 At Davis, he helped determine the relationships among the B complex vitamins through experiments on chickens.He then left academia to work for American Cyanamid's Lederle Laboratories, where he helped established that folic acid is a vitamin and discovered that feeding livestock a continual supply of antibiotics significantly enhances growth (a practice that has become widespread in the meat industry).Following the rise of molecular biology, Jukes returned to UC Berkeley, where he spent the rest of his career.