imprint:
[Erscheinungsort nicht ermittelbar]: HAL CCSD, 2019
Language:
French
Origination:
University thesis:
Dissertation, HAL CCSD, 2019
Footnote:
Description:
Various studies have shown that events that occurred very early in the life of an animal could have programming" effects on the physiology of the adult. Recently, it has been shown that embryonic thermal manipulation (TM) has an impact on hepatic metabolism in Pekin ducks, 15 days post hatch.The first objective of this thesis was to measure the impact of an embryonic TM on the performances of mule ducks, used for the production of "foie gras". For that, we tested three experimental modalities of temperature increase on mule ducks embryos. Our results showed that all the embryonic TM significantly increased liver weight (up to + 16.9%, P <0.0001) after overfeeding, compared to the control group (without TM), associated with an increase in lipid content in the three TM groups (+2.5 to 3%). These results therefore demonstrate the great reproducibility of this technique, and pave the way for a new simple and inexpensive procedure for the industry. However, two of the TM groups have the same cumulative increase of temperature (+ 332 °C) also had a lower hatchability and a higher lipid-melting rate at cooking. This suggests that optimization of embryonic thermal manipulation could be considered to improve the quality of the "foie gras", especially by choosing a moderate and discontinuous TM.In a second step, we therefore undertook to identify the best possible TM window without exceeding + 332 ° C to reduce the negative effects. For this, we have studied the expression of genes of interest in mule duck liver throughout development. We have demonstrated a peak expression for many genes involved in carbohydrate and lipid metabolism around embryonic day E20, suggesting that a reduction in the programming window could be considered for the production of "foie gras" in mule ducks.In a third study, we studied the effect of embryonic TM on the expression, measured after gavage in 95-day-old ducks, of numerous genes involved in lipid and carbohydrate metabolism, stress and thyroid hormones. After overfeeding, only the expressions of some genes seem specifically modulated by the embryonic TM. These results being analyzed could allow us to identify targets that are particularly sensitive to TM applied during incubation, and that play an important role in the phenotype observed after overfeeding, characterized by better fattening of the liver.