Investigation of different enzyme markers in some pathological disorders of the dromedary camels in comparison with other species.

Camel adaptation to its arid and semi-arid environment and its genetic make-up created some differences in its enzyme systems compared with other domestic animals. The camel is similar to ruminants in most of the diagnostic enzymes used to evaluate liver functions. However, some differences from other domestic species were noticed in muscular, neuromuscular, pancreatic, bone, drug metabolizing, metalo and antioxidant enzymes in serum and/or tissue. The drug-metabolizing enzymes are low in camel liver and it looks that it has not developed a potent drug metabolizing enzyme system as xenobiotic are low in its natural habitat although its liver was found to be potent in the detoxification of some carcinogens. The low plasma pseudcholinesterase in camel compared with ruminants may explain why it is more vulnerable and less adapted to the toxicity of the organophosphorus compound in agricultural pesticides and herbicides; not previously found in its arid and semiarid habitat. The antioxidant system in the camel looks to be very potent to prevent or reduce oxidative stress which may be another adaptation mechanism to its natural environment. More research is required in serum and tissue enzymes in the camel. There is a great variation in a reference range of diagnostic enzymes in camels. This is due to differences in pre-analytical, analytical and post-analytical procedures and the number of specimens used to define the reference range. Indeed, different laboratories may have the different analytical equipment, different reagents and sources, different specimen's collection and handling procedures, different analytical methods and validation, different storage facilities, different staff qualifications, experience and quality background and the presence or not of a proficiency testing program. Moreover, the physiological, pathological, nutritional, genetical, environmental and geographical factors are of paramount importance in camel enzyme activity. Specifically, the effects of season, sex, age, breed and stage of lactation were emphasized in comparison with other species. Therefore, laboratories should establish their own reference values.