Isolation, characterization and selection of potential probiotic lactic acid bacteria from feces of wild boar, native pig and commercial pig

In livestock production, lactic acid bacteria (LAB) play an important role in improving performance, mitigating diseases due to their ability to maintain the balance of gastrointestinal microbes and resistance to pathogenic bacteria. As resident adapted microorganisms, LAB should be isolated and characterized from the homologous host to improve their efficiency as additives in pig feeding. In present study, cultivable LAB numbers from commercial pig (CP), native pig (NP) and wild boar (WB) samples ranged from 4.64 to 7.39 (log10 CFU/g), and the LAB counts in commercial pig and native pig feces were much higher than wild boar. Ninety-six LAB strains were detected in commercial pig, native pig and wild boar feces, being represented by thirteen different species of Enterococcus, Lactobacillus, Pediococcus and Weissella genera. Tests in vitro were conducted including survival in simulated gastrointestinal tract conditions, antimicrobial activity, organic acid production, hydrophobicity, auto-aggregation, Caco-2 surface adhesion, haemolytic activity and antibiotic resistance. According to the results of acid and bile salt resistant and bacteriostatic test, twelve LAB strains were selected as potential probiotics and their cell surface properties were further evaluated. Based on multivariate principal component analysis, nine probiotic LAB strains (Lactobacillus plantarum NCUA001005 and NCUA001014, Pediococcus pentosaceus NCUA006009, Lactobacillus reuteri NCUA064001 and NCUA064006, Lactobacillus johnsonii NCUA063001, NCUA063006 and NCUA063008, Lactobacillus casei NCUA011001) showed better characteristics and might be selected to explore their potential use as probiotics. These strains were good candidates for further investigation in vivo studies to assess their potential health benefits as feed supplements.