%0 Journal Article %A Banerjee, Sohini %A Sar, Abhijit %A Misra, Arijit %A Pal, Srikanta %A Chakraborty, Arindom %A Dam, Bomba %T Increased productivity in poultry birds by sub-lethal dose of antibiotics is arbitrated by selective enrichment of gut microbiota, particularly short-chain fatty acid producers %D 2018 %J Microbiology, %V 164 %N 2 %P 142-153 %@ 1465-2080 %R https://doi.org/10.1099/mic.0.000597 %K gut microbiota %K short chain fatty acid %K butyrate %K 16S rDNA amplicon sequencing %K sub-lethal dose of antibiotics %I Microbiology Society, %X Antibiotics are widely used at sub-lethal concentrations as a feed supplement to enhance poultry productivity. To understand antibiotic-induced temporal changes in the structure and function of gut microbiota of chicken, two flocks were maintained for six weeks on a carbohydrate- and protein-rich diet. The feed in the conventional diet (CD) group was supplemented with sub-lethal doses of chlorotetracycline, virginiamycin and amoxicillin, while the organic diet (OD) had no such addition. Antibiotic-fed birds were more productive, with a lower feed conversion ratio (FCR). Their faecal samples also had higher total heterotrophic bacterial load and antibiotic resistance capability. Deep sequencing of 16S rDNA V1-V2 amplicons revealed Firmicutes as the most dominant phylum at all time points, with the predominant presence of Lactobacillales members in the OD group. The productivity indicator, i.e. higher Firmicutes:Bacteroidetes ratio, particularly in the late growth phase, was more marked in CD amplicon sequences, which was supported by culture-based enumerations on selective media. CD datasets also showed the prevalence of known butyrate-producing genera such as Faecalibacterium, Ruminococcus, Blautia, Coprococcus and Bacteroides, which correlates closely with their higher PICRUSt-based in silico predicted ‘glycan biosynthesis and metabolism’-related Kyoto Encyclopedia of Genes and Genomes (KEGG) orthologues. Semi-quantitative end-point PCR targeting of the butyryl-CoA: acetate CoA-transferase gene also confirmed butyrate producers as being late colonizers, particularly in antibiotic-fed birds in both the CD flocks and commercial rearing farms. Thus, antibiotics preferentially enrich bacterial populations, particularly short-chain fatty acid producers that can efficiently metabolize hitherto undigestable feed material such as glycans, thereby increasing the energy budget of the host and its productivity. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.000597