S27 from chicken faeces as a potential probiotic to replace antibiotics: evidence.

This study reports the probiotic attributes of strains isolated from chicken faeces and mainly their capabilities to prevent infectious diseases and improve chicken production performance. Thus, 22 strains were isolated from 50 chickens' faeces samples and assessed for their resistance to gastric acidity (pH 0.5, 1, 1.5, 2 and 2.5), tolerance to bile salts, adherence to broiler intestinal cells and antibacterial activity. These screening analyses revealed S22 and S27 as the only strains capable to survive at pH 2.0 in MRS broth (log cfu/ml=5.02 and 8.46 log respectively), while the remaining strains were not resistant to pH≤2.0. Similarly, 21 strains were resistant to bile at 0.5% (log cfu/ml=0.09-3.32 log), but only S26, S22 and S27 were able to grow in the presence of 0.1% (w/v) bile (8.23±0.15; 8.39±0.17 and 8.57±0.07 respectively). Most of these isolates (19/22) were active against ATCC 25922, SL2016 and CIP 81-3. Lactic acid is likely the main antibacterial compound produced since the neutralised supernatant was devoid of any antibacterial activity characterisation of these 22 novel strains, based on the aforementioned criteria revealed S27 as the most suitable strain for analyses. To this end, this strain was assessed for its sensitivity to different antibiotics and adhesion to poultry intestinal cells to ascertain it probiotic attributes. The administration of S27 to the chicks at 10 cfu/ml permitted to improve the animal food intake and weight. Taken together, data from and analyses indicated that S27 might be a worthy probiotic for chickens rather than adding antibiotics to animals feeding.