干旱区生态环境知识资源中心

"Krafft's disease" occurring in camels living in very arid areas from North Africa is characterized by spontaneous fractures of costal and/or appendicular bones. We studied the influence of water restriction upon plasma and urinary markers of bone metabolism in these animals. Eight two-year-old non-pregnant, non-lactating camels were used at the research station of Laayoune (Morocco). After a 10-day period of daily watering, five animals were watered only every ten days during a 50-day period, then again daily watered during the last 10-day period (rehydration). The three control animals were watered daily during the whole experimental period (70 days). Each camel was fed a ration of straw, lucerne hay and barley garin. Water restriction induced a decrease in daily urinary volume and an increase in plasma osmolality. These symptoms of dehydration were not associated with any significant change either in markers of osteoblastic activity (plasma alkaline phosphatase activity and osteocalcin concentration) or in markers of bone resorption ( urinary excretion of calcium, hydroxyproline pyridinoline and deoxypyridinoline). Thus, in well-fed camels, water restriction does not affect bone metabolism. However these results do not allow conclusions regarding the possible influence of dehydration associated with calcium and/or phosphorus deficiency in the etiology of "Krafft's disease".