Endotoxin and Arachidonic Acid Metabolites in Portal,Hepatic and Arterial Blood of Cattle with Acute Ruminai Acidosis

Andersen, P. Haubro, M. Hesselholt and N. Jarlev: Endotoxin and arachidonic acid metabolites in portal, hepatic and arterial blood of cattle with acute ruminai acidosis. Acta vet.scand.1994,35,223-234.– Ruminai acidosis was induced experimentally with 70 g barley / kg body weight in 2 rumen fistulated cows with chronic indwelling catheters in the portal vein, in a hepatic vein and the carotid artery. The cows were followed for 24 and 20h after the overfeeding and evaluated clinically and by clinical chemistry. The 2 cows exerted different responses to the treatment. Both cows showed signs of severe ruminai acidosis. Both cows had endotoxin in portal and hepatic vein blood, but only 1 of the cows convincingly developed a systemic endotoxaemia. A pre-hepatic release of the stable prostacyclin and thromboxane metabolites, 6-ketoprostaglandin F_lα and thromboxane B₂ was demonstrated in this cow. The results of the present study show that endotoxin and arachidonic acid metabolites of pre-hepatic origin may be factors involved in the pathogenesis of ruminai acidosis, and that investigation of the factors affecting translocation of ruminai endotoxin and subsequent clearing in the liver, will be of importance.     

Effects of Endotoxin Contaminated FSH-preparations in Heifers

Superovulation is one important step in embryo transfer. By administration of gonadotropins a multiple ovulation is induced. Several FSH-preparations for superovulation are commercially available. Most of these consist of extracts from pituitary glands from slaughtered farm animals. According to some studies (Yagoda et al. 1990a,b), drugs can easily be contaminated with endotoxins. Endotoxins are commonly found in the environment, for example in water and silage, and in medical preparations (Yagoda et al. 1990b). Endotoxins can have several effects on animals and on human beings. They can cause endotoxaemia with effects like fever, ruminai stasis, release of prostaglandins, leukopenia and decrease of the plasma levels of calcium, zinc, iron and bile acids (Aiumlamai 1991). The severity and range of the effects caused by endotoxin are very dose-dependent. Animals receiving a low dose of endotoxin may not show the clinical signs of endotoxaemia, but can still have subclinical changes like leukopenia, prostaglandin release, mild hypocalcaemia and decreases in the plasma levels of zinc and iron (Yagoda et al. 1990b, Kindahl & Aiumlamai 1991). For humans, 5 EU/kg bodyweight is considered to be the threshold dose for appearance of clinical effects. (Anon. 1987).     

Isolation of Ascaris Suum Eggs for Experimental Purposes

Eggs from the pig roundworm Ascaris suum are easily obtainable in large numbers from uterus of adult worms. It is therefore natural that eggs isolated from that organ have been used almost exclusively in experimental ascariasis, both in the natural host (Kelley & Nayak 1965, Gaafar & Keittevuti 1972, Andersen et al. 1973, Jørgensen et al. 1975 and others) and in small laboratory animals (Jeska et al. 1969, Berger 1971 and others). In some cases no details are given on the origin and preparation of the infective eggs or the eggs may originate both from uteri of adult worms and from pig faeces (Kelley et al. 1957).     

Investigation of the possible role of endotoxin, TXA2, PGI2 and PGE2 in experimentally induced rumen acidosis in cattle

Rumen acidosis was induced experimentally with 70 g barley/kg b.w. in 2 rumen fistulated cows. The cows were followed for 80 h after the grain engorgement. Endotoxin was monitored in cell-free ruminal fluid and peripheral plasma together with inflammation mediators TXA2, PGI2 and PGE2 and several clinical and clinical-chemical parameters. The results do not support the theory of systemical endotoxemia due to a large increase in rumen endotoxin concentration in cattle suffering from rumen acidosis. However, both clinical and clinical-chemical data suggest that an endotoxicosis developed, but the levels of inflammation mediators TXB2, FGI2 and PGE2 were not significantly elevated in the peripheral circulation. An absorbtion of endotoxins and synthesis of inflammation mediators are therefore suggested to take place prehepatically.     

Equine endotoxemia: cardiovascular, eicosanoid, hematologic, blood chemical, and plasma enzyme alterations

Ponies with electromagnetic blood flow transducers implanted around the main pulmonary and left main coronary arteries, were used to evaluate effects of chronic sublethal endotoxin on cardiac output (CO), stroke volume, and left coronary blood flow (LCBF). Plasma thromboxane (TX), as indicated by TXB2, prostacyclin as indicated by 6-keto-prostaglandin (PG) F1 alpha, and hematologic and blood chemical values also were evaluated. Over 24 hours, 2 groups of ponies were given progressively increasing IV and intraperitoneal doses of Escherichia coli lipopolysaccharide (LPS) at 0, 6, 12, and 18 hours. Group 1 was not treated and group 2 was treated with flunixin meglumine, before each LPS insult. Initial LPS inoculation in group 1 led to 10-fold increases in TXB2 and 6-keto-PGF1 alpha values by 30 and 90 minutes, respectively. These eicosanoid values returned to base line by 6 hours after each insult. Although repeated LPS injections stimulated recurring high plasma concentrations of 6-keto-PGF1 alpha, TXB2 production became less with each successive LPS insult. Cardiac output decreased to 55% to 60% of base-line values in association with increased 6-keto-PGF1 alpha values. Left coronary blood flow could not be evaluated accurately. Severe lactic acidosis developed in group 1. Group-2 ponies remained clinically normal, indicating protection of cardiovascular function and peripheral perfusion with flunixin meglumine. Seemingly, flunixin meglumine helped to maintain acceptable cardiovascular function and tissue perfusion during endotoxemia. Flunixin meglumine given to healthy ponies had no effect on cardiovascular function.(ABSTRACT TRUNCATED AT 250 WORDS)     

The generalized Shwartzman reaction induced by a single injection of endotoxin in pigs fed 2 vitamin E deficient commercial diet.

An experimental generalized Shwartzman reaction (GSR) induced in pigs by endotoxin from Escherichia coli has been reported previously (Teige et al. 1973, Quast 1973). The diet given to the pigs seemed to influence the outcome of the experiments. It has been found difficult to provoke GSR in pigs fed a commercial diet, even when the E. coli endotoxin is given as a single, relatively large dose or as 2 properly spaced doses (Teige et al., Nordstoga 1976). Quast induced the GSR by continuous infusion of endotoxin. In connection with 1 experiment in pigs, changes indicative of GSR were observed among a group of animals fed a commercial diet and receiving a small single dose of endotoxin. These observations are presented in this paper.     

Bovine Abortions Associated with Neospora in Denmark

During recent years protozoa of the Neospora genus have been identified as a major cause of bovine abortions world wide (Barr et al. 1991, Mcintosh & Haines 1994, Thornton et al. 1991, Yaeger et al. 1994). A presumptive diagnosis of Neospora abortion can be made on the foetal histopathology as infected foetuses have a distinctive pattern of multifocal necrotizing and non-suppurative encephalitis often with an accompanying nonsuppurative myocarditis and a varying degree of focal inflammation in other organs (Barr et al. 1990, Thornton et al. 1991). However, confirming the diagnosis of Neospora abortion requires detection of protozoa in foetal tissues that react positively by immunohistochemistry with Neospora specific antisera (Barr et al. 1990, 1991).     

奶牛静脉血内毒素浓度及其与产奶量的相关性

为调查我国当前主流饲喂方式下奶牛静脉血内毒素浓度的范围及内毒素浓度与产奶量的相关性,本试验首先验证了应用鲎试剂法定量奶牛静脉血中内毒素浓度的可行性,在此基础上,分别检测了安徽牧场 １（６０头,饲粮精粗比 ４５∶５５）、江苏牧场（１５头,按产奶量高低精粗比分别为 ２０∶８０、４５∶５５、５０∶５０）和安徽牧场 ２（１４头,饲粮精粗比 ７０∶３０）共 ８９头奶牛的尾静脉血中内毒素浓度,并进行了内毒素浓度与产奶量的相关性分析。结果表明：鲎试剂法可有效检测奶牛静脉血中内毒素浓度,３个牧场奶牛静脉血中内毒素浓度高低不等,在 ０～１．５０ＥＵ／ｍＬ范围内。奶牛静脉血中内毒素浓度与产奶量之间的相关性皆不显著（Ｐ＞０．０５）,但安徽牧场 ２的相关系数（０．１９５２）大于安徽牧场 １（０．０２０５）和江苏牧场（０．０３７６）。结果提示,鲎试剂法可用于定量检测奶牛血中内毒素浓度,在我国当前的饲喂方式下,奶牛血液中普遍含有内毒素,静脉血内毒素浓度与产奶量无显著相关性。     

Comparison of blood glucose concentrations after administration of a glucose solution via the jugular vein and portal vein in cows

The goals of the present study were to determine whether the infusion of a glucose solution into the portal vein is tolerated in cows and whether the glucose concentration differs after administration of glucose into the jugular vein and portal vein. Fifteen healthy Swiss Braunvieh cows were used. An indwelling catheter was placed in both jugular veins and a balloon-tipped indwelling catheter with a diameter of 2 mm was placed in the portal vein under the guidance of ultrasonography. Three cows received 500 ml of 20% glucose solution over 60 min via the left jugular vein. Three other cows received the same solution over 60 min via the portal vein. Blood samples were collected from the right jugular vein before and for 24 h after the infusion of glucose for the determination of the concentrations of glucose and bilirubin and the activities of glutamate dehydrogenase, sorbitol dehydrogenase and gamma-glutamyl transferase. Infusion via the portal vein did not result in abnormalities in the general condition of the cows or increases in the concentration of bilirubin or the activities of liver enzymes. The blood glucose concentration increased to the same extent after both intraportal and intrajugular infusion. Over a 12-h period, three cows received 10 l of 20% glucose solution via the left jugular vein and three others received the same solution over a 12-h period via the portal vein. Blood samples were collected from the right jugular vein before and for 30 h after the start of infusion. Infusion via the portal vein did not affect the general condition of the cows or the activities of the liver enzymes. There was no significant difference in the blood glucose concentration between the two groups throughout the study.     

Thromboxane and prostacyclin production in ponies with colonic volvulus.

Effects of 1 hour of colonic volvulus and 3 hours of reperfusion on concentrations of thromboxane (TXB2) and prostacyclin (6-keto-PGF1 alpha) in portal, pulmonary arterial, and jugular blood were determined by radioimmunoassay to assess the site of production and clearance of these eicosanoids from the circulation in 5 anesthetized ponies. Colonic volvulus had no significant effect on mean arterial pressure or TXB2 concentrations, but significantly (P less than 0.05) increased 6-keto-PGF1 alpha concentrations in all blood samples. Immediately after colonic reperfusion, all eicosanoid concentrations were significantly (P less than 0.05) increased. Then, TXB2 returned to baseline values, whereas 6-keto-PGF1 alpha concentrations remained significantly (P less than 0.05) high for the remainder of the study. Eicosanoid concentrations were significantly (P less than 0.05) greater in portal blood than in pulmonary arterial and jugular blood samples at all periods. This suggests that the splanchnic circulation is the primary site of eicosanoid production during and after colonic volvulus and the liver appears to provide most of the circulatory clearance of thromboxane and prostacyclin.     

Gene expression in different tissues of lactating cows of differing metabolic type: 1. Comparison of mRNA patterns by the differential display method

Among other factors the nutrient utilization of a cow is influenced by its individual physiological and genetic predisposition. There are large differences within cows in the manner of partition of the nutrients that may affect the size and activity of the individual organs and the whole body composition. High genetic merit dairy cows have a higher potential rate of protein excretion than medium genetic merit dairy cows even when energy and protein intake are equal. Medium genetic merit dairy cows show higher potential rates of protein and fat deposition of the body. This phenomenon was partly explained by the regulatory functions of the hormone insulin (see Brockman and Laarveld 1986; Broucek et al. 1991; Wylie et al. 1998). Additionally, it is widely considered that the somatotropic axis [growth hormone, growth hormone releasing factor and insulin-like growth factor I (IGF-I)], could be involved, as one of the key control and balance mechanisms which regulate the partition of nutrients (Breier and Sauerwein 1995; Schams 1995; Knight 1997). Several studies have provided insights into the physiological action of these and further hormones, transport proteins and enzymes, e.g. the erythrocyte-type glucose transporter, the insulin-responsive glucose transporter or the glycerol-3-phosphate dehydrogenase, and indicate that these molecules may affect nutrient repartitioning and utilization as well as milk yield, growth and fat accumulation (Mathews et al. 1988; Bauman and Vernon 1993; Burton et al. 1994; Girard et al. 1994; Binelli et al. 1995; Zhao et al. 1996; Abe et al. 1997). However, the mechanisms of regulation of most of these processes are insufficiently known. This paper presents a comparison of mRNA patterns of tissues potentially associated with protein and energy turnover in lactating cows of different metabolic types. The technique of differential display of messenger RNA species originally described by Liang and Pardee (1992), has already been applied as a powerful tool for cloning genes that are differentially expressed in various tissues or under altered conditions in the same tissue (e.g. Liang et al. 1993; Aiello et al. 1994; Li et al. 1994; Nishio et al. 1994). This method was applied to characterize the expression patterns in 12 tissues of three cows with divergent metabolic types (milk type, meat/milk type, and meat type) by the display of differentially and identically expressed cDNA bands. The aims of this exploratory study were first to indicate which of the 12 tissues analysed are mainly involved in trait differentiation according to their differentially displayed mRNA patterns. Secondly, the results of this study represent the prerequisite for the identification of tissue-specific expressed sequence tags in general, and individual or type-dependent differentially expressed sequence tags in particular.     

Feed-induced Changes in the Transport of Butyrate,Sodium and Chloride Ions Across the Isolated Bovine Rumen Epithelium

A short-chain fatty acid (SCFA) burst feeding strategy to dry cows (periodically high SCFA concentration in the ruminal fluid) has been hypothesized to increase the ruminal surface area and absorptive capacity. The present paper deals with the effects of a SCFA burst feeding strategy on epithelial transport function in dry cows. The epithelial transport capacity for [¹⁴C]butyrate and Na⁺ across the rumen epithelium in vitro was significantly increased by the SCFA burst feeding strategy, compared with the controls. The transport of Cl^- was significantly increased by the SCFA burst feeding strategy at the high feeding level, but non-significantly decreased at the low feeding level. The increase in transport capacity could not be attributed to changes in epithelial resistance, to the concentration of Na⁺/K⁺-ATP-ase or to the epithelial surface area and structure (data on epithelial surface area and structure were published by Andersen et al., Report No. 23 from the National Institute of Animal Science, Denmark, 1994). The observed changes in transport must reflect a change in either composition of the cell membranes or processes that facilitate transport through the cell, including metabolic processes. The presented results support the existence of a saturable SCFA transport system in the epithelial cells and the results show that the capacity of this transport system can be the subject for feed-induced regulation.     

A Case of Neospora Associated Bovine Abortion in Sweden

Neospora caninum is a recently recognized protozoan organism that causes fatal neuromuscular disease in dogs and abortions and stillbirths in cattle and other animals (Dubey & Lindsay 1993). The parasite is morphologically similar and phylogenetically very closely related to the cyst-forming coccidium Toxoplasma gondii (Ellis et al. 1994, Holmdahl et al. 1994). This group of parasites has a two-host life cycle principally involving a carnivorous definitive host and a herbivorous or omnivorous intermediate host. However, with N. caninum, there is as yet no knowledge of any definitive host harbouring sexual stages of the parasite. The only known route of transmission is vertical from mother to foetus (Dubey & Lindsay 1993).     

Perchloric acid treatment and use of chromogenic substrate in the Limulus test: Application to veterinary diagnosis

The Limulus test was carried out for endotoxin determination using a synthetic chromogenic substrate after perchloric acid(PCA) treatment to remove inhibiting substances in the blood.PCA treatment completely removed non-specific amidolytic activity and other factors which interfered with the Limulus test. The recovery of added endotoxin was about 100% irrespective of animal species.Endotoxin levels in PCA-treated blood plasma of healthy domestic animals were invariably below 1 pg ml^?1.Many of the cows with gangrenous mastitis, from which Gram-negative rods were isolated, showed high endotoxin levels ranging from 22.8 to 138.0 pg ml^?1. Endotoxin was also detected in the blood of cows affected with salmonellosis, colibacillosis, Haemophilus somnus infection and urethritis associated with Proteus.     

Effect of amount and degradability of dietary starch on animal performance and meat quality in beef bulls

Introduction   Even at a similar energy concentration of the diet, energy source may affect animal performance. O wens et al. (1997) reported that daily dry matter (DM) intake tended to be lowest for wheat-based diets and highest for milo and oat-based diets. O'M ara et al. (1997) found a lower pH and less ammonia in the rumen of lactating cows, when unmolassed beet pulp was replaced with ground wheat. Contrary to the results of O'M ara et al. (1997), M alestein et al. (1984) found a greater risk for lactic acidosis for citrus and beet pulp than for maize meal and tapioca. For years it has been known that rapidly degradable carbohydrates may provoke acidosis (H untington and B ritton 1979; F iems et al. 1993). Furthermore, low ruminal pH may inhibit cellulose digestion (M ould et al. 1983) and decrease efficiency of microbial protein synthesis (R ussell et al. 1979).
As energy concentration of the diet is important for finishing cattle (B oucqu & eacute ; et al. 1980), the amount of roughage is rather limited. This may result in sub-clinical acidosis with a negative impact on animal performance (O wens et al. 1998), especially when the diet is rich in rapidly fermentable carbohydrates. Therefore an experiment was conducted to investigate the impact of energy source in the finishing diet on voluntary daily feed intake, daily liveweight gain, feed efficiency, blood metabolites and carcass quality.
Energy source may also affect meat quality. C asteels et al. (1969) found differences in meat colour when concentrates were based on cereals or sugarbeet pulp. W ood (1984) reported that the concentrate : forage ratio in the diet affects the fatty acid composition of body fat through an increase in propionate production in the rumen. Therefore the effect on meat quality was also studied.     

Prevalence of Antibodies to Neospora caninum and Toxoplasma gondii in Swedish Dogs

Neospora caninum is a newly described coccidian parasite which has been found in various species such as the dog, cattle, horse, sheep and goat. Morphologically it resembles Toxoplasma gondii with which it is related (Holmdahl et al. 1994), and with which it has earlier been confused. The life cycle of N caninum is only partially known. Tachyzoites and tissue cysts are the only known stages of the parasite, and transplacental transmission is the only known route of infection. Subclini-cally infected dams can transmit the parasite to their fetuses and successive offspring from the same mother might be born infected (Dubey et al. 1990b). Clinical neosporosis is mostly seen in pups or young dogs, and the majority or all pups in a litter are often affected. The disease is characterized by ascending paralysis of the legs, with the hind legs more severely affected than the front legs, paralysis of the jaw, difficulty in swallowing and muscle flaccidity and atrophy (Dubey 1992, Dubey & Lindsay 1993). Fatal infections with N caninum in dogs have been reported from many countries, e.g. Norway (Bjerkäs & Presthus 1988), USA (Dubey et al. 1988), Sweden (Uggla et al. 1989a,b) and the United Kingdom (Dubey et al. 1990a). Serological surveys for antibodies to N. caninum in dogs from Kansas, USA and England have shown a prevalence of 2 and 13%, respectively (Lindsay et al. 1990, Trees et al. 1993).     

Pathophysiology of experimental bovine endotoxicosis: endotoxin induced synthesis of prostaglandins and thromboxane and the modulatory effect of some non-steroidal anti-inflammatory drugs.

Endotoxin-induced synthesis of thromboxane A2 (TXA2), prostacyclin (PGI2) and prostaglandin E2 (PGE2) was studied in 3 cows after intravenous E. coli endotoxin (055:B5-0.025 mg/kg b.w.) administration. Blood sampling and monitoring of clinical signs were performed from 2 h prior to until 6 h after endotoxin challenge. Blood samples were analyzed for stable hydrolysis products of TXA2 (TXB2), PGI2 (6-keto PGF) and PGE2 (bicyclic PGE2), biochemical and haematological parameters. In a similar experimental design the efficacy of the non-steroidal anti-inflammatory drugs (NSAID) flunixin meglumine (FM) and phenylbutazone (PB) in suppressing eicosanoid synthesis and clinical signs in response to endotoxin challenge was investigated. Two groups of cows, each comprising 2 animals, were treated with FM and PB prior to endotoxin challenge. It was observed that plasma concentrations of TXB2, 6-keto PGF and bicyclic PGE2 increased rapidly after endotoxin challenge. Concentrations were significantly elevated for hours and were correlated to the severity of clinical signs of endotoxicosis. Pretreatment with NSAID suppressed mediator production and alleviated clinical signs. The experiments suggest a certain pathophysiological role of TXA2, PGI2 and PGE2 for the early systemic ill-effects of bovine endotoxicosis.     

胃肠道脂多糖对奶牛健康及生产性能的影响及其防治措施

脂多糖是革兰氏阴性细菌细胞外膜的主要组成成分,奶牛饲粮中精料比例过高或有效中性洗涤纤维含量过低均会显著增加胃肠道脂多糖含量。脂多糖可与pH等胃肠道环境因素共同作用,损伤胃肠道上皮,一旦胃肠道上皮受损,脂多糖便会易位进入机体外周循环系统,导致奶牛机体发生一系列免疫代谢反应,进而影响奶牛健康及生产性能。本文从脂多糖的结构及来源、胃肠道脂多糖对奶牛健康及生产性能的影响及其缓解方法方面进行综述,以期为现代化奶牛生产中保障奶牛健康、提高奶牛生产性能提供理论依据。     

Effect of heat stress on endotoxin flux across mesenteric-drained and portal-drained viscera of dairy goat

This study was designed to evaluate the effect of heat stress on endotoxin flux across mesenteric-drained and portal-drained viscera of dairy goats. Three Saanen first lactation dairy goats were surgically fitted with indwelling catheters in the portal vein, the mesenteric vein and carotid, and were kept in thermal-neutral and then heat stress environment, for examining the effect of heat stress on endotoxin absorption and redox status. Average net absorption of endotoxin (EU/h) across mesenteric-drained viscera (MDV) and portal-drained viscera (PDV) during the whole period of heat stress increased by 279.05% and 227.92% in relation to thermo-neutral period. Plasma concentration of glutathione peroxidase (GSH-Px) and catalase (CAT) in mesenteric and portal vein, and that of superoxide dismutase (SOD) in mesenteric vein, increased significantly during heat stress. Main conclusions were: (i) net absorption of endotoxin in portal vein is mainly from non-mesenteric tissues both in heat stress and in thermo-neutral condition; (ii) heat stress may lead to the significant decrease in plasma SOD, GSH-Px, CAT flux across PDV and MDV, and the significant increase in endotoxin flux across PDV and MDV; and (iii) the increase in gastrointestinal permeability in dairy goats during heat stress may not be induced by the increase in oxidative stress.     

Studies with Radioactive Endotoxin II. Clearance of 3H-Labelled Endotoxin from the Blood of Calves

The clearance of ³H-labelled Pseudomonas endotoxin from the blood was studied in a nontolerant and in an endotoxin tolerant state. Calves were rendered tolerant to the toxic effects of the endotoxin by four daily intravenous injections of endotoxin at the dose rate of 5 µg/kg body weight.

Clearance of ³H-endotoxin from the blood of nontolerant calves occurred more slowly than did clearance of ⁵¹Cr-endotoxin and was not significantly (P<0.05) affected by the development of tolerance. The lungs and liver were the major organs involved in the clearance of ³H-endotoxin from the blood of calves. Leukocytes and erythrocytes, but not platelets, were shown to participate in endotoxin clearance in calves. ³H₂O, the control substance used in calves, was not concentrated within any particular organ but rapidly equilibrated with total body water and was slowly excreted.