Spontaneous hyperlipoproteinaemia in the Arabian dromedary.

The Arabian camel or dromedary is considered to be a vital livestock species for poor communities living in hot arid regions and it is an important sporting animal in richer countries. Despite this importance, the camel has been relatively poorly studied from the biochemical point of view when compared with other major domesticated species. Our laboratories are collaborating in studies of lipid and lipoprotein metabolism in the camel, particularly with regard to reproduction and parasitic diseases such as "surra". One of the principle studies being undertaken is an investigation of camel lipoprotein metabolism in pregnancy. A study during which, one non-pregnant animal with spontaneous hyperlipoproteinaemia was identified and studied over a period of about ten months. Blood samples were taken from a group of 24 female camels after an overnight fast and kept on ice until processed within two hours to give serum and plasma ( lmg sodium EDTAlml). These samples were utilized for enzymo-colorimetric determinations of plasma total, free and high density lipoprotein (HDL) cholesterol and triacylglycerols using commercially available kits (Boehringer Mannheim GmbH, Germany). In addition serum lipoproteins were separated by electrophoresis on agarose gel using the Paragon system (Beckman Instruments Inc., U.S.A.) and plasma very low density lipoproteins were separated by preparative ultracentrifugation [ l ] and their lipid and protein composition was analysed. The camels were the recipient group in an embryo transfer programme [2] and were studied in all on 8 occasions as follows: three weeks before and immediately after artificially-induced superovulation, three weeks after embryo transfer when success or failure of the procedure was confirmed by diagnostic ultrasound and thereafter at monthly intervals. Pregnancy was not confirmed in 13 camels and plasma and serum from one of these animal at the first collection was noticed to be lipaemic and this forms the main subject of this communication. Data for the pregnant animals will be presented elsewhere. The results for the 12 non-pregnant camels showed little variation throughout the study. At the first collection plasma total and free cholesterol and triacylglycerols were 0.78 f 0.16 , 0.28 2 0.12 and 0.29 + 0.09 mM respectively. Electrophoresis showed that p-lipoproteins (low density lipoproteins LDL) were the dominant lipoprotein particle in camel serum and this was confirmed by the distribution of total plasma cholesterol between VLDL, LDL and HDL, which was 0.05 2 0.02, 0.44 2 0.14 and 0.29 2 0.16 mM respectively. The remaining camel which showed lipaemia initially had plasma total and free cholesterol and triacylglycerols of 6.23, 4.10 and 29.04 mM respectively. Electrophoresis revealed a greatly increased pre-p lipoprotein band (VLDL) but no chylomicrons, and plasma cholesterol Biochemical Society Transactions (1 995) 23 281 S