Cycad Toxicosis in Chickens

In one experiment, day-old chicks were fed continuously 2 or 5% cycad-seed kernel or 2 or 5% husk in the diet until they were 14 days old. All 4 groups gained less weight than the controls, but in the group fed 5% kernel, gains were the most severely depressed. The combined weight of this latter group was only 37% of the weight of the controls. Microscopic lesions were minimal. In another experiment, chickens were fed 0.5 or 1.0% kernel or 0.5 or 1.0% husk for 28 and 68 weeks. Those fed cycad and those fed a control diet did not differ significantly in weight. Lesions in those chickens fed for 68 weeks were not more severe than those fed for 28 weeks. They included focal necrosis and fatty degeneration in the liver and cystic renal tubules with cellular atrophy. These lesions were mild compared to those produced in rats by the feeding of cycads. No chickens had tumors attributable to cycads, nor did they have clinical signs of central nervous system disturbances.