Natural induction of spontaneous liver steatosis in Greylag Landaise geese (Anser anser)

Abstract

The present experiment aimed at demonstrating that the Greylag geese (Anser anser), commonly used for the production of foie gras, are able to develop spontaneous hyperphagia and subsequent liver steatosis under specific handling conditions and without overfeeding. One hundred and eighty male geese were used in this experiment. After a period of feed restriction, at the age of 19 wk, corn was provided ad libitum. From wk 21 to 23, the daylight duration was progressively reduced from 10 to 7 h and kept as such until the end of the experiment (wk 31). Thirty birds were slaughtered at wk 19, 23, 25, 27, 29, and 31. During the first 2 wk after corn delivery, the average consumption rose up to 600 g/bird/d and decreased slowly thereafter to reach 270 g at wk 31. The liver weight increased from 95 (wk 19) to 514 g (wk 31), and most of these changes were due to the increase in liver lipid content from 6 to 50% of liver weight. There was no mortality during the experimental period. Histological observations indicate that the accumulation of fat in the livers occurred through a large increase in the size of the hepatocytes without modification of the cell boundaries and without any sign of inflammation or degeneration. Our data clearly show that under specific management conditions of feeding and photoperiod, the geese are able to initiate spontaneous liver steatosis. These results demonstrate their natural ability to store fat in the liver without any visible sign of tissue alteration. However, the variability in the response remains very high (at wk 31, the CV in liver weight was 45%). Further research is needed to better understand the origin of this variability.

A kinetic study of the natural induction of liver steatosis in Greylag Landaise geese: the role of hyperphagia

“…Thereafter, in GH geese, the liver weight increased from 328 g (c v 76%) at week 27 to 497 g (c v 65%) at week 32 (Figure 4). In our previous experiment (Guy et al, 2013), the liver weight at week 31 was 514 g (c v 45%), a value similar to the one obtained in the present work but with a lower variability. It is notable that in the present work, the corn feeding period was extended up to week 36, as compared to our previous work (Guy et al, 2013) where it ended at week 31.…”

“…These figures are far above the data found in the literature reporting feed consumption by geese under ad libitum feeding ranging from 200 to 380 g/day according to age and reproductive cycle (Sauveur et al, 1988;Arroyo et al, 2012). Thus, the present results not only confirm but strengthen our previous demonstration (Guy et al, 2013) that hyperphagia can be initiated after a feed restriction period in adult geese raised in group, and under the environmental conditions of temperature and light cycle used in the present experiment.…”

“…In a previous work (Guy et al, 2013), we clearly demonstrated that hyperphagia and spontaneous liver steatosis could be experimentally induced in domestic Greylag geese by combining a short photoperiod and a sequence of feed restriction followed by ad libitum corn feeding during the fall and the winter. This set of conditions was supposed to mimic pre-migratory changes.…”

“…The feeding programme used was identical to that described by Guy et al (2013) and based on a feed restriction period which aimed to ensure normal growth while preventing excessive fattening (McLandress and Raveling, 1981) and to induce hyperphagia when stopped. The birds were fed ad libitum from birth to 5 weeks of age, then 300 g/day during week 6, 350 g/day during weeks 7 to 9, 300 g/day during weeks 10 to 11, 280 g/day during weeks 12 to 14 and 250 g/day during weeks 15 to 19.…”

“…However, the goose is a gregarious bird whose feed intake is influenced by group behaviour (Arroyo et al, 2013) and different feeding behaviours between group and individually housed (IH) geese could therefore be expected. Thus, contemporary geese were also raised in groups, as described by Guy et al (2013), in order to compare the consumption of corn and subsequent liver steatosis between the two housing conditions.…”