1. The
triglyceride,
cholesterol ester and total
phospholipid fractions were isolated from the livers and yolk sacs of normal and
vitamin B(12)-deficient chick embryos after 13, 15, 17, 19 and 21 days of incubation, and the
fatty acid compositions were determined. 2. At all stages of incubation, the concentration of
cholesterol ester in the livers of the normal embryos were greater, and on days 15 and 17 the concentrations of
triglyceride were considerably less, than the corresponding concentrations in the livers of the deficient embryos. 3. Between day 13 and day 21 of incubation the concentration of
oleic acid in the liver
triglycerides of the normal embryos increased, whereas the concentrations of
palmitic acid and
docosahexaenoic acid decreased.
Vitamin B(12) deficiency resulted in higher concentrations of
palmitic acid in the liver
triglycerides on days 15, 17 and 19, higher concentrations of C(18) polyunsaturated
acids on days 13 and 15 and lower concentrations of
oleic acid on days 13, 15, 17 and 19. 4. At all stages of development,
cholesterol oleate accounted for almost 80% of the total liver
cholesterol esters in both normal and deficient embryos. 5. As development of the normal embryos progressed, the concentrations of
palmitic acid and
arachidonic acid in the liver
phospholipid decreased, whereas the concentrations of
stearic acid and
docosahexaenoic acid increased.
Vitamin B(12) deficiency resulted in markedly higher concentrations of
stearic acid and
palmitic acid and markedly lower concentrations of
arachidonic acid and
docosahexaenoic acid in the liver
phospholipids. 6.
Vitamin B(12) deficiency did not influence the
fatty acid composition of the
triglyceride,
cholesterol ester and
phospholipid fractions either in the yolks of fertile unincubated eggs or in the yolks obtained from eggs that had been incubated for 13, 15, 17, 19 and 21 days.