Photosensitizing effects of Cymopterus watsonii and Cymopterus longipes in chickens and turkey poults.

Two-week-old straight-run white broiler chicks and 2-week-old straight-run white turkey poults were fed seed or whole plants Cymopterus watsonii or seed of Cymopterus longipes at 0.4, 0.8, and 1.6% of body weight, and then placed in sunlight for 5 hours each day for 7 days. All plant material produced moderate to severe photosensitivity in chicks. Toxic signs included photophobia; red discoloration of beak, comb, and feet; loss of feathers in the periorbital area; dried serous fluid on comb and edge of beak; keratoconjunctivitis; and multiple lesions on feet and legs. Turkey poults showed a syndrome similar to that of chicks. Mortality was particularly high in turkeys fed C. longipes seed. Toxic signs in turkeys 6 weeks after treatment included tremors in the legs; upturning and shortening of the upper beak; and shortening disfigurement, and gangrene of the toes. Two phototoxic furocoumarins, oxypeucedanin and isoimperitorin, were isolated from C. longipes seed. Either compound, administered orally, produced photosensitivity in 2-week-old chicks.