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Updated: Jul 18, 2026
Primary Endodermal Epithelial Cell Culture from the Yolk Sac Membrane of Japanese Quail Embryos
Published on: March 10, 2016
Changes in the size and docosahexaenoic acid content of adipocytes during chick embryo development
K Farkas1, I A Ratchford, R C Noble
1Department of Biochemical Sciences, Scottish Agricultural College, Ayr, United Kingdom.
Insights
Chick embryo adipose tissue development is linked to yolk lipid levels. Docosahexaenoic acid (DHA) is mobilized from fat stores to support rapid brain growth during hatching.
Area of Science:
- Embryology
- Lipid Metabolism
- Developmental Biology
Background:
- Adipose tissue plays a crucial role in energy storage and mobilization during embryonic development.
- Yolk lipids serve as the primary source of nutrients for the developing chick embryo.
- Docosahexaenoic acid (DHA) is an essential fatty acid vital for neural development.
Purpose of the Study:
- To investigate the development of adipose tissue in chick embryos in relation to initial yolk lipid content.
- To examine the dynamics of triacylglycerol and docosahexaenoic acid (DHA) deposition and mobilization in adipose tissue.
- To correlate adipose tissue development with DHA transfer to neural tissues.
Main Methods:
- Comparison of adipose tissue development in chick embryos from eggs with differing initial yolk lipid levels.
- Quantification of triacylglycerol content in subcutaneous adipose depots.
- Computerized image analysis microscopy to determine adipocyte size distribution.
- Analysis of docosahexaenoic acid (DHA) levels in adipose tissue triacylglycerol and brain phospholipids.
Main Results:
- Adipose triacylglycerol content increased significantly from day 12 to hatching, correlating with yolk lipid transfer.
- Initial yolk lipid content influenced adipose triacylglycerol levels, with a decrease during hatching in lower-lipid groups.
- Adipocyte diameter increased substantially, though cell size decreased during hatching in embryos with lower initial yolk lipids.
- Docosahexaenoic acid (DHA) levels in adipose tissue decreased during hatching, while brain phospholipid DHA increased significantly.
Conclusions:
- Chick embryo adipose tissue development and triacylglycerol accumulation are dependent on yolk lipid availability.
- Docosahexaenoic acid (DHA) is preferentially mobilized from adipose tissue to support rapid brain development during the late embryonic and hatching periods.
- This mobilization suggests a critical role for adipose tissue as a donor of essential fatty acids for neural tissue growth.
Abstract:
The development of adipose tissue in the chick embryo was investigated using two groups of fertile eggs which differed by 1.7-fold in their initial yolk lipid levels. The triacylglycerol content of the subcutaneous adipose depot in both groups increased dramatically from day 12 of the 21-day embryonic period, attaining a maximal value just prior to hatching. During this period, the amount of triacylglycerol deposited in the adipose tissue was very highly correlated with the amount of lipid transferred from the yolk. The triacylglycerol content of the depot was also dependent on the initial yolk lipid content. During the hatching period, the amount of adipose triacylglycerol remained approximately constant in the group with the higher initial yolk lipid content but, in the case of the group with the lower initial yolk lipid levels, decreased by approximately 25%. The size distribution of adipocytes isolated from the tissue was determined by computerized image analysis microscopy. The mean adipocyte diameter increased from approximately 6 to 35 microns between days 12 and 19, irrespective of the initial yolk content, although development within the eggs with the lower initial yolk content resulted in a decrease in cell size over the hatching period. Both the triacylglycerol and phospholipid fractions of the isolated adipocytes contained substantial proportions (approximately 6%, w/w) of docosahexaenoic acid (DHA) at days 12 and 14, and lower levels of this fatty acid at the later stages. The amount (mg/depot) of DHA in adipose triacylglycerol decreased dramatically over the hatching period. The amount (mg/brain) of DHA in brain phospholipid increased by more than 5-fold between day 12 of development and hatching. A possible explanation for the data may be that DHA is preferentially mobilized from adipose tissue in order to deliver the fatty acid to the developing neural tissues in a form suitable for uptake.
