Structured lipid made from fish oil and medium-chain triglycerides alters tumor and host metabolism in Yoshida-sarcoma-bearing rats

The effects of structured lipid composed of fish oil and medium-chain triglycerides (Fish/MCT) on tumor and the host metabolism was compared with conventional long-chain triglycerides (LCTs) in Yoshida-sarcoma-bearing rats receiving TPN for 3 d. The two parenterally fed groups were divided into two treatments, saline or tumor necrosis factor (TNF), given intravenously at 20 µg/kg body wt. Changes in tumor volume, body weight, urinary nitrogen, whole-body and tissue protein kinetics, and fatty acid composition were measured. The study revealed that Fish/MCT feeding inhibited tumor growth, which could be attributed to decreased tumor protein synthesis. Body weight and nitrogen were better maintained by Fish/MCT feeding. In addition, the effects of Fish/MCT on tumor growth were synergistic with TNF treatment. The results demonstrate that dietary fat composition can influence fatty acid compositions of tumor tissue as well as tumor protein kinetics after a short period of TPN feeding.