Agricultural By‐Products as Supplemental Feed for Crayfish, Procambarus clarkii

Growth of crayfish (Procambarus clarkii) fed six agricultural by‐products was determined in the laboratory. In addition, the aerobic breakdown of 10 by‐products was monitored to evaluate nutritive changes in their composition. Dried sweet potato vines produced the highest final average weight of crayfish, followed by sweet potato trimmings, rice stubble, and rye hay. Crayfish fed soybean stubble and dried sugarcane stalks grew poorly. A decrease in the carbon:nitrogen ratio for corn leaves, deciduous tree leaves, soybeans, and the above six by‐products occurred during a 3‐month period of storage in water. Except for dried sugarcane stalks and tree leaves, all by‐products attained C:N ratios less than 17:1. Sweet potato vines and trimmings may be fed directly to crayfish; rice stubble and rye hay, however, should be composted for a period of time to enhance their nutritive value through the process of microbial decomposition. Soybean stubble and dried sugarcane stalks do not appear suitable as supplemental feeds for crayfish.