Long-term storage influence on volatile amines (TVB-N and TMA-N) in sardines and herring utilized as food for tuna fattening

P>The study investigated the influence of volatile amines, total volatile bases nitrogen (TVB-N) and trimethylamine nitrogen (TMA-N) quantities in sardines (Sardina pilchardus) and herring (Clupea harengus) after 1 year of frozen storage. TVB-N quantities for both species were within the tolerance limit (25-35 mg/100 g). TVB-N and TMA-N increase factors over the initial values for sardines were 1.6 and 4.9, and 1.4 and 3.6 for herring. Results showed that TMA-N quantities were twice those registered as acceptable for these species, rendering the analysed fish unsuitable for tuna fattening. Previously registered increases in tuna mortalities were caused by secondary bacterial infection (pasteurellosis) from these baitfish. Tissue samples from diseased animals and the control group differed widely in their histological architecture, suggesting that rearing conditions, e.g. quality of administered baitfish, indirectly influenced tuna health.