Creatine kinase isoenzymes in serum of pigs having myocardial and skeletal muscle necrosis.

Serum creatine kinase (CK) and lactic dehydrogenase (LD) isoenzyme activities were measured in blood serum of pigs having myocardial damage and skeletal muscular lesions. Myocardial and muscular damage was induced by restraint stress provoked by intravenous infusion of a pharmacological restraint (succinylcholine-chloride) during 12 minutes. Pigs of Swedish Landrace and Swedish Landrace X Yorkshire breed, stress-susceptible (halothane-sensitive) and nonreacting pigs were studied. Severe myocardial damage and slight to moderate skeletal muscle necrosis were found 24 hours after restraint stress in the stress-susceptible pigs whereas in nonreacting pigs generally only myocardial lesions of moderate extent were registered. No significant increase was detected in the serum CK-BB (CK-1) or CK-MB (CK-2) activity whereas a pronounced elevation of the CK-MM (CK-3) activity was found, particularly in the stress-sensitive animals. In the myocardial tissue of pigs only a low CK-MD activity was found (about 4-5% CK-MD in addition to CK-MM) and this may explain the low CK-MB activity in serum of pigs subjected to severe myocardial damage. This is further supported by the pronounced increase in the anodal serum fractions LD 1-2 in animals free from skeletal muscular lesions. In the halothane-sensitive pigs skeletal muscle necrosis besides the myocardial lesions contributed to the high levels of CK-MM activity in serum.     

Hormone concentrations in the plasma of pigs kept under various husbandry methods]

A comparison of pigs weighing 30-50 kg reared either in groups or in individual cages showed that the management system affected the concentrations of catecholamines, 11-hydroxy corticosteroids and protein-bound iodine. Pigs kept in individual cages showed high concentrations of catecholamines and iodine, and low concentrations of corticosteroids. Pigs kept in groups showed high corticosteroids and low catecholamines and protein-bound iodine. The values for hormone concentrations in caged pigs were similar to those reported for the Poland China breed, which are not very resistant to stress produced by temperature and restraint.     

CO2-stunning of slaughter pigs: effects on EEG, catecholamines and clinical reflexes

Investigations were carried out on the response of slaughter pigs to CO2 stunning with two different gas concentrations (80 vol%, 90 vol%, 73 s) under practical conditions in a one gondola-dip-lift system. EEG measurements were performed and blood constituents such as catecholamines (adrenaline, nor-adrenaline) and lactate as well as clinical reactions (nasal septum and corneal reflex, heart beats) investigated. Special EEG-electrodes were adapted for the measurement on pigs and a mobile data logger was prepared for the use in the lairage of the slaughter house and in the stunning unit. The CO2 concentrations were measured continuously close to the head of the pigs when transported up and down in the stunning gondola. The results show that the technique is suited to monitor the effects of different CO2 gas concentrations on the EEG of the pigs under practical conditions. There is strong evidence that CO2 concentrations of 80 vol% applied over 70 s as required by law are not sufficient to stun pigs properly. A large part of the animals still showed typical reflexes when leaving the stunning pit. When an atmosphere of 90 vol% CO2 is applied, most animals are already dead before bleeding commences. This may create problems in respect to meat hygiene. The blood analysis revealed very high concentrations of catecholamines after stunning. The values for adrenaline and nor-adrenaline in the sticking blood rose by a factor of about 1000 as compared to the concentrations in blood samples taken in the lairage before stunning. It seems necessary to revise the current legislation on gas stunning and to look in greater detail in the effects of CO2 stunning on the welfare of slaughter pigs.     

The pathomorphology and pathogenesis of acute cardiovascular failure in swine. 3. Histopathologic findings in the myocardium of swine with transport-related cardiovascular insufficiency

Quantitative pathohistological investigations were performed on 300 samples of five different myocardial regions from 50 pigs with had suffered stress-related myocardial insufficiency on their transport to the slaughterhouse (transport exhaustion). The findings were compared to 1,200 myocardial samples from 200 clinically intact pigs for slaughter. Animals with transport-related damage exhibited with significance more and more severe inflammatory and degenerative myocardial alterations, such as round-cell infiltration, fiber necrosis, calcification, and fat infiltration. Many of these lesions had been manifest already prior to transport. Myocardially predamaged pigs were less capable than others of sustaining transport stress and were more predisposed to cardiac failure. Stress-related cardiovascular insufficiency, consequently, depended not only on direct stress but also on the general health condition of the myocardium. Causes and pathogenetic relevance of these alterations are discussed in some detail.     

Autonomic responsiveness in stress-sensitive and stress-resistant pigs

The responsiveness of the autonomic nervous system was studied in twenty-six 140 day old thiopentone anaesthetized lean stress-sensitive Pietrain (P) and fatter stress-resistant Gloucester (G) pigs, using the Valsalva like manoeuvre (VLM), and the i.v. tyramine, noradrenaline (NA) and phenylephrine tests. The heart rate responses to the VLM and tyramine tests were greater in P. The pressor response to NA was lower in P, and the change in heart rate per unit change in blood pressure-during phenylephrine infusion was the same in the two breeds. The sympathetic nervous system in P was, therefore, more responsive than that in G, and this was attributable to a higher pre-adrenoreceptor responsiveness in P. The potentially greater sympathetic responsiveness in stress-sensitive pigs could account for their greater leanness, their stress-induced metabolic acidosis, and for their susceptibility to myocardial failure.     

Clinical hematology of rodent species

Pet rodents, such as rats, guinea pigs, and chinchillas, differ from more traditional companion animal species in many aspects of their hematologic parameters. Animals within this order have much diversity in size, anatomy, methods of restraint, and blood collection technique. Appropriate sample collection is often the most challenging aspect of the diagnostic protocol, and inappropriate restraint may cause a stress response that interferes with blood test results. For many of these patients, sedation is required and can also affect results as well. In most cases, however, obtaining a standard database is necessary and very possible when providing medical care for this popular group of pets.     

Autonomic and non-autonomic control of cardiovascular function in stress-sensitive pigs

The T-wave characteristics, heart rate, stroke volume, cardiac output and blood pressure were examined in acidosis-prone Pietrain and acidosis-resistant Gloucester Old Spot pigs, before and after autonomic blockade with propranolol, atropine and phentolamine. Assessments were made at normal arterial blood pH and pCO2, and at either the same age or live weight in the two breeds. T-wave amplitude was influenced by alpha-adrenergic activity in the absence of beta-adrenergic and parasympathetic receptor activation. The initial cardiac output was 25% greater in the Pietrains, and 75% of this breed difference was due to autonomic factors. Myocardial chronotropic responsiveness to noradrenaline was similar in the two breeds. Initial blood pressure was greater in the Gloucester Old Spots because of a non-autonomic factor, and vasopressor responsiveness to noradrenaline was greater in the Gloucester Old Spots. Although acidosis-prone pigs may be afforded some degree of protection from a sympathetic crisis by having a low vasopressor responsiveness to adrenoreceptor stimulation, enhanced catecholamine output is the likely cause of their stress-induced myocardial lesions. A high catecholamine output may also account for the reduced body fatness in this type of pig.     

Transport stress in Southern chamois (Rupicapra pyrenaica) and its modulation by acepromazine

Chamois have been translocated for more than 100 years but their stress response to transport remains to be elucidated. In this study, 21 free-ranging Southern chamois were captured, physically restrained and then transported. The animals were randomly injected intramuscularly with acepromazine (nine adult males, one adult female and one yearling male) or saline (five adult males, two adult females and three yearling males). Heart rate and body temperature were monitored with telemetric devices, and blood samples were obtained at capture, immediately before and immediately after transport to determine haematological and serum biochemical parameters. Heart rate and blood parameters (erythrocytes, haemoglobin, packed cell volume, leukocytes, monocytes, band neutrophils, lactate, muscular enzymes and creatinine) indicated that transport was more stressful than previous physical restraint. Acepromazine reduced the adverse consequences of transport stress, as demonstrated by heart rate, body temperature, cortisol, creatinine, muscular enzymes, urea, sodium and potassium.     

Effects of acepromazine on the stress response in Southern chamois (Rupicapra pyrenaica) captured by means of drive-nets

This study was conducted to assess the stress response of Southern chamois (Rupicapra pyrenaica) to capture and physical restraint and the effects of acepromazine (a short-acting neuroleptic) on this response. Forty free-ranging Southern chamois were captured, injected intramuscularly with acepromazine (19 animals, randomly selected) or saline (the other 21 animals), and physically restrained for 3 h. Heart rate and body temperature were monitored with telemetric devices, and blood samples were obtained at capture and every hour thereafter to determine hematologic and serum biochemical parameters. The lower heart-rate variability, temperature, erythrocyte count, hemoglobin concentration, packed cell volume (PCV), and serum creatine kinase activity in the animals treated with acepromazine indicated that this agent reduced the adverse effects of stress. According to the differences in heart rate, erythrocyte count, hemoglobin concentration, PCV, lymphocyte count, and serum concentrations of glucose, creatinine, chloride, and potassium, alpha-adrenergic stimulation by catecholamines seemed to be stronger in females, whereas the adrenal-cortex reaction seemed to be stronger in males. The differences in erythrocyte parameters, temperature, serum creatine kinase activity, and serum concentrations of potassium and chloride indicated that acepromazine's beneficial effects were greater in females.     

Role of birds in transmission of classical swine fever virus

Active transmission of classical swine fever virus (CSFV) was studied in six birds (five ravens, one hooded crow) and two laying hens. Cloacal swabs, blood and organs of birds and hens as well as blood and organ samples of pigs which had been fed with faeces derived from CSFV infected birds or which had come in contact with faeces of infected hens were negative for CSFV. None of the animals seroconverted during the study. This result demonstrates that active virus transmission by these animals is unlikely. Dissemination of CSFV from wild boar to domestic pigs is discussed.     

Physiological responses to treadmill exercise and ambient temperature in normal and malignant hyperthermia susceptible pigs.

Ten susceptible and ten resistant pigs to malignant hyperthermia were used to observe the effects of exercise and ambient temperature on selected physiological parameters. Pigs were submitted to a ten minute exercise on a treadmill operating at a speed of 1.8 km/h and inclined to 11 degrees. Exercise in the first group was at an ambient temperature of 14 degrees C, and in the second at 29 degrees C. The right carotid artery was previously cannulated for blood pressure measurements and for repeated blood sampling during exercise. Arterial pressure, heart rate, rectal and cutaneous temperatures were recorded. Levels of cortisol, creatine kinase and its isoenzymes were measured. At 14 degrees C, exercise caused some physiological adjustments in susceptible animals; heart rate, skin temperature and cortisol levels increased (P less than 0.05). In resistant pigs, only the heart rate was elevated significantly following exertional stress at 14 degrees C. Exercise at 29 degrees C produced severe stress and marked physiological changes: heart rate, rectal and skin temperatures and cortisol levels increased significantly in both susceptible and resistant swine. At 29 degrees C, susceptible pigs also had higher levels of serum cortisol, total creatine kinase and MM isoenzyme (P less than 0.05) compared to resistant pigs. The results indicate that, following exertional or thermal stress, susceptible pigs undergo more extensive physiological changes than do resistant pigs. Similar levels of stress prior to slaughter may trigger physiological changes which in the susceptible pigs would likely result in pale, soft exudative myopathy.     

Gross and histopathological findings in unusual lesions caused by Streptococcus suis in pigs. I. Cardiac lesions.

Unusual lesions caused by Streptococcus suis involved the heart of 48 pigs necropsied over a four-year period. Lesions included fibrinopurulent pericarditis (six pigs), hemorrhagic, necrotizing myocarditis resembling mulberry heart disease (21 pigs), and vegetative valvular endocarditis (21 pigs). Histologically, the myocarditis was characterized by focally extensive and diffuse hemorrhages and necrosis, with infiltrations of neutrophils and mononuclear cells, and thrombosis of small and large myocardial vessels. The 21 pigs with vegetative valvular endocarditis generally were over ten weeks old and had died suddenly. The left atrioventricular valve was affected in 18 hearts. Most of an affected valve was replaced by a layer of granulation tissue covered by a mixture of fibrin, inflammatory cells, necrotic debris and large numbers of coccoid bacteria.     

Secondary effects caused by feed medication in swine

Giving medical feed to weanling pigs it is possible to produce a vitamin K-deficiency as a side effect, which is caused by destruction of the intestinal flora. In this investigation the effect of different drugs in a vitamin K-deficient diet on blood coagulation of weanling pigs was examined. In a first trial clinical symptoms of a vitamin K-dependent coagulation disorder could be seen in five from six animals after feeding a combination of sulfadimidine, tylosin, furazolidone and arsanilic acid. Animals showed haemorrhages, when they were housed on flatdecks as well as on concrete floor. This indicated that coprophagy plays no role in pigs for supply of vitamin K. Feeding these drugs in other combinations or one of the drugs alone caused no clinical signs in a second trial. Significant differences to untreated control pigs were found only in one group (sulfadimidine/arsanilic acid) for activities of coagulation factors. Other groups demonstrated only prolongation of clotting times in single animals. Pigs, which received sulfadimidine within their ration, were more often affected than other animals. In a third trial suckling pigs were treated over a period of three weeks with a drug combination used in the first trial to allow an adaptation of the intestinal flora. Same treatment after weaning was unable to produce any clinical symptoms, but led to distinct coagulation disorders in pigs treated before as well as in untreated animals. It is supposed that the development of a vitamin K-deficiency depends on faecal bacterial count and on the specific resistance of intestinal flora in individuals.(ABSTRACT TRUNCATED AT 250 WORDS)     

Porcine salivary analysis by 2-dimensional gel electrophoresis in 3 models of acute stress: A pilot study

The purpose of this research was to study changes in the salivary proteome of healthy pigs in stressful situations to identify any potential new salivary biomarker of stress. Three groups of animals were subjected to 3 stress models: snaring restraint followed by simulated sampling of vena cava blood; brief transport by road; and restriction of movement in a digestibility cage. Saliva was obtained from each animal before and 15 and 30 min after the induction of stress. The samples from the animals that showed the greatest increase in salivary cortisol concentration were pooled and run on 2-dimensional gels. Coomassie Brilliant Blue R-250 was used for spot detection and mass spectrometry for spot identification. Statistical analyses showed that 2 proteins had significant differences in expression before and after the induction of stress. These proteins were identified as odorant-binding protein and fragments of albumin. Further studies will be necessary to confirm the value of using these proteins as salivary biomarkers of stress in pigs.     

The influence of restraint immobilization stress on the concentration qf bioamines and cortisol in plasma of Pietrain and Duroc pigs

Forty-five Duroc (recognized as not susceptible to stress) and 34 Pietrain (susceptible to stress) pigs were subjected to immobilization stress in a prone position for 5, 15, 30 and 60 min. Plasma concentrations of epinephrine (E), norepinephrine (NE), dopamine (DA) and cortisol (C) were determined in response to restraint stress. The concentrations of E, NE and DA were different between the two strains of pigs (some significant interactions); the highest response was seen after 5 min of stress. The concentration of plasma C increased with duration of stress and there was a significant interaction between strain of animals and the time of stress. Our data substantiate the use of E, NE, DA and C as indicators of stress in swine as early as 5 min after exposure to the stressor. It is also shown that stress-susceptible Pietrain pigs had higher plasma concentrations of E, NE and DA than Duroc pigs.     

Plasma cortisol and norepinephrine concentrations in castrated male pigs maintained in pairs in outdoor pens and in a confinement finishing house: assessment of stress

A catheter-backpack system was developed for repeated blood collection in pigs. Castrated male pigs (n = 12) were maintained in pairs in outdoor pens and later in a slotted-floor confinement finishing house. Blood collection required no restraint and appeared to be stress free. Serum cortisol concentration was unchanged by mode of maintenance. However, diurnal variation of cortisol was more pronounced when pigs were housed. A significant decrease (P less than 0.05) in serum norepinephrine concentration occurred during the housing period.     

Diagnostic tests for Trichinella spiralis infection in pigs. A comparative study of ELISA for specific antibody and histamine release from blood cells in experimental infections.

A study on the histamine release test (HR) for the demonstration of infections with Trichinella spiralis in pigs was carried out on 18 pigs, six infected with 200 larvae, six infected with 5000 larvae and six non-infected (control group). The results obtained by HR during a 7 week infection were compared with those of the enzyme-linked immunosorbent assay (ELISA). All inoculated pigs were found to be positive on Day 40 post-inoculation (p.i.) by necropsy examination of selected muscle groups, with mean recoveries of 7.9 and 225 larvae g-1 of tissue in the low- and high-dose group, respectively. At this time, all animals of the high-dose group and five out of six animals of the low-dose group were antibody positive in ELISA with any of three coating antigens employed (a crude muscle larva extract, an excretory/secretory (ES) antigen and a purified 45 kDa antigen). HR performed on whole blood was positive in four out of six pigs of the high-dose group and one out of six pigs of the low-dose group. The earliest ELISA seroconversions took place at Day 15 p.i. with crude and ES antigens. The earliest measurable reaction in HR performed on whole blood was found on Day 19 p.i. There was considerable individual variation regarding which test was the most sensitive for the early detection of infection. Washing of the blood cells prior to antigen provocation led to a markedly improved sensitivity of HR, all animals of the high-dose and three out of six animals of the low-dose group being positive by Day 40 p.i. The time course of the development of ELISA titres and HR reactivity indicated that this effect is due to the removal of blocking antibodies.     

Preslaughter stress and muscle energy largely determine pork quality at two commercial processing plants

The objective of the present experiment was to study physiological changes elicited in response to stress in the immediate preslaughter period and to link them to pork quality characteristics. Crossbred, halothane-free pigs (n = 192) were processed in eight groups (24 pigs per group) on various days at one of two commercial processing plants operating different stunning systems (electrical and CO2 stunning in Plants A and B, respectively). In each group, half the pigs were exposed to either minimal or high preslaughter stress. Blood samples were taken at exsanguination, and lactate, cortisol, and catecholamines, as well as blood pH and temperature, were assessed and linked to various longissimus muscle quality attributes. Additionally, muscle pH and temperature were measured 30 min postmortem, and muscle glycolytic potential was determined 22 h postmortem. At both processing plants, high preslaughter stress resulted in higher (P < 0.05) blood cortisol and lactate; however, the effects of preslaughter stress on catecholamines and blood pH were believed to be biased by the different stunning methods employed at the plants. High preslaughter stress increased (P < 0.05) blood temperature at Plant A but not at Plant B. At both plants, high stress increased (P < 0.05) 30-min muscle temperature and decreased (P < 0.05) 30-min muscle pH. Ultimate pH was increased (P < 0.05) and muscle glycolytic potential was decreased (P < 0.05) by high preslaughter stress. At both plants, high stress resulted in inferior pork quality attributes (P < 0.05), including reflectance, electrical conductivity, filter paper moisture, drip loss, and L* value. The effect of stress was greater on water-holding capacity than on pork color, with drip losses increased by 56%. Of all stress indicators measured at exsanguination, only blood lactate was strongly correlated with pork quality attributes. Regression analyses revealed that blood lactate and glycolytic potential accounted for 52 and 48% of the variation in drip loss and L* value, respectively. In combination with high preslaughter stress, high glycolytic potentials were related to increased drip losses. We conclude that high preslaughter stress leads to impaired pork quality, with high muscle energy levels aggravating the negative effects of preslaughter stress. Monitoring stress level by blood lactate measurement in combination with strategies to control muscle energy present at slaughter may help to improve meat quality.     

Morphologic changes in the intestine of swine after infection with verotoxin-producing Escherichia coli

Spontaneous morphologic lesions are described in 12 of 66 pigs submitted for necropsy. All 12 pigs were culture positive for Verotoxin-producing E. coli (VTEC). 10 of them were weaned pigs, one a suckling piglet and one a fattening hog. In 6 cases E. coli serovar 0139:H1 and in one case each the serovars 0139:H40; 0138:H-; 0125ac:H27 and 0154:H- were isolated. From the fecal samples of 2 animals E. coli ONT (O-group non typable):H- were cultured. Macroscopically there were cyanosis, edema of the eye lids, catarrhal enteritis and/or colitis as well as edema of the mesentery, swelling of the mesenteric lymph nodes and congestion of the lung to varying degrees. Histopathologic examination of 5 animals was carried out. In 3 animals atrophy and edema of the villi in the jejunum and ileum were discovered. In one animal an additional infection with corona virus was confirmed electron microscopically. Furthermore there was disseminated necrosis of lymphocytes in Peyer's patches of the small intestine and in secondary follicles of the mesenteric lymph nodes. In one of the animals a hemorrhagic-necrotising ileitis, occurred characterized by necrosis of villi and thrombosis of blood vessels in the mucosa. The highest number of VTEC with seven out of twelve animals was found in weaned pigs in association with the E. coli serovar 0139.     

Sensory and processing properties of cured semimembranosus muscle from stress-susceptible pigs treated with porcine somatotropin.

Forty-eight Yorkshire cross pigs of three stress susceptibility classes (stress positive, stress-carrier, and stress negative) were injected daily with porcine somatotropin (pST; 4 mg/d) or placebo. Each pig was injected in the neck once daily until taken off test, starting when the pigs weighed 59 kg. Porcine somatotropin treatment was terminated at weekly intervals as individual pigs reached 109 kg, but animals continued to be fed for six additional days to allow for required withdrawal time. The effect of pST and stress classification on the sensory, physical, chemical, and processing characteristics of cured semimembranosus (SM) muscle was evaluated. Treatment of animals with pST had no effect on the sensory scores, lipid and protein content, cooking yields, or color values of SM muscle slices. Semimembranosus muscles from stress-positive animals, however, had reduced sensory scores for texture, flavor, and overall palatability. Semimembranosus muscles from stress-positive pigs also had smaller cooking yields and greater Hunter a and b values of processed slices. The greater Hunter a and b values suggested that the color of these slices were redder and yellower than the color of SM muscle slices from negative and carrier animals. Semimembranosus muscles from stress-susceptible animals also had a significantly lower lipid content. Treatment of animals with pST did not significantly alter sensory, chemical, or processing characteristics of SM muscle slices from these animals.