal, and hepatic veins. Plasma GSH, glutamate, cysteine, cystine, and cysteinylglycine levels in each vessel were monitored following a bolus injection [Experiment (Exp.) 1] or 30 min continuous infusion (Exp. 2) of GSH, or a gamma-glutamyltranspeptidase inhibitor (AT125) into the hepatic portal vein. Controls received saline alone. The GSH and AT125 treatments were used to determine the effect of increasing the prehepatic GSH load and of inhibiting systemic GSH degradation, respectively, on the GSH cycle. Hepatic export of GSH was clearly evident in all three treatment groups in both experiments (Exp.). The GSH and AT125 treatments raised amino acid levels in some or all of the vessels, whereas cysteinylglycine was elevated by AT125 and depressed by the GSH treatment compared to Controls. Hepatic uptake of glutamate, cysteine, and/or cystine was observed in Controls and GSH-treated birds, but not in birds given AT125 (Exp. 2). Neither hepatic export nor uptake of cysteinylglycine was observed in any treatment group. The results clearly demonstrate the ability of the avian liver to export GSH into the general circulation despite alterations that might arise from changes in extra-hepatic ability to utilize GSH or its constituent amino acids.

Animals↗

PubMed1998

Lung lining fluid antioxidants in male broilers: age-related changes under thermoneutral and cold temperature conditions.

The purpose of this study was to determine age-related changes in lung lining fluid antioxidants in broilers reared under thermoneutral or cold temperature conditions. Male broilers (Cobb 500) were placed in floor pens within environmental chambers and fed a standard commercial starter diet. The thermoneutral Control chamber was maintained at 32, 30, 27, and 22 to 25 C for Weeks 1, 2, 3, and 4 to 7, respectively, whereas temperature in the Cold chamber was lowered to 18 C during Week 3 and maintained between 15 and 18 C for the rest of the study. At 2, 4, and 7 wk, four to six birds per chamber were selected randomly. The lungs were lavaged with heparinized saline (2 mL/g lung) to obtain lung lining fluid. Antioxidants [reduced (GSH), oxidized (GSSG), and total (TGSH) glutathione, uric acid, ascorbic acid, and alpha- and gamma-tocopherol] in lung lining fluid were determined by HPLC; protein was determined colorimetrically. In Controls, levels of alpha- and -gamma-tocopherol, uric acid, and GSH in lung lining fluid decreased between 2 and 7 wk of age. Birds in the Cold chamber exhibited higher protein, a higher GSSG:TGSH ratio, and a decrease in ascorbic acid (7 wk) in lung lining fluid relative to Controls. Lung lining fluid antioxidants were not correlated with antioxidants in plasma. To determine the effect of vitamin E supplementation on lung lining fluid antioxidants, birds were given a supplement of 200 IU alpha-tocopherol per day for 7 d. Alpha-tocopherol supplementation elevated alpha-tocopherol levels in lung lining fluid, but lowered ascorbic acid, GSH, and GSSG and had no effect on uric acid in lung lining fluid. The results of this study suggest that antioxidant protection in lung lining fluid may diminish with age, that cold conditions in this study produced an oxidative stress in lung lining fluid in broilers, and that oral supplementation of alpha-tocopherol elevated lung lining fluid alpha-tocopherol.

Aging↗

PubMed1998

Antioxidant defenses in lung lining fluid of broilers: impact of poor ventilation conditions.

Lung lining fluid antioxidants represent a potentially important protective barrier of lung epithelial cells to damaging effects of air pollutants, yet no information is apparently available concerning lung lining fluid antioxidants in broilers. Therefore, goals of this study were to establish uric acid, ascorbic acid, reduced (GSH) and oxidized (GSSG) glutathione, and protein concentrations in lung lining fluid obtained from male broiler chickens maintained for 6 to 7 wk within environmentally controlled rooms (Control) or chronically exposed to high levels of dust and ammonia within a broiler rearing house (House). The entire respiratory tract was carefully removed following an overdose of anesthetic and lavage fluid was collected after flushing the lungs with heparin-saline (10 mL per lung). There was no difference in GSH, but GSSG, uric acid, and protein concentrations were higher in House birds than in Controls. An increase in the GSSG to total glutathione (GSx) ratio, an indicator of oxidative stress, was also observed in birds maintained in the House environment. Ascorbic acid was not detected in House-reared birds and detected in only 4 of 12 Controls. Regression analysis revealed positive correlations between lung lining fluid protein and uric acid (r = 0.71; P < 0.01), protein and GSSG (r = 0.73; P < 0.01), and uric acid and GSSG concentrations (r = 0.69, P < 0.01). Additionally, GSSG was positively correlated (r = 0.66; P < 0.01) with the right ventricular weight ratio, an index commonly used in identifying the development of pulmonary hypertension syndrome in broilers. These data, the first to document lung lining fluid antioxidants in avian species, indicate an oxidative stress can be detected in fluid of broilers exposed to high levels of dust and ammonia in a simulated poultry house environment.

Animals↗

PubMed1998

Effects of dietary vitamin E on the immune system in broilers: altered proportions of CD4 T cells in the thymus and spleen.

To gain insight into the immunomodulatory effects of vitamin E (VE), immune cell population analyses were conducted using thymus and spleen from male broilers fed diets with various levels of VE supplementation (0, 17, 46, and 87 mg dl-alpha-tocopherol acetate/kg of feed). At 2 and 7 wk of age, the percentages of B cells, macrophages, and T cell subsets, delineated by the expression of CD4, CD8, and T cell receptor (TCR) isotype, in thymus and spleen were determined by flow cytometry. The percentages of thymic and splenic B cells and macrophages from 2- and 7-wk-old chickens, as well as the percentage of thymic T cells in 2-wk-old chickens, were unaffected by VE treatment. However, 7-wk-old broilers maintained on 87 mg VE/kg feed had a higher percentage of CD4+CD8- thymocytes, a higher CD4+CD8- to CD4-CD8+ thymocyte ratio, and a lower percentage of CD4+CD8+ thymocytes than chickens receiving no dietary VE supplementation. The VE-induced increase in the percentage of CD4+CD8- thymocytes was due to an increase in the TCR2+CD4+CD8- thymocyte subset, whereas the decrease in the percentage of CD4+CD8+ thymocytes involved all TCR defined T cell subsets. In the spleen, the percentage of CD4+CD8- T cells was lower in 2-wk-old chickens and higher in 7-wk-old chickens maintained on 87 mg/kg feed than in chickens receiving no dietary VE supplementation. The decrease in CD4+CD8- splenocytes at 2 wk of age was due to a decline in the percentage of TCR2+CD4+CD8- splenocytes, whereas the increase in CD4+CD8- splenocytes in 7-wk-old chicks was due to an increase in the percentages of all TCR defined CD4+CD8- T cell subsets. These data support an immunomodulatory effect of VE on CD4+CD8- T cells.

Administration, Oral↗

PubMed1998

Age-related changes of plasma glutathione and cysteine in broilers: effect of dithiothreitol reduction vitro on free and bound pools.

A study was conducted to determine free and protein-bound pools of glutathione and cysteine in the plasma of male broiler chicks. Birds were brooded in battery cages and provided ad libitum access to a starter diet and water. Plasma was treated with a reducing agent, dithiothreitol (DTT), or left untreated, and analyzed by HPLC to determine free and protein bound pools of reduced (GSH) and oxidized (GSSG) glutathione, cysteine (Cys), and cystine (Cyss). With respect to total plasma pools of GSH and Cys, between 0 and 21 d of age; 1) free GSH increased from 30 to 90% with a reciprocal decrease in protein-bound GSH, but GSSG was not detected; and 2) free Cys decreased from 20 to 10%, free Cyss increased from 24 to 45%, and protein-bound Cys decreased from 55 to 44%. The majority of the GSH plasma pool in this study was present in a free, acid-soluble form, whereas most of the total Cys pool was present as Cyss or bound to protein.

Aging↗

PubMed1997

Effect of dietary dl-alpha-tocopherol on tissue alpha- and gamma-tocopherol and pulmonary hypertension syndrome (ascites) in broilers.

The objectives of this experiment were to determine the effects of high dietary levels of vitamin E on growth performance and pulmonary hypertension syndrome (PHS) mortality. Male broiler chicks (Cobb 500) were randomly assigned to one of four dietary treatments consisting of standard starter and grower diets supplemented with 0, 17, 46, and 87 mg dl-alpha-tocopherol acetate/kg. To encourage the development of PHS, air temperature in the house was 32 and 28 C for Weeks 1 and 2, dropped to 18 C during Week 3, and kept between 10 and 15 C during Weeks 4 through 7. Also, chicks were placed in floor pens on litter used for five previous flocks and ventilation reduced to increase dust and ammonia in the house. Ammonia levels increased from an initial 18 to 36 ppm on Day 42 with the increase in ammonia corresponding to an obvious increase in dust in the air. Lung and liver tissue obtained at 2, 5, and 7 wk of age were analyzed for tissue alpha- and gamma-tocopherol by liquid chromatography. Dietary vitamin E had no effect on body weight, feed intake, or feed efficiency. Cumulative PHS mortality through 7 wk of age was 21% and was also unaffected by dietary treatment. Liver and lung alpha-tocopherol concentrations exhibited a dose-response increase to dietary tocopherol and there was a high correlation between lung and liver tissue alpha-tocopherol (r = 0.72, P < 0.05). Whereas gamma-tocopherol concentrations in lung and liver were unaffected by dietary treatment, liver and lung exhibited age-dependent increases in both alpha- and gamma-tocopherol. Despite dose-dependent increases in tissue alpha-tocopherol, supplementation of diets with up to 87 mg dl-alpha-tocopherol acetate had no effect on growth performance or PHS mortality in broilers under the conditions used in this study.

Ammonia↗