The aim of this study was to investigate possible action of Spirulina platensis on serum adiponectin, phospholipid and some enzyme levels, performance metrics and organ weights, in rats induced by hydrogenated vegetable oil and/or cholesterol, which can open the way for using microalgae for therapeutic purposes. Sixty-four Sprague-Dawley rats were divided into eight equal groups and the groups consisted of one control and seven experimental groups. The control group was fed on a basal diet. In addition to the basal diet, the experimental groups were fed with: Group 1, 43% hydrogenated vegetable oil; Group 2, 10% cholesterol; Group 3, 43% hydrogenated vegetable oil and 10% cholesterol; Group 4, 3% Spirulina platensis; Group 5, 43% hydrogenated vegetable oil and 3% Spirulina platensis; Group 6, 10% cholesterol and 3% Spirulina platensis; and Group 7, 43% hydrogenated vegetable oil and 10% cholesterol and 3% Spirulina platensis. Blood samples were taken from all rats on Days 30 and 60. Feed intake was determined by measuring the amount of feed consumed and released daily. The feeding with cholesterol and/or Spirulina platensis significantly lowered the serum adiponectin levels. Dietary hydrogenated vegetable oil increased the serum phospholipids. Spirulina platensis supplementation significantly reduced serum aspartate aminotransferase activity on only Day 60. Hydrogenated vegetable oil supplementation to diet has increased the serum alanine aminotransferase activities. Gamma-glutamyl transpeptidase levels did not show a significant difference between the groups. The dose and treatment duration of Spirulina platensis in this study may not be sufficient. Higher doses of Spirulina platensis and its longer application period should be tested with different animal species.