Assessment of a Novel Synbitotic of Pomegranate Peels Extract and Multi-Specie Probiotics as an Antibiotics Alternative in Ruminants

A synbiotic composed of pomegranate peels extract, Saccharomyces (S.) cerevisiae, Lactococcus (L.) lactis, Lactobacillus (Lact) paracasei, and Lact. plantarum was fabricated in free (FPLYS) and (NPLYS) nano-encapsulated forms. The encapsulation efficiency, physichochemical properties, and antioxidant and antimicrobial activities of FPLYS and NPLYS were tested. For in vitro rumen fermentation study, a basal diet was supplemented with FPLYS-H (10⁹ CFU probiotics/g diet), NPLYS-H (10⁹ CFU probiotics/g diet), NPLYS-L (10⁷ CFU probiotics/g diet), 40 mg/kg diet monensin (MONS), or not supplemented (CON). The encapsulation efficiency of gum arabic-gelatin complex for prebiotic and probiotics was 75.26% and 91.80%, respectively. The size and zeta potential of gum arabic-gelatin were 27.72 nm and 11 mV, respectively. NPLYS showed two-time higher antioxidant activity than FPLYS. NPLYS showed antimicrobial activity against Escherichia (E.) coli and Staphylococcus (Staph.) aureus similar to gentamicin, while FPLYS showed lower activity (p < 0.05). NPLYS and FPLYS showed antimicrobial activity against Pseudomonas (Ps.) aeruginosa and antifungal activity against Aspergillus (A.) niger and A. flavus, but lower than getntamicin and fluconazol, respectively (p < 0.05). NPLYS-L significantly increased total gas production compared to CON, MONS, and NPLYS-H. Compared to CON, both MONS and FPLYS-H significantly reduced methane production, followed by NPLYS-H and NPLYS-L. Among treatments, MONS significantly increased propionate, while reducing butyrate and acetate/propionate ration. All treatments increased cellulose digestibility and protozoal count (p < 0.05). NPLYS-L significantly decreased rumen ammonia concentration compared to CON, however other treatments recorded intermediate values. The synbiotic developed in this study can be either used as an antimicrobial agent and/or a rumen fermentation modifier, replacing synthetic antibiotics used for these purposes. Nanoencapsulation process improved biological activities of the synbiotic.