Vitamin A alleviates heat stress-induced damage to hair follicle development in Rex rabbits

BACKGROUND Rex rabbits are important fur rabbits. Heat stress severely reduces the fur quality of Rex rabbits. The aim of this study was to experimentally investigate the effect of dietary vitamin A (VA) addition on hair follicle development and related signal pathways in Rex rabbits under heat stress. RESULTS In the experiment, 90 Rex rabbits were randomly divided into three groups: control group (20-25 degrees C, fed basic diet), heat stress group (30-34 degrees C, fed basic diet), and heat stress + VA group (20-25 degrees C, fed 12 000 IU/kg VA in addition to the basic diet). VA could significantly increase the hair follicle density (P < 0.01), hair length (P < 0.05), and the ratio of secondary to primary hair follicles (P < 0.05). In addition, VA could significantly inhibit the expression of BMP2, BMP4, FGF5, TGF-beta 1, and miR-214 in heat-stressed Rex rabbits and significantly increase the expression of noggin, IGF1, IGF1R, Wnt10b, CTNNB1, SHH, and miR-203 and the levels of Wnt10b and p-beta-catenin; however, there was no significant effect of VA on the expression of EGF and miR-205. CONCLUSION The dietary addition of VA can increase the hair follicle density and fur quality of heat-stressed Rex rabbits. Wnt10/beta-catenin, insulin-like growth factor 1 (IGF1), fibroblast growth factor 5 (FGF5), noggin-BMP, and sonic hedgehog (SHH) signaling were associated with VA regulation under heat stress. It is possible that miR-205 and miR-194 contribute to the regulation of Wnt10/beta-catenin and bone morphogenetic protein (BMP) signaling. (c) 2021 Society of Chemical Industry.