Relationships between storage and secretion of hepatic lipids in two breeds of geese with different susceptibility to liver steatosis

INRA, Nouzilly, France.

Susceptibility to liver steatosis was studied in Landes and Poland geese, which are hyper- and hyporesponsive, respectively, to overfeeding. Plasma lipoproteins were characterized at different stages of the overfeeding process, whereas fatty liver composition was determined after completion of overfeeding and slaughtering. Before overfeeding, plasma lipoprotein profile was typical of birds in both breeds, except that very low density lipoproteins (VLDL) were low in triglyceride (approximately 30%). Moreover, high-density lipoprotein (HDL) concentration was higher in the Poland geese (6.44 vs 4.97 g/L). During overfeeding, hepatic lipogenesis was increased, and fatty liver resulted from accumulation of primarily triglyceride (approximately 95% of lipid content), but also of all other lipids. This accumulation was significantly greater in the Landes geese for all lipids but phospholipid. Thus, the liver weight was 100% higher in this breed (1,005 g vs 485 g), whereas lipid release during sterilization was twofold higher (26.3 vs 7.5%). Parallel, plasma concentration and triglyceride content of hepatic lipoproteins, VLDL and HDL, increased about one- to twofold, this effect being greater in the Poland geese. Therefore, channeling of triglyceride towards secretion rather than in situ storage may be responsible for the hyporesponsiveness of this breed to overfeeding. In both breeds, and especially in the Landes geese, a relative deficiency in phospholipid synthesis together with an enhanced secretion may be limiting factors of hepatocyte hypertrophia and, therefore, of steatosis.