Project description:The chicken gastrointestinal tract (GIT) harbours a complex microbial community, involved in several physiological processes such as host immunomodulation and feed digestion. Other studies were already performed to define the chicken gut metagenome and its fecal metaproteome. For the first time, the present study analysed dietary effects on the protein inventory of the microbiota in crop and ceca of broilers. We performed quantitative label-free metaproteomics by using 1D-gel electrophoresis coupled with LC-MS/MS to identify the structural and functional changes triggered by diets supplied with varying amount of mineral phosphorus (P) and microbial phytase (MP). Phylogenetic assessment based on label-free quantification (LFQ) values of the proteins identified Lactobacillaceae as the major family in the crop section regardless of the diet, whereas proteins belonging to the family Veillonellaceae increased with the P supplementation. Within the ceca section, proteins of Bacteroidaceae were more abundant in the P-supplied diets, whereas proteins of Eubacteriaceae decreased with the P-addition. Proteins of the Ruminococcaceae increasedraised with the amount of MP while proteins of Lactobacillaceae werewas more abundant in the MP-lacking diets. Classification of the identified proteins into COGs and KEGG pathways underlined a diverse microbiota activity depending on the dietary regimen, indicating a thriving microbial community in the case of P and MP supplementation, and stressed microbial community when no P and MP were supplied. Insights oninto the identified KEGG pathways, as well as comparison between the GIT sections, dietary treatments, and the bacterial families encoding for the pathways of interest are provided. T) harbours a complex microbial community, involved in several physiological processes such as host immunomodulation and feed digestion. Other studies were already performed to define the chicken gut metagenome and its fecal metaproteome. For the first time, the present study analysed dietary effects on the protein inventory of the microbiota in crop and ceca of broilers. We performed quantitative label-free metaproteomics by using 1D-gel electrophoresis coupled with LC-MS/MS to identify the structural and functional changes triggered by diets supplied with varying amount of mineral phosphorus (P) and microbial phytase (MP). Phylogenetic assessment based on label-free quantification (LFQ) values of the proteins identified Lactobacillaceae as the major family in the crop section regardless of the diet, whereas proteins belonging to the family Veillonellaceae increased with the P supplementation. Within the ceca section, proteins of Bacteroidaceae were more abundant in the P-supplied diets, whereas proteins of Eubacteriaceae decreased with the P-addition. Proteins of the Ruminococcaceae increasedraised with the amount of MP while proteins of Lactobacillaceae werewas more abundant in the MP-lacking diets. Classification of the identified proteins into COGs and KEGG pathways underlined a diverse microbiota activity depending on the dietary regimen, indicating a thriving microbial community in the case of P and MP supplementation, and stressed microbial community when no P and MP were supplied. Insights oninto the identified KEGG pathways, as well as comparison between the GIT sections, dietary treatments, and the bacterial families encoding for the pathways of interest are provided.