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1.
OBJECTIVE: To determine the pharmacokinetics of praziquantel following single and multiple oral dosing in loggerhead sea turtles. ANIMALS: 12 healthy juvenile loggerhead sea turtles. PROCEDURE: Praziquantel was administered orally as a single dose (25 and 50 mg/kg) to 2 groups of turtles; a multiple-dose study was then performed in which 6 turtles received 3 doses of praziquantel (25 mg/kg, PO) at 3-hour intervals. Blood samples were collected from all turtles before and at intervals after drug administration for assessment of plasma praziquantel concentrations. Pharmacokinetic analyses included maximum observed plasma concentration (Cmax), time to maximum concentration (Tmax), area under the plasma praziquantel concentration-time curve, and mean residence time (MRTt). RESULTS: Large interanimal variability in plasma praziquantel concentrations was observed for all dosages. One turtle that received 50 mg of praziquantel/kg developed skin lesions within 48 hours of administration. After administration of 25 or 50 mg of praziquantel/kg, mean plasma concentrations were below the limit of quantification after 24 hours. In the multiple-dose group of turtles, mean plasma concentration was 90 ng/mL at the last sampling time-point (48 hours after the first of 3 doses). In the single-dose study, mean Cmax and Tmax with dose were not significantly different between doses. After administration of multiple doses of praziquantel, only MRTt was significantly increased, compared with values after administration of a single 25-mg dose. CONCLUSIONS AND CLINICAL RELEVANCE: Oral administration of 25 mg of praziquantel/kg 3 times at 3-hour intervals may be appropriate for treatment of loggerhead sea turtles with spirorchidiasis.  相似文献   

2.
The pharmacokinetics of orphenadrine (ORPH) following a single intravenous (i.v.) dose was investigated in six camels (Camelus dormedarius). Orphenadrine was extracted from the plasma using a simple sensitive liquid–liquid extraction method and determined by gas chromatography/mass spectrometry (GC/MS). Following i.v. administration plasma concentrations of ORPH decline bi-exponentially with distribution half-life (t1/2α) of 0.50 ± 0.07 h, elimination half-life (t1/2β) of 3.57 ± 0.55 h, area under the time concentration curve (AUC) of 1.03 ± 0.10 g/h l−1. The volume of distribution at steady state (Vdss) 1.92 ± 0.22 l kg−1, volume of the central compartment of the two compartment pharmacokinetic model (Vc) 0.87 ± 0.09 l kg−1, and total body clearance (ClT) of 0.60 ± 0.09 l/h kg−1. Three orphenadrine metabolites were identified in urine samples of camels. The first metabolite N-desmethyl-orphenadrine resulted from N-dealkylation of ORPH with molecular ion m/z 255. The second N,N-didesmethyl-orphenadrine, resulted from N-didesmethylation with molecular ion m/z 241. The third metabolite, hydroxyl-orphenadrine, resulted from the hydroxylation of ORPH with molecular ion m/z 285. ORPH and its metabolites in camel were extensively eliminated in conjugated form. ORPH remains detectable in camel urine for three days after i.v. administration of a single dose of 350 mg orphenadrine aspartate.  相似文献   

3.
Five days after the induction of acute systemic inflammation in greyhounds by intramuscular and subcutaneous injections of Freund's adjuvant, the hepatic concentrations of cytochromes P-450 and b5, the activities of the hepatic microsomal enzymes aniline p-hydroxylase and aminopyrine n-demethylase and the disposition and urinary excretion of phenylbutazone were determined. The mean plasma concentrations of phenylbutazone after intravenous administration were described by the bi-exponential equations: Cp = 144·2e−34·6t + 171·5e−0·104t for five normal greyhounds and Cp = 113·6e−16·13t + 163·1e−0·108t for five febrile greyhounds. The elimination half-lives, total body clearances and apparent volumes of distribution were 6·7 hours, 18·4 ml kg−1 hour−1 and 0·18 litre kg−1, for the normal greyhounds, and 6·4 hours, 19·5 ml kg−1 hour−1 and 0·18 litre kg−1, for the febrile greyhounds. There were no significant differences between the pharmacokinetic parameters describing the distribution and elimination of phenylbutazone, or between the quantities of phenylbutazone, oxyphenbutazone and hydroxyphenylbutazone excreted in the urine. In the febrile greyhounds, there were significant decreases in the hepatic microsomal concentrations of cytochromes P-450 and b5 and in the activities of aniline p-hydroxylase and aminopyrine n-demethylase.  相似文献   

4.
Fluconazole (100 mg) was administered to six adult cats as an intravenous infusion over 30 minutes, and the same cats received 100 mg of the drug orally 16 weeks later. The cats were bled repeatedly through an indwelling jugular catheter, the plasma fluconazole concentrations were assayed by high performance liquid chromatography, and the concentration-time data were subjected to a non-compartmental pharmacokinetic analysis. The mean (SD) intravenous half-life (13·8 [2·6] hours) was similar to that observed after oral dosing (12·4 [3·0] hours). The plasma clearances (intravenous 0·9 [0·1], oral 0·9 [0·2] ml min−1 kg−1) and the volumes of distribution at steady state (intravenous 1·1 [0·1], oral 1·0 [0·1] litre kg−1) were also similar after the two routes of dosing. The peak plasma concentration was reached 2·6 hours after oral dosing and the drug was completely bioavailable (1·09 [0·05]). On the basis of this single dose study, the administration of 50 mg fluconazole every eight hours to a 4 kg cat should produce average steady state plasma fluconazole concentrations of approximately 33 mg litre−1.  相似文献   

5.
Heat shock protein (HSP) expression is an adaptive mechanism against the disruption of cell homeostasis during exercise. Several antioxidant supplementation strategies have been used to enhance tissue protection. In this study, we examined the effects of a redox modulator, α-lipoic acid (LA) on HSP responses in six standardbred trotters following intense aerobic exercise. DL–LA supplementation (25 mg kg−1 d−1) for five weeks increased the resting levels of HSP90 (1.02 ± 0.155 in control and 1.26 ± 0.090 after supplementation in arbitrary units) and the recovery levels of inducible HSP70 (0.89 ± 0.056 in control and 1.05 ± 0.089 after supplementation in arbitrary units) in skeletal muscle. Furthermore, LA increased skeletal muscle citrate synthase activity at rest and lowered the blood lactate concentration during exercise without any changes in the heart rate. LA had no effect on concentrations of HSP60, HSP25 or GRP75 in skeletal muscle. LA decreased the exercise-induced increases in plasma aspartate aminotransferase and creatine kinase concentrations during recovery. Our results suggest that LA supplementation may enhance tissue protection and increase oxidative capacity of the muscle in horse.  相似文献   

6.
The effect of dietary chloride content (0·2, 0·4 and 1·3 per cent chloride on a dry matter basis) on the disposition of a single oral dose of bromide (14 mg kg−1 was evaluated in normal beagles. Increasing the dietary chloride content from 0·2 to 1·3 per cent resulted in a significant decrease in the mean apparent elimination half-life from 69 ± 22 days to 24 ± 7 days. The mean area under the concentration curve ( ) for dogs fed 1·3 per cent chloride was significantly smaller than the for dogs fed 0·2 per cent chloride. Dietary chloride had no effect on the maximum serum concentrations (Cmax) or on the time (Tmax) to reach the maximum concentrations. The steady-state serum bromide concentrations predicted from the single dose data for daily doses of 14 mg kg−1 of bromide were significantly lower in dogs fed 1·3 per cent chloride (310 ± 150 mg litre−1) than in dogs fed 0·2 per cent chloride (1950 ± 1140 mg litre−1). The predicted mean daily doses of bromide necessary to maintain serum levels within the therapeutic range for dogs fed 1·3 per cent chloride (43 ± 13 mg kg−1) were almost twice as high as the dose estimated for dogs fed 0·4 per cent chloride (22 ± 3 mg kg−1) and nearly three times as high as the dose estimated for dogs fed 0·2 per cent chloride (15 ± 4 mg kg−l). These differences were statistically significant (P=0·002).  相似文献   

7.
Gentamycin sulphate ( ) and gentamycin oleate ( ) were encapsulated in liposomes composed of phosphatidylcholine ( ) and cholesterol ( ) (molar ratio 7:7:2 and 5:5:l, respectively), and were administered via intramuscular injection to rabbits, to evaluate their potential use as sustained release formulations. Five groups of five animals each were used for the pharmacokinetic study, and treatments were established as follows: 3 mg kg−1 of i.v., 3 mg kg−1 of i.m., 3 mg kg−1 of liposome-containing gentamycin sulphate ( ) i.m., 3 mg kg−1 of i.m., and 3 mg kg−1 of liposome-containing gentamycin oleate ( ) i.m. Gentamycin plasma concentrations after i.m. administration of LGS were extremely low compared with those obtained after the i.m. administration of ; the peak plasma concentration ( max) showed an eight-fold decrease with , and the area under the concentration-time curve ( ) was four-fold lower for the liposomal form. The apparent elimination half-life estimated after administration of showed a three-fold increase compared with values calculated for free . After the administration of the same dose of , max obtained showed a 2·5-fold decrease in relation to peak concentrations of free , and the apparent β-half life of encapsulated showed a three-fold increase compared with i.m. . Large-size liposomes containing gentamycin administered i.m. to rabbits gave sustained drug release from the injection site, providing prolonged plasma concentrations of the drug in the body.  相似文献   

8.
This study quantitatively investigated the analgesic action of a low-dose constant-rate-infusion (CRI) of racemic ketamine (as a 0.5 mg kg−1 bolus and at a dose rate of 10 μg kg−1 min−1) in conscious dogs using a nociceptive withdrawal reflex (NWR) and with enantioselective measurement of plasma levels of ketamine and norketamine. Withdrawal reflexes evoked by transcutaneous single and repeated electrical stimulation (10 pulses, 5 Hz) of the digital plantar nerve were recorded from the biceps femoris muscle using surface electromyography.Ketamine did not affect NWR thresholds or the recruitment curves after a single nociceptive stimulation. Temporal summation (as evaluated by repeated stimuli) and the evoked behavioural response scores were however reduced compared to baseline demonstrating the antinociceptive activity of ketamine correlated with the peak plasma concentrations. Thereafter the plasma levels at pseudo-steady-state did not modulate temporal summation. Based on these experimental findings low-dose ketamine CRI cannot be recommended for use as a sole analgesic in the dog.  相似文献   

9.
The study investigated rumen dry matter (DM) degradability characteristics in a completely randomized design and the effects of milk, sweet potato foliage (SPF) from three cultivars (A = TIS-87/0087; B = TIS-8164; C = TIS-2532.OP.1.13), dried brewers' grains (DBG) and cottonseed meal (CSM) as supplements to Panicum maximum (Panicum) for pre-weaned calves in randomized complete block designs. Diet 1 = milk + SPF-A foliage + Panicum, Diet 2 = milk + SPF-B foliage + Panicum, Diet 3 = milk + SPF-C foliage + Panicum, and Diet 4 = milk + DBG & CSM + Panicum (as control). Dry matter (130 ± 0.4 to 864 ± 3.9 g kg− 1), ash (54 ± 4.2 to 173 ± 2.8 g kg− 1 DM), OM (827 ± 4.2 to 946 ± 5.7 g kg− 1 DM), N (7.4 ± 0.6 to 38.6 ± 1.4 g kg− 1 DM), and NDF (439 ± 1.4 to 774 ± 8.5 g kg− 1 DM) contents were highly significant (P < 0.01). In Trial I, 16 pre-weaned calves were used over 70 d with milk intake (34.8 ± 4.4 ml kg W− 0.75 d− 1), Panicum DMI (22.3 ± 2.77 g kg W− 0.75 d− 1), total DMI (35.7 ± 2.83 g kg W− 0.75 d− 1), and LWG (198 ± 44.6 g d− 1) not significantly different (P > 0.05). Supplement DMI varied (P < 0.05) from 11.6 g kg W− 0.75 d− 1 in Diet 3 to 16.6 g kg W− 0.75 d− 1 in Diet 4. In Trial II, 16 pre-weaned local and crossbred calves were involved over 77 d with initial age of calves, Panicum intake, metabolic DMI, and LWG similar (P > 0.05) among crosses. Birthweight varied (P < 0.05) from 17.3 kg for N'Dama × Jersey crosses to 21.2 kg for White Fulani × Brown Swiss crosses. Supplement and total DMI ranged (P < 0.05) from 172 to 483 g d− 1 for N'Dama × Jersey crosses to 233 and 674 g d− 1 for non-inseminate or purebred calves, respectively. The LWG in the White Fulani × Brown Swiss and the N'Dama × Jersey calves were respectively 30% and 24% better, though not significantly, than purebred calves. In Trial III, rumen DM degradability characteristics of feeds in three N'Dama steers showed no significant differences (P > 0.05) in slowly degradable fraction (b) and rate of degradation of b (c). Soluble fraction (a), 48-h degradation, potential degradability (PD) and effective degradability (ED) varied significantly (P < 0.05) and were lowest in Panicum, but similar for foliage among the three sweet potato cultivars. Panicum fodder showed improvements in degradation characteristics with supplementation.  相似文献   

10.
The cerebral state index (CSI) is used for monitoring EEG and depth of anaesthesia. The objective of this study was to analyse the correlation between ocular reflexes, CSI and estimated propofol plasma concentrations (PropCP) in dogs during induction of anaesthesia with propofol.Fourteen dogs were premedicated with acepromazine 0.05 mg kg−1 IM. Anaesthesia was induced with a 200 ml h−1 propofol 1% constant infusion rate until loss of corneal reflex using RugLoop II software with Beths’ pharmacokinetic model to estimate PropCp.Palpebral reflex (PR) and the corneal reflex (CR) were tested every 30 s and classified as present (+) or absent (−), and eyeball position was registered as rotated ventromedialy (ERV) or centred (EC).Heart rate (HR), mean arterial pressure (MAP) and CSI values were analyzed from baseline before the beginning of propofol infusion (T0) until loss of CR; CSI and PropCp, CSI and anaesthetic planes, and PropCp and anaesthetic planes were compared using correlation analysis.PropCp reached 7.65 ± 2.1 μg ml−1 at the end of the study. CSI values at T0 were 89.2 ± 3.8. Based on the observation of ocular reflexes and eyeball position, it was possible to define five anaesthetic planes: A (superficial) to E (deep), being A (PR+/CR+/EC), B (PR+/ERV/CR+), C (PR−/ERV/CR+), D (PR−/EC/CR+) and E (PR−/EC/CR−). There was a significant correlation between PropCp and the anaesthetic planes (R = 0,861; P < 0.01). No significant correlation was observed between CSI and the anaesthetic planes or between CSI and PropCp. MAP decreased significantly from T0 until loss of corneal reflex (from 98 ± 14 mmHg to 82 ± 12 mmHg); HR did not change significantly (from 101 ± 30 bpm to 113 ± 16 bpm).The CSI monitoring was not consistent with the clinical observations observed in the different stages of depth anaesthesia. This could limit the use of CSI for monitoring depth of anaesthesia with propofol.  相似文献   

11.
Intravenous infusions of hydrocortisone sodium succinate (HSS) were given at 0·625 mg kg−1 hour−1 and 0·312 mg kg−1 hour−1 to six dogs. Plasma cortisol concentrations were measured by radioimmunoassay at 0, 15, 30, 45 and 60 minutes and then every 30 minutes for a further five hours. Chronic hypocortisolaemia was induced and maintained with mitotane and the HSS infusions were repeated after 31 and 50 days. No statistically significant difference was observed in the plasma cortisol concentrations after either period of hypocortisolaemia, but the plasma cortisol concentrations tended to be higher in most of the dogs.  相似文献   

12.
The influence of training on blood lactate concentrations during treadmill exercise and a 40-minute inactive recovery period was examined in seven trained and seven detrained thorough-bred horses. Lactate concentrations were measured in venous blood collected at the end of each exercise state, and at intervals for 40 minutes afterwards. Measurements were made of maximum oxygen uptake (V̇O2max, ml kg−1 min−1), VLA4 (velocity at which blood lactate concentration was 4 mmol litre−1); LA8 (lactate concentration [mmol litre−1] during exercise at 8 m sec−1), peak lactate (highest lactate concentration after exercise), LA40 (lactate concentration 40 minutes after exercise), the time of peak lactate concentration (minutes after exercise) and the rate of disappearance of blood lactate (Rtd). The trained horses had a significantly lower LA8 (2·1 ± 0·1 vs 6·5 ± 1 mmol litre−1, P<0·01), higher VLA4 (9·8 ± 0·2 vs 5·8 ± 0·6 m sec−1, P<0·01) and higher V̇02max (156·3 ± 3·8 vs 107·1 ± 3·9 ml kg−1 min−1, P<0·001). The value of Rtd and the time of peak lactate concentration were not significantly different.  相似文献   

13.
In an open, controlled, multi-centre clinical field trial, seven ‘naturally occurring’ outbreaks of acutefebrile (rectal temperature ≥ 39·5°C) respiratory disease in housed calves were treated with a single antimicrobial agent, and either the non-steroidal anti-inflammatory drug (NSAID) carprofen (n=95) or flunixin meghunine (n=92) on an alternate basis. Carprofen was administered as a single subcutaneous injection at a mean dosage of 1·4 mg kg−1 (range 1·2 to 1·9 mg kg−1) body weight on the first day and flunixin meglumine by intravenous injection at a mean dosage of 2·0 mg kg−1 (range 1·2 to 2·6 mg kg−1) body weight on the first 3 consecutive days. All calves were examined clinically immediately prior to initial treatment and on three occasions up to 1 week after the end of treatment. There were no statistically significant differences between NSAID groups in reduction of clinical parameters between examinations, or in overall efficacy. This trial demonstrated that a single dose of carprofen was equally effective as three daily closes of flunixin meglumine as adjunctive therapy to antimicrobial treatment in acute respiratory disease in calves.  相似文献   

14.
The pharmacokinetics of doxycycline were investigated in sheep after oral (PO) and intravenous (IV) administration. The IV data were best described using a 2- (n = 5) or 3- (n = 6) compartmental open model. Mean pharmacokinetic parameters obtained using a 2-compartmental model included a volume of distribution at steady-state (Vss) of 1.759 ± 0.3149 L/kg, a total clearance (Cl) of 3.045 ± 0.5264 mL/kg/min and an elimination half-life (t1/2β) of 7.027 ± 1.128 h. Comparative values obtained from the 3-compartmental mean values were: Vss of 1.801 ± 0.3429 L/kg, a Cl of 2.634 ± 0.6376 mL/kg/min and a t1/2β of 12.11 ± 2.060 h. Mean residence time (MRT0−∞) was 11.18 ± 3.152 h. After PO administration, the data were best described by a 2-compartment open model. The pharmacokinetic parameter mean values were: maximum plasma concentration (Cmax), 2.130 ± 0.950 μg/mL; time to reach Cmax (tmax), 3.595 ± 3.348 h, and absorption half-life (t1/2k01), 36.28 ± 14.57 h. Non-compartmental parameter values were: Cmax, 2.182 ± 0.9117 μg/mL; tmax, 3.432 ± 3.307 h; F, 35.77 ± 10.20%, and mean absorption time (MAT0–∞), 25.55 ± 15.27 h. These results suggest that PO administration of doxycycline could be useful as an antimicrobial drug in sheep.  相似文献   

15.
The pharmokinetic properties of amoxycillin, and its penetration into respiratory tract tissue, were determined in 18 Actinobacillus pleuropneumoniae infected pigs, after a single i.v. dose of 8·6 mg amoxycillin kg−1 bodyweight. Pleuropneumoniae was produced experimentally in pigs by an aerosol infection model. The infection created a homogenous response, characterised by depression of breathing and increased body temperature. The clinical symptoms were accompanied by increased haptoglobin levels and circulating white blood cell counts. At necropsy the findings were characterised by a bilateral fibrinous pleuropneumonia. Twenty hours after infection, the pigs were administered amoxycillin i.v. The plasma concentration-time curve was described by a three compartment open model. The mean residence time and the elimination half-life were l·5 and 3·4 hours, respectively. The steady-state volume of distribution was 0·67 litres kgl, and the clearance was 0·46 litres kg−1 hour−1. There were no significant differences between these values and those reported previously for healthy pigs. The concentration of amoxycillin in bronchial secretions, lung tissue and diseased lung tissue peaked two hours after intravenous drug administration, while amoxycillin concentration in pleural fluid, lymph nodes and tonsil tissue peaked at the first sampling point one hour after drug administration. The concentration of amoxycillin in secretions and tissue decreased by a slower rate than amoxycillin concentration in plasma, resulting in an increasing tissue-to-plasma concentration ratio. The distribution ratios (AUCtissue/JAUCplasma) was 0·53 for bronchial secretions, 0·44 for pneumonic lung tissue, 0·42 for lung tissue, 1·04 for pleural fluid, 0·58 for lymph nodes and 0·37 for tonsil tissue. The distribution of amoxycillin to secretions was increased compared with that previously reported for healthy pigs, while only minor changes were observed in lung tissue.  相似文献   

16.
Five diets containing concentrate, grass silage and whole crop barley silage (WCBS) harvested at different maturity stages were fed to 15 multiparous dairy cows in an incomplete change-over design over three periods. Three diets contained 10.7 kg dry matter (DM) concentrate, 4 kg DM grass silage, and ad libitum access to WCBS harvested at either the heading stage (B1), the early milk stage (B2) or the early dough stage (B3) of maturity. The other two diets contained 10.7 kg DM concentrate, whereas grass silage and WCBS at heading were mixed at two different ratios with a DM content of WCBS of either 0.30 (M1) or 0.70 (M2), and the mixtures were fed ad libitum. Intakes of DM (kg day− 1: B1 = 21.0, B2 = 20.6 and B3 = 20.0) and neutral detergent fibre (NDF; kg day− 1: B1 = 7.0, B2 = 6.4 and B3 = 6.3) decreased, whereas starch intake increased (kg day− 1: B1 = 3.1, B2 = 3.5 and B3 = 4.0) with increasing maturity at harvest. The apparent organic matter (OM) digestibility (g kg− 1: B1 = 800, B2 = 774 and B3 = 729) decreased with increasing maturity stage, and consequently so did the digestible OM intake. Milk (kg day− 1: B1 = 27.2, B2 = 26.1 and B3 = 25.9) and energy corrected milk (ECM; kg day− 1: B1 = 31.0, B2 = 29.4 and B3 = 28.2) yields, and protein concentration (g kg− 1: B1 = 37.1, B2 = 36.4 and B3 = 36.0) decreased with increasing maturity stage of the WCBS. When cows were fed diet B3 the milk fat concentration decreased (46.4 g kg− 1) compared to diets B1 (49.3 g kg− 1) and B2 (49.4 g kg− 1). The difference in ECM yield between diets B1 and B3 was due to a combined effect of lower milk yield, and lower protein and fat concentrations. This was caused by the higher starch and lower NDF intakes with diet B3, which decreased the milk fat concentration. Moreover, a lower energy intake of diet B3 due to lower OM digestibility decreased milk protein concentration and milk yield. Mixing WCBS at the heading stage with grass silage (M2) decreased digestibility, compared to feeding the forages separately (B1). However, the differences were small and may be a result of soil contamination at harvest of some of the silages, which made the method with using incomplete faecal collection and internal marker acid insoluble ash less reliable. Including WCBS at the heading stage at 0.30 or 0.70 of forage DM did not affect DM intake or diet digestibility, probably because the grass silage in the study was very similar in energy content to the WCBS harvested at heading.  相似文献   

17.
Ketoprofen is a nonsteroidal anti‐inflammatory and analgesic agent that nonselectively inhibits cyclooxygenase, with both COX‐1 and COX‐2 inhibition. Recent studies on COX receptor expression in reptiles suggest that nonselective COX inhibitors may be more appropriate than more selective inhibitors in some reptiles, but few pharmacokinetic studies are available. The goal of this study was to determine single‐ and multidose (three consecutive days) pharmacokinetics of racemic ketoprofen administered intravenously and intramuscularly at 2 mg/kg in healthy juvenile loggerhead turtles (Caretta caretta). The S‐isomer is the predominant isomer in loggerhead sea turtles, similar to most mammals, despite administration of a 50:50 racemic mixture. Multidose ketoprofen administration demonstrated no bioaccumulation; therefore, once‐daily dosing will not require dose adjustment over time. S‐isomer pharmacokinetic parameters determined in this study were Cmax of 10.1 μg/ml by IM injection, C0 of 13.4 μg/ml by IV injection, AUC of 44.7 or 69.4 μg*hr/ml by IM or IV injection, respectively, and T½ of 2.8 or 3.6 hr by IM or IV injection, respectively. Total ketoprofen plasma concentrations were maintained for at least 12 hr above concentrations determined to be effective for rats and humans. A dose of 2 mg/kg either IM or IV every 24 hr is likely appropriate for loggerhead turtles.  相似文献   

18.
The effects of feeding diets with different milliequivalents (mEq) of dietary ([Na+ + K+] − [Cl− + SO4=]) to dairy cows during the last seven weeks of pregnancy on bone morphology at parturition were studied. Nine monozygotic twin pairs of pregnant cows (five pairs of parity 1 or 2 and four pairs of parity 3 or more) were allocated to two diets which were formulated to provide either −4 mEq (anion diet) or +572·5 mEq (cation diet) of ([Na+ + K+] − [Cl− + SO4=]) kg−1 dietary dry matter. Bone biopsies were taken from the tuber coxae between three and eight hours after parturition. The plasma concentrations of calcium and inorganic phosphorus, the total plasma alkaline phosphatase activity and the urinary hydroxyproline:creatinine ratio were not significantly affected by diet during the experimental period. In low parity (2 or less) cows the percentage trabecular bone volume, the percentage osteoclast surface and the mean number of osteoclasts per microscopic field (identified by Goldner staining) were lower on the anion diet than on the cation diet (P<0-02). In the high parity cows, the percentage osteoid volume (P<0·05) and the ratio of percentage osteoid volume to percentage osteoid surface (P<0·001) were greater in the cows fed the anion diet than in the cows fed the cation diet. The results show that reducing the mEq of dietary ([Na+ + K+] − [Cl− + SO4=]) to −4 mEq kg−1 dietary dry matter affected some of the parameters of bone formation but did not enhance bone resorption.  相似文献   

19.
Ureaplasma species were isolated from semen samples collected sequentially from one Awassi and three Assaf breeding rams. Each ram was injected subcutaneously with an aqueous solution of lincomycin and spectinomycin for five consecutive days at a dose equivalent to 4·5 mg kg−1 lincomycin and 9·0 mg kg−1 spectinomycin daily. Serum and semen samples were collected at intervals during the treatment and assayed for lincomycin. No Ureaplasma species were isolated from semen samples collected during the course of the treatment and at intervals for 17 days after the last treatment. The concentration of lincomycin in semen ranged from 0·51 μg ml−1 four hours after treatment to 0·08 μg ml−1 24 hours after treatment, and these levels were three to nine times higher than the corresponding serum concentrations.  相似文献   

20.
High muscle camosine and anserine contents contribute significantly to intra-cellular physico-chemical buffering. Our aim was to measure carnosine, anserine and taurine contents directly in individual type I, HA and IIB fibres from the middle gluteus muscle of the camel. Mean carnosine contents in type I, IIA and IIB were 24·6 ±9·2, 39·4 ±11·4 and 42·8 ±18·8 mmol kg−1 dry weight (dw), respectively. Mean anserine contents in type I, HA and IIB fibres were 30·0 ±8·4, 37·3 ±10·1 and 34·5 ±9·7 mmol kg−1 dw, respectively. Mean taurine contents in type I, IIA and HB fibres were 42·4 ±15-9, 203 ±12·9 and 24·7 ±15·9 mmol kg−1 dw, respectively. Higher carnosine contents in type II fibres emphasise the importance of carnosine to intra-muscular acid-base regulation. A specific role for taurine in type I fibres is unclear.  相似文献   

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