We investigated the molecular characterization of a Tilapia by-product hydrolysate to asses its nutritional
potential in aquafeed. The proximate composition and amino acid composition showed that the
hydrolysate had high protein content and contained all the essential amino acids required for carnivorous
fish nutrition. The molecular weight profile determined by High Performance Size Exclusion
Chromatography (HPSEC) indicated that the hydrolysate was mainly composed of polypeptides (46.9%)
and oligopeptides (35.8%). We also characterized the peptide fraction by nLC-ESI-MS/MS and OFFGELnLC-
MALDI-TOF/TOF. We identified 1374 peptides, and highlighted a high diversity of oligopeptides and
polypeptides. Finally, the Tilapia by-product hydrolysate exhibited antimicrobial activity against Yersinia
ruckeri and to a lesser extent against Edwardsiella tarda and Bacillus megaterium. These preliminary results
suggest the strong nutritional and functional potential of Tilapia by-product hydrolysates.