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1.
Cholecystokinin exerts a composite influence on gastrointestinal motility but little is known about its effect on small-intestinal slow waves. Thus, six rams were implanted with four bipolar serosal electrodes onto the duodeno-jejunal wall. In the course of chronic experiments the myoelectric activity was continuously recorded in the non-fasted animals. After recording of the full normal migrating myoelectric complex (MMC), 0.15 M NaCl or CCK peptides were injected intravenously during various phases of the next MMC cycle. Five ml of saline was injected over 30 s during phases 1, 2a, or 2b of the MMC. Cerulein was administered at doses of 1 (over 30 s), 10 (over 30 or 60 s), or 100 ng/kg (over 30, 60, 120 or 300 s) and cholecystokinin octapeptide (CCK-OP) at doses 20 times higher. CCK peptides were applied during early or late phase 1 of the MMC and during phases 2a and 2b of the MMC. In the course of additional experiments, saline and hormone administration was directly preceded by infusion of proglumide, an unspecific CCK receptor antagonist, at a dose of 10 mg/kg. The myoelectric recordings were continued until the arrival of a subsequent regular phase 3 of the MMC. In the duodenal bulb, slow waves were occasionally observed. In the duodenum the slow-wave frequency oscillated between 20 and 24 cpm and in the jejunum between 19 and 22 cpm before or after CCK peptides and proglumide. In the duodenum the slow-wave amplitude increased significantly after all doses of cerulein injected during phase 2b of the MMC. After administration of CCK-OP changes in duodenal slow-wave amplitude were not significant but exhibited a tendency similar to those after cerulein. In the jejunum, injection of cerulein and CCK-OP during phase 2 of the MMC increased the slow-wave amplitude significantly and the duration of these changes was longer than in the duodenum. After infusion of proglumide, administration of cerulein at the low dose over 30 s and at the high dose over 300 s in the course of late phase 1 and phases 2a and 2b of the MMC, significantly increased the duodenal slow-wave amplitude. Cerulein injection during phase 2b of the MMC at the high dose over 30 and 60 s, preceded by proglumide infusion, significantly inhibited the duodenal slow-wave amplitude. In the jejunum these changes were even more pronounced and their duration was much longer. It is concluded that CCK peptides affect slow-wave amplitude in the duodeno-jejunum in non-fasted sheep. This effect is stronger in the jejunum and is altered but not abolished by pretreatment with proglumide. Cerulein evokes more pronounced alterations in the slow-wave amplitude than CCK-OP in conscious sheep.  相似文献   

2.
As feeding is not a factor disrupting the migrating motor (myoelectric) complex (MMC) in sheep, it is presumed that the fed pattern is absent in this animal species. In turn, feeding may stimulate ovine gastrointestinal motility. To verify this discrepancy the myoelectric activities of the antrum and duodeno-jejunum were recorded in seven adult sheep. Additionally, the relationship between electrical and mechanical activity was tested in four of these animals by means of strain gauge force transducers mounted near the duodenal electrodes. Chronic experiments were conducted in fasted and non-fasted sheep before, during, and after standard feeding. Fodder was offered during the duodenal phases 1, 2a, or 2b of the MMC. Two types of responses to feeding (an unspecific and a specific fed pattern) were denoted. A simple increase in spike burst intensity, i.e. without their special deployment and assessed as the myoelectric activity index (unspecific fed pattern), was observed in the abomasal antrum and small bowel during and after feeding in the course of phase 2b of the MMC in non-fasted and fasted sheep. In the abomasal antrum its duration was longer than in the small intestine. In non-fasted animals the unspecific fed pattern was more pronounced in the abomasal antrum than in the small bowel, while its duration was longer in fasted animals. The specific fed pattern was evoked in the duodeno-jejunum during feeding initiated in the course of phase 2b of the MMC exclusively in non-fasted animals. During this pattern, the spike burst series were significantly reduced compared with those which appeared during phase 2b of the MMC and dispersed single spike bursts predominated. The average duration of the specific fed pattern was 3-4 min and it arrived 2-7 min after feeding onset. In the remaining periods during feeding, the spike burst pattern resembled that often observed during phase 2b of the MMC. Thus the confined fed pattern is present in sheep and its character depends upon the gastrointestinal region and feeding habits.  相似文献   

3.
Eight adult conscious rams were used to characterize further the minute rhythm and to determine the role of cholinergic receptors in nervous control of this event. In chronic experiments, the myoelectrical and motor activity of the gastrointestinal tract and gallbladder were recorded. Physiological experiments were performed in fasted or non-fasted rams before, during and after feeding, and the occurrence of minute rhythm during various phases of the migrating motor myoelectric complex was observed. The pattern occurred most frequently in the small intestine, where it exhibited mostly the propagating character. It was also detectable in the ileum. In the gallbladder, the minute rhythm arrived systematically and its character was irregular, propagating, retropropagating or stationary. In all episodes observed, it was well correlated with that in the small intestine. In the pyloric antrum, the minute rhythm was identified occasionally. During pharmacological experiments, 0.15 M NaCl or graded doses of hexamethonium, atropine and pirenzepine were administered intravenously during various phases of the migrating motor myoelectric complex, in fasted and non-fasted animals, before and during feeding. The drugs inhibited the minute rhythm in the small bowel for a longer period than in the gallbladder. However, the smallest dose of pirenzepine (0.02 mg/kg) exerted a non-significant effect both in the small intestine and in the gallbladder. It is concluded, that in normal conditions the minute rhythm occurs regularly in the entire small intestine and in the gallbladder. In the small intestine the pattern is organized more precisely. The minute rhythm is controlled by nicotinic receptors and by muscarinic receptor subtypes.  相似文献   

4.
The changes induced in the electrical activity of the small intestine by atropine sulphate, diphemanil methylsulphate, hyoscine butylbromide and prifinium bromide were studied in conscious sheep fitted with chronically implanted electrodes. Increased spike potential activity was induced by carbachol. The mean slow-wave frequency of the antrum was 7.35 ± 0.18/min with burst of spike potentials randomly superimposed on about 63% of the slow waves. The occurrence of the spike bursts was inhibited for 18—30 min after an intravenous injection of atropine (0.75 mg/kg) and during its infusion at the rate of 0.05 mg/kg/min. The activity of the proximal part of the small intestine, which is characterized by migrating myoelectric complexes moving down slowly at hourly intervals, was replaced by irregular series consisting of spike bursts of about 3 min duration, at intervals of about 12 min for a total of 110 min. Such an effect, in which the level of spike activity was reduced, was also observed with hyoscine, diphemanil and prifinium during 80, 120 and 180 min periods respectively. The injection of carbachol was followed by continuous spike activity in which the mean spike level was nearly doubled, as occurs at the onset of diarrhoea. An inhibitory effect was observed at both antral and duodeno-jejunal levels with the four drugs used, that of hyoscine being least marked. The effect of prifinium was more pronounced than that of atropine or diphemanil, especially on the jejunum. The results suggest that the ability of these drugs to reduce the level of spike activity accompanying disruption of migrating myoelectric complexes and to inhibit the carbachol-induced increased level of spiking may account for the antispasmodic effects observed after the use of anticholinergic drugs in gastrointestinal disorders. Prifinium had the longest lasting effect at both antral and duodeno-jejunal levels and seemed to be a good atropine substitute to alleviate gastro-intestinal hypermotility.  相似文献   

5.
There are no precise data concerning the effect of cerulein on the small-intestinal migrating motor complex (MMC) in sheep. Thus, the effort was directed towards the elucidation of the role of cerulein, a cholecystokinin (CCK) amphibian analogue, in the regulation of MMC cycle in conscious fasted and non-fasted sheep in various regions of the small intestine. In six sheep, equipped with bipolar electrodes in the entire small intestine and with one duodenal strain gauge force transducer in four of these animals, the continuous myoelectric and motor activity recordings were performed. During control period, two normal consecutive MMC cycles were recorded in fasted and non-fasted animals and then cerulein was slowly injected at the dose 1 (during 30 s), 10 (during 30 s or 60 s) or 100 ng/kg (during 30 s, 60 s or 120 s) or infused at the dose 0.5 or 1.5 ng/kg/min during 60 min. After cerulein administration at least two consecutive MMC cycles were also recorded. It was found that cerulein in moderate and higher doses injected in both fasted and non-fasted animals, especially during phase 2a or 2b MMC, inhibited phase 3 in the duodenum in at least one-third of the experiments and significantly increased the MMC cycle duration. The application of 100 ng/kg of cerulein during 120 s in the course of phase 2b MMC prolonged cycle duration from 70 +/- 21 to 113 +/- 19 min (p < 0.05) or from 51 +/- 18 to 113 +/- 19 min (p < 0.01) in fasted and non-fasted sheep respectively. The first phase 3 MMC arriving after cerulein administration at the highest dose was usually abnormal in approximately 60% of the experiments. The second phase 3 observed following the hormone injection was abnormal much less frequently and to the lesser extent. Furthermore, both cerulein doses significantly shortened the duration of phase 3 MMC either in fasted (from approximately 5.5-6.5 cpm to 4-5 cpm) or in non-fasted sheep (from approximately 4.5-5.5 to 3-4.5 cpm). The effects of cerulein exhibited the dose-response character. They were more pronounced when cerulein was injected during phase 2b or 2a MMC when compared with phase 1 MMC. The effects of cerulein on the ileal MMC were less evident, although the inhibition of the ileal phase 3 in response to both higher injected doses was observed occasionally. Infusions of cerulein in non-fasted sheep exerted similar effects as cerulein injections. It was stated that cerulein exerts marked regulatory effect upon the small-intestinal MMC in sheep. Although it remains uncertain whether the efficient doses of cerulein used in the present study correspond to physiological or pharmacological doses of CCK it seems likely that most of these doses were physiological. Thus, it is concluded that cerulein participates in the control of MMC cycles in the digestive and interdigestive states in sheep. It is possible that CCK is a physiological regulator of the ovine small-intestinal MMC.  相似文献   

6.
Safe, effective, and reversible immobilization protocols are essential for the management of free-ranging red wolves (Canis rufus). Combinations using an alpha2-adrenoceptor agonist and ketamine have been shown to be effective for immobilization but are not reversible and can produce severe hypertension and prolonged or rough recoveries. To minimize hypertension and provide reversibility, 24 red wolves were immobilized using three medetomidine-butorphanol (MB) combinations without the use of ketamine in the initial injection. All wolves were administered medetomidine (0.04 mg/kg i.m.) and butorphanol (0.4 mg/kg i.m.). Seven wolves received no other immobilization agents (MB wolves), nine received diazepam (0.2 mg/kg i.v.) at the time they were instrumented (MBD wolves), and eight received ketamine (1 mg/kg i.v.) 30 min after instrumentation (MBK30 wolves). Physiologic parameters were monitored during immobilization. The heart rate was similar among the three groups for the first 30 min, and marked bradycardia was noted in one wolf from each group. Hypertension was observed initially in all three groups but was resolved within 10-30 min. The MBK30 wolves had significant elevations in heart rate and transient hypertension after intravenous ketamine administration. Most wolves had mild to moderate metabolic acidemia. Immobilizing drugs were antagonized in all wolves with atipamezole (0.2 mg/kg i.m.) and naloxone (0.02 mg/kg i.m.). The medetomidine-butorphanol-diazepam wolves were also given flumazenil (0.04 mg/kg i.v.). All wolves were standing within 12 min and were fully recovered within 17 min. Medetomamine-butorphanol and MBD combinations provided effective and reversible immobilization of red wolves without the sustained hypertension associated with the use of alpha2-adrenoceptor agonist-ketamine combinations. Delaying the administration of ketamine reduced its hypertensive effects.  相似文献   

7.
We assessed prokinetic action of gastroprokinetic agent, mosapride in dogs. Open-label cross-over study. Six healthy beagles were administered single oral mosapride at doses of 0.5, 0.75, 1, and 2 mg/kg 30 min prior to feeding, followed by 1-week interval. The motility index (MI) of gastric contraction was ultrasonographically evaluated by change rate of antral area and contraction number. Significant increases in MI were observed at doses of 0.75 mg/kg (mean ± SEM, 11.11 ± 0.19), 1 mg/kg (11.65 ± 0.34), and 2 mg/kg (12.04 ± 0.34), compared with that of the control (9.37 ± 0.51). Mosapride administration (2.0 mg/kg, BID) for 1 week had no adverse effects on blood tests or health of the animals. In conclusion, 0.75 to 2 mg/kg of mosapride produces gastric prokinetic actions without adverse effects.  相似文献   

8.
OBJECTIVE: To measure the effect of lidocaine on the duration of the migrating myoelectric complex (MMC) and Phases I, II, and III of the MMC, spiking activity of the jejunum, and number of Phase III events when administered postoperatively to normal horses. STUDY DESIGN: Nonrandomized cross-over design. METHODS: Horses were anesthetized and via flank laparotomy 4 silver-silver chloride bipolar electrodes were sutured to the proximal jejunum. Electrical activity was recorded for 6 hours during 3 recording sessions beginning 24, 48, and 72 hours postoperatively. Saline (0.9% NaCl) solution was administered for 3 hours followed by lidocaine administration for 3 hours (1.3 mg/kg bolus intravenously [IV], 0.05 mg/kg/min IV constant rate infusion). RESULTS: Duration of MMC was unchanged during lidocaine administration (77 minutes-saline versus 105 minutes-lidocaine, P=.16). Durations of Phase I and II were unchanged during lidocaine administration (P=.19 and .056, respectively). Phase III was shorter during lidocaine administration (P=.002). Spiking activity was unchanged at all time periods during lidocaine administration (24 hours-P=.10; 48 hours-P=.95; and 72 hours-P=.12). The number of Phase III events was unchanged over all time periods during lidocaine administration (P=.053). CONCLUSIONS: Duration of MMC, spiking activity, and number of Phase III events was unchanged during lidocaine administration. CLINICAL RELEVANCE: Use of lidocaine as a prokinetic agent cannot be supported by this study in normal horses; however, results may differ in clinically affected horses.  相似文献   

9.
Pharmacokinetic studies of antibiotics in South American camelids are uncommon, therefore drugs are often administered to llamas and alpacas based on dosages established in other domestic species. The disposition of ceftiofur sodium was studied in llamas following intramuscular administration and in alpacas following intravenous and intramuscular administration. Eleven adult llamas were given ceftiofur sodium by intramuscular injection. Each animal received either a standard dose of 2.2 mg/kg or an allometrically scaled dose ranging from 2.62 to 2.99 mg/kg in a crossover design. Ten adult alpacas were given ceftiofur sodium by intravenous and intramuscular injections. Each animal received a standard dosage of 1 mg/kg or an allometrically scaled dose ranging from 1.27 to 1.44 mg/kg i.v., and 1.31-1.51 mg/kg i.m. Blood samples were collected at 0, 0.25, 0.5, 1, 2, 4, 8, 12, 24, 36, 48, and 72 h after administration of the ceftiofur. Pharmacokinetic parameters of ceftiofur in llamas and alpacas were similar following i.m. dosing at both dose levels. The only differences noted were in the total AUC between dose levels, but the AUC/dose values were not different. A sequence effect was noted in the alpaca data, which resulted in lower AUCs for the second dose when the i.v. dose was given first, and with higher AUCs for the second dose when the i.m. dose was given first. Overall, ceftiofur pharmacokinetics in llamas and alpacas are similar, and also very similar to reported parameters for sheep and goats.  相似文献   

10.
The efficacy of closantel against experimentally induced Fascioloides magna infection in sheep was studied. In each of 3 experiments, closantel was administered 8 weeks after the sheep were given (oral inoculation) 100 metacercariae of F magna. In the 1st experiment, closantel was given orally to 5 groups of 6 sheep each at dosages of 0 (nontreated control), 5, 7.5, 10, and 15 mg/kg of body weight. In the 2nd and 3rd experiments, groups of 10 or 12 sheep were treated to confirm the efficacy of the previously determined optimal dosage of 15 mg/kg. An additional group of sheep (n = 10) was used in the 3rd experiment to evaluate the efficacy of closantel given IM at a dosage of 7.5 mg/kg. Closantel given orally at a dosage level of 15 mg/kg was highly effective (94.6% to 97.7%) in reducing F magna burdens. Also, pathologic scores associated with the F magna infection were reduced by 81.3% to 92.6% in sheep given this dosage of closantel. Efficacy of the IM administered dosage of 7.5 mg of drug/kg was equivalent to that of the 15 mg/kg oral dosage. Other than mild, transient lameness of the limbs which were injected with the drug (group 10), side effects were not observed.  相似文献   

11.
The sedative effect induced by administering xylazine hydrochloride or detomidine hydrochloride with or without butorphanol tartrate to standing dairy cattle was compared in two groups of six adult, healthy Holstein cows. One group received xylazine (0.02 mg/kg i.v.) followed by xylazine (0.02 mg/kg) and butorphanol (0.05 mg/kg i.v.) 1 week later. Cows in Group B received detomidine (0.01 mg/kg i.v.) followed by detomidine (0.01 mg/kg i.v.) and butorphanol (0.05 mg/kg i.v.) 1 week later. Heart rate, respiratory rate, and arterial blood pressure were monitored and recorded before drugs were administered and every 10 minutes for 1 hour after drug administration. The degree of sedation was evaluated and graded. Cows in each treatment group had significant decreases in heart rate and respiratory rate after test drugs were given. Durations of sedation were 49.0 +/- 12.7 minutes (xylazine), 36.0 +/- 14.1 (xylazine with butorphanol), 47.0 +/- 8.1 minutes (detomidine), and 43.0 +/- 14.0 minutes (detomidine with butorphanol). Ptosis and salivation were observed in cows of all groups following drug administration. Slow horizontal nystagmus was observed from three cows following administration of detomidine and butorphanol. All cows remained standing while sedated. The degree of sedation seemed to be most profound in cows receiving detomidine and least profound in cows receiving xylazine.  相似文献   

12.
The antinociceptive activity of the intravenously administered alpha 2-adrenoceptor agonists, clonidine and xylazine, was measured in sheep using thermal and mechanical pressure threshold detection systems. Both drugs demonstrated clear antinociceptive activity for both forms of threshold stimuli and clonidine at 6 micrograms/kg i.v. was more potent and longer lasting than xylazine at 50 micrograms/kg i.v. The antinociceptive effects were reversed by idazoxan (0.1 mg/kg i.v.), but were not affected by naloxone at 0.2 mg/kg i.v. indicating that these effects were mediated by alpha 2-adrenoceptors.  相似文献   

13.
Five 5 to 6 month old horses were surgically prepared with silver electrodes sutured to the serosa of gastric antrum, duodenum and proximal portions of the jejunum. Normal migrating motility complex (MMC) periodicity was determined during daytime hours in horses that were fed and horses from which food was withheld for 24 hours. Periodicity was defined as time span from the end of one period of regular spike activity (RSA) to the end of the next RSA in the MMC. The periodicity was 120.5 +/- 9.5 (SEM) minutes in horses from which food was withheld, and was 125.7 +/- 20.3 minutes in horses fed hay free choice. Coincident with each duodenal RSA, antral spike activity ceased. Xylazine (0.25 and 0.5 mg/kg), given IV during the period of intermittent spike activity of the MMC to either fed or unfed horses induced, within 2 minutes, a RSA complex in the duodenum that migrated to the proximal portion of the jejunum. This was followed by a period of no spike activity of normal duration, which proceeded on to a period of intermittent spike activity of varying duration to complete the MMC cycle. Pretreatment IV administration of an alpha 2-adrenergic antagonist, tolazoline (1 mg/kg) also provoked a RSA complex, but blocked the xylazine effect. The results indicated that xylazine resets the duodenal MMC in the horse, but does not seriously disrupt proximal gastrointestinal tract motility, and that control of MMC periodicity in this region probably involves more than alpha 2-adrenergic receptors.  相似文献   

14.
In dwarf goats fasted for 2 h, i.v. administration of the benzodiazepine (BZ) agonists diazepam (60 micrograms/kg), brotizolam (2 and 4 micrograms/kg) and climazolam (100 micrograms/kg) induced hyperphagic effects, whereas i.v. injections of the BZ-antagonist flumazenil (R degrees 15-1788; 0.5 mg/kg), the anthelmintic ivermectin (0.1 mg/kg), the 5-HT2 antagonist ritanserine (0.1 mg/kg), ACTH (10 micrograms/kg) and prednisolone (1 mg/kg) were inactive in a 30-min feeding test. Both the BZ-antagonist R degrees 15-3505 (greater than or equal to 0.1 mg/kg) and the opiate receptor antagonist naloxone (0.1 mg/kg) had anorectic effects in dwarf goats given 30 min access to a palatable pelleted concentrate. The hyperphagic effects of climazolam and brotizolam were not antagonized by flumazenil, whereas similar doses of this drug completely reversed muscle incoordination and ataxia induced by much higher doses of these BZ-agonists. In the combination experiments with naloxone and BZ-agonists, naloxone antagonized the hyperphagic effects of both diazepam and brotizolam. Similarly, in the diazepam-R degrees 15-3505 study, there was a significant effect of diazepam and a significant inhibition of this effect by R degrees 15-3505 (50 micrograms/kg). In the diazepam-ivermectin combination experiment no evidence for drug potentiation was found. These results and the mode of action of the above mentioned drugs are discussed in relation to feeding behaviour.  相似文献   

15.
The pharmacokinetics of a 2:1 ampicillin-sulbactam combination after intravenous (i.v.) and intramuscular (i.m.) injection at a single dose rate of 20 mg/kg bodyweight (13.33 mg/kg of sodium ampicillin and 6.67 mg/kg of sodium sulbactam) were studied in 10-day-old neonatal calves (n = 10). The plasma concentration-time data of both antibiotics were best fitted to an open two-compartment model after i.v. administration. After i.m. administration, an open two-compartment model demonstrated first order absorption. The apparent volumes of distribution of ampicillin and sulbactam, calculated by the area method, were 0.20+/-0.01 and 0.18+/-0.01 L/kg, respectively, and the total body clearances were 0.51+/-0.03 and 0.21+/-0.01 L/kg h. The elimination half-lives of ampicillin after i.v. and i.m. administration were 0.99+/-0.03 and 1.01+/-0.02 h, respectively, whereas for sulbactam the half-lives were 2.24+/-0.02 and 3.44+/-0.94 h. The bioavailability after i.m. injection was high and similar for both drugs (70.31+/-0.2% for ampicillin and 68.62+/-4.44% for sulbactam). The mean peak plasma concentrations of ampicillin and sulbactam were reached at similar times (0.47+/-0.02 and 0.72+/-0.01 h, respectively) and peak concentrations were also similar but not proportional to the dose administered (17.88+/-0.91 mg/L of ampicillin and 12.92+/-0.79 mg/L of sulbactam). Both drugs had similar pharmacokinetic behaviour after i.m. administration. Since the plasma concentrations of sulbactam were consistently higher during the elimination phase of their disposition, consideration could be given to formulating the ampicillin-sulbactam combination in a ratio higher than 2:1.  相似文献   

16.
Kaya, F., Van Duin, C.T.M. & Van Miert, A.S.J.P.A.M. Food intake and rumen motility in dwarf goats. Effects of some dopamine receptor agonists. J. vet. PharmacolTherap, 17 , 120–126. In ruminants, the dopaminergic regulation of feeding behaviour has not been investigated. Therefore, the effects of dopamine receptor agonists and antagonists on food intake and forestomach motility were studied in dwarf goats Goats treated i.v. with bromocriptine (1 μg or 2.5 μg/kg body wt/min during 10 min) ate less food than when treated with saline. This inhibitory effect on food intake could not be prevented by the peripheral dopamine receptor antagonist domperidone (0.5 mg/kg body wt i.v.). In contrast, dopamine (i.v. 20 μg/kg body wt/min during 15 min), levodopa (i.v. 40 μg/kg body weight during 10 min), apomorphine (i.v. 2 μg/kg body wt/min during 10 min) and lisuride (i.v. 0.2 μg/kg body wt/min during 15 min and 0.5 μg/kg body wt during 10 min) failed to modify food intake. Given in association with benserazide, a decarboxylase inhibitor (i.v. 20 μg/kg body wt/min during 10 min), levodopa was still inactive as an anorectie agent. Levopoda, bromocriptine and lisuride administered at similar dose rates to those which were used in the food intake experiments, induced some clinical signs including inhibition of forestomach contractions. The inhibition of rumen contractions induced by these drugs was completely antagonized by domperidone pretreatment. These results, together with earlier in vivo and in vitro observations, suggest that the inhibitory effects of dopamine receptor agonists on forestomach contractions are due to interactions with peripheral dopaminergic receptors. The change in smooth muscle tension, which leads to a change in the signals transmitted via vagal afferents to the central nervous system, probably does not modify feeding behaviour in dwarf goats. Furthermore, i.v. infusion of lisuride induced rumination when the inhibition of the forestomach contractions was prevented by domperidone; this effect may involve α2-adrenoceptor activation.  相似文献   

17.
1. The effects of dietary aflatoxin (AF, 0.5, 1.0 and 2.0 mg/kg), ochratoxin (OA, 1.0, 2.0 and 4.0 mg/kg) or combinations of these on body weight gain, feed efficiency, organ weights and immune response were studied in broilers. 2. Significant growth depression, reduced food consumption and poor food conversion efficiency were recorded in broilers fed a diet containing the greater concentrations of AF (1 and 2 mg/kg) and OA (2 and 4 mg/kg). 3. The combination of 2 mg/kg AF and 4 mg/kg OA exerted the maximum adverse effect on growth, feed intake and feed efficiency, indicating a synergistic effect on performance. 4. AF at 2 mg/kg in the diet caused a significant increase in the relative weight of liver, whereas the relative weight of kidney was significantly increased at 4 mg/kg of OA. A significant decrease in the relative weight of the bursa of Fabricius was noted at the highest concentration of AF (2 mg/kg) and combinations of 1 and 2 mg/kg AF and 2 and 4 mg/kg OA. 5. Cell mediated immunity (CMI), in terms of mean skin thickness (MST) sensitive to dinitrochlorobenzene (DNCB), was significantly reduced in chicks given the combination of 2 mg/kg AF and 4 mg/kg OA. Haemagglutination (HA) titre against sheep red blood cells (SRBCs) peaked at 42 d of age. At 42 and 47 d of age, a significant decrease in HA titres was recorded in chicks given 4 mg/kg OA or a combination of AF (1 or 2 mg/kg) and OA (2 or 4 mg/kg). 6. AF at a dietary concentration of 1 mg/kg or more and OA at 2 mg/kg or more, either alone or in combination, caused severe reductions in growth and immune response.  相似文献   

18.
Gastric myoelectric activity was measured in 10 dogs with spontaneous gastric dilatation-volvulus (GDV). Myoelectric activity was recorded with temporary, retrievable wire electrodes placed on the serosal surface of the stomach after derotation and tube gastrostomy. Gastric myoelectric activity was recorded for 1 hour daily, beginning with the day of surgery (less than 24 hours), 24, 48, 72, 96, 120, 144, and 168 hours after surgery. Recordings were also obtained for 1 hour daily after feeding, beginning 24 hours after surgery. Bradygastria was the predominate dysrhythmia immediately after surgery and at hour 24. The mean slow wave frequency was more than normal at hours 48 to 168 due to an increase in tachygastria and arrhythmias. The slow wave frequency significantly decreased after feeding at hours 120 and 144. The overall mean percentage of dysrhythmias was significantly decreased after feeding at hour 72 only. The mean percentage of spike activity ranged from 37.7 +/- 12.5 to 75.7 +/- 6.2 throughout the 8-day study period. Thus, gastric myoelectric activity was disrupted in these dogs with spontaneous GDV and subsequent tube gastrostomy. Feeding did not greatly diminish these dysrhythmias.  相似文献   

19.
Effects of medetomidine on intestinal and colonic motility in the dog   总被引：1，自引：0，他引：1  
The motor responses of the jejunum and colon to stimulation of α2-adrenoceptors by medetomidine and clonidine were investigated in four dogs. In fasting dogs, medetomidine, at a dose rate of 30 μg/kg i.v., disrupted the migrating myoelectric complex (MMC) pattern of the small intestine for about 2 h. Similar, but shorter-lasting effects were also induced by clonidine (30 μg/kg i.v.) on the jejunum. The administration of α2-agonists inhibited colonic motility in fasting dogs, although medetomidine-induced inhibition was preceded by a short period of increased muscle tone. All these effects were reversed by the α2-antagonists atipamezole (0.15 mg/kg i.v.) and yohimbine (0.20 mg/kg i.v.). In fed dogs, medetomidine (30 μg/kg i.v.) induced a strong increase of the tone on the proximal colon, while the activity of the medium and distal colon was completely suppressed. Yohimbine (0.50 mg/kg i.v.) immediately restored the activity of the colon and induced a propagated giant contraction and defaecation by the animal. These data confirm the importance of a2-adrenergic receptors in the control of intestinal and colonic motility in the dog.  相似文献   

20.
伊维菌素浇泼剂对绵羊线虫的驱虫效力与安全性试验   总被引：3，自引：0，他引：3  
应用0.5%伊维菌素浇泼剂按0.3,0.4,0.5mg/kg.b w剂量对绵羊沿背中线皮肤一次浇泼给药,并以伊维菌素注射剂0.2mg/kg.b w剂量做对照。结果:伊维菌素浇泼剂0.3mg/kg,0.4mg/kg.b w剂量对消化道线虫虫卵转阴率分别为85%和90%,减少率分别为89.1%和95.9%;对原圆科线虫幼虫转阴率分别为60%和75%,减少率分别为77.2%和86.7%;0.5mg/kg.b w剂量对消化道线虫虫卵转阴率和减少率均为100%,对原圆科线虫幼虫转阴率为85%,减少率为95.4%。解剖检查结果:伊维菌素浇泼剂三种剂量对绵羊消化道、呼吸道多属线虫均有效,总计驱虫率分别为90.8%,95.6%和99.7%,伊维菌素浇泼剂0.5mg/kg.b w剂量与伊维菌素注射剂0.2mg/kg.b w剂量驱虫效果基本一致;绵羊经皮给药可耐受1.0mg/kg.b w剂量。试验证明:伊维菌素浇泼剂经皮给药驱除绵羊线虫高效安全,临床推荐剂量以0.5mg/kg.b w为宜。  相似文献   

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