The use of probiotics in the diet of bivalves poses a great potential in aquaculture as an alternative to antibiotics. The aim of this study was to assess the effect of Lactiplantibacillus plantarum I on the phenolic content and antioxidant capacity (AC) of queen scallop extracts after one month of feeding. Total phenols (TP) ranged from 28.17 ± 3.11 to 58.58 ± 8.57 mg GAE/100 g, total non-flavonoids (TNF) from 23.33 ± 3.66 to 36.56 ± 9.91 mg GAE/100 g, and total flavonoids (TF) from 10.56 ± 5.57 to 30.16 ± 1.69 mg CE/100 g. AC was assessed via three different methods: the ferric-reducing ability of plasma assay (FRAP), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic) acid assay (ABTS), and 2,2-diphenyl-1-picryhydrazyl assay (DPPH). FRAP values ranged from 0.13 ± 0.03 to 0.17 ± 0.02 µM AA/g, ABTS from 0.68 ± 0.11 to 2.79 ± 0.34 µM AA/g, and DPPH from 1.75 ± 0.17 to 2.98 ± 0.53 µM AA/g. Among all extracts, the best phenolic content and AC were observed in water extracts from queen scallops. The bivalves treated with the Lactiplantibacillus plantarum I-enriched diet showed higher AC according to the FRAP assay in all extracts. A significant correlation was observed between AC and TP and TNF in control and Lactiplantibacillus plantarum I-treated scallops.
Keywords: Lactiplantibacillus plantarum I; antioxidant capacity; phenolic content; probiotic.