Abstract
Background:
Olive oil and Nigella sativa oil are recognized for their lipid-lowering effects and antioxidant properties. Limited comparative data are available on their effects in mice without any dietary intervention.

Aim:
This study assesses the impact of olive oil and N. sativa oil on the serum lipid profiles of mice without any other dietary intervention or hyperlipidemia induction.

Methods:
Fifteen male Swiss mice were randomly divided into three groups of 5 each. The control group was orally administered with 5 ml/kg of body weight/day of sunflower oil for 60 consecutive days. The doses of olive oil and N. sativa oil were at 0.4 ml/kg of body weight/day for 60 consecutive days, orally, after mixing them separately with the vehicle sunflower oil up to 5 ml/kg. Twenty-four hours after the last treatment, blood samples were obtained from the heart of each mouse, and the serum was used for lipid profile analyses using analytical kits.

Results:
Both olive oil and N. sativa oil significantly (p < 0.05) decreased serum levels of cholesterol, triglycerides, LDL, and VLDL in comparison with those of control values. Treatments significantly increased serum HDL levels compared with the control value. Changes in lipid profiles were not significantly different between the olive oil and N. sativa oil groups. The ratios of cholesterol, triglycerides, and LDL versus HDL of mice treated with olive oil and N. sativa oil were all significantly below the respective control values as a result of reducing lipid profiles and increasing HDL levels.

Conclusion:
Olive oil and N. sativa oil can significantly improve blood lipid levels in mice, particularly by lowering atherogenic lipids and increasing HDL. These changes result in favorable cholesterol, triglyceride, and low-density lipoprotein/high-density lipoprotein ratios, which play an important role in lowering cardiovascular disease risk and highlight the potential therapeutic and possibly protective benefits of these oils in managing lipid disorders.

Key words: Olive; Hyperlipidemia; Cholesterol; Triglycerides; High-density lipoprotein.