Different effects of chemically defined structured lipids containing ω3 or ω6 fatty acids on nitrogen retention and protein metabolism in endotoxemic rats

Abstract

Alternative lipids like structured triacylglycerols and ω3 fatty acids were reported to have protein-sparing effects in the hypercatabolic state. The aim of the present study was to determine the effects of chemically defined structured lipids (SL) with ω3 fatty acids in position sn-2 (MFM) compared to SL with ω6 fatty acids in position sn-2 (MLM) on protein and energy metabolism in a low dose endotoxin (1 mg/kgBW/d) rat model. We used L-[1- 14C] leucine isotope measurements for the estimation of whole body and tissue leucine kinetics. Twenty-four male Sprague Dawley rats were randomly assigned to 4 groups (n=6; MFM, MFM+E, MLM, MLM+E; E:endotoxin) and received 48 h of total parenteral nutrition. Endotoxin infusion resulted in a significant decrease in mean body weight and nitrogen balance in rats of group MLM+E compared with the control group MLM (p<0.05), whereas no significant decrease was observed in rats of group MFM+E. Rats of group MFM+E had significantly higher liver weight means and rectus muscle protein contents compared with rats of group MLM+E (p<0.05). This is the first study comparing effects of structured lipids containing either ω3 or ω6 fatty acids in position sn-2 on protein and nitrogen metabolism in response to sepsis. The results point to a possible protein-sparing effect of the fish oil containing diet that needs to be confirmed, however, by further studies based on a larger number of experimental animals.