Differential channelling of liver lipids in relation to susceptibility to hepatic steatosis in the goose

INRA, Station de Recherches Avicoles, Nouzilly, France. dominique.hermier@ibaic.u-psud.fr

In response to overfeeding for the production of "foie gras," the Poland goose differs from the Landes goose by a lesser susceptibility to hepatic steatosis, resulting in a lower accumulation of hepatic triacylglycerol (TG), together with a greater exportation of hepatic phospholipid (PL) in very low density lipoproteins (VLDL) and high density lipoproteins (HDL) (Fournier et al., 1997). A study was designed 1) to compare the liver composition in overfed and nonoverfed geese of the two breeds of geese and 2) to determine whether the differential channelling of lipids in response to overfeeding is reflected in the PL and fatty acid profiles of the different hepatic lipids, whether stored or secreted. In nonoverfed geese, there were no breed-related differences in liver weight (approximately 90 to 100 g), hepatic lipid content (3 to 4%), and lipid and PL composition. However, plasma VLDL and HDL of the Landes breed contained a higher phosphatidylcholine (PC) to phosphatidylethanolamine (PE) ratio than those of the Poland breed (20.7 and 33.8 vs 12.6 and 25.6 in VLDL and HDL, respectively). After 14 d of overfeeding, hepatic PL profiles were identical in the two breeds and similar to that in control livers; choline-containing PL accounted for 95% of total PL. In contrast, plasma HDL concentrations of the Landes geese were lower than those of the Poland geese (9.4 vs 12.9 g/L) and their PC:PE (13.6%) and PL-polyunsaturated fatty acids (PUFA) content (25%) were decreased compared with the Poland geese (21.2 and 30%). It is likely that the higher susceptibility to fatty liver of the Landes breed involves a differential channelling of PL, resulting in a greater hepatic retention of PC and PUFA that are necessary for plasma membrane growth and cell hypertrophy.