CHANGES OF BLOOD METABOLITES IN HORSES AFTER RACING, WITH PARTICULAR REFERENCE TO URIC ACID

Changes in concentration of a number of blood metabolites in 30 thoroughbred horses were recorded after an 1110 metre race. No significant changes occurred in blood urea or aspartate aminotransferase during the three hours after racing. Plasma sodium, potassium and calcium levels were increased immediately after racing but had returned to normal one hour after racing. Plasma phosphate showed a significant fall in concentration one hour after racing. Creatinine and lactic acid concentrations were elevated ten minutes after racing and although they subsequently decreased, the level of lactic acid was still significant one hour later. Uric acid levels were well above resting levels at ten minutes after racing but rose even more in the subsequent hour. Urinary uric acid levels were also elevated during this time. Three hours after racing some horses still had elevated plasma uric acid levels and all of them showed a significant rise in creatine phosphokinase. The possible physiological basis of these findings is discussed.     

Endocrine effects of heat stress in boars

The purpose of this study was to describe the temporal changes in peripheral plasma levels of testosterone and Cortisol in boars during and after heat stress. A total of 8 boars were utilized, 4 of them were exposed to 35°C, for 100 h in a climatic room, and 4 served as controls and were kept at 20 °C for 100 h in the climatic room.Blood samples were obtained via permanent vein catheters 3 times daily from 5 days before heat stress until 20 days after termination of heat stress. Testestorone levels were determined by radioimmunoassay and Cortisol by a competitive protein binding technique.For both hormones the pre-exposure levels were similar in both groups of boars. The control boars had significantly higher testosterone levels, while being in the climatic room, than during any other period. The experimental boars had slightly increased testosterone levels during the first day of heat stress and thereafter continuously decreased levels. In the control boars the testosterone levels returned to pre-exposure levels immediately after removal from the climatic room, whereas in the experimental boars the testosterone levels were dramatically increased during the first 5 days after exposure. The differences in Cortisol levels, between the 2 groups of boars were restricted to the period spent in the climatic room. During this period the experimental boars had significantly higher Cortisol levels.Key words: boars, heat stress, testosterone, cortisol     

Stimulation of in vitro muscle cell proliferation by sera from swine injected with porcine growth hormone

The proliferation-promoting activity of sera obtained from pigs before and after porcine growth hormone injections was tested in a muscle cell culture bioassay. For 3 d, purified porcine growth hormone (pGH) was administered by intramuscular injection to crossbred barrows. Two levels of pGH were administered: 18 micrograms pGH X kg-1 body weight X d-1 (low dose) or 143 micrograms pGH X kg-1 body weight X d-1 (high dose). Multiple blood samples were withdrawn from jugular catheters for 3 d prior to the injection, during the injection period and for 6 d after the last injection. Although serum pGH levels in low-dose pigs were raised from two to three times pre-injection levels, there was no significant change in serum proliferation-promoting activity or somatomedin-C (SmC), insulin or cortisol levels during or after administration of pGH. In contrast, the proliferation-promoting activity of sera obtained during and after the high-dose pGH injections was higher (P less than .005) than the pre-injection levels. Serum pGH levels were increased approximately 30-fold by 4 h after each injection, and increases in SmC levels were observed 10 to 16 h after the pGH injection. During the injection period SmC levels increased from 1.7 to 4 times pre-injection levels. Insulin and cortisol levels did not change significantly during the 3-d treatment period. We believe that this muscle cell culture bioassay system will be a useful addition to traditional radioimmunoassays and whole animal studies in elucidating the mode of action of pGH in pituitary-intact swine.     

Changes in serum immunoglobulin levels in Jerseys and Friesians near calving.

IgG1 and IgM levels were significantly lower in bovine serum from four weeks before, until at least two months after calving, whereas IgG2 levels were elevated at this time. The shapes of the changes in Ig levels were different for first and second calving and it appeared that IgG1 levels were secreted earlier, from serum to colostrum, in heifers. Changes in management caused marked changes in Ig levels particularly after third calving when the cows were transferred from a balanced complete diet to grass or hay. IgG1 levels increased by 130 per cent and stayed high whereas the increase in IgM was transitory, and IgG2 levels largely unaffected. In Friesians the IgG2 levels increased with age as anticipated from previous studies but in Jerseys the levels appeared to decline with age. Mean IgG2 levels in Jerseys were also significantly lower than in Friesians.     

Estimation of dietary lysine requirement using plasma amino acid concentrations in mature thoroughbreds

Four experiments were conducted to estimate dietary lysine (Lys) requirements using plasma amino acid concentrations as a criterion in mature thoroughbreds. In each experiment four adult thoroughbreds were used. The changes in plasma Lys concentration after feeding were observed in Experiment 1. Blood samples were taken from the cervix vein 0.5 h before, and 1, 3, 5.5, and 10 h after feeding. The plasma Lys concentration increased and remained constant until 3 h after feeding, decreased until 5.5 h and remained constant after then. Therefore, the bleed was done at 3 h after feeding in all later experiments. To make sure of the response speed of the plasma Lys to changes of dietary Lys levels, dietary Lys levels were changed from high to low, and low to high levels in Experiment 2. Blood samples were taken just on the changing day and 1, 2 and 3 days after changing diets. The plasma Lys concentration decreased until 2 days after changing the diet, and then remained constant with advancing days after changing the diet from high Lys to low Lys. On the other hand, the plasma Lys increased until one day after changing the diet, and then remained constant with advancing days after changing dietary Lys levels. Thus, blood samples were taken 3 days after feeding in the next experiments. The possibility of estimating the Lys requirement for maintenance using plasma Lys concentration was elucidated by two methods in Experiments 3 and 4. In Experiment 3, the horses were fed a diet containing 0.33 percent Lys for 3 days. After this the diet was changed to diets containing higher levels of Lys to 0.40, 0.47, 0.54, and 0.61 percent every third day. The Lys requirement was estimated to be 0.46 percent of diet from the response of plasma Lys concentration of five Lys levels. In Experiment 4, a 4 × 4 Latin square design was used for four dietary Lys levels. The Lys requirement was estimated to be 0.47 percent of the diet with a plasma Lys concentration of four Lys levels.     

Local antibody responses in the bile and faeces of sheep infected with Fasciola hepatica

The effect of infection with the liver fluke Fasciola hepatica on serum, bile and faecal immunoglobulin and antibody levels was studied in Scottish Blackface sheep. In the serum the immunoglobulins showing the most marked increase were IgG1 and IgG2 and their maximal values were reached at 16 weeks after infection. In the bile IgG2 rose to peak values at two weeks and IgG1, IgA and IgM were maximal at four weeks after infection. The levels of faecal IgG and IgA were low after primary infection but after reinfection a rapid increase in IgA concentration was observed within one to two weeks. Haemagglutinating antibody levels against egg antigens, juvenile and adult excretory-secretory antigens and adult fluke somatic antigens were evaluated. In the sera high titres were observed starting from two to four weeks after infection and persisting until 14 to 16 weeks. Bile haemagglutinating antibodies against excretory-secretory antigens showed the highest level at two and four weeks after infection while antibodies against adult somatic antigens reached maximal titres between four and eight weeks. Faecal antibody levels after primary infection were low but increased rapidly within two weeks after reinfection, coinciding with the elevation in faecal IgA concentration. However, there was no reduction in the number of flukes established in reinfected animals.     

Plasma lipopolysaccharide elevations in cattle associated with early-stage infection by Fasciola hepatica

Fasciolosis is an endemic zoonotic parasitic disease with significant impacts on human health and both animal health and production. Early post-infection impacts on the host remain unclear. The objective of this study was to determine the changes, if any, to levels of endotoxin in cattle plasma in response to early-stage infection with Fasciola hepatica. Thirty-six (36) commercial bred cattle were experimentally infected with approximately 400 viable metacercariae. Plasma lipopolysaccharide (endotoxin) levels were examined on 24 occasions from 0 h before infection to 336 h after infection using the Limulus Amoebocyte Lysate chromogenic end point assay and compared with that of six (6) uninfected control animals. Peak lipopolysaccharide levels in infected animals were reached at 52 h after infection and returned to pre-infection levels at time 144 h after infection. Infected animals had significantly elevated lipopolysaccharide levels between 24 and 120 h after infection when compared to uninfected animals. The mean change in endotoxin units (EU)/mL over time after infection was statistically significant in infected animals. Elevations of lipopolysaccharide occurred in all infected animals suggesting a possible repeatable and titratable endotoxemia conducive to therapeutic agent model development.     

Changes in serum thyroid hormone levels in newborn calves as a diagnostic index of endemic goiter

Maximum serum thyroxine (T4) and triiodothyronine (T3) levels of healthy calves were seen at 1 day after birth, and thereafter rapidly decreased until 5 days after birth. They stabilized until 2 weeks after birth, then gradually decreased until 4 weeks after birth. Serum T4 levels of calves with endemic goiter tended to be lower than those of healthy ones, but showed similar levels to those of adult cows. T3 levels of calves with goiter were similar to those of healthy ones, but showed higher variation. T4/T3 ratio of calves with goiter were significantly lower than those of healthy ones and adult cows. While individual levels of serum T4 and T3 at just after birth could not be considered as a diagnostic index, the T4/T3 ratio could be adopted as a diagnostic index of endemic goiter.     

Experimental chronic copper toxicity in sheep. Changes that follow the cessation of dosing at the onset of haemolysis.

Eight sheep were given daily oral doses of copper sulphate until haemolysis occurred. Three of the sheep developed further periods of haemolysis after dosing ceased. Serum enzyme and urea levels were measured throughout the experiment and compared to those obtained from three undosed control sheep. Serum enzyme levels rose prior to haemolytic crises and urea levels rose subsequent to haemolysis in animals that died or were killed in extremis. Severe morphological changes were seen in liver, kidney and brain. Tissue levels of copper and iron were markedly elevated. It is concluded that tissue damage continues even after the cessation of ingestion of copper and that the damage can be severe enough to lead to repeated haemolytic crises.     

Presence of salicylic acid in standardbred horse urine and plasma after various feed and drug administrations

Plasma and urinary levels of salicylic acid were examined in Standardbred mares after administration of various feeds, containing different compositions of hay. In addition, horses were administered acetylsalicylic acid orally and methyl salicylate topically. Elevated salicylic acid levels were observed in horse urine and plasma in animals fed lucerne hay. The plasma and urinary elimination of salicylic acid exhibited a diurnal pattern which was related to the type of feed and the feeding schedule. Within 24 h after oral administration of acetylsalicylic acid, plasma and urine salicylic acid levels were consistent with residual levels observed after feeding lucerne hay. Elimination of salicylic acid was rapid and complete, with a half-life between 5 and 7 h. Topical administration of methyl salicylate (8.4 g) produced elevated urinary salicylic acid levels for 6 h. A smaller dose of methyl salicylate (3.4 g) did not elevate plasma or urine salicylic acid levels above those observed following administration of lucerne hay.     

Physiologic manifestations of stress from capture and restraint of free-ranging male African green monkeys (Cercopithecus aethiops).

Adrenal gland weights, stomach mucosal lesions, and morning serum cortisol and prolactin levels were measured in 15 juvenile and adult male African green monkeys (Cercopithecus aethiops) that were shot by a hunter, euthanized after 24 hr of captivity, or euthanized after 45 days of captivity and intermittent blood sampling. Hormone levels were measured in seven additional males that had been in captivity for 7 mo. Mean serum cortisol concentrations were significantly lower in free-ranging wild monkeys at the time they were shot than in the monkeys after 1 day in captivity. Cortisol concentrations were significantly higher in wild-caught monkeys on the day after capture than they were in the same animals after 18 and 26 days of captivity. Cortisol concentrations were also significantly higher in the wild-caught monkeys 18 days after capture than in the laboratory-habituated monkeys in captivity for 7 mo. Mean prolactin concentration was significantly lower in the wild-caught monkeys on day 2 after capture, and the levels increased gradually to 45 days in captivity and was highest in monkeys that had been captive for 7 mo.     

Comparative endocrinological responses to short transportation of Equidae (Equus asinus and Equus caballus)

In order to evaluate the effects of short transportation on β‐endorphin, adrenocorticotropic hormone (ACTH) and cortisol changes, 12 healthy stallions of Equidae (Equus asinus and Equus caballus) were studied before and after transportation of 50 km. Blood samples were collected 1 week before transportation in basal conditions, immediately before loading and after transportation and unloading, on their arrival at the breeding station. Compared to basal and before values, donkeys showed an increase in circulating ACTH (P < 0.001) and cortisol (P < 0.0005) levels after transportation and higher ACTH (P < 0.01) levels than horses after transportation. A positive and significant correlation (r = 0.885; P < 0.01) between ACTH and cortisol levels after transportation was found. No significant differences were observed for β‐endorphin levels. Compared to basal and before values, horses showed higher cortisol (P < 0.005) levels after transportation and no significant differences were observed for ACTH and β‐endorphin levels in donkeys. Horses facing forward (direction of travel) showed higher (P < 0.01) β‐endorphin levels after transportation than donkeys; horses facing backward (the opposite direction of travel) showed lower (P < 0.05) ACTH levels after transportation. The results indicate that short transportation induces a preferential activation of the hypothalamus‐pituitary‐axis (HPA), with significant release of ACTH and cortisol in donkeys and only of cortisol in horses, suggesting that transportation for donkeys may be more stressful than horses.     

Pharmacokinetic study of chloramphenicol in calves using sensitive gas-liquid chromatographic analysis.

Chloramphenicol was given intravenously and intramuscularly to calves and the blood levels determined over 27 hours. At a dosage of 11 mg/kg chloramphenicol was detected in the blood for 25 hours after intravenous and 27 hours after intramuscular administration. The blood levels after intravenous administration indicate that chloramphenicol in animals moves in a two compartment model. Kinetic parameters were determined for intravenous but not intramuscular chloramphenicol treatment. The blood levels of chloramphenicol were higher following intramuscular than intravenous administration from five hours onward. Chloramphenicol distributed quickly and widely throughout the animal's body.     

The content of Hb in blood and proteins, Fe, Fe-binding capacity, Cu and Zn in the blood plasma of sows and their piglets at the time of birth, after the uptake of colostrum and with different Fe supply

Keeping of piglets on slatted metal floor, without complementary iron supply, caused anaemia within seven days from parturition. Hb levels in the blood dropped from 7.00 +/- 1.16 to 3.47 +/- 0.74 mmol/l. Iron deficit reduced growth and vitality. The iron levels in blood plasma of the piglets tested varied between 5 and 35 mumol/l, immediately after parturition. Intraperitoneal or oral administration of Fe-dextran (150 mg Fe) on the first day after parturition resulted in physiological iron levels in blood plasma, after seven days. Yet, when 14 days had passed, the levels were similar to those recorded from piglets without additional iron supply. Iron bonding capacity of blood plasma increased in piglets of all groups up to the seventh day from birth. Death occurred, on the second day of age, to many piglets with protein levels below 50 g/l plasma. Copper levels in blood plasma of newborn piglets were below those recordable from sows, but they went up by more than three times of their original values up to the seventh day from birth. In piglets, zinc, levels of blood plasma after parturition were higher than those of sows and went up by some 50 percent, within seven days from birth.     

Effects of central administration of glucagon on feed intake and endocrine responses in sheep

This study was conducted to investigate effects of glucagon intracerebroventricularly administered on feed intake and endocrine changes in sheep. Four male sheep (48–55 kg BW) were used. The animals were acclimatized to be fed alfalfa hay cubes at 12.00 hour. Human glucagon (40 and 80 µg/0.5 mL) was injected into the lateral ventricle at 12.00 hour. Blood samples were taken every 10 min from 30 min before to 180 min after the glucagon injection. Soon after the injection, the animals were given alfalfa hay cubes, and the amounts of the feed eaten within 2 h were measured. Feed intakes were significantly (P < 0.05) suppressed by 80 µg of glucagon. Plasma glucose levels in control animals were gradually decreased after the feeding, whilst those in glucagon‐treated animals were temporarily elevated just after the feeding and then kept higher than control levels. Plasma insulin was abruptly elevated after the feeding and was maintained at higher levels than before the feeding in all treatments. Plasma NEFA concentrations were decreased after the feeding in all treatments. A tendency of increase in plasma cortisol levels occurred in glucagon‐injected animals. The present study provides the first evidence that glucagon directly acts on the brain, then inhibiting feeding behavior and inducing endocrine responses in ruminants.     

Response of sheep to challenge infection with Fasciola hepatica

Sheep were infected with 100 metacercariae of Fasciola hepatica and reinfected 16 weeks later with a further 100 metacercariae. Serum samples were taken weekly for 36 weeks after primary infection. Serum was assayed for the presence of the enzymes glutamate dehydrogenase (GLDH) and gamma-glutamyl transferase (gamma-GT), as indicators of liver and bile duct damage respectively, and for levels of precipitating antibody. Antibody and GLDH levels rose following the primary infection but fell after patency had been reached . A peak in gamma-GT activity was associated with the onset of patency. After the challenge infection levels of both enzymes rose substantially and there were persistent fluctuations in activity. Antibody levels did not rise markedly following challenge but fluctuated at low levels until autopsy, 20 weeks after challenge. There was no resistance to challenge judged by worm recoveries at autopsy. It is suggested that the presence of adult flukes in the bile ducts suppresses the antibody response to challenge infection. Tissue damage, which is shown by fluctuations in GLDH and gamma-GT levels after adult flukes have become established in the bile ducts, is considered to be due to the feeding activity of adult flukes and the deposition of immune complexes in the liver parenchyma.     

Extracellular heat shock protein 70 levels in tumour-bearing dogs and cats treated with radiation therapy and hyperthermia

Hyperthermia is a form of a cancer treatment which is frequently applied in combination with radiotherapy (RT) to improve therapy responses and radiosensitivity. The mode of action of hyperthermia is multifactorial; the one hand by altering the amount of the blood circulation in the treated tissue, on the other hand by modulating molecular pathways involved in cell survival processes and immunogenic interactions. One of the most dominant proteins induced by hyperthermia is the major stress-inducible heat shock protein 70 (Hsp70). Hsp70 can be found in the blood either as a free-protein (free HSP70) derived from necrotic cells, or lipid-bound (liposomal Hsp70) when it is actively released in extracellular vesicles (EVs) by living cells. The aim of the study was to evaluate the levels of free and liposomal Hsp70 before and after treatment with RT alone or hyperthermia combined with radiotherapy (HTRT) in dogs and cats to evaluate therapy responses. Peripheral blood was collected from feline and canine patients before and at 2, 4, 6 and 24 h after treatment with RT or HTRT. Hsp70 enzyme-linked immunosorbent assays (ELISAs) were performed to determine the free and liposomal Hsp70 concentrations in the serum. The levels were analysed after the first fraction of radiation to study immediate effects and after all applied fractions to study cumulative effects. The levels of free and liposomal Hsp70 levels in the circulation were not affected by the first singular treatment and cumulative effects of RT in cats however, after finalizing all treatment cycles with HTRT free and liposomal Hsp70 levels significantly increased. In dogs, HTRT, but not treatment with RT alone, significantly affected liposomal Hsp70 levels during the first fraction. Free Hsp70 levels were significantly increased after RT, but not HTRT, during the first fraction in dogs. In dogs, on the other hand, RT alone resulted in a significant increase in liposomal Hsp70, but HTRT did not significantly affect the liposomal Hsp70 when cumulative effects were analysed. Free Hsp70 was significantly induced in dogs after both, RT and HTRT when cumulative effects were analysed. RT and HTRT treatments differentially affect the levels of free and liposomal Hsp70 in dogs and cats. Both forms of Hsp70 could potentially be further investigated as potential liquid biopsy markers to study responses to RT and HTRT treatment in companion animals.     

Influence of nutritional deprivation on insulin-like growth factor I, somatotropin, and metabolic hormones in swine

Although growth hormone (GH) is a primary stimulus for the synthesis of insulin-like growth factor I (IGF-I), other factors such as nutritional status, insulin, and thyroid hormones are important modulators of circulating IGF-I levels. Thus, the effects of feed restriction and subsequent refeeding on plasma levels of IGF-I, GH, insulin, and thyroid hormones were studied in swine. Despite an elevation in plasma GH levels after 48 h of feed restriction, circulating IGF-I levels were decreased by 53% (P less than .05). Plasma triiodothyronine (T3) and insulin were lower (P less than .05) within 24 h after the feed restriction began, whereas thyroxine (T4) did not decrease until 48 h after removal of feed. Blood glucose levels remained unchanged throughout the experiment. Refeeding after the 48-h fast was associated with a decline (P less than .05) in circulating GH levels within 2 h, concomitant with an elevation (P less than .05) in plasma insulin and T3. Refeeding fasted pigs was associated with an increase (P less than .05) in plasma IGF-I; however, levels still had not returned to prefast concentrations within 24 h after refeeding. These data indicate that the GH-IGF-I axis becomes uncoupled during nutritional restriction in swine and that inadequate nutrient supply may limit the expression of the anabolic effects of GH.     

Effect of terbufos poisoning on the blood cholinesterase and hematological values in a dairy herd

This report describes the effects of a sublethal dose of terbufos (counter 15G formulation) in a dairy herd. Ingestion of terbufos depressed whole blood cholinesterase activity. No recovery of this enzyme was evident until 30 days after ingestion after which a constant rate (0.65%/day) increase was observed.

There was a good correlation between blood cholinesterase levels and clinical signs. Normal cholinesterase levels were reached at approximately 150 days after exposure. Cholinesterase levels in animals, ill prior to exposure, were slow to recover, while levels of healthy cattle surpassed those of control animals. Anemia was observed in some cows at approximately 30 days after exposure. The degree of anemia paralleled the severity of poisoning. The increase in packed cell volume paralleled the return of blood cholinesterase activity.

     

Plasma chloramphenicol concentrations in cats after parenteral administration of chloramphenicol sodium succinate

Five cats were dosed on five occasions with 20 mg chloramphenicol/kg body weight. The drug was given three times as chloramphenicol sodium succinate (by intravenous, intramuscular and subcutaneous injections) and twice as crystalline chloramphenicol in capsules. Plasma chloramphenicol concentrations were determined at fixed intervals after administration. Parenteral injection of the ester usually produced highest plasma levels at the initial sampling, 0.5 h after dosing. When capsules were given, there was greater variation between cats: highest plasma levels were recorded usually at 0.5-2 h after dosage but delayed absorption was evident in some cases. There were no statistically significant differences between the different routes with regard to mean plasma antibiotic levels at each sampling or mean area under the curve of plasma level versus time, except that mean plasma levels at 0.5 h were higher with intravenous or intramuscular injection than with oral administration.