General anti-microbial properties of the integument in fleece producing sheep and goats

Based on lectin histochemical methods, this study describes the production and distribution of various terminal sugars in the integument of Merino sheep and Angora goats. Additionally, pH measurements were performed for information about environmental conditions of microbes on the skin surface and in the fleece. The results demonstrated strongly positive reactions for alpha-L-fucose in the stratum corneum of Merino sheep, and in the secretions of the skin glands of Angora goats. Moreover, alpha-D-mannose, beta-D-N-acetylglucosamine, alpha-D-N-acetylgalactosamine, alpha-D-galactose and beta-D-galactose were very distinct in the secretions of the skin glands of both species. The skin products containing saccharide residues are deposited on the skin surface and in the fleece as part of wool grease, and the terminal sugars may be liberated by bacterial and fungal activities. All of these sugars are of specific interest because of their ability of inhibiting the adherence of different bacteria and fungi to the epidermal cells. Thus, free sugars impede attacks of skin micro-inhabitants against the integrity of the epidermal barrier. In contrast to these results, the skin pH-conditions were strongly alkaline, particularly in the fleece of Merino sheep (pH 6-9), so that proliferation of microbes may be promoted. This negative influence can only be countered by high production rates of sugar-containing skin products, which is normally the case based on long and intense activity of hair follicles in fine-wool producing sheep and goats.In conclusion, this study demonstrates that a basic anti-microbial biological system exists on the skin surface and within the hair coat, that operates with free sugars before the immune system is activated.