Super-dosing of Vitamin B2 Induces Beneficial Hindgut Transcriptome Responses in Weaned Piglets

High dietary levels of vitamin B2 on the caecal transcriptome of weaned piglets was explored, to evaluate if super-dosing of riboflavin could reach the hind gut, and consequently trigger a beneficial host response. Caecal gene expression was evaluated using Agilent transcriptome microarray, 14 and 28 days after supplementation in three experimental groups; a control group (recommended dose of riboflavin: 10 mg/kg diet), and two groups additionally supplemented to reach 50 or 100 mg/kg of riboflavin, respectively. Both supplementation levels significantly changed the caecal transcriptome pattern compared to the control. The 100 mg/kg dose resulted in the highest number of differentially expressed genes. At day 14, the top modulated genes were related to oxidative stress and immune response, confirming the antioxidant effect of riboflavin. Furthermore, pathways involved in the response of the host to changes in the microbiota were modulated, indicating modulatory effects of riboflavin on the microbiome, and indirectly the host response. Finally, the highest dose of riboflavin triggered molecular mechanisms involved in aldosterone and bile acid metabolism, demonstrating the potential of vitamin B2 in improving hind gut health status. A lower impact of the 100 mg/kg supplementation of riboflavin on caecal gene expression was found at day 28. Nevertheless, some positive gene responses were shown against DNA damage for both supplementation levels, and some pathways related to cell signaling were modulated. The data presented in this study confirm that super-dosing vitamin B2 affects caecal physiology, and further investigation is needed to support the findings of the possible modulation on the microbiota and bile acid metabolism. In conclusion, super-dosing of vitamin B2 positively impacts the transcriptome response of the weaned piglets’ caecum. This creates the opportunity for considering riboflavin as part of a novel solution to reduce the incidence and severity of digestive problems associated with the period immediately post-weaning. Keywords: transcriptomics, microarray, piglets, riboflavin, vitamin DEG: Differentially Expressed Gene PCA: Principal Component Analysis PCR: Polymerase Chain reaction UPLC: Ultra Performance Liquid Chromatography RNA: Ribonucleotide Acid LC/MS: Liquid Chromatography / Mass spectrometry Ct: Cycle threshold RIN: RNA Integrity Number FDR: False Discovery Rate KEGG: Kyoto Encyclopedia of Genes and Genomes HSP: Heat Shock Protein ROS: Reactive Oxygen Species BA: Bile Acid