Figure 1.

Alpha diversity of faecal samples. Faecal pellets were collected from UV-irradiated and nonirradiated mice that had been given either a high-dose (D++), standard-dose (D+), or no vitamin D (D−) diet. Mice were first established on diets for 24 days (days 0–24), then half were UV-irradiated daily with 1 kJ/m² UVR for 4 consecutive days (days 24 to 28), followed by biweekly exposures. Samples were collected after 6 UV treatments (day 35) and at the end of follow-up (protocol day 63). After faecal DNA was extracted, the V3–V4 segment of 16S rRNA was sequenced using the Illumina MiSeq. Alpha diversity is represented by Chao1. n = 5/group. UVR = ultraviolet radiation.