Dietary probiotic in broiler chickens submitted to antibiotic therapy: performance and intestinal microbiota

Author(s)

Rafaela Pereira

• Document type: Doctoral Thesis
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2014-12-03

Examining board members

José Fernando Machado Menten; Fernando Dini Andreote; Luiz Lehmann Coutinho; Daniel Emygdio de Faria Filho; Marcos Macari

• Advisor: José Fernando Machado Menten

Abstract

The purpose of this study was to verify the ability of a probiotic in the feed to maintain the stability of gut microbiota in chickens after antibiotic therapy and associations with the performance. The dietary treatments consisted of a cornsoybean meal basal diet that was supplemented or not with a probiotic (Bacillus subtilis) in the concentration of 3×109 cfu/kg of feed. Starting on day 21, the birds were submitted to the antibiotic therapy consisting of 200 ppm of bacitracin methylene disalicylate (for Gram-positive bacteria) and 1,000 ppm of neomycin sulfate (for Gram-negative bacteria) in the drinking water, during 3 days. The trial was conducted with broiler chickens from 1 to 42 days of age, however, from 1 to 21 days, the chickens received only the dietary treatment, and after of the 21 days, the birds received the dietary and therapeutic treatments. At 2, 4 and 6 days after the antibiotic therapy, three chickens from each experimental unit were euthanized and the contents of the small intestine and ceca were collected and pooled by pen. The trial was conducted in a completely randomized design with 4 treatments and 9 replicates in a 2×2 factorial arrangement for performance characteristics (with and without probiotic × with and without antibiotic therapy), and in a 2×2×3 factorial arrangement for gut microbiota (with and without probiotic × with and without antibiotic therapy × 2, 4 and 6 days after of the antibiotic therapy) with 3 replicates per treatment. The DNA was extracted from the contents of the small intestine and ceca to isolate the 16S r RNA and study of the bacterial communities. The molecular techniques used were the terminal restriction fragment length polymorphism (TRFLP), quantitative PCR (qPCR) and sequencing, considering the 16S rRNA -genetargeted. The dietary and therapeutic factors modulated the gut microbiota independently. The probiotic and antibiotic therapy affected the main groups within of the gut content from the phylogenetic classification at the phylum level until the phylogenetic classification at the genera level. Some phylogenetic groups were equally affected by the two factors while other groups were changed in a distinct form depending on of the probiotic or antibiotic therapy. The antibiotic therapy and dietary probiotic decreased the number of taxonomic operational unit (OTUs) in cecal content. The improved performance observed in birds supplemented with probiotic was probably related to changes in the structure of intestinal bacterial communities and phylogenetic groups such as higher Lactobacillus and decreased Clostridiales. Antibiotic therapy modified the bacterial community structure; however it did not cause loss of broiler performance. The gut bacterial community in birds medicated and supplemented with probiotic had high similarity with the gut community of birds that received dietary probiotic only, indicating the possible recovery of the gut bacterial community 6 days after the antibiotic therapy. (AU)

• FAPESP's process: 11/12998-0 - Maintaining the balance of intestinal microbiota of broilers with probiotics after antibiotic
• Grantee: Rafaela Pereira
• Support Opportunities: Scholarships in Brazil - Doctorate