Acute phase response in horses: changes in plasma cation concentrations after localised tissue injury

An acute phase reaction was elicited in four horses to which Freund's adjuvant was administered intramuscularly. The localised inflammation was accompanied by changes in the plasma concentrations of copper, iron and zinc. The plasma copper concentration, the plasma ceruloplasmin copper concentration and the ceruloplasmin oxidase activity in the plasma steadily increased to a maximum 24 days after the administration of the adjuvant. At this time, the plasma copper concentration was 2.2 micrograms/ml, a 90 per cent increase over the baseline concentration. The ratio of the concentration of plasma ceruloplasmin copper to plasma copper remained constant, indicating that the non-ceruloplasmin bound copper component of the plasma is also an acute phase reactant in the horse. The plasma zinc and iron concentrations decreased to 59 per cent and 30 per cent of their respective baseline concentrations and the severity of the inflammation appeared to influence the plasma concentrations of each metal. Weak correlations between the plasma fibrinogen concentration and the plasma copper and zinc concentrations of 25 horses with plasma fibrinogen concentrations of 5 g/litre or greater indicated that a single measurement of plasma copper concentration is not useful in the diagnosis of non-specific inflammatory disorders of the horse. However, the results suggest that the plasma copper concentrations in serial samples may be used to monitor the resolution of inflammatory disorders in the horse.     

Two major ruminant acute phase proteins,haptoglobin and serum amyloid A,as serum biomarkers during active sheep scab infestation

Two ruminant acute phase proteins (APPs), haptoglobin (Hp) and serum amyloid A (SAA), were evaluated as serum biomarkers (BMs) for sheep scab–a highly contagious ectoparasitic disease caused by the mite Psoroptes ovis, which is a major welfare and production threat worldwide. The levels of both APPs increased in serum following experimental infestation of sheep with P. ovis, becoming statistically significantly elevated from pre-infestation levels at 4 weeks post-infestation. Following successful treatment of infested sheep with an endectocide, Hp and SAA serum levels declined rapidly, with half lives of less than 3 days. In contrast, serum IgG levels which specifically bound the P. ovis-derived diagnostic antigen Pso o 2 had a half-life of 56 days. Taking into account pre-infestation serum levels, rapidity of response to infestation and test sensitivity at the estimated optimum cut-off values, SAA was the more discriminatory marker. These studies illustrated the potential of SAA and Hp to indicate current sheep scab infestation status and to augment the existing Pso o 2 serological assay to give disease-specific indications of both infestation and successful treatment.     

Acute phase protein response, food intake, liveweight change and lesions following intrathoracic injection of yeast in sheep

Acute phase protein concentrations in blood, food intake and liveweight changes were compared in 10 sheep given intrathoracic injections of yeast and 10 control sheep over a period of 61 days. The yeast injections caused acute pleuritis and limited necrotising lung lesions which progressed to fibrous pleural adhesions and walled-off abscesses. The responses of ceruloplasmin, fibrinogen and haptoglobin were closely correlated (r = 0·87 to 0·91) in the yeast-injected sheep with peaks on days 5 or 7 after treatment (4, 4·6 and over 130 times control, respectively). Albumin concentration fell to a nadir of 89 per cent of control on day 12 after treatment. Depression of food intake was temporally related to the ‘positive’ acute phase protein responses with a nadir on day 5 after treatment (30 per cent of control). Liveweight showed a pronounced fall to five days after treatment and thereafter remained depressed relative to the controls for most of the experimental period. The data suggest that the ‘positive’ acute phase proteins may be useful indicators of production losses due to inflammatory diseases in sheep.     

Changes in the concentrations of bile acids in the plasma of sheep with liver damage

The concentration of total plasma bile acids was measured in normal sheep and in sheep in which liver damage was induced by chronic copper poisoning, ligated bile ducts or induced ketosis. All three treatments produced a rise in total bile acid concentration in plasma which was proportional to the degree of hepatic damage seen histologically and which tended to parallel changes in activity of iditol, and glutamate dehydrogenase and aspartate amino-transferase in plasma. Plasma bile acid concentration was a more sensitive method of detecting these types of liver damage than was the measurement of total plasma bilirubin concentration, and could be used to assess alterations in liver function in sheep.     

Association between major histocompatibility complex microsatellites, fecal egg count, blood packed cell volume and blood eosinophilia in Pelibuey sheep infected with Haemonchus contortus

The objective of this study was to assess the correlation among traits associated with resistance or susceptibility to Haemonchus contortus infestation and to evaluate the participation of the ovine major histocompatibility complex (MHC) in Pelibuey sheep, a prevalent breed in tropical and sub-tropical regions in Mexico and elsewhere. Association among the fecal egg count (FEC), blood packed cell volume (PCV), antibody (AB) levels, serum proteins (SP) and blood eosinophil count (EOS) was assessed in 52 lambs experimentally infected with H. contortus, and the participation of the MHC was evaluated using polymorphisms in three microsatellites, located at the class I (OMHC1) and class II (OLADRB1, OLADRB2) regions of the MHC. Spearman correlation analysis among the traits showed a negative association (P<0.01) between FEC and PCV (-0.35), EOS (-0.50), SP (-0.30) and AB (-0.57), and a positive correlation of antibodies with EOS (0.50). The homozygotes for the OMHC1-188 and OLADRB2-282 alleles were associated with a reduction in FEC (-813 and -551, respectively). Conversely, the OMHC1-200 and OMHC1-206 alleles were associated with an increase in FEC (1704 and 1008, respectively). Furthermore, the OLADRB1-482 allele was associated with an increase of 163 EOS by allele copy, while the OMHC1-200 allele showed a reduction of 95 EOS in homozygotes. The associations among microsatellite MHC loci and the remaining variables were not significant. These results reinforce the evidence that MHC polymorphisms have an important role in parasite resistance or susceptibility in Pelibuey sheep and could be used as genetic markers to assist selection and improve parasite resistance to H. contortus.     

Acute monensin toxicosis in sheep: light and electron microscopic changes

Monensin was administered orally to 3 sheep at dosages of 12 (the LD50), 16, and 24 mg/kg of body weight, respectively. Clinical signs of monensin toxicosis were observed in the sheep in 24 to 36 hours of administration. Clinical signs included CNS depression, anorexia, diarrhea, and stiffness. Increased serum creatine phosphokinase and aspartate aminotransferase activities identified possible muscle damage. Sheep were euthanatized at 54 hours after dosing; at necropsy, there were skeletal muscle hemorrhages, pale myocardium, and pulmonary edema. Ultrastructural lesions were in the liver, diaphragm, and myocardium; diaphragm and myocardium were most severely affected. Mitochondrial swelling and cristolysis, swollen sarcoplasmic reticulum, and disruption of myofibrillar architecture were prominent. These ultrastructural changes are consistent with the hypothesis that monensin causes muscle cell necrosis due to its ionophorous properties and disruption of cellular Na+:Ca2+ balance. It is proposed that this upset of normal ionic processes allows increased intracellular calcium, which directly leads to the functional and structural mitochondrial changes observed.     

Acute phase response and mastitis in the cow

The levels of three plasma proteins, which are classed as acute phase reactants, were compared in a group of cows which suffered from mastitis with those in a group of cows which were clinically normal. The plasma levels of haptoglobin, ceruloplasmin and alpha 1 antitrypsin were higher in the cows with mastitis than in normal cows.     

Temporal changes in concentrations of serum amyloid-A and haptoglobin and their associations with weight gain in neonatal reindeer calves

Age-related changes in serum concentrations of two acute phase proteins (APPs), haptoglobin (Hp) and serum amyloid-A (SAA) were investigated in newborn reindeer calves. Repeated blood samples were obtained from 51 reindeer calves at ages 0-32 days (2-4 samples from each calf). An increase of SAA concentrations was observed during the first 2 weeks of life. However, by the end of the observation period, SAA concentrations had decreased to levels below those of the first week. Serum Hp concentrations increased throughout the observation period. SAA concentrations in the second week had a negative association with weight gain during the entire study period (4 months). These time-related changes in APP concentrations suggest that these proteins have a role in the defence and adaptation mechanisms of newborn reindeer calves. Possible reasons for these changes include the presence of APP mediators in the colostrum, exposure to environmental pathogens after birth and age-related changes in hepatic synthesis of APP.     

Changes in blood glucose concentration are associated with relatively rapid changes in circulating fructosamine concentrations in cats

The aim of the study was to determine the time required for plasma fructosamine concentration to increase after the onset of hyperglycaemia and decrease after resolution of hyperglycaemia. Healthy cats (n=14) were infused to maintain either moderate hyperglycaemia (n=5) (actual mean glucose 17 mmol/l) or marked hyperglycaemia (n=9) (actual 29 mmol/l) for 42 days. Fructosamine exceeded the upper limit of the reference range (331 micromol/l) after 3-5 days of marked hyperglycaemia, took 20 days to plateau and, after cessation of infusion, took 5 days to return to baseline. Fructosamine concentration for moderate hyperglycaemia took longer to exceed the reference range (7 days, range 4-14 days), and fewer days to plateau (8 days) and return to baseline (1 day). In cats with moderate hyperglycaemia, fructosamine concentration mostly fluctuated under the upper limit of the reference range. The range of fructosamine concentrations associated with a given glucose concentration was wide. The critical difference for fructosamine was 33 micromol/l.     

Influence of dietary ss-glucan on growth performance, lymphocyte proliferation, specific immune response and haptoglobin plasma concentrations in pigs

Immunomodulatory feed additives might offer alternatives to anti-microbial growth promoters in swine production. The present study was conducted to assess the effects of beta-1,3/1,6 glucans, i.e. of specific yeast cell wall components, on immune function and growth performance in pigs. After weaning at 4 weeks of age, 75 piglets were allocated to 3 different groups for 4 weeks, the diet was supplemented with 0, 0.015 or 0.03% of beta-glucan, respectively. All animals were vaccinated against porcine reproductive and respiratory syndrome (PRRS). After 4 weeks, average daily gains (ADG) of beta-glucan treated pigs were not different from the controls. Feed intake was tendentiously (p < 0.1) increased at 0.03%beta-glucan, without alteration of feed efficiency. Serum haptoglobin concentrations at the end of the 4 week treatment were increased in all groups when compared to the initial levels (p < 0.001), without differences between the groups (p > 0.05). Haptoglobin levels were inversely related to ADG. Lymphocyte proliferation indices were not different in control and treatment groups. Specific vaccination responses, as quantified by the PRRS antibody titres occurred in all animals, but no relation with beta-glucan feeding was observed. Our results indicate marginal benefits of beta-glucan supplements for growth performance and no effect on the immune parameters tested. The observed trend towards increased feed intake needs further elucidation.     

Immunomorphologic and morphometric changes in pulmonary lymph nodes of sheep with progressive pneumonia

Morphologic, immunohistochemical, and morphometric studies were conducted on the posterior mediastinal lymph nodes of eleven sheep with naturally occurring ovine progressive pneumonia and four apparently healthy sheep with no pulmonary lesions (three seropositive, one seronegative for antibody to ovine progressive pneumonia virus). Compared with lesion-free sheep, sheep with ovine progressive pneumonia had a seven-fold increase in B lymphocyte areas and a 21/2-fold increase in T lymphocyte areas of these lymph nodes. Immunochemistry revealed cytoplasmic immunoglobulin G in scattered cells of germinal centers, medullary cords and interfollicular areas and membrane-associated immunoglobulin G in dendritic cells of germinal centers. Immunoglobulin M staining cells were widely scattered in germinal centers and medullary cords. Although B cell hyperplasia seemed to be the predominant process in lymph nodes of sheep with ovine progressive pneumonia, this was not accompanied by the expected degree of plasmacytosis, morphologically and immunohistochemically. These findings may represent an aberrancy of immunoregulation in ovine progressive pneumonia.     

Serum fluoride concentrations,biochemical and histopathological changes associated with prolonged sevoflurane anaesthesia in horses

The volatile anaesthetic sevoflurane is degraded to fluoride (F-) and a vinyl ether (Compound A), which have the potential to harm kidney and liver. Whether renal and hepatic injuries can occur in horses is unknown. Cardiopulmonary, biochemical and histopathological changes were studied in six healthy thoroughbred horses undergoing 18 h of low-flow sevoflurane anaesthesia. Serum F- concentrations were measured and clinical laboratory tests performed to assess hepatic and renal function before and during anaesthesia. Necropsy specimens of kidney and liver were harvested for microscopic examination and compared to pre-experimental needle biopsies. Cardiopulmonary parameters were maintained at clinically acceptable levels throughout anaesthesia. Immediately after initiation of sevoflurane inhalation, serum F- levels began to rise, reaching an ongoing 38-45 micromol 1(-1) plateau at 8 h of anaesthesia. Serum biochemical analysis revealed only mild increases in glucose and creatinine kinase and a decrease in total calcium. Beyond 10 h of anaesthesia mild, time-related changes in urine included increased volume, glucosuria and enzymuria. Histological examination revealed mild microscopic changes in the kidney involving mainly the distal tubule, but no remarkable alterations in liver tissue. These results indicate that horses can be maintained in a systemically healthy state during unusually prolonged sevoflurane anaesthesia with minimal risk of hepatocellular damage from this anaesthetic. Furthermore, changes in renal function and morphology observed after sevoflurane inhalation are judged minimal and appear to be clinically irrelevant; they may be the result of anaesthetic duration, physiological stressors, sevoflurane (or its degradation products) or other unkown factors associated with these animals and study conditions.