Stability of shark (Centrophorus sp.) liver oil rich in squalene as an immunostimulant

Abstract

Shark liver oil has been widely produced in Indonesia; however, many shark liver oil products still do not meet the established standards. This research involves the addition of antioxidants to stabilize the oil as an effort to extend its shelf life. The objectives of this study were to determine the immunostimulant activity, assessed the synergistic effect of vitamin E in shark liver oil rich in squalene, and identified the optimum concentration of the antioxidant vitamin E in maintaining its stability. Immunostimulant activity was tested by observing spleenocyte proliferation, phagocytic index, and capacity in the peritoneal cavity cells of mice. The stability of the oil was examined by an accelerated method using an oven, what was called the schaal oven test at 40 °C. The research results indicate that shark liver oil possesses immunostimulant effects; however, with an increasing dosage of fish oil, there is no significant improvement. The presence of vitamin E in cod liver oil exhibited a synergistic effect on spleenocyte proliferation for all dosages, while the phagocytic index and capacity at a dosage of 100 μg/mL showed synergy. However, at a dosage of 50 μg/mL, the phagocytic index and capacity did not exhibit synergy with the immunostimulant. The optimal concentration of the antioxidant vitamin E in maintaining oil stability was found to be 100 ppm.