Positional characteristics of triacylglycerol in soft-shelled turtle oil and its effects on lipid metabolism in hamsters fed a high fat diet

Soft-shelled turtle is a highly economic species and plays a mystical role in traditional Chinese medicine. The present study analyzed the positional distribution in triacylglycerol (TG) of soft-shelled turtle oil (STO) and its effects on lipid metabolism in hamsters fed a high fat diet. Analysis showed that TG made up the maximum fragments among lipid classes of STO, with eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) integrated in the sn-1,3 position of TG. For the animal study, forty male hamsters were randomly divided into five groups and fed a control diet (5% fat), high fat diet (HF, 10% fat) and HF diets containing 2% (STO2), 4% (STO4) or 6% (STO6) soft-shelled turtle oil for 28 days. The body weight gain and food intakes were comparable between hamsters fed HF diet and HF diet containing STO from 2% to 6% during the experiment. Hamsters fed HF diets containing 2–6% STO showed decreased liver TG, and HF diets containing 4% or 6% STO showed decreased serum TG but increased serum total cholesterol. In addition, enzyme activities of lipogenesis in hepatic malic enzyme and glucose-6-phosphate dehydrogenase were lower in hamsters fed 4% or 6% STO than in those fed the high fat diet. These results suggest that dietary 4% or 6% STO, with different intramolecular distributions of n-3 PUFA, might decrease serum and liver TG concentrations by diminishing enzyme activities involved in liver fatty acid synthesis.