Propionibacteria as potential probiotic for poultry: studies of interaction with the cecal microbiota of hens

ELOY ARGAÑARAZ MARTÍNEZ; JAIME DANIEL BABOT; MARÍA CRISTINA APELLA; ADRIANA PEREZ CHAIA

Rosario - Santa Fe

Congreso; IX Congreso Argentino de Microbiología General; 2013

SAMIGE

The genus Propionibacterium has been focus of extensive research in the last years in the field of probiotics. The genus produces short chain fatty acids (SCFA) by carbohydrates fermentation. In the intestinal environment, some dairy species of propionibacteria (PAB) may influence the intestinal microbiota balance and SCFA production. This may contribute to controlling pathogens colonization. An investigation was conducted to evaluate in vitro the effects of selected strains of PAB on the composition and activity of the poultry intestinal microbiota. Healthy hens were sacrificed and their cecal contents homogeinized, under aseptic conditions, to obtain cecal slurries (CS) 5%(w/v). Five strains of Propionibacterium acidipropionici (dairy PAB) and 4 of P. avidum (cutaneous PAB) were inoculated individually at levels of 106 or 108 CFU/mL in CS and incubated for 10h at 41ºC in anaerobiosis. Microbiota composition was assessed by FISH with genus specific probes and SCFA were measured by HPLC in samples of 0 and 10h of incubation. Dairy PAB showed increased SCFA production for both inocula tested, compared to a CS control incubated at the same time. P. acidipropionici LET107 was the major producer of organic acids in the dairy group of strains, with 278.5±38.5, 149.4±21.9 and 52.4±9.1 µmol/g of cecal content of acetic, propionic and butyric acids, respectively (molar ratio 58:31:11). In the cutaneous group, P. avidum LET106 reached values of 184.15±22.97 and 72.33±11.04 µmol/g of cecal content of acetic and propionic acids, respectively (65:25:10), with the highest inoculum used. The influence in the microbiota composition was evidenced by changes in counts of Lactobacillus sp., Enterococcus sp., Clostridium sp. and Bacteroides sp.The effect was dependent on the PAB strain used. Additionally, it was determined whether the concentrations of SCFA produced by PAB in CS, would inhibit the growth of Salmonella Typhimurium (ST), a pathogen with impact on human and animal health. For this purpose, freshly prepared CS were centrifuged and filter-sterilized to obtain sterile cecal water (CW). This matrix was supplemented with SCFA in the concentrations produced by PAB, and adjusted to pH 7.5 or 5.5. ST grew in the supplemented CW in a pH-dependent way. At pH 7.5, counts were reduced in 1 order log compared to a control prepared without the acids supplement and adjusted to the same pH value. In CW of initial pH 5.5, counts were reduced in 1.5 order log related to the correspondent control without acids and the same pH value. Higher inhibition may be obtained in vivo during long term administrations of PAB. We concluded that PAB administered as a dietary supplement in raising poultry, may interact with the cecal microbiota and influence the balance of SCFA with positive impact on the health of the host contributing to the inhibition of potential pathogens.