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1.
The significant role of voltage gated calcium channels (VGCC) L-type antagonists used concomitantly with opioids in attenuation of clinical pain has been confirmed. The aim of this study was to evaluate the effect of centrally administered verapamil on behavior and biochemical parameters in sheep that have undergone experimental duodenal distension (DD) and to determine whether verapamil exerts any anti-nociceptive effects under these conditions. The study was carried out using 24 mature crossbred ewes, each weighing 38-43 kg. Verapamil, a VGCC blocker, was administered through an intracerebroventricular cannula at the following doses: 0.25, 0.5, 1.0 and 2.0 mg in toto. Ten minutes later experimental DD was conducted by insertion and the distension of rubber balloon (containing 40 ml of warm water) inserted into sheep duodenum. After 5 min of mechanical DD the following reactions were then observed: the significant increase in behavioral pain responses, i.e. tachycardia, hyperventilation, inhibition of reticulo-ruminal contractions (70% approximately, during 15 min), an increase of plasma catecholamine concentration (over 7-fold increase of epinephrine during 2 h following DD, 2-times norepinephrine and ±80% increase of dopamine). Verapamil infusion administered 10 min prior to DD decreased intensity of visceral pain responses, such as: behavioral changes, tachycardia, hyperventilation, inhibition of the reticulo-rumen motility and efficiently prevented the appearance of catecholamine release. These data demonstrated that the development and persistence of duodenal hyperalgesia depends on the activation of Ca2+ ion flux leading to neurotransmitters release and modulation of membrane excitability. The observed antinociceptive action of VGCCs type-L blockers suggests that these channels play a crucial role in the modulation of acute visceral hyperalgesia in sheep.  相似文献   

2.
Present study examined the effect of VGCC L-type blocker - nifedipine given i.c.v. (0.25, 0.5, 1 and/or 2 mg in toto) on the development of nociceptive behavior, clinical symptoms, plasma catecholamin concentration and reticulo-rumen motility following 5 min lasting mechanical duodenal distension (DD) in sheep. After 24 h of fasting, all animals received i.m. ketamine analgesia (20 mg kg−1 B.W) and anesthetized with pentobarbital (20 mg kg−1 B.W., i.v. infusion) The permanent stainless steel cannula 29 mm in length and 2 mm in diameter was inserted into the lateral cerebral ventricle (controlled by cerebro-spinal efflux) 10 mm above the bregma and 5 mm laterally from the midline sutures using stereotaxic method.Under the same general anesthesia/analgesia a T-shaped silicon cannula (inside diameter of 21 mm), was inserted into the duodenum (12 cm from pylorus). Second identical cannule was inserted into the dorsal sac of the rumen, a previously described. After surgery each animal was kept in individual boxes for 10 days prior to experiment and was treated i.m. with benzyl procaine penicillin 30,000 I.U kg−1 B.W.) + dihydrostreptomycine sulfate (10 g kg−1 B.W.) + prednisolone acetate (1.2 mg kg−1 B.W.) combination and i.m. ketamine (20 mg kg−1 B.W.) every day by seven consecutive days.Experimental DD was conducted by insertion and then distension of rubber balloon (containing 40 ml of warm water) inserted into sheep duodenum. Duodenal distension produced a significant increase in behavioral pain manifestations, tachycardia, hyperventilation, inhibition of reticulo-ruminal contractions rate (from 87.2 to 38.0% during 15-20 min), an increase of plasma catecholamine concentration (over 6.4-fold increase of epinephrine during 2 h following DD, 2-times norepinephrine and 84% increase of dopamine). Nifedipine infusion administered 10 min prior to DD decreased intensity of visceral pain manifestations such as: behavioral changes, hyperventilation, reticulo-rumen motility and efficiently prevent appearance of catecholamine release. These data demonstrated that the development and persistence of duodenal hyperalgesia depends on the activation of Ca2+ ion flux leading to neurotransmitters release and modulation of membrane excitability. It seems that nifedipine given i.c.v. 10 min prior to DD (as a source of visceral pain), inhibited specific receptors 1 subunits of VGCCs in target tissues, prevented depolarization of cell membranes and release of neurotransmitters responsible for pain sensitivity in sheep. The observed antinociceptive action of VGCCs type L blockers suggest that these channels play a crucial role in the modulation of acute visceral hyperalgesia in sheep.  相似文献   

3.
Cholecystokinin (CCK) released in the CNS inhibits the analgesic action of exogenous opioids and may antagonize analgesia resulting from the activation of an endogenous pain inhibitory system. The aim of this study was to analyse the central action of PD 140.548 N-methyl-D-glucamine--a peptide antagonist of a specific peripheral type CCK receptor--on animal behaviour, catecholamines (CA) and cortisol concentration, as well as clinical symptoms of visceral pain induced by duodenal distension (DD). A 5 min distension of the duodenum wall, using a 10 cm long balloon filled with 40 and/or 80 ml of water (DD 40 and/or DD 80) at animal body temperature, produced a significant increase in plasma CA and cortisol levels, an increase in the heart rate, hyperventilation and other clinical symptoms (inhibition of rumen motility, bleating, teeth grinding, prostration, urination, defecation) that may be related to pain, proportionally to the degree of intestinal distension. Intracerebroventricular administration of PD 140.548 at the dose of 1 or/and 2 mg in toto 10 min before applying DD 40 completely blocked the increase in blood plasma cortisol, epinephrine (E), norepinephrine (NE) and dopamine (DA) concentration. It is suggested that the central inhibitory action of CCK antagonist on the cortisol and catecholamine release produced by visceral pain is due to the inhibition of peripheral CCK1 type receptors in the central centrifugal descending pain facilitatory system in sheep perhaps via the hypothalamic-pituitary-adrenal axis.  相似文献   

4.
The aim of this study was to determine the influence of nifedypine--competitive antagonist of voltage-gated dependent L-type Ca2+ channels (VGCCs)--on inhibition of reticulo-ruminal motility, heart beats, respiratory rates and other nociceptive behavior symptoms caused by duodenal distention (DD). The animals, which were under general anesthesia, had duodenal and ruminal fistulas and intracerebroventriculary (i.c.v.) cannulas inserted into the lateral ventricle. Reticulo-ruminal contractions were recorded mechanographically using an electronic tensometer. The frequency of reticulo-ruminal contractions was determined by the number of mechanograms with 5 min intervals prior to and after DD (for 180 min). The duodenal distention was performed using a rubber balloon (10 cm length), which was inserted via the duodenal fistula and filled with 40 ml water. Five min DD caused immediate and almost complete inhibition of reticulo-ruminal contractions, nociceptive behavior symptoms, tachycardia and hyperventilation. Nifedypine per se did not change the reticulo-ruminal motility, general behavior or clinical symptoms; however, doses of 1 and 2 mg of nifedypine in toto infused i.c.v 10 minutes before DD prevented all signs of reticulo-ruminal disorders, as well as the general nociceptive behavior. Nifedypine inhibited particularly clinical symptoms such as tachycardia and hyperventilation. The observed antinociceptive action of VGCCs type-L blockers suggests that these channels play a crucial role in the modulation of acute visceral hyperalgesia. Nifedipine can be useful in controlling acute visceral pain associated, for example, with different kinds of colic.  相似文献   

5.
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6.
The aim of this study was to determine the influence of mechanically induced duodenal distension (DD) and PD 140.548 N-methyl-D-glucamine (a specific peptide antagonist of a CCK1 receptor) premedication on mechanographical reticulo-ruminal activity, animal general behaviour, catecholamines (CA) and the blood plasma cortisol levels, as well as the clinical symptoms of visceral pain induced by DD in sheep. After 24 h fasting, 6 animals, Polish merino sheep were praeanaesthetised by i.m. injection of ketamine (20 mg x kg(-1) b.w.) and anaesthetised with i.v. infusion of pentobarbital (20 mg x kg(-1) b.w.) and a permanent stainless steel cannula (gate cannula) was inserted inside the lateral cerebral ventricle (controlled by cerebrospinal fluid efflux) 10 mm above the bregma and 5 mm laterally from the midline suture using stereotaxic method. Under the same general anaesthesia and analgesia a T-shaped silicon cannula, was inserted into the duodenum (12 cm from pylorus) and a second one was inserted into the dorsal sac of the rumen. During 7 consecutive days after surgery each animal was treated i.m. with procaine penicillin (300000 I.U..kg(-1) b.w.), dihydrostreptomycine (DHS, 10 microg x kg(-1) b.w.), prednisolone acetate 1.2 mg x kg(-1) b.w.) together and i.m. injection of ketamine (20 mg x kg(-1) b.w.), separetely. The influence of PD 140.548 N-methyl-D-glucamine on the unfavourable effects of duodenal distension using a 10 cm long balloon filled with 40 and 80 ml (DD40 and DD80) water at animal body temperature was investigated in this study. Five minutes DD40 and DD80 caused an immediate and compete inhibition of the reticulo-ruminal frequency, a significant increase in plasma CA and cortisol levels, an increase in the heart rate, hyperventilation and other symptoms of pain, proportionally to the degree of intestinal distension. Intracerebroventricular (i.c.v.) administration of PD 140.548 alone at a dose of 0.25, 0.5, 1 or 2 mg in toto did not significantly change the reticulo-ruminal motility, CA and cortisol concentrations, but 10 min after the i.c.v. infusion (or 10 min before DD) at a dose 1 and 2 mg in toto , it completely blocked the increase of blood plasma cortisol, epinephrine (E), norepinephrine (NE) and dopamine (DA) concentrations for 20 min. In the some time it prevented the reticulo-ruminal atony provocked by DD. It is concluded that PD 140.548 N-methyl-D-glucamine--an antagonist of the central CCK1 receptor can be an effective analgesic agent in duodenal pain. This action is due to the inhibition of peripheral CCK1 type receptor in the central descending nerve pathway, facilitating pain transmission in sheep perhaps in the hypothalamic-pituitary-adrenal axis.  相似文献   

7.
The present study describes the occurrence of various gastrointestinal helminths, lungworms and liver flukes in Norwegian sheep and goats as assessed from faecal samples and post mortem examinations performed between 2007 and 2010. Faecal samples for gastrointestinal nematode egg counts were collected from 77 sheep flocks and 30 dairy goat flocks from three geographical regions in Norway. Additionally, thirty-two lambs and 16 adult goats were euthanized for necropsy examination and for identification of adult gastrointestinal nematodes and tapeworms, lungworms and liver flukes. The survey showed that there was a higher mean excretion of trichostrongyle eggs in sheep than in goats at the individual level (392 EPG vs. 154 EPG, p < 0.001). For both host species, the mean prevalence and intensity of excreted trichostrongyle eggs were significantly higher in the southern coastal region compared with the inland and northern regions (p < 0.001). Third stage larvae of Trichostrongylus/Teladorsagia, Haemonchus and Nematodirus type were the most prevalent ones in the coprocultures from sheep, whereas larvae of Trichostrongylus/Teladorsagia and Nematodirus type dominated in goats. The most prevalent gastrointestinal nematode species found at necropsy was Teladorsagia circumcincta (75.0 and 81.2% respectively in sheep and goats), while the largest mean worm burdens were recorded for Haemonchus contortus in sheep (724 ± 623) and T. circumcincta in goats (377 ± 529). Other gastrointestinal nematode species were present at low prevalence or in low numbers.  相似文献   

8.
The aim of this study was to determine the influence of mechanically induced duodenal distension (DD) and lorglumide (CCK1 receptor antagonist) premedication on electrical activity of various parts of gastrointestinal (GI) tract and the blood plasma cortisol level in sheep. The influence of lorglumide on the unfavourable effects of duodenal distension (performed with a balloon filled with water--40 and 80 ml; DD40 and DD80) was investigated in this study. These effects in sheep were as follows: the atony of forestomachs and abomasum and the transitory stimulation of myoelectrical activity of small intestine and distal parts of large intestine. The animals, under general anaesthesia, had electrodes inserted into the muscular layers of the organ, the duodenal fistula and (in another group of animals) also the ruminal fistula. Five minute duodenal distension (DD40 and DD80) caused an immediate and complete inhibition of the frequency of spike bursts as well as reticulo-ruminal and abomasal contractions, but also a transitory significant increase of spike bursts of the intestinal wall. The duodenal distension (DD40 and DD80) caused a significant increase of plasma cortisol concentration. Lorglumide did not significantly change the motility of gastrointestinal tract and cortisol concentration, but 10 min after the intracerebroventricular (i.c.v.) infusion in the doses of 1 and 2 mg in toto (i.e. 25 and 50 micrograms/kg B.W.) it decreased the cortisol concentration by 59.7%, as compared with the control values. Lorglumide administered in the above mentioned doses 10 min before the DD40 prevented all signs of intestinal stress and decreased the release of cortisol, but only for 10 min since the beginning of the duodenal distension. It is concluded, that lorglumide--an antagonist of the central CCK1 receptors can be an effective antistressoric agent in the stomach atony caused by the duodenal distension (mechanical-algetic-emotional stress) in sheep.  相似文献   

9.
We investigated cortisol and behaviour for the first hour after hot-iron disbudding of calves aged 37 ± 4 days: disbudded after i/m xylazine (n = 10); disbudded after i/m xylazine and regional anaesthesia with lidocaine (n = 10); sham-disbudded after xylazine and lidocaine (n = 11); sham-disbudded after i/m saline and lidocaine (n = 10). Xylazine-treated groups had higher cortisol than saline-treated animals and showed no differences among them at any time. Sham-disbudded calves with xylazine had lower cortisol at 60 min compared with all other times. Xylazine-alone disbudded calves struggled more during the procedure than all other groups. Xylazine-alone disbudded calves showed more ear-flicks at 10, 25 and 40 min and head-shakes at 40 min than all other groups. We conclude that cortisol should not be used as an indicator of pain in disbudded calves while under the sedative effect of xylazine and that some behaviours during and after the procedure are useful in showing that xylazine alone does not control hot-iron disbudding pain.  相似文献   

10.
Seroprevalence of and risk factors for toxoplasmosis in sheep from different properties in the Jaboticabal microregion, São Paulo State, Brazil were determined. Antibodies to Toxoplasma gondii were found in sera of 52.0% of 488 sheep tested by indirect fluorescent antibody test (IFAT ? 64). T. gondii seropositivity in sheep was significantly associated with gender of the sheep, pasturing system, contact with cats, and the use of mineral supplements and the type of feed.  相似文献   

11.
The objective of this study was to determine if sheep could be averted to Mascagnia rigida, a toxic plant found in the semiarid region of northeastern Brazil. Twelve female sheep naïve to M. rigida were randomly allocated to two treatment groups: control (treated with 15 mL water orally by a drenching gun) and lithium group (treated with 150 mg LiCl/kg body weight orally by a drenching gun). For conditioning, sheep were allowed to feed on M. rigida leaves for 15 min, followed by LiCl or water administration. The time spent eating M. rigida leaves was measured. The conditioning was repeated daily until the LiCl-treated sheep stopped eating M. rigida, which occurred at days 2 and 3. Persistence trials were conducted on day 10, 24, 40, 55, and 70 of the trial using single-choice tests. There was no difference between the two treatment groups with respect to the consumption of M. rigida on the first day of aversion conditioning. On the second day, three out of the six sheep in the lithium group did not eat the leaves, but on the third day, all the sheep in the lithium group did not ingest M. rigida. This aversion persisted throughout all the persistence trials. This indicates that sheep can be easily conditioned by using lithium chloride to avoid eating M. rigida.  相似文献   

12.
The effect of age/body weight in the plasma disposition kinetics of ivermectin (IVM) and nitroxynil (NTX) after their co-administration as a combined formulation to sheep was studied. Sixteen (16) male sheep were allocated into two experimental groups (n = 8 each): (a) high body weight (high bw) (18-20 months old), and (b) low body weight (low bw) (6-8 months old). Animals in both groups were subcutaneously (sc) treated with IVM (200 μg/kg) and NTX (10 mg/kg) using a commercially available combined formulation (Nitromectin®, Lab. Ovejero, Spain). Blood samples were taken by jugular venopuncture before (time 0), at 2, 4, 8, 12 h and at 1, 2, 3, 5, 7, 10, 15, 20, 25, 35, 40, 50 and 60 days after administration. Recovered plasma was analysed to quantify IVM and NTX by HPLC. Higher IVM plasma concentrations were measured until 20 days post-administration in “low bw” compared to “high bw” animals, where IVM was recovered up to 35 days post-treatment. The IVM absorption process greatly differed between experimental groups. A significantly higher (p < 0.01) Cmax (36.7 ± 7.52 ng/ml) value was obtained at a delayed (p < 0.05) Tmax (48.0 ± 0.0 h) in light compared to heavy (Cmax: 8.0 ± 0.80 ng/ml; at 34.0 h) body weight sheep. IVM elimination half-life and mean residence time were significantly shorter in light compared to heavy (older) sheep. NTX mean plasma concentrations were lower in “low bw” compared to those measured in “high bw” sheep, with elimination phases declining up to 60 d post-administration in both experimental groups. The NTX AUC value in “low bw” (1188.5 ± 122.6 μg day/ml) was significantly lower (p < 0.05) than that obtained in the “high bw” (oldest) animals (1735.0 ± 155.8 μg day/ml). Shorter NTX elimination half-life and mean residence time (p < 0.01) were obtained in the youngest (“low bw”) compared to the oldest (high bw) sheep. The work reported here assessed for the first time the disposition of IVM and NTX after their combinated injection to sheep, demonstrating that animal body weight/development greatly affects the kinetic behaviour of both anthelmintic drugs.  相似文献   

13.
Molecular mechanisms, responsible for the impaired insulin-sensitivity state due to the obesity are not fully understood in both humans and animals. The purpose of this study was to investigate the effects of castration-induced visceral obesity and the influence of two antioxidants on constituents of blood lipid profile and insulin sensitivity in New Zealand white rabbits. Twenty-six clinically healthy male New Zealand white rabbits were used in the experiment and were divided into 3 groups: first group (CI, n = 7) - castrated-obese and treated with antioxidants “Immunoprotect” for 2 months; second group (CO, n = 7) - castrated-obese; third group (NC, n = 12) - control group (non-castrated, non-obese). At the end of the follow-up period of 2 months after castration an intravenous glucose tolerance test (IVGTT) was performed after a 12-h fasting period as the blood samples for determination of glucose and insulin and their kinetic parameters were obtained at 5 and 0 min before and at 5, 10, 30, 60 and 120 min after the infusion of the glucose. The constituents of lipid profile, triglycerides (TG), total cholesterol (TC) and HDL-cholesterol (HDL-C) were also assessed in the overnight fasting blood samples. The body weight (BW), body mass index (BMI), amount of the visceral fat (VF) and VF/BW ratio were both measured and calculated before the IVGTT and at the end of the experimental period. All measured markers of obesity (BW, BMI, VF, VF/BW) were significantly higher in both groups of castrated rabbits than in the control group. Apart HDL-C, the plasma concentrations of all constituents of lipid profile (TG, TC, HDL-C) were the highest in CO group. There were generally no differences between CI and NC groups for the same traits. After glucose injection blood glucose concentrations and glucose and insulin kinetic parameters were considerably higher (except of glucose elimination rate) in CO rabbits than in NC ones. Castrated rabbits treated with “Immunoprotect” showed lower fasting plasma insulin and improved glucose kinetics dynamics than CO rabbits, but commensurable values of glucose and insulin kinetics parameters than NC group. The results of the current study clearly indicated that castration-induced visceral obesity affected negatively the lipid profile and insulin sensitivity and/or responsiveness. Treatment with antioxidant supplementation, consisted of d-limonene and vitamin E, improved blood lipid profile, fatty liver, glucose homeostasis and insulin sensitivity in obese rabbits. In addition, based on our results we may suggest that castrated male New Zealand white rabbits might be considered as an appropriate animal model to study various metabolic abnormalities related to visceral obesity, such as dyslipidemia and impaired insulin sensitivity.  相似文献   

14.
Johne's disease is chronic granulomatous infectious enteritis of animals caused by Mycobacterium avium subspecies paratuberculosis. A total of 153 animals from 19 dairy farms, 2 gaushalas (unproductive-animal rehabilitation centers), 2 goat and 2 sheep farms from different districts of the Punjab region were selected on the basis of clinical signs of disease. All samples from cattle (n = 86), buffalo (n = 34), goat (n = 25) and sheep (n = 26) were subjected to Ziehl-Neelsen staining and DNA extraction by a freeze and thaw method. Ziehl-Neelsen staining detected 71% samples positive for acid-fast bacilli whereas IS900 PCR detected 55% positive for Map DNA. IS1311 PCR-REA analysis of IS900 positive samples revealed ‘Bison’ type as the most prevalent (82%) genotype of Map, infecting all domestic ruminants. ‘Cattle’ type was present in a minority of cases (15%) from cattle, buffaloes and goats. This is the first report of ‘Cattle’ type Map from buffalo and goat species in India.  相似文献   

15.
In light of rapidly spreading triclabendazole resistance alternative fasciocidal drugs are urgently needed. Following up on promising results obtained with artemether in Fasciola hepatica infected sheep, we here report the efficacy and safety of artesunate in sheep with a natural F. hepatica infection. Artesunate was administered intravenously and intramuscularly, adverse events were monitored and drug efficacy was elucidated by means of faecal egg and worm burden reductions. A single 40 mg/kg intravenous dose of artesunate induced an egg count reduction of 68.9% and a worm burden reduction of 77.4%. Intramuscular artesunate at 40 mg/kg reduced faecal egg count and worm burden by 97.6% and 91.9%, respectively; whereas at 60 mg/kg it caused 93.2% and 87.1% reduction in faecal egg count and worm burden, respectively. Three sheep died 24-72 h post-treatment with a double dose of 40 mg/kg intramuscular artesunate, showing lethargy, sialorrhoea, reduced rumination and tremors. Egg and worm burden reductions of 93.3% and 83.9%, respectively, were calculated in the three surviving sheep. In conclusion, the interesting fasciocidal properties of artesunate in sheep warrant further investigations with an emphasis on toxicity studies.  相似文献   

16.
The development of anthelmintic resistance has made the search for alternatives to control gastrointestinal nematodes of small ruminants imperative. Among these alternatives are several medicinal plants traditionally used as anthelmintics. This work evaluated the efficacy of Cocos nucifera fruit on sheep gastrointestinal parasites. The ethyl acetate extract obtained from the liquid of green coconut husk fiber (LGCHF) was submitted to in vitro and in vivo tests. The in vitro assay was based on egg hatching (EHT) and larval development tests (LDT) with Haemonchus contortus. The concentrations tested in the EHT were 0.31, 0.62, 1.25, 2.5 and 5 mg ml−1, while in the LDT they were 5, 10, 20, 40 and 80 mg ml−1. The in vivo assay was a controlled test. In this experiment, 18 sheep infected with gastrointestinal nematodes were divided into three groups (n = 6), with the following doses administered: G1—400 mg kg−1 LGCHF ethyl acetate extract, G2—0.2 mg kg−1 moxidectin (Cydectin®) and G3—3% DMSO. The worm burden was analyzed. The results of the in vitro and in vivo tests were submitted to ANOVA and analyzed by the Tukey and Kruskal–Wallis tests, respectively. The extract efficacy in the EHT and LDT, at the highest concentrations tested, was 100% on egg hatching and 99.77% on larval development. The parameters evaluated in the controlled test were not statistically different, showing that despite the significant results of the in vitro tests, the LGCHF ethyl acetate extract showed no activity against sheep gastrointestinal nematodes.  相似文献   

17.
The neonate's development and survival is dependent upon being vigorous at birth and receiving appropriate maternal care. However, difficulty at delivery can result in less vigorous offspring and maternal care can be altered, probably as a consequence of exhaustion, pain and human intervention. The first 3 h after expulsion of the calf were observed continuously from videos following twelve natural calvings and sixteen calvings assisted by farm staff (including four malpresentations) from Holstein cows. Calvings were balanced within groups for parity of the dam, genetic group, sex and birth weight of the calf, calving pen and calving season. Assisted calves were less vigorous with higher latencies to attempt to stand, achieve standing, walk and reach the udder than unassisted calves (P < 0.05). Furthermore, assisted calves also tended to be less likely to stand and walk within the first 3 h after birth (P < 0.1), spent more time lying on their flank (P = 0.019) and had more frequent bouts of this behaviour (P = 0.033). Assisted dams did not take longer to lick the calf and performed as much licking as unassisted dams (P > 0.05), indicating no delayed onset or impaired expression of maternal behaviour in dams given assistance at delivery. Study of potential pain-related behaviours revealed that assisted dams spent less time self-grooming (P = 0.033) than dams delivering naturally, which could suggest greater pain. However, there were no significant differences in any of the other pain-related behaviours. Our results suggest that, although maternal behaviour was unaffected by a difficult delivery, dairy calves born following difficult calvings have lower vigour in the first 3 h after birth than unassisted calves. This might have longer-term effects on the health and survival of the calves.  相似文献   

18.
It was the aim of the present study to collect basic data on calcium (Ca) and phosphorus (P) homoeostasis in sheep. Two series of experiments were carried out to investigate the effects of 1,25-dihydroxyvitammin D3 (calcitriol) in supraphysiological dosage in combination with varying alimentary Ca supply. In the first series, blood samples were collected over 72 h to determine the concentrations of total Ca (Ca), ionized Ca (Ca2+), inorganic phosphate (Pi), and the bone resorption marker CrossLaps (CL). In the second series, measurements were carried out over 12 h. In addition, urine samples were collected to calculate the fractional excretions (FE) of Ca and Pi. Changes in plasma macromineral concentrations (P < 0.01) as well as in CL (P < 0.001) and endogenous calcitriol (P < 0.05) were observed in the alimentary Ca-restricted animals, indicating that the reduction of daily Ca intake challenged the animals’ macromineral homeostatic mechanisms. However, the Ca-restricted diet had an effect on neither FE of Ca nor on FE of Pi. The treatment resulted in peak serum calcitriol concentrations between 1,900 and 2,500 pg/mL, and supraphysiological concentrations were maintained for the next 48 h. Irrespective of dietary Ca, calcitriol had hypercalcemic and hyperphosphatemic effects. An increase in CL was revealed only in the Ca-restricted, calcitriol-treated sheep (P < 0.01), reflecting a remarkable enhancement of Ca mobilization from the bone by calcitriol exclusively in this group. From these data, it can be concluded that the sheep can be a suitable animal model for studying catabolic effects of Ca deficiency and calcitriol on bone metabolism.  相似文献   

19.
Some animals routinely endure serious injuries from predators or during intraspecific territorial conflicts. Such is the case for Amphiuma tridactylum, an aquatic salamander that lives in an environment rich in potentially infectious microbes, apparently with rare or no pathogenic infection. Some vertebrates possess innate immune mechanisms, but whether this is the case for Amphiuma is unknown. To assess this potential, plasma from 19 A. tridactylum was pooled and used for characterisation of serum complement activity. The ability of A. tridactylum plasma to hemolyse unsensitised sheep red blood cells (SRBCs) was titer-dependent, with low activity observed even at high plasma titers. The kinetic characterisation of SRBC hemolysis revealed that significant activity could be measured within 10 min of incubation, and maximal activity occurred within 60 min. The SRBC hemolysis by A. tridactylum plasma was also temperature-dependent, with maximal activity at 30 °C. In addition, this activity was sensitive to mild heat treatment, with 96% of activity inhibited by incubation at 56 °C for 30 min. The SRBC hemolysis could also be inactivated by pretreatment of the plasma with proteases, indicating that this activity was protein dependent. The activity required divalent metals ions, with activity inhibited by EDTA, citrate, or phosphate. However, the chelator-inhibited activity could be restored by the addition of excess Ca2+ or Mg2+, but not Cu2+ or Ba2+, indicating specificity of the divalent metal ion requirement. The sensitivity to heat, proteases, and divalent metal ion chelators strongly suggests that A. tridactylum plasma-mediated hemolysis of SRBCs is mediated by the serum complement system of proteins.  相似文献   

20.
During an experimental infection of sheep with Fasciola hepatica or F. gigantica, MM3-SERO and MM3-COPRO ELISA tests were applied to compare the kinetics of antibody production and coproantigen release between the 2nd and 32nd week post-infection (wpi). The Kato-Katz technique was used to measure the kinetics of egg shedding by both Fasciola species (eggs per gram of feces, epg). The kinetics of IgG antibodies for all sheep infected with F. hepatica and F. gigantica followed a similar pattern. Optical density (OD) increased rapidly between the 4th until the 12th wpi, when the highest values were reached and then decreased slowly until the 32nd wpi. Coproantigen levels increased above the cut-off value between 6 and 9 wpi in the F. hepatica group, and between 9 and 11 wpi in the F. gigantica group. The comparison between coproantigen levels and epg indicated that F. hepatica-infected sheep had detectable amounts of coproantigens 4–7 weeks before patency (egg shedding), while F. gigantica-infected sheep had detectable amounts of coproantigens 3–6 weeks before patency. When comparing the kinetics of coproantigen release vs the kinetics of epg, a similar pattern emerged, but with a two-week time-lag in epg, for both F. hepatica and F. gigantica infections. The amount of coproantigen release by each adult was not burden dependent for F. hepatica infection (burden of 33–66 adults), while it was for F. gigantica infection (burden of 17–69 adults). The results demonstrate the usefulness of the MM3-SERO and MM3-COPRO ELISAs as tools for the diagnosis of early as well as long-term fascioliasis infections, and suggest that they can potentially be applied to human fascioliasis even in countries where F. hepatica and F. gigantica co-exist. These tests can be employed not only in the diagnosis, but also in studies on epidemiology as well as pathogenesis and treatment in animals and humans since they allow post-treatment infection monitoring.  相似文献   

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