Figure 4.

External morphology and skeletal staining of embryos at E18.5. External fetal morphology from VAD dams supplemented with RP (A; representative of 38 fetuses from five litters), RP in combination with 250 μg of atRA per g of diet (B; representative of 48 fetuses from five litters), or fed 250 μg of atRA per g of diet alone (C; representative of 31 fetuses from four litters) was indistinguishable between the different diet groups. None of the embryos exhibited external malformations associated with retinoid toxicity (20). An extranumerary lumbar (14th) rib was present in 10 of 16 fetuses examined from VAD dams fed RP in combination with 250 μg of atRA per g and in 7 of 13 fetuses from VAD dams fed 250 μg of atRA per g of diet alone. An example of the range of skeletal malformations that were observed is shown in D (full 14th rib) and E (rudiment of a 14th rib).