Hepatic steatosis in waterfowl : metabolic basis and genetic susceptibility

Abstract

In waterfowl, the controlled induction of hepatic steatosis by overfeeding allows the production of “foie gras”. However, metabolic response to overfeeding varies considerably and depends, among other factors, on species or breed, which may be indicative of a genetic determinism. After a review that takes into account the most recent data available on overfeeding steatosis and its mechanism, the present article describes the studies conducted on the Landes geese (highly susceptible to hepatic steatosis) and the Poland geese (partly resistant). Before overfeeding, there are very few differences in lipid metabolism of the two breeds of geese. By contrast, and despite the same food intake during overfeeding, the Poland geese respond by a more effective exportation of hepatic triglycerides in lipoproteins, as well as phospholipids and associated polyunsaturated fatty acids (PUFAS). Thus, when compared to the Landes geese, they exhibit a greater extrahepatic fattening. The Landes geese exhibit a higher hepatic lipogenesis together with a better retention of triglycerides and, most probably, phosphatidylcholine and PUFAS, which allow membrane synthesis and cell hypertrophy, and result in a greater hepatic steatosis.