A study on the utilization of lactic acid bacteria fermented seaweed as aqua feed for growth and disease resistance in oreochromis niloticus

Abstract

Consumption of fermented foods are known to provide various health benefits. Fermentative microbes present in traditional foods are reported to confer health benefits. The present study was aimed to isolate a novel potent probiotic strain from the homemade fermented Indian recipe Moor Kuzhambu and Pickle, and its characterization to elucidate the efficacy of isolate in cholesterol and heavy metal reduction. Cultures isolated from Pickle (CK2) and Moor Kuzhambu (CK3) were newlineidentified as different strains of Pediococcus pentosaceus using 16S rDNA newlinesequence based bacterial identification method. The isolated strains exhibited newlinetolerance to gastric juice and was able to exhibit a broad range of tolerance to newlinevarying temperatures, pH, NaCl, solvent, phenol, trypsin, and artificial gastric newlinejuice. Cell surface studies such as auto aggregation, co-aggregations, and cell newlinesurface hydrophobicity determined the ability of the strains to aggregate on to intestinal cell surface and manifest competitive pathogen displacement. Remarkable biofilm reduction of 48% to 80% was observed in the probioticsupplemented samples. Similarly, a reduction of 80% to 85% free cholesterol was newlinenoted in cholesterol assimilation assays, and heavy metal (Cu+, Pb+, Zn+ and Fe+) newlineassimilation ability was observed. Pediococcus pentosaceus MK459541 strain newlineCK2 and (MK459539) CK3 were assessed for EPS synthesis, structural characteristics, antioxidant properties and heavy metal assimilation abilities. Maximum yield of EPS was observed in carbon source Xylose for CK3 and fructose for CK2. Similarly, EPS production was found to maximum when bacteria newlinewere supplemented with meat extract (CK2) and yeast extract (CK3). FTIR results exhibited the presence of functional groups such as Imine/Oxime group, carboxylic group, Halo groups, Nitro compounds, etc. Further studies on EPS CK2 and EPS CK3 revealed a strong antioxidant capacity of 73.92% to 97.75%. Heavy metal assimilation ability of the EPS was found to be strong and in decreasing order as follows Cu+, Fe+ and Zn+.