To investigate the metabolic effects of intravenously administered odd-numbered medium-chain triglycerides in healthy non-stressed animals, trinonanoin/long-chain triglyceride (LCT) (7/3) fat emulsions were given in a high dose (46.5% energy) to rabbits (n = 8) for 11 days within a total parenteral nutrition regimen. In comparison with medium-chain triglyceride (MCT)/LCT fat emulsions, higher plasma glucose (day 4), plasma lactate and pyruvate (day 11) and liver glycogen concentrations were found for the test group, indicating a glucogenic effect of the trinonanoin/LCT emulsion. With the present study design, nitrogen balance of the rabbits was not significantly influenced by the kind of fat emulsion administered.