Discussion
A highly significant increase in temperature, heart rate, pulse rate and
respiration rate were observed after exercise when compared to before
exercise. An increased heart rate and respiration rate in the present
study is in concurrence with Snow and Mackenzie (1977); Katz et
al. (2000); Hassan et al. (2015). The elevated heart rate and
respiration rate following exercise may be attributed to the activation
of the sympathetic nervous system and the subsequent rise in
catecholamine levels. An increase in rectal temperature in the present
study is in accordance with Gisolfi (2001) and Hassan et al. (2015). It is mainly due to continues muscular contractions that needs a
continuous energy supply derived from fat metabolism and the energy
obtained through the breakdown of ATP molecules typically serves to
maintain body temperature (Fritzsche and Coyle, 2000; McKeever and
Kearns, 2001) and it may also be due to compromised cardiovascular,
respiratory and heat loss mechanism (Malinowski et al ., 1993).
After exercise there was a highly significant increase in Hb, RBC and
PCV and significant increase in MCV when compared to pre-exercise.
Similar findings were also reported by Andrews et al. (1995),
Thompson et al. (2001), Ricketts (2004) and Hassan et al. (2015). This increase in hematological parameters might be attributed to
the release of splenic erythrocytes influenced by catecholamines during
exercise and hemoconcentration resulting from dehydration, as suggested
by Ricketts (2004).
In the present study there was a highly significant increase in WBC and
lymphocytes after exercise when compared to before exercise. This result
was in accordance with Rose and Hodgson (1982); Snow et al. (1983); Hassan et al. (2015). The exercise-induced leukocytosis
is likely attributed to catecholamine. The spleen not only releases
stored erythrocytes but also releases leukocytes into the peripheral
circulation. The spleen plays a crucial role as a production site,
especially for lymphocytes. Consequently, the increase in leukocytes in
the peripheral circulation is predominantly comprised of lymphocytes
than other type of leukocytes.
In the present study there was a significant decrease in platelet count
and highly significant increase in MPV after exercise when compared to
before exercise. These findings are in accordance with Zobba et
al. (2011). Mild exercise tends to have minimal effects on platelet
activation and may even dampen it, while strenuous exercise causes
increase in platelet activation which depends on intensity of exercise
(Wang et al., 1994).
In this study, highly significant elevation of glucose was observed
after exercise when compared to before exercise. These findings were
agreed with Nakata et al. (1999), Simões et al. (1999) and
Hassan et al. (2015). These increases in glucose levels might be
attributed to the hyperactivity of the sympathetic nervous system and
the release of adrenaline, which, trigger hepatic glycogenolysis (Trilket al ., 2002).
The values of total protein and albumin showed highly significant
increase after exercise when compared to before exercise. This was in
accordance with the findings of Sommardahl et al. (1994); Zobbaet al. (2011) and Hassan et al. (2015). They reported that
redistribution of fluid and electrolytes from the vascular compartment
to the extra-cellular fluid spaces within the tissues, along with a
decrease in plasma volume resulting from removal of fluid from
bloodstream, leading to hemoconcentration and dehydration.
Highly significant increase in cholesterol after exercise was documented
when compared to before exercise. This finding was in accordance with
Hassan et al. (2015). The rise in cholesterol concentration could
be due to lipid mobilization resulting from intensive physical activity.
Aspartate transaminase (AST) showed highly significant increase after
exercise when compared to before exercise. These findings were
consistent with Kobluk et al. (1995) and Hassan et al. (2015). The rise in AST levels could be attributed to the increased
permeability of enzyme from muscle cell caused by muscular stress
(Watson, 1998). Alkaline phosphatase (ALP) showed highly significant
increase after exercise when compared to before exercise. These findings
are consistent with Rose et al. (1980). He found that the rise in
ALP after exercise was unclear whether the source was skeletal or
hepatic.
In this study elevated levels of lactate dehydrogenase were observed
after exercise when compared with before exercise. This is in accordance
with Tateo et al. (2008) and Hassan et al. (2015). They
observed that the release of LDH from tissues after exercise and it has
been mostly from muscles. In this study triglycerides showed significant
increase after exercise when compared to before exercise. These results
are similar with Rose et al. (1980). This increase might be
attributed to the rapid increase of free fatty acid concentration in the
bloodstream. Horse liver possesses a considerable ability to convert FFA
into triglycerides (Pösö et al., 1983) and consequently, the rate
of triglyceride synthesis is influenced by the availability of FFA.
Creatinine and Blood urea nitrogen (BUN) showed highly significant
increase after exercise when compared to before exercise. These findings
are in accordance with Pringle (1995). These increases might be
attributed to extensive fluid loss in the sweat, the reduction in renal
blood flow and glomerular filtration rate that leads to elevation of
urea concentration after exercise as quoted by Piccione et al. (2010). Härtlová et al. (2010) suggested that the increased level
of creatinine might be due to release of creatinine from working
muscles.
In this study, calcium and magnesium showed significant decrease after
exercise when compared to before exercise. This result was similar to
that reported by Schryver et al. (1978) and Hassan et al. (2015). The decline in calcium levels could potentially be attributed to
the persistent action of calcitonin, which might decrease the serum Ca
concentration. In addition to that the decline in serum calcium
concentration in exercising horses could be attributed to the loss of
calcium through sweat during exercise.Top of Form
The reduction in magnesium levels following exercise might be attributed
to the loss of magnesium through sweat (Weiss et al., 2002).
In this study, phosphorous showed highly significant increase after
exercise when compared to before exercise. This was in accordance with
Hassan et al. (2015) who reported this change to the release of
phosphate from muscles during the breakdown of high-energy phosphate
(ATP) during exercise.
In our study there was a highly significant increase in sodium after
exercise when compared to before exercise. This finding was in
accordance with Hassan et al . (2015) and Prado et al. (2019). They reported that the release of aldosterone due to dehydration
after exercise which results in the resorption of sodium into
bloodstream.
In our study there was a significant increase in potassium after
exercise when compared to before exercise. There was a similar finding
reported by Harris and Snow (1986); Hassan et al. (2015) and
Prado et al. (2019). The K+ ion is the predominant cation present
within the cells, with its concentration in the extracellular space
being low due to the activity of the Na+/K+-ATPase pump, which expels
three Na+ ions from the cell in exchange for two K+ ions. Approximately
98% of the total body K+ ions are stored intracellularly, primarily in
muscle tissue (Terker et al., 2015). Reduction in
H2O muscle, K+ ions exit muscle cells and enter the
bloodstream, leading to an increase in their concentration as reported
by Prado et al. (2019).
In our study there was a significant decrease in chloride after exercise
when compared to before exercise. These findings were consistent with
Mckeever (2002), Hassan et al. (2015) and Prado et al. (2019). The decrease in the concentration of chloride after exercise is
due to significant loss of chloride ion in the sweating with a
subsequent reduction in blood serum (Demirtaş et al., 2015).