The ratio of structural proteins in the wool of sheep of different breeds and with different categories of fibers depending on the zones of their breeding

Wool fiber consists of a complex of protein-keratins, which differ in both their physical and chemical properties and functional characteristics. Despite the progress achieved in the study of the structural organization of fibers, the issue of the influence of environmental factors, the nature and level of nutrition, as well as breed characteristics, remains poorly understood. With this in mind, we investigated the ratio of structural proteins in the wool of sheep of different breeds, which are bred in separate zones of Ukraine, in particular, fine-wool, semi-fine-wool, and coarse-wool. Therefore, during the study of the structural proteins of the wool of sheep of different breeds, which differ among themselves in the thinness of the fibers, it was established that by the method of electrophoretic separation, these proteins are clearly divided into three different groups, in particular, these are proteins of intermediate filaments (IF) of I and II types with a molecular weight of 55–65 and 45–55 kDa, respectively, as well as keratin-associated proteins (KAP) with a molecular weight of 25–35 kDa. However, in some breeds, in particular, the Askanian meat-wool of the black-headed type and the Ukrainian Mountain Carpathian type, two more fractions of proteins were found among IF type I, which almost do not differ from each other in terms of percentage. It was established that within the studied groups of sheep, certain interbreed features are observed, so in the group of thin-wooled breeds, the largest percentage falls on IF II (35.9%). The other two factions account for almost the same percentage — 32.1% (IF I) and 31.8% (KAP). An almost similar picture of the ratio of protein fractions was recorded in the group of animals with coarse wool. At the same time, in the group of sheep with semi-fine wool, in particular, the fibers of sheep of the Ascanian meat-wool breed have the highest percentage of KAP and, accordingly, less IF II, and in the fibers of the Ascanian meat-wool black-headed type, respectively, less proteins of IF II and KAP. Therefore, the obtained data clearly indicate breed characteristics of the content and ratios of certain groups of proteins, which can be genetically determined, and therefore serve as appropriate markers both within individual breeds and within breeds with different fiber categories.