Variability of protective properties of the epidermal barrier of pig skin (<i>Sus scrofa</i> (Linnaeus, 1758)) in connection with domestication

Materials and methods. The research materials included the skin samples taken from purebred Poltava Meat Breed boars of the main herd and from adult male wild boars. The epidermal barrier variability in the skin of wild and domestic boars was studied by comparing the structural and functional parameters in similar topographic areas of the animal bodies, with similar natural and climatic conditions (such as: the season of the year, the animals’ habitation area). On stained skin sections, the thickness of the stratum corneum (i.e. the outer epidermis layer) and the thickness of the epidermis layers underlying stratum corneum (i.e. the inner underlying layers), the length of the epidermis projections in tenfold repetition were determined. Based on the primary data, the total thickness of the epidermis and the ratio of the outer and inner epidermis layers were calculated, folding of the epidermis. All the results obtained were processed by statistical methods.Results. Poltava Meat Breed boars have a number of structural and functional features associated with the performance of protective functions by the skin epidermis. These features, most of which are related to the stratum corneum layer, reliably differ from those in the wild boars. We found that the stratum corneum thickness (by 11.89 microns (p≤0.001) or 32.91%), the relative thickness of the stratum corneum in relation to the thickness of the epidermis (by 12.96% (p≤0.001), the ratio of the stratum corneum and the inner (underlying) layers (by 0.415 or 41.29% (p≤0.001)), are lower in domestic boars. The variability of the thickness ratios of the stratum corneum with the epidermis and the inner underlying layers was higher in the group of domestic boars. The thickness of the underlying epidermis layers did not differ significantly in thickness, regarding the studied groups of pigs. The morphological difference between the inner (underlying the stratum corneum) epidermis layers of the Poltava Meat Breed boars, and those of the wild boars, is the presence of more intense basophilia and clearly visible nuclei of keratinocytes. The performed correlation analysis showed the presence of a greater number of reliable correlations between the indicators in the group of Poltava Meat Breed boars.