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Objective: To estimate the normal values of serum lipids and lipoproteins and their correlations with thyroid hormones in clinically healthy male and female Lori-Bakhtiari sheep.
Design: Descriptive study (correlation type ). Animals: A total of 118 Lori-Bakhtiari sheep.
Procedure: Blood samples were collected from the jugular vein of 118 clinically healthy Lori-Bakhtiari sheep according to their age «I, 1-2,2-3,3-4, and 4-5 years) and sex. In each serum sample the concentrations of cholesterol, triglyceride, total lipids, HDL ¬cholesterol, LDL-cholesterol, VLDL-cholesterol, thyroxine (T 4), triiodothyronine (T 3), T 3 uptake and free thyroxine index (FTI) were measured by routine procedures.
Statistical analysis: Data were analysed by analysis of variance (ANaVA), regression analysis and Duncan's multiple range test to detect significant differences among the means, using SPSSIPC software. All values were expressed as and standard error of mean (SEM). P<0.05 was considered as significant.
Results: The concentrations of cholesterol, triglyceride, LDL-¬cholesterol, T4, T3, T3 uptake and FTI in the different age groups were significantly different (P<0.05). With an increase in the age of the animals there were significant increases in the concentrations of cholesterol (P<0.05; r = 0.24) and LDL-cholesterol (P<0.05; r=0.20). The concentrations of cholesterol, total lipid, HDL¬cholesterol, LDL-cholesterol, T 4 and FTI were higher in females as compared with males (P<0.05). In contrast, the concentrations of triglyceride and VLDL - cholesterol were higher in male animals as compared to females (P<0.05). There were no significant correlations between thyroid hormones (T3 and T4) and serum cholesterol, triglyceride, total lipids and lipoproteins (HDL, LDL and VLDL).
Conclusion: The results of this study indicate that in Lori - Bakhtiari
sheep, there were no correlations among thyroid hormones and lipids and lipoproteins probably due to specific lipids metabolism in ruminants. J. Fac. Vet. Med. Univ. Tehran. 58, 4: 301-306, 2003.