Sodium butyrate promoted the skin wound healing in turbot, Scophthalmus maximus L.

This study investigated the beneficial effects of dietary sodium butyrate (NaBT) supplementation on skin wound healing in turbot and the potential involvement of the skin microbiota. Turbot were fed either a control diet (CON; commercial diet) or a NaBT-supplemented diet (0.1 % NaBT in commercial diet) for 30 days, with each diet administered in triplicate. Fish were sampled at the end of feeding period and at 1, 3, and 7 day post-wounding (dpw). Digital image analysis revealed that NaBT accelerated the skin wound closure compared to the CON group. Histological analysis demonstrated that NaBT promoted faster re-epithelialization, vacuolization, and muscle tissue degradation, while reducing admixed leucocytes infiltration at the wound sites. Furthermore, NaBT decreased the number of gland cells at the wound sites at 3 and 7 dpw. NaBT also suppressed the inflammation, accelerated localized extracellular matrix cleavage, and enhanced keratinocyte migration and proliferation within the wounds. Concurrently, NaBT elevated the formation of the temporary matrix in the wound bed. Over time, NaBT increased the deposition of both collagenous and non-collagenous constituents and stimulated neovascularization, facilitating the maturation of the newly formed tissue. In addition, NaBT increased the abundance of potential probiotics and butyrate-producing bacteria while suppressing potential pathogens. Dietary NaBT also significantly upregulated the gene expression of the hepcidin antimicrobial peptide in the skin. Tax4Fun analysis indicated that skin microbiomes might mediate the effects of NaBT on wound healing by enhancing the butanoate metabolism and skin immune status, while concurrently inhibiting pathogen invasion and biofilm formation during the healing process. Our findings demonstrate that dietary NaBT supplementation enhanced the skin wound healing in turbot, with the skin microbiota playing important regulatory roles in this process.