Levels of thyroid hormones and their correlation with lipid and lipoprotein concentrations in blood serum of male camels (Camelus dromedarius) in the Egyptian oasis.

摘要

Thyroid dysfunction is an endemic condition in man and animals in the Egyptian oasis due to the environmental iodine deficiency. The aim of this work was to estimate the circulating thyroid hormone concentrations and their correlation with lipid and lipoprotein profile in the blood serum of male dromedary camels in the Egyptian oasis. Blood for serum collection was sampled from 92 randomly selected apparently healthy male camels, 2-10 years old (divided into 4 groups; 2-4, 4-6, 6-8 and 8-10 years) from their natural habitat in the periurban areas at El-Kharga oasis. The recorded overall mean values of blood serum triiodothyronine (T3) and thyroxine (T4) concentrations in dromedary camels were 1.179+or-0.03 and 80.59+or-2.27 nmol/litre, respectively. The effect of age of camels was not significant for both T3 (F=1.446, P=0.235) and T4 (F=2.014, P=0.096). The overall mean concentrations of blood serum lipids of camels were 369.0+or-7.504 mg/dl for total lipids, 0.898+or-0.028 mmol/litre for total cholesterol and 0.606+or-0.021 mmol/litre for triglycerides. The effect of the age of the camels was significant for total lipids (F=3.870, P=0.016), total cholesterol (F=3.987, P=0.011) and triglycerides (F=5.626, P=0.003). It was noticed that old camels (8-10 years) had the highest mean values of these blood serum lipids. The overall recorded mean values for lipoproteins was 0.462+or-0.023 mmol/litre for high density lipoprotein-cholesterol (HDL-C), 0.314+or-0.010 mmol/litre for low density lipoprotein-cholesterol (LDL-C) and 0.121+or-0.004 mmol/litre for very low density lipoprotein-cholesterol (VLDT-C). The age of camels had a significant effect on the mean concentrations of blood serum HDL-C (F=4.051, P=0.009), LDL-C (F=3.698, P=0.024) and VLDL-C (F=5.584, P=0.002). Aged camels (8-10 years) showed the highest values of HDL-C and VLDL-C, whereas LDL-C was highest in camels aged 4-8 years. The linear regression analysis revealed that the regression factor (R2) and correlation coefficient (r) between file estimated blood serum T3 concentrations and lipogram in blood serum of camels was not significant. Also R2 and r between T4 and total lipids, HDL-C and VLDL-C were not significant. On the other hand, there was significant inverse linear regression (R) and negative correlation (r) between T4 and each of total cholesterol (R2=0.167, r=-0.290, P=0.037), triglycerides (R2=0.193, r=-0.375, P=0.021) and LDL-C (R2=0.196, r=-0.397, P=0.015). It can be concluded that dromedary camels in the Egyptian oases have low values of circulating thyroid hormones. However, there were no apparent clinical signs of goitre. It seems that these camels are suffering from a state of subclinical hypothyroidism with a pronounced effect on lipid metabolism..