>b<Arquitetura e estrutura da pelagem da Alpaca(>i<Vicugna pacos>/i<)>/b<

Abstract

Alpacas are mainly raised for fiber production, which is a highly valued product in the textile industry. Therefore the purpose of this project aims to evaluate morphological and quantitative aspects of alpaca´s coat in Huacaya and Suri breeds, comparing the structure and architecture of the skin forelimb lateral region, thoracic lateral region, and hind limb lateral region, with three sub-regions: scapular, costal and lateral femoral respectively. For this project, 8 mm biopsies were collected from the coat of 12 alpacas, from the Pacomarca Experimental Fund, located in the city of Puno-Peru. The samples were weighed, immersed in 10% aqueous formaldehyde solution and then processed. After that, they were cut into fragments of 2 mm each, in order to obtain random samples for Stereological analyzes. Hematoxylin and Eosin, Picrosirius Red and Masson's Trichrome stains were used for the microscopic analysis. This last staining was also required for Stereological analysis. After obtaining the images, a slide with the points system was added to each sample in order to count the structures to be evaluated. Subsequently, markers for type I, III and IV collagen proteins were used to perform immunohistochemical analysis, as well as for S100. The structures found in the integumentary system of alpacas were the components of the skin, such as the epidermis, the dermis, and separating the two structures, the basal lamina. In the dermis it was possible to observed the sebaceous glands and sweat glands, as well as the follicular groups formed by primary follicles and secondary hair follicles in abundance. From each of these follicles a hair emerged called fiber. One of the factors used for this evaluation was the observation of the fibers diameter, which was measured in samples obtained from the costal region of the alpacas, and carried out by means of scanning electron microscopy technique. Measurements of 12.65 μm up to 55.00 μm were obtained. It was possible to observed fibers that had marrow and others that did not have marrow, making it possible to differ them in the three layers that composed the hair. Together, with the marrow, they composed the cortex and the cuticle, in addition to the layers of the hair follicle. Extracellular matrix proteins were also evaluated, in which type III collagen fibers were found, which marked only the collagen and reticular fibers present in the dermis and presenting a different marking when compared to the other collagens including S100 protein. The volume of the skin, dermis, follicular groups, sebaceous glands and sweat glands were evaluated through Stereological analysis, among the three body regions of each group of alpacas at a significance level of p <0.05, resulting in differences in the mean volume of the dermis and the mean volume of follicular groups in dark-colored Suri alpacas. The four groups of alpacas for each body region were also compared, with a significance level of p<0.05, and p>0.05 for the mean volumes of skin and dermis in the lateral femoral region.