Investigation of the Role of Biotin in the Regulation of Wool Growth in Sheep Hair Follicles Cultured in vitro

An experiment was conducted to develop an in vitro technique to study the role of biotin in controlling growth and viability of sheep wool follicles. Small samples of skin wee taken from mid-rib are of three Suffolk wether lambs and after discarding epidermal layer, anagen secondary wool follicles were isolated from the dermal layer and maintained in William`s E Medium supplemented with 0.0,0.25 or 0.5 mg L 1 biotin. The results showed significantly increase in vitro wool shaft elongation up to 144 h culture in media. There was no significant differences between rate of fibre elongation of viable cultured follicles. Biotin supplementation significantly increased the proportion of follicles remaining viable after 72 h with the order of response of 0.5>0.25>0.0 mg L 1 supplement. ATP concentration in follicles maintained in the medium containing 0.50 mg L 1 biotin were significantly (p< 0.01) higher than those maintained in medium containing 0.0 or 0.25 mg L 1. Hair follicles maintained in the presence of 0.5 or 1.0 mg L 1 biotin exhibited a significantly (p< 0.01) higher incorporation of [U-14C] Leucine into protein than in follicles in unsupplemented media. DNA concentration per follicle was not affected by biotin concentration. Visual examination of the bulb of hair follicles confirmed the occurrence of mitotic bodies in the matrix of follicles and indicated the presence of viable cells in growing follicles after 144 h of incubation. An examination of cell proliferation sites, using Brdu, in the hair follicles maintained in the presence of 0.0 or 0.50 mg L 1 biotin showed that majority of mitotic activity was concentrated in the bulb adjacent to dermal papilla and outer root sheath in fresh and growing follicles, up to 72 h incubation in different treatments.