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

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

Rosario

Congreso; IX Congreso Argentino de Microbiología General SAMIGE; 2013

Propionibacteria (PAB) have been the focus of extensive research in the last years. Studies of physiological and functional properties allowed consider members of this genus as potential probiotics for humans and animals. These aerotolerant anaerobes produce short chain fatty acids (SCFA) by carbohydrates fermentation that may influence on the intestinal microbiota controlling the colonization and development of potential pathogens. Therefore, an investigation was conducted to evaluate the effects of the inclusion of selected strains of PAB in cecal homogenates (CH) of hens as in vitro intestinal model. Healthy hens were sacrificed and their cecum removed; theirs contents were collected and homogenates 5%(w/v) were carried out under aseptic conditions. Five strains of Propionibacterium acidipropionici and 4 of P. avidum were inoculated independently in two levels (106 ,108 CFU/mL) and incubated for 10h in anaerobiosis. The microbiota composition was assessed by FISH with genus specific probes and SCFA were measured by HPLC, in samples taken at 0 and 10h of incubation. All strains of P. acidipropionici showed increased SCFA production compared to the control for both inocula tested, showing differences between strains. 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 contents of acetic, propionic and butyric acids, respectively (molar ratio 58:31:11). In the cutaneous group, P. avidum LET106 with the highest inoculum, showed differences with a value of 184.15±22.97, 72.33±11.04 µmol/g of cecal contents of acetic and propionic acids, respectively (65:25:10). The profile of the microbiota during fermentation was strain dependent and evidenced changes in populations as Lactobacillus sp., Enterococcus sp. and some anaerobic as Clostridium sp. and Bacteroides sp. Apparently the microbiota influences SCFA levels, maintaining the molar ratios of these acids even when the presence of PAB increases its concentrations. Additionally, it was determined whether the concentrations of SCFA produced by PAB in CH, would inhibit the growth of Salmonella Typhimurium (ST) (pathogen with impact over human and animal health). For this purpose, a matrix of sterile cecal water (CW) supplemented with SCFA, at initial pH of 7.5 or 5.5 was used. ST grew in the presence of concentrations of SCFA produced as PAB levels, and was markedly influenced by the initial pH used. At pH 7.5 its counts were significantly reduced in 1 CFU/mL compared to control without supplements, but at pH 5.5, the effect was even more marked, with a viability loss of 1.5 CFU/mL compared with control. We concluded that PAB administered as a dietary supplement in raising poultry, may interact with cecal microbiota and influence the balance of SCFA with positive impact on the health of the host contributing to the inhibition of potential pathogens.