Introduction:
The gut microbiota consists of microorganisms inhabiting various body sites, playing essential roles in pathogen defense, digestion, vitamin synthesis, and immune regulation. In the gut, dominant phyla include Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, and Verrucomicrobia. Exercise, especially endurance training, can modulate microbiota composition, increasing metabolites such as short-chain fatty acids (SCFAs), which benefit metabolism and inflammation. This study aimed to assess gut microbiota composition in elite female futsal players across a competitive season.

Materials and Methods:
A longitudinal descriptive observational study was conducted on 14 elite female futsal players. Quarterly, a food frequency questionnaire (CFA-95) and fecal samples were collected using self-sampling kits (Ubiome,inc. United States). Participants received sampling instructions and nutritional guidance to optimize diet and microbiota diversity. For each sample, the amplicons of the 16S rDNA region were individually barcoded and sequenced in multiplex mode on the NextSeq 500 platform, using 150 bp paired-end reads. Taxonomic classification was performed using reference cluster (99% similarity groups) against SILVA 138.1 database to determine relative abundances.

Results:
The mean diversity index was 7.96 ± 0.46, with a Firmicutes/Bacteroidetes ratio of 2.03 ± 0.079. Relative abundances were as follows: Actinobacteria, 0.40 ± 5.63; Proteobacteria, 0.87 ± 1.57; and Lactobacillus, 1.38 ± 5.02. An increase in Verrucomicrobia and Proteobacteria was observed towards the season’s end.

Discussion:
The reduction in the Firmicutes/Bacteroidetes ratio may reflect a lower risk of obesity-related metabolic profiles. Higher Actinobacteria abundance is linked to improved immune function and reduced intestinal inflammation, potentially supporting sustained performance. Verrucomicrobia, notably Akkermansia, may enhance intestinal barrier protection. Lower Proteobacteria levels could indicate a reduced susceptibility to inflammatory bowel diseases.

Conclusion:
Elite female futsal players exhibited a stable, less inflammation-prone microbial environment in their gut microbiota profiles. This composition may optimize energy metabolism and immune modulation. Microbiota profiling could serve as a potential biomarker for intestinal health and athletic performance.