Effect of physical exercise on cortisol concentration and neutrophil oxygen metabolism in peripheral blood of horses

Abstract

the aim of the study was to evaluate the effect of regular physical exercise on cortisol concentration and oxygen-dependent bactericidal activity of neutrophils in peripheral blood in recreational and competitive sport horses (racehorses -ra, trotters -t, jumping horses -J, driving horses -d). the study was conducted on 55 clinically healthy horses. blood samples were collected from the external jugular vein three times: before exercise, immediately after exercise, and after 30-min rest. blood samples were subjected to haematological examination, cortisol concentration was determined by radioimmunoassay (ria) and neutrophil oxygen metabolism of neutrophils was determined using a chemiluminescence method. the analysis showed that cortisol concentration was significantly higher (P<0.05) post-exercise only in the blood of sport horses. This finding, along with a significant correlation (P<0.00005) with the heart and respiratory rates, suggests that the magnitude of cortisol secretion is associated with the intensity and duration of exercise. the relatively small post-exercise increase in cortisol concentration during different exercises of horses resulted in a transient increase of chemiluminescence activity of neutrophils, mainly in d (P<0.00001) and J horses (P<0.01). In the studied groups analysis of the correlation between cortisol concentration and other parameters showed significant correlation only in the case of the CL total in T (P<0.02) and D horses (P<0.004). It is therefore apparent that in a limited concentration, this hormone may stimulate the activity of these cells, although the effect of other neurohormonal factors cannot be excluded. This result confirms that regular and moderate training loads have a beneficial effect on the immunological status of horses.

Immune Response in Young Thoroughbred Racehorses under Training

“…Acute exercise has an effect on white blood cells and cytokines [ 53 ]; the effect of training is less known, especially in horses, and we hypothesized that it should mimic, if well planned, the positive effects of prolonged moderate exercise [ 57 , 58 ].…”

“…Concerning the trend of neutrophils, we observed an increase of these cells at each time of sampling, with higher levels 90 days after the start of training. Since the prevalence of band neutrophils was always negligible, we can reasonably rule out infectious agents underlying the observed neutrophilia [ 59 , 60 ], which is reminiscent instead of a stress leukogram due to endogenous corticosteroid release [ 58 ]. Monocytes and eosinophils showed the same trend of neutrophils, with a significant increase at 90 days for eosinophils ( p < 0.05), at 30 days for basophils ( p < 0.05), and a tendency of increase ( p < 0.1) for monocytes and lymphocytes followed by a decrease and a return to starting values after a further 60 days (T90).…”

“…One explanation of this trend in leukocytes can be cortisol secretion in response to exercise. In addition to that, catecholamines such as epinephrine cause leukocytes to detach from the vascular wall and microvasculature into the main circulation; this, as well as splenic contraction, may significantly elevate white blood cell counts [ 58 ]. Indeed, young horses are characterized by higher blood cortisol levels post-exercise compared to older animals and those with greater training experience [ 51 , 61 ].…”

Fecal Cortisol Metabolites in Dairy Cows: A Cross-Sectional Exploration of Associations with Animal, Stockperson, and Farm Characteristics

“…Although provision of attractive feed by hand is considered a pleasant human–animal interaction and was shown to be associated with less fearful responses towards humans [ 39 ], manual concentrate provision was associated with increased FCM levels in the present investigation. This might be explained by increased arousal, physical activity [ 40 ], and possibly also social stress during feeding, when the attractive feed is provided.…”

Original article In vitro changes in adaptive cell-mediated immunity under medicinal plant extract treatment in resting horses from different workout backgrounds

“…Strenuous exercise suppresses the function of these phagocytic cells (Robson et al, 2003;Raidal et al, 2000). Prolonged and also short-term high intensity exercices induce a prolonged suppression of phagocyte function in horses (Raidal et al, 2000;Krumrych et al, 2018). After prolonged exercise may occur significant leucocyte and hormonal perturbations and a long-term suppression of the innate immune system function (Burrell et al, 1996;Raidal et al, 2000;Robson et al, 2003), followed by an increase of infections in horses during training (Burrell et al, 1996).…”