American Cockroaches...synthesize vitamin A...

[kinyonga]

http://russia-ic.com/education_science/breakthrough/62/#.VYzRw6U9l0s

 

[JoeVet]

I'd have to see the analysis of the cockroach feed. Wheat, oat, corn and germ of barley have significantly enhanced carotenoid levels and I assume the bread and flakes made from them. http://www.ncbi.nlm.nih.gov/pubmed/23561159