[Description of methods used for collection/generation of data] The protocol was approved by the Experimental Animal Committee of the Complutense University of Madrid and Community of Madrid (PROEX. 224.0/21). Young (n 40) (8 weeks old) ICR-CD1 female (H) and male (M) mice were housed (five per cage and separated by sex) and distributed into control (C) and experimental (CGN) groups (10 per group and sex). Mice received orally 540 mg/kg/day of κ-carrageenan resuspended in 200 μL of PBS for 15 days in the experimental groups and PBS the controls. Faecal material were collected from each mouse before (T0) and after (T2) two weeks of treatment. About 200 mg of stools were washed with 0.9% peptone water, centrifuged (10,000 ×g, 10 min) and the pellet used for genomic DNA purification. DNA was extracted using the EZNA Stool DNA Kit (Omega Bio-Tek) and quantified using the NanoDrop 1000 UV/VIS Spectrophotometer (Thermo Fisher). DNA samples were analyzed by amplicon-based metagenomic sequencing of the 16S rDNA V3-V4 region, performed by Novogen (Cambridge, UK), on an Illumina platform to generate 250 bp paired-end reads. [Dictionaries/codebooks used] The first letter of the sample code corresponds to whether the mice are female (H) or male (M). The second letter refers to whether they are carrageenan-fed mice (CGN) or control mice (C). Then, T0 or T2 is added depending on whether they are samples collected before or at the end of the treatment, respectively. J1 or J2 refers to the cage number, and the last number refers to the identification number of each mouse in each group.

The objective of this study was to test the effects of CGN consumption on the gut microbiota and the intestinal homeostasis of male and female young mice. Female and male ICR-CD1 mice (8 weeks old) received orally 540 mg/kg/day of CGN. Fecal material was analyzed to describe changes in the fecal microbiota, based on the analysis of bacterial 16S rRNA gene (V3-V4 region) amplicon sequences. Non-significant microbiota taxonomical changes associated to CGN intake were obtained in the mice stools, resulting the housing time in an increase of bacterial groups belonging to the Bacteroidota phylum. The PICRUSt2 functional predictions based on 16S rDNA amplicons showed an overall increase in functional clusters of orthologous genes (COG) involved in carbohydrate transport and metabolism. A significant increase in citotoxicity of fecal supernatants was observed in CGN-fed mice.

MCIN/ AEI /10.13039/501100011033 (project reference: PID2019- 382 106071RB-I00).

Peer reviewed