Beneficial Microbes, 2020; 11(2): 163-173 Wageningen Academic Publisher s ISSN 1876-2883 print, ISSN 1876-2891 online, DOI 10.3920/BM2019.0116 163 1. Introduction Since their discovery, antibiotics permitted unparalleled roles in both human and veterinary medicines. Nonetheless, their overuses to prevent, control, and treat infectious diseases in humans and animals has led to development, emergence and spread of resistant and multi-resistant bacterial strains (Aslam et al., 2018). Reducing antibiotics use is currently seen as a major objective, and this depends on eliminating inappropriate uses, misuses and, also in finding other alternatives. Recently, the O’Neil commission (O’Neil, 2016) predicted important increase of the number of deaths attributable to antimicrobial resistance by 2050. Indeed, this report said that 10 million people will die from antibiotic resistance and causing a cumulative global economic cost of US$100 trillion. It should be noted that whilst antibiotic resistance is escalating, the number of antibiotics in the development pipeline is decreasing (Stanton, 2013). Because of this concern, Sweden has prohibited the use of some antibiotics used in animal feeds during 1986 (Castanon, 2007), and then European Union (EU) banned all antibiotic growth promoters according to Regulation 1831/2003/EC. According to Stanton (2013) this ban has impacted rather negatively animal production industries in EU, because of the increase of infections and decrease in animal production. Actions have been taken in different countries, but still global approach and urgent need of alternatives are requested. Related to that, a joint committee from the European Medicine Agency (EMA) and the European Food Safety Authority (EFSA) Lactobacillus plantarum S27 from chicken faeces as a potential probiotic to replace antibiotics: in vivo evidence T. Benbara 1 , S. Lalouche 1 , D. Drider 2* and F. Bendali 1* 1 Laboratoire de Microbiologie Appliquée, Faculté des Sciences de la Nature et de la Vie, Université de Bejaia, Bejaia 06000, Algeria; 2 EA 7394 Institut Charles Viollette, Université Lille, 59000 Lille, France; djamel.drider@univ-lille.fr; bendali.farida@univ-bejaia.dz Received: 11 September 2019 / Accepted: 11 December 2019 © 2020 Wageningen Academic Publishers RESEARCH ARTICLE Abstract This study reports the probiotic attributes of Lactobacillus strains isolated from chicken faeces and mainly their capabilities to prevent infectious diseases and improve chicken production performance. Thus, 22 Lactobacillus 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 in vitro screening analyses revealed Lactobacillus plantarum S22 and L. plantarum S27 as the only strains capable to survive at pH 2.0 in MRS broth (log 10 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 10 cfu/ml=0.09-3.32 log), but only Lactobacillus fermentum S26, L. plantarum S22 and L. plantarum 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 Escherichia coli ATCC 25922, E. coli SL2016 and Salmonella enterica CIP 81-3. Lactic acid is likely the main antibacterial compound produced since the neutralised supernatant was devoid of any antibacterial activity. In vitro characterisation of these 22 novel strains, based on the aforementioned criteria revealed L. plantarum S27 as the most suitable strain for in vivo 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 L. plantarum S27 to the chicks at 10 9 cfu/ml permitted to improve the animal food intake and weight. Taken together, data from in vitro and in vivo analyses indicated that L. plantarum S27 might be a worthy probiotic for chickens rather than adding antibiotics to animals feeding. Keywords: Lactobacillus plantarum, antibiotics, probiotics, chickens, performance https://www.wageningenacademic.com/doi/pdf/10.3920/BM2019.0116 - Sunday, November 29, 2020 6:07:27 PM - Gothenburg University Library IP Address:130.241.16.16