Benefits of Polyphenol-Based Synbiotics in Crustacean Diet

Abstract

Here, the olive leaf extract (OLE) rich in polyphenols was employed as a prebiotic agent, together with Lactobacillus reuteri and Bacillus clausii, to develop synbiotics. The prebiotic effect of olive leaf extract on the probiotic strains was tested at concentrations of 0, 50, 100, 400, and 1000 μg mL−1, and also 20 and 40 mg mL−1. Olive leaf extract at 40 mg mL−1 showed the best prebiotic activity on L. reuteri and B. clausii. A basal diet and two experimental synbiotic-containing diets were prepared. The synbiotic diets were manufactured by adding to the basal diet 5 × 106 CFU g−1 L. reuteri + 5 × 106 CFU g−1 B. clausii + 0.25 mg g−1 OLE and 1 × 107 CFU g−1 L. reuteri + 1 × 107 CFU g−1 B. clausii + 0.25 mg g−1 OLE. The diets were administered to the freshwater crayfish Astacus astacus (1.35 ± 0.04 g) in an 84-day feeding trial. The diet containing 5 × 106 CFU g−1 L. reuteri + 5 × 106 CFU g−1 B. clausii + 0.25 mg g−1 OLE significantly improved (p < 0.05) final weight, specific growth rate, body condition, and survival rate. A significant growth of Enterobacteriaceae, which include strains with proven beneficial activities for intestinal health and general animal welfare, significantly increased in crayfish fed with synbiotics. The obtained results could be suitable for functional feed development in crayfish farming.

Vine-Winery Byproducts as Precious Resource of Natural Antimicrobials: In Vitro Antibacterial and Antibiofilm Activity of Grape Pomace Extracts against Foodborne Pathogens

“…Growing scientific evidence suggests that polyphenolic molecules have the potential to exert important bioactive properties [ 9 , 10 ], including antimicrobial effects [ 11 ]. Several recent studies have shown how polyphenols extracted from different botanical matrices are able to exert significant in vitro antibacterial and antifungal activity in in vitro models and beneficial effects in in vivo systems [ 12 , 13 , 14 , 15 , 16 , 17 ]. Regarding waste from vine-winery chains, some studies have demonstrated the antibacterial potential of polyphenolic extracts from winemaking byproducts [ 18 , 19 ].…”