Environmental stress and the loss of urea, sodium and potassium in the sweat of camels (Camelus dromedarius), under semi-arid coastal conditions El-Zeiny Wissam T. Department of Physiology, Animal and Poultry Research Division Desert Research Centre, Al-Matareya, Cairo, Egypt Email: wissamtaha49@yahoo.com
Online published on 3 September, 2012. Abstract Sweating rate, Na, K and urea concentrations in sweat and serum, and sweat Na, K and urea output were determined in eight non-pregnant and non-lactating female dromedary camels fed at the maintenance level. Half of the animals were watered daily whereas the other half was intermittently watered once every seven days. There were two levels of protein intake, however 100% and 50% of their estimated maintenance requirements. Moreover, half the animals were kept outdoors and not sheltered whereas the other half was housed indoors. The experimental treatments were repeated three times between April and August to represent spring, early summer and late summer seasons. The present study was intended to investigate the effects of watering regimen, protein intake, housing environment and season on the potential losses of urea, sodium and potassium in the sweat of the dromedary camel. The sweating rate in daily watered camels in summer was about 220 ml/m2/h. The outdoor camels had significantly higher sweat rates than those kept indoors. Also, the sweating rate of camels in early and late summer was significantly higher than those in spring. The sweating rate of water deprived camels was significantly lower than that of the daily watered ones. The level of protein intake did not affect sweating rate. In water deprived camels both housed indoors and outdoors, sweating rate was high on the watering day, then decreased through the water deprivation cycle. All urea, sodium and potassium excreted in sweat followed changes in sweating rate. Output increased in animals kept outdoors as compared to indoors, and in summer as compared to spring. In water deprived animals, on the other hand, sodium and potassium output decreased as the sweating rate decreased whereas urea output remained unchanged. The sweat-serum urea concentration ratio was always less than one. Camels may well be able to conserve some of the urea excreted in sweat as observed in the low vs. high protein intake groups in the present experiment especially when camels were water deprived. Sweat-serum concentration ratios ranged from 1 to 2 for sodium and 68 to 128 for potassium for the different environmental treatments. Therefore, the sweat output of K was much greater than that of sodium (sweat K/Na ranged from 2–4) even though its serum concentration was much less than Na. The increase in K/Na ratio may suggest the presence of Na+ K+ exchange in the duct of the sweat gland as in the distal tubule of the kidney. Top Keywords Camel, potassium, sodium, stress, sweat, urea. Top |