CAUSE OF HYPERPIGMENTATION IN BLACK SHEEP SKINS

Black sheep skins available in South India are affected by a defect ca used by hyperpigmentation. The defect greatly devaluates skin and leat her quality. Correlation between hyperpigmentation and certain physiol ogical factors in sheep showed that there was increased epidermal pigm entation and tyrosinase activity in the affected area of the skin. Ser um albumin levels were decreased and globulin levels slightly increase d. There was no variation in the levels of free amino acids in the ser um. Plasma levels of iron, copper and zinc were not influenced by the defect. Vitamin A, beta-carotene, nicotinic acid, and pantothenic acid levels in serum showed slight decreases in affected animals. From the results it is difficult to conclude that any one of the factors was s olely responsible for the defect. A combined action may be responsible .