Insight Into Dynamics of Gut Microbial Community of Broilers Fed With Fructooligosaccharides Supplemented Low Calcium and Phosphorus Diets

We investigated how the microbiota in the ileum and cecum of broiler chickens fed a diet of low calcium (Ca) and available phosphorus (aP) and prebiotic fructooligosaccharides (FOS) supplements changed over a 3 weeks period. Three dietary treatments were randomly assigned to four replicate cages of five birds each, including: positive control (PC), a wheat-corn-soybean meal-based diet; negative control (NC), as PC with 0.2% reduced Ca and aP; and NC + FOS, as NC supplemented with 0.5% of FOS. Ileal and cecal digesta were sampled from each replicate (n = 4) on d21 and processed for 16S rRNA gene amplicon (V4 region) sequencing using Illumina platform. Statistical differences were observed in the microbiome by GI location as determined by 2-way ANOVA and Permutational MANOVA. On average, 24,216 sequence reads per sample were generated resulting in 800 and 1,280 operational taxonomic units in the ileal and cecal digesta, respectively. Difference (P < 0.0001) on alpha diversity and abundances of several phyla was observed between ileal and cecal digesta. ß-diversity was different (P < 0.05) between each treatment groups in the ileum but not in the cecum. In the cecum, species richness, phylogenetic diversity, and the number of observed species were higher in PC compared to NC + FOS (P < 0.05). Several phyla, including Cyanobacteria, Firmicutes, and Proteobacteria, had significantly different abundance in the ileal and cecal digesta (P < 0.05). In the ileal digesta, positive correlation were observed between Salinibacterium and Lysobacter and PC diet. Blautia, Faecalibacterium and Pseudomonas and the NC diet and Lactobacillus and Escherichia and the NC + FOS diet. In the cecal digesta, Butyrivibrio, and Allobaculum were positively correlated to PC. Although, Clostridium and Anaerotruncus were positively correlated to NC + FOS, they showed negative correlation to PC and NC. The study concludes that dietary Ca and aP level and FOS supplementation alters ileal microbiota of the broiler chickens.