Identification and characterization of potential probiotic lactic acid bacteria isolated from pig feces at various production stages

UEZEN DAVID; ARISTIMUÑO FICOSECCO, MARÍA CECILIA; FÁTIMA NADER-MACIAS, MARÍA E.; GRACIELA VIGNOLO

CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE.

CANADIAN VET MED ASSOC

Año: 2023

0830-9000

Lactic acid bacteria (LAB) were isolated, identified, and characterized from pig feces at various growth stages and feed rationsin order to be used as probiotic feed additives. Lactic acid bacteria numbers ranged from 7.10 6 1.50 to 9.40 log CFUs/g forgrowing and lactating pigs, respectively. Isolates (n = 230) were identified by (GTG)5-polymerase chain reaction and partialsequence analysis of 16S rRNA. Major LAB populations were Limosilactobacillus reuteri (49.2%), Pediococcus pentosaceus (20%),Lactobacillus amylovorus (11.4%), and L. johnsonii (8.7%). In-vitro assays were performed, including surface characterizationand tolerance to acid and bile salts. Several lactobacilli exhibited hydrophobic and aggregative characteristics and were ableto withstand gastrointestinal tract conditions. In addition, lactobacilli showed starch- and phytate-degrading ability, as wellas antagonistic activity against Gram-negative pathogens and the production of bacteriocin-like inhibitory substances. Whenresistance or susceptibility to antibiotics was evaluated, high phenotypic resistance to ampicillin, gentamicin, kanamycin,streptomycin, and tetracycline and susceptibility towards clindamycin and chloramphenicol was observed in the assayedLAB. Genotypic characterization showed that 5 out of 15 resistance genes were identified in lactobacilli; their presence did notcorrelate with phenotypic traits. Genes erm(B), strA, strB, and aadE conferring resistance to erythromycin and streptomycinwere reported among all lactobacilli, whereas tet(M) gene was harbored by L. reuteri and L. amylovorus strains. Based on theseresults, 6 probiotic LAB strains (L. reuteri F207R/G9R/B66R, L. amylovorus G636T/S244T, and L. johnsonii S92R) can be selectedto explore their potential as direct feed additives to promote swine health and replace antibiotics