Table 5.

Distribution of phenotypes of CMOI+/−RBP^−/− embryos from double knockout dams on the vitamin A-deficient diet during pregnancy with and without β-carotene supplementation

Dietary regimen	n	Embryonic phenotype (%)
		Normal	RBP-like	Cleft	Exencephaly
VitA-def	89	0	62	36	2
VitA-def + bC	82	61	32	0	7

CMOI^−/−RBP^−/− females, mated with RBP^−/− males, were maintained on the vitamin A-deficient (VitA-def) diet during pregnancy, with or without supplementation with 10× β-carotene (bC) emulsion (see Materials and Methods) from 6.5 to 9.5 dpc (1 i.p. injection/d). Dams were sacrificed at 14.5 dpc, and the gross morphology of CMOI^+/−RBP^−/− embryos was analyzed. Normal, embryos looked like wild-type embryos from wild-type dams bred on vitamin A-sufficient diet; RBP-like, embryos showed peripheral edema and malformed eyes; Cleft, embryos showed peripheral edema, malformed eyes and abnormal mid-facial region; Exencephaly, embryos showed peripheral edema, malformed eyes, and exteriorized brain. n = total number of embryos.