Purpose. The effects of embryonic development on lipid composition in
the retina were studied in 7, 11, 15, and 18-day-old chick embryos and
newly hatched chicks. Methods. The proportions of phospholipids, free
and esterified cholesterol, diacylglycerides, and free fatty acids we
re determined using the Iatroscan TLC/FID procedure. Gas chromatograph
y and mass spectrometry were used to determine the fatty acid composit
ion. Results. The major phospholipid species were phosphatidylethanola
mine, phosphatidylcholine, phosphatidylserine, phosphatidylinositol, l
ysophosphatidylcholine, and sphingomyelin. Concentrations of the analy
zed components have been related to the chronology of concrete stages
of retinal development. The fatty acid composition of the total lipids
, (n-6):(n-3) and saturated:unsaturated fatty acid ratios, and other p
arameters are reported. The proportions of total saturated and total m
onounsaturated fatty acids decreased very little from day 7 to hatchin
g, whereas total polyunsaturated fatty acids nearly doubled over the s
ame period. The increase in C18:2(n-6) from day 11 onwards was not fol
lowed by a similar increase in C20:4(n-6), hence the C20:4 to C18:2 ra
tio decreased with age. Conclusions. The cholesterol:phospholipid rati
o decreased from day 7 to day 15 and increased from day 15 to hatching
. High proportions of esterified cholesterol, very probably originatin
g in the retinal pigment epithelium, were also recorded. Total saturat
ed and monounsaturated fatty acids decreased, while polyunsaturated fa
tty acids increased during the period of initial retinal growth.