Positive Impact of Thermal Manipulation During Embryogenesis on Foie Gras Production in Mule Ducks

Ontogeny of hepatic metabolism in mule ducks highlights different gene expression profiles between carbohydrate and lipid metabolic pathways

“…Lastly, the drop in carbohydraterelated gene expression observed at D1 might reflect the decline of endogenous resources after hatching, a process involving high energy demand. Since carbohydrate metabolism is a major pathway involved in fattening the liver during overfeeding, the present results showing high expression of carbohydrate-related genes around E20 may explain phenotypic differences observed in our previous study (3). Indeed, based on several embryonic thermal programming data in chickens (26,27) and Pekin ducks (28,29), we applied a thermal stimulus between E13 and E27, covering about 50% of the total incubation period, and showed that this programming induced an increase in fatty liver production after overfeeding at the age of three months (3).…”

“…Indeed, beta-oxidation of fatty acids provides a large part of the energy demand during embryogenesis (32). Consequently, the application of a thermal stimulus during this period could potentially program a differential response to force-feeding and thus participate in the phenotypic differences observed in our previous study (3). However, the negative correlation measured between the expression of several carbohydrate and lipid-related genes during embryogenesis suggest that these two pathways, which seem to work in mirror mode during development (22,32), could be affected differently by early-life programming.…”

“…Therefore, even though hyperplasia does not seem to be involved in fatty liver enlargement during overfeeding (18), it is conceivable that an increase in the number of hepatocytes at birth may enhance the fattening of the liver during force-feeding, since the ability of each cell to expand (hyperphagia) may not be affected. Moreover, recent studies (3,19) suggest that the histological structure of the liver after overfeeding, particularly the number and size of cells, may play a role in the final quality of the product, mainly indicated by fat loss after cooking. It would therefore be very interesting to determine the precise impact of the embryonic thermal stimulus on the number of hepatic cells at birth and after overfeeding in order to accurately modulate the final yield of fatty liver through a specific programming protocol.…”

Ontogeny of hepatic metabolism in mule ducks highlights different gene expression profiles between carbohydrate and lipid metabolic pathways

“…In poultry, it has been shown that embryonic thermal programming improves the survival of animals exposed to subsequent heat stress, and it is particularly interesting to note that the best embryonic period to apply the stimulus corresponds to the maturation period of the hypothalamo-hypophysis-thyroid axis, which is involved in thermal regulation (13). Remarquably, the adapted phenotype may also respond differently to new environmental challenges, such as embryonic thermal manipulation resulting in increased foie gras production in mule ducks at the age of three months (3). Although the mechanisms are not yet fully understood, the timing of the application of the environmental stimulus for programming seems to be very important.…”

“…Moreover, recent studies (3,21) suggest that the histological structure of the liver after overfeeding, particularly the number and size of cells, may play a role in the nal quality of the product, mainly indicated by fat loss after cooking. It would therefore be very interesting to determine the precise impact of the embryonic thermal stimulus on the number of hepatic cells at birth and after overfeeding in order to accurately modulate the nal yield of fatty liver through a speci c programming protocol.…”