Evaluation of the effect of different sedative doses of dexmedetomidine on the intestinal motility in clinically healthy donkeys (Equus asinus)

AIM: Gastrointestinal effects of different doses of dexmedetomidine in donkeys are still unidentified. The current study aimed to evaluate the impact of different doses of dexmedetomidine on the motility of selected parts of the gastrointestinal tracts in donkeys using transabdominal ultrasonography. MATERIALS AND METHODS: An experimental crossover study was conducted on 30 healthy donkeys of both sexes (15 males and 15 females; 160 ± 60 kg). With a two-week washout period, each donkey received an injection of either a normal saline solution or three different doses of dexmedetomidine (3, 5, and 7 μg/kg, respectively). All medications were administered intravenously in equal volumes. The contractility of selected intestinal segments (duodenum, jejunum, left colon, right colon, and cecum) was measured 3 min before administration (zero time) and at 15, 30, 45, 60, 90, and 120 minutes after administration. RESULTS: Small and large intestinal motility was within the normal ranges before IV injection of normal isotonic saline or dexmedetomidine at a dose of 3, 5, and 7 μg/kg. Two Way Repeated Measures ANOVA output of the data displayed a statistically significant the between time and treatments for the contractility of each of the duodenum (P = 0.0029), jejunum (P = 0.0033), left colon (P = 0.0073), right colon (P = 0.0035), and cecum (P = 0.0026), implying that the impact of treatment on the gastric motility varied among different time points. The simple main effect analysis revealed that the IV dexmedetomidine at 3, 5, and 7 μg/kg doses significantly inhibited (P ≤ 0.01) the bowel contractility compared to the administration of isotonic saline. CONCLUSION: Dose-dependent inhibitory effect of dexmedetomidine on intestinal motility was reported in donkeys following intravenous administration. This inhibitory effect on intestinal motility should be considered in clinical practice.