Effect of high ammonia level on stress-induced hematological changes in rabbits: preventive effect of pyridoxine

D. Gudev, M. Dyavolova, P. Moneva, I. Yanchev

Abstract: The object of the present experiment was to evaluate the effect of air ammonia on some hematological parameters and rabbit response to short-term psychological stress as well as to test the effect of supplemental pyridoxine. Eighteen New Zealand rabbits at the average age of 3.6 months were divided into 3 groups as follows: Control group - reared under low air ammonia levels (6.79±2.55 ppm) and two experimental groups- reared under higher air ammonia levels (21.98±7.84 ppm). The second experimental group was given supplemental pyridoxine (200 mg/l) throughout the 10 day long experimental period. Arterial blood samples were taken at the start (1-st day) and at the end of the experiment (10-th day) as well as before and following exposure to psychological stress. Stress was induced on day 10 by 1 minute “dog barking” PC record in a triple 110 dB playback. The following parameters were evaluated: total erythrocyte and leukocyte counts, hematocrit, peripheral blood leukocyte distribution, rectal temperature, respiratory rate and air ammonia concentration. Ammonia augmented leukocyte counts (P<0.05) and hematocrit levels (P<0.05) while at the same time it thwarted the expected rise in heterophil to lymphocyte ratio in response to stress. Pyridoxine prevented ammonia-provoked increase in total leukocyte numbers (P<0.05) and hematocrit levels (P<0.05) in response to stress. Pyridoxine caused a decrease in respiratory rate (P<0.05) and an increase in rectal temperature (P<0.05) as compared to the unsupplemented rabbits. The results are interpreted to suggest that nitric oxide mediates the effects of both ammonia and glucocorticoids on leukocyte subpopulations, which ultimately may compromise the effect of glucocorticods on heterophil to lymphocyte ratio.

Keywords: air ammonia; pyridoxine; rabbits; stress

Date published: 2019-02-20