Effects of long-term consumption of high doses of fish oil concentrates onclinical parameters in male and female rats

Many studies suggest that a diet supplemented with fish oil concentrates (F OCs) may provide protection against cardiovascular and other diseases. The possible harmful effects of long-term consumption of high doses of FOCs, ho wever, have not been adequately investigated. Corn oil, fish oil (MaxEPA) a nd various mixtures of the oils were administered by gavage to 120 male and 120 female rats, 5 d/wk for 13 wk at the rate of 5 mL/kg/d. Although MaxEP A had no effect on prothrombin time or activated partial thromboplastin tim e, it caused a statistically significant diminution of the total serum chol esterol level. Correlations between relative liver and spleen weights and d ose levels were positive but a negative correlation was found between dose levels and serum vitamin E concentration. In female rats, the negative corr elations between dose levels and serum iron and triglyceride levels were hi ghly significant. The pathology data showed no remarkable lesions in any of the tissues examined. Results of this study suggest that long-term consump tion of high levels of FOCs in rats may reduce serum cholesterol and trigly cerides and adversely affect serum iron level and relative liver weight in female rats and relative spleen weights in both sexes.