Digestive enzyme activities of African catfish and Nile tilapia reared in RAS Elena Skvortsova, Irina Golovanova, Irina Postrash, Andrey Filippov and Ekaterina Kulivatskaya BIO Web Conf., 160 (2025) 02011 Published online: 12 February 2025 DOI: 10.1051/bioconf/202516002011