THICKNESS OF THE SKIN AND ITS LAYERS AT DEGERESS SHEEP OF VARIOUS STRIPES

AGRICULTURAL SCIENCES (CROP SCIENCES, ANIMAL SCIENCES) THICKNESS OF THE SKIN AND ITS LAYERS AT DEGERESS SHEEP OF VARIOUS STRIPES Nazym Alzhaxina, Kyrgyzbay Begembekov, Kazakh National Agrarian University nazjomka@mail.ru Abstract The article discusses the results of comprehensive studies histomorphological signs of skin and hair of sheep (Degeress) of various stripes, especially the thickness of the skin and its layers that are commonly identified indicators. Studies allow to bring the scientific basis for the proper development of activities aimed at increasing production of wool, quantity and quality of which skin microstructure largely depends on. Sheep of different colors have a specific feature on the histological structure of the skin, which is essential for the development of effective methods of selection that enhance productivity of sheep wool. The researches have established that brown suit sheep has thickened skin as compared to red and gray color (p<0.01). In turn, pilar layer of the skin is also much thicker at brown coloration sheep (2029.7 10-6 m) than in sheep red (1850.6 10-6 m) and sulfur (1773.7 10-6 m) suits, the difference is statistically highly significant (p<0.001). The thickness of the pilar layer is up to 70% of the dermis, which varies depending on sheep lear ranging from 1773.7 10-6 m to 2029.7 10-6 m. Reticular layer thickness varies depending on sheep lear ranging from 743.5 10-6 m to 826.4 10-6 m. Key words: thickness of skin, sheep, epidermis, pilar layer, reticular layer. Introduction Questions to study patterns of development of productive-biological characteristics of sheep (Degeress) and identification of the nature of formation of the most important properties of economically useful animals are very closely linked to food production and providing industry with raw materials for the production of high quality products for the consumer. Sheep (Degeress) characterized by a peculiar combination of elements histostructure skin that distinguishes them from other fat-tailed breeds, but at the same time, has significant inbreeding variability indicators such as the thickness of skin and its individual layers, depending on the fineness of the animals wool (Nogaybekov, 1987; Montagna and Parakkal, 1974). Formation of the structure of the skin and its individual elements causes physical and technical properties of semi-finished products, and ultimately determines the quality of finished products in terms of the strength of the leather, its softness, durability, its presentation, etc. In that case, the study of the histological structure of the sheep s skin is relevant and has important scientific and practical importance in ensuring internal and external markets, consumer goods of high demand. In this regard, the age-structure formation of the skin and its individual elements, determines physical and technical properties of the half finished products and ultimately determines the quality of finished products in terms of the durability of leather, its softness, its presentation, etc. (Mohammadi et al., 2009). Skin is an important and very functionally multilateral body. It forms a dense and durable cover that protects the internal tissues and organs from mechanical damage. The skin is an organ involved in thermoregulation. It is an important sensory organ, which has tactile, thermal and painful nerve endings. Also, the skin is involved in metabolism. In the skin, sheep s wool is formed and it plays a physiological role as a component of thermoregulatory mechanisms. Leather - one of the organs, which provides a constant contact with the external environment. Sheep s skin development and its structural elements become particularly important in the view of fact that it is a carrier of valuable products, and it is not only the fur, but also the skin itself. The skin has a significant impact on the growth of different lengths of wool (Ismailov, 2001; Trukhachev, 2007). Part of the problem of knowledge formation of sheep wool products is studying the structure of the skin and the quality of wool fibers, which has not only general biological, but also has a great practical importance. In this regard, studies allow to bring the scientific basis for the proper development of activities aimed at increasing the production of wool, quantity and quality of which skin microstructure largely depends on. Skin is an important protective and adaptive tissue of sheep. The morphology of skin is closely related to the type of animal constitution, which in turn causes productivity, especially fur productivity. According to the results of morphological studies of features of sheep skin, there is a possibility to adjust the selection of pairs to estimate genetic feature to 118 Research for Rural Development 2014, volume 1

THICKNESS OF THE SKIN AND ITS LAYERS Nazym Alzhaxina, Kyrgyzbay Begembekov, predict future productivity in the earlier stages of ontogeny animals (Begembekov, 1989). Improving the quality of the skin, the formation of quantitative and qualitative characteristics in sheep productivity largely depends on the scrutiny of the skin, structure and functions of the relevant structures of the skin. Consequently, the study of sheep skin goes far beyond the interest of the morphology and becomes important in practical sheep breeding. New breeds and types of sheep created in Kazakhstan are grown taking into account the specific geographical and natural feeding conditions of the regions for which they were created, where paratypic factors had the main influence on the type and productivity of animals. In connection with above mentioned, the sheep (Degeress) bred in different conditions characterized certain adaptive qualities, respectively reflected in their morphological indicators and economically useful productivity. The purpose of the study was to study the histological structure of the sheep (Degeress) skin and its individual elements, which determine physical and technical properties of half finished products and ultimately determine the quality of finished products. Work task resulting from the purpose was to set the main features of the sheep s skin (Degeress) histostructure: the epidermis, the derma, thickness of pilar layer and reticular layer, the increasing thickness bundles of collagen fibers, the layer thickness of the subcutaneous tissue. Materials and Methods Sheep (Degeress) have double productivity both meat and wool. They successfully combine high fleece quality, precocity and meat productivity, have a strong constitution, strong, well-developed bones, correct forms of build, hardy and well adapted to the specific conditions of their breeding areas in southern Kazakhstan. Besides wool and meat products, also fur sheepskin from these sheep can be obtained. The material for research was skin samples obtained from ewes semi-coarse type breed in Limited partnership (LP) MKS-Akboz that is located at Panfilov district of Almaty region (Kazakhstan). The skin samples were taken for histological examination by a skin biopsy on the side of the test animals. A selection of animals was carried out by random sampling method of pair peers. Experimental animals were similar in age, gender and productivity. There were 5 studied animals in three groups according to the methods of Diomidova N.A., Panfilova E.P., Suslina E.S. (Diomidova et al., 1960; Korostyleva et al., 2009; Plohinskiyi, 1969). Investigated experimental animals were divided by suit into three groups: brown, red, gray. The study of the development of the sheep skin was performed according to the method of Diamidova N.A. and other scientists: 1. Ablution after fixation; 2. Dehydration in spirits of increasing concentration (50 C and 60 C) for 4-6 hours, at 70 C, 80 C, and 90 C for 8-12 hours, and in two portions of 96 C alcohol for 12-24 hours; 3. Alcohol chloroform treatment (2-3 hours); 4. Immersion in pure chloroform (2-3 shifts for 1.5 hours); 5. Impregnation in chloroform and paraffin at 37 C for 3-6 hours. At 56 C for 1.5 hour; 6. Paraffin impregnation (in three portions for 1-1.5 hours); 7. Paraffin treatment. The side was a topographical plot of sampling. Histological preparations were prepared in conventional manner. Staining with hematoxylin of Erlich and eosin counterstaining was performed; Veyger s hematoxylin and then van Gieson s picrofucsin. An isolated piece of skin was placed in the fixative solution in a ratio of not less than 20, and each one was put into a separate bowl. The skin sample covered with hair was attached to the cortical plate flesh side up with plant needles, and it was sunk down in the fixative solution in the same ratio of 1 cm 2 skin to 20-25 cm 3 fixative. Fixative liquids are used depending on the objectives of the study. Fixative, which is used to detect the general characteristics of the structure of the skin, was 10% formalin. In the above mentioned fixative, the object was kept for 24 hours. After that it was transferred into 5% formalin, where it can be kept safe for a long time. After fixation, the skin with the hair was oriented to obtain the desired direction of roots and glands. A section was cut out of a length of 2 cm, a width of no thicker than 0.3-0.5 cm on a fixed sample of skin. For skin preparations, they were covered with celloidin + paraffin. The skin covered with hair is recommended to take through gelatin to freeze using carbon dioxide and to prepare cuts on a freezing microtome. Speed processing through gelatin, leaving out dehydration through alcohols of increasing content, preserves the true location and integrity of the tissue elements, which are greatly distorted when processing through alcohols and gives incomparably incorrect data when measuring. However, for purposes of studying cytological elements in the skin of animals of all ages, it is absolutely necessary to use a fill of celloidin + paraffin wax and one paraffin wax that provides preparation of thin sections of 6-8 10-6 m and Research for Rural Development 2014, volume 1 119

Nazym Alzhaxina, Kyrgyzbay Begembekov, THICKNESS OF THE SKIN AND ITS LAYERS identifying the finest structures inside cells. When cutting on a freezing microtome the thickness of sections is not less than 15-20 10-6 m. The process of getting paraffin and gelatinous units ready for cutting microtomes, passed the preliminary preparation. After fixing in solutions of Zenker and Gelli and the subsequent removal of mercuric chloride in alcohol solution with iodine, the skin was conducted through the spirits of increasing concentration in a mixture of celloidin with ether, and then the paraffin was poured. Time delay in separate mixtures did not exceed 6 hours, except for a mixture of chloroform with paraffin, where it was kept up to 12-24 hours. The study of morphological changes in the structure and evolution of the skin was produced by describing separate structures and elements and the determination of their quantitative indicators. With this purpose vertical and horizontal sections were used. The measurements were performed with the help of micrometrology line, which was placed inside the eye-glass. Before the measurements the price of one division of the eyepiece micrometer was set, which was achieved by comparison with divisions of object micrometer. The thickness of the skin and its layers were determined on the vertical sections. On histological preparations diameter bundles of collagen fibers were studied, angle weave between themselves, which gave the opportunity to consider the impact of link types on trademark properties and characteristics of sheepskin. Bundles of collagen fibers, their sizes and link types, which were formed by the interweaving of these fibers, influenced on such trademark properties of fur sheepskin, like the strength of the leather on the gap, elasticity, firmness and others. Results and Discussion It is known that the thickness of the skin is closely connected with many of characteristics of the organism, but above all it depends on the overall development of the animal, its productivity, and hence with breeding feature. It varies depending on the age and conditions of animals. As can be seen from Figure 1, the epidermal layer of sheep consists of two layers: the superficial stratum and lower sprout. The surface layer is formed by a single row of flat, horizontally - elongated cells with large round and oval nuclei. Cells of the surface layer are clearly expressed keratinization, as the push, approaching the surface, solidification occurs. Lower germ or Malpighian layer is the deepest layer of the epidermis, consisting of soft living cells of a cylindrical shape. These cells are adjacent to the fibrous layer of the dermis and are powered via the special conical elevation, called the dermal papilla. The thickness of epidermis depends on the age of animals and the time of taking the material for the study. Presenting the original outer shell, the epidermis first perceives the external environment. Therefore, it is very important that the animal epidermis was well developed, so it should be 1/20 of the thickness of the skin (Avsadzhanov, 1985; Braun, 1983). Figure 1. Structure of the epidermal layer of the sheep skin. Derma (skin actually) is the most powerful layer as for the thickness and the most important for the functional significance. Dermis gives the skin surface strength, provides nutrition and respiration of the epidermis, and participates in all functions of the sheep skin. Derma of sheep is located directly beneath the epidermal layer (Fig.2). Figure 2. The structure of derma of the sheep skin. In the dermis, two layers are clearly distinguished: pilar (or papillary) and reticular (or mesh), which occupy 68 75% of the total thickness of the skin. 120 Research for Rural Development 2014, volume 1

THICKNESS OF THE SKIN AND ITS LAYERS Nazym Alzhaxina, Kyrgyzbay Begembekov, As seen in Figure 3, the thickness of the pilar layer is up to 70% of the dermis, which is the basic structure of the skin, and it is the main reproductive layer. It houses a hair follicle, a dense network of blood vessels and nerve endings, sebaceous and sweat glands, muscles lifting hair, collagen and elastic fibers that provide strong adhesion of all structures. Thickness of pilar layer varies depending on sheep lear ranging from 1773.7 10-6 m to 2029.7 10-6 m. Figure 3. Pilar structure layer of the sheep skin. Reticular layer (or mesh) is located under the pilar layer (Figure 4). Sheep different directions depending on the age, sex and productivity, reticular layer occupy in the range of 19 to 41% of the dermis. In the test animals with different genotypes, the reticular layer ranges from 30 to 32% of the total thickness of the skin. In this intergroup differences are small and not statistically significant. Reticular layer thickness varies depending on the sheep lear ranging from 743.5 10-6 m to 826.4 10-6 m. in building tendons, cartilage, bone, dentin, ligaments, fascia, and other connective tissue structures. Skin s derma contains about 98% of the protein. As seen in Figure 5, our studies have shown that bundles of collagen and elastic fibers of considerable thickness intersect, forming the so-called script. Direction and nature of the tie collagen bundles determines the density and strength of the skin dermis. This change is reflected in the increasing thickness bundles of collagen fibers and improves the tie by forming more loops, branching and vertically extending beams. In a period of declining growth rate of animals, there is also the simplification and reduction of the thickness of the tie bundles of collagen fibers. Therefore, we can say that at different ages, the skin is not of the same strength. Collagen fibers are formed from a plurality of thinnest filaments fibrils, which are interconnected with a particular interfibrillar substance. The thickness is from 1 10-6 m to 12 10-6 m, wherein the length of the fiber on its thickness varies little. By stretching the skin in different directions, the bundles of collagen fibers are arranged at an angle to each other with a dense weave in certain directions. Character of ligature collagen, thickness of beams and their mutual interlocking depend on the age, sex, and breed of the individual characteristics of sheep. Figure 5. Interlacing bundles of collagen fibers of the sheep skin. Figure 4. Reticular structure layer of the sheep skin. Reticular layer is formed from more densely interwoven bundles of collagen fibers. Collagen is the major protein that makes up the skin of sheep, involved Subcutaneous tissue of the test animals is composed of loose connective tissue formed of collagen fibers and clay, which is located under reticular layer below bordered by the muscles. Subcutaneous tissue serves as a movable bridge between the dermis and the body of the sheep. It permeates the blood and lymphatic network (Figure 6). The layer thickness of the subcutaneous tissue varies in different anatomical areas of the sheep skin. This layer is most developed in the blade tip; hence, the bundles of muscle fibers diverge radially along the Research for Rural Development 2014, volume 1 121

Nazym Alzhaxina, Kyrgyzbay Begembekov, THICKNESS OF THE SKIN AND ITS LAYERS back, on the sides and front limbs, gradually thinning. Subcutaneous tissue is strongly developed in the area of breast and under the scalp. Subcutaneous tissue, being the place of localization of body fat, reduces body heat and softens the blow, thus, protecting the body of sheep from mechanical damage. Subcutaneous tissue forms a loose weave of thin bundles of collagen fibers and elastin fibers network between which fat cells are placed. In the subcutaneous tissue there are many cellular elements, where numerous blood vessels are located. Figure 6. The structure of subcutaneous tissue of the sheep skin. Thus, the formation of the skin and its derivatives, which begins during fetal development and continues throughout life of sheep, is a complex process. Diomidova N. (1954), who conducted a detailed description of the formative processes of the skin and wool sheep, notes that the thickness of the skin depends on the breed, sex, age, nutritional status, constitutional and individual characteristics of the animal. The results of our studies on the histological structure of skin and the total thickness of its individual layers in different sheep lears are presented in Table 1. As can be seen from these data, in the nature of the structure of the skin, there are significant differences due to the color of the covering hair on the face and legs (suit). Sheep leather of brown suits is thicker than sheep red and gray stripes. The total thickness of the skin on the first 259.0 10-6 m or 2.25%, the criterion of reliability of a difference (t d = 6.16) is thicker than that of sheep skin red stripes, which in turn is thicker at 88.1 10-6 m or 1.9%, the criterion of reliability of a difference (t d = 2.05) sheep skin gray suit. In turn, the gray skin of sheep is thinner at 202.0 10-6 m or 1.14% (t d = 8.86) of the skin brown color sheep. Thus, thickened skin has brown suit sheep as compared to red and gray color (p<0.01). On development of the epidermis, the brown color sheep also has the advantage, which is accordingly 34.6 10-6 m or 1.20% of the total thickness of 28.5 10-6 m against the skin, or 1.08% of the total thickness of the skin of the sheep red color. In turn, the epidermis red suit is 28.5 10-6 m or 1.08% of the total thickness of 26.4 10-6 m against the skin, or 1.04% of the total thickness of the skin of the sheep grays. Mostly, brown suit sheep compared to red and gray suit (p<0.01) have significantly thicker skin. In turn, the pilar layer of the skin is also much thicker at brown coloration sheep (2029.7 10-6 m) than in sheep red (1850.6 10-6 m) and sulfur (1773.7 10-6 m) suits, the difference is statistically highly significant (p<0.001). It should also be noted that the reticular layer is much thicker in sheep brown color (826.4 10-6 m) than in sheep skin red (752.6 10-6 m) and grey (743.5 10-6 m) colors, the difference is statistically Thickness of the skin and its layers at sheep of various stripes, 10-6 m Table 1 Data Suit brown red grey On average Number of animals 5 5 5 The total thickness of the 2890.7±27.06 2631.7±32.18 2543.6±28.31 2688.7±29.18 skin Including thickness of Epidermis 34.6±0.42 28.5±0.27 26.4±0.31 29.8±0.33 % 1.20 1.08 1.04 1.11 Pilar layer 2029.7±16.18 1850.6±29.01 1773.7±19.08 1884.6±21.42 % 70.2 70.3 69.7 70.1 Reticular layer 826.4±7.26 752.6±6.18 743.5±5.32 774.2±6.25 % 28.6 28.6 29.2 28.8 122 Research for Rural Development 2014, volume 1

THICKNESS OF THE SKIN AND ITS LAYERS Nazym Alzhaxina, Kyrgyzbay Begembekov, highly significant (p<0.001). Differences noted in the reticular layer, did not affect the thickness of the layer of the pilar, where rates fluctuate within 743.5-826.4 10-6 m. Microscopic study of individual layers of the sheep skin also revealed that histoarchitectonics connective tissue fibers have clearly expressed cellular structure, and it is expressed most clearly in the reticular layer (Figure 4). Spatial density of interposition of connective tissue fibers is higher in the skin samples of sheep that has brown coloration. Conclusions 1. Sheep (Degeress) of different colors have a specific feature on the histological structure of the skin, which is essential for the development of effective methods of selection that enhance productivity of sheep wool. 2. Thickened skin has brown suit sheep as compared to red and gray color (p<0.01). Mostly, brown suit sheep compared to red and gray suit (p<0.01) have significantly thicker skin. Differences noted in the reticular layer did not affect the thickness of the layer of the pilar, where rates fluctuate within 743.5-826.4 10-6 m. References 1. Avsadzhanov G. (1985) Закономерности формирования и развития структуры кожи и шерстного покрова у некоторых пород овец и помесей в условиях Северного Кавказа (Regularities of Formation and Development of the Structure of the Skin and Coat in Some Breeds of Sheep and Hybrids in the Conditions of the North Caucasus). Автореферат на соискание докторской диссертаци, Орджоникидзе, 45. c. (in Russian). 2. Begembekov K. (1989) Гистоструктура кожи дегересских полу тонкорунных баранов с разной тониной шерсти (Histostructure skin degeress floor with fine-wool sheep wool of different fineness). Сборник научных трудов АЗВИ и СЗВИ, Alma-Ata, 55 58. c. (in Russian). 3. Braun А. (1983) Гистологическое строение кожи сельскохозяйственных животных (Histological Structure of the Skin of Farm Animals). Таджикский НИИ животноводства. Душанбе: Дониш, 79 c. (in Russian). 4. Diomidova N., Panfilova E., Suslina E. (1960) Методика исследования волосяных фолликулов у овец (Technique to Study the Hair Follicles of Sheep). 27. c. (in Russian). 5. Ismailov I. (2001) Тонина шерсти и живая масса у овец различного происхождения (Fineness of Wool and Live Weight of Sheep of Different Origin). Sheep, goats and wool business, 22 24. c. (in Russian). 6. Korostyleva N., Kondrashkova I., Rudishina N., Kamardina I. (2009) Биометрия в животноводстве (Biometrics in Animal Breeding). Barnaul, 210. c. (in Russian). 7. Mohammadi A., Abbasi M., Moghaddam A., Zare Shahneh A. (2009) Estimation of Growth Traits in Iranian Afshari Sheep Breed Under Rural Production System. Journal of Animal and Veterinary Advances. Volume, pp. 1449 1454. 8. Montagna W., Parakkal P.F. (1974) The Structure and Function of Skin. N.Y. Acad. Press, 433 p. 9. Nogaybekov M. (1987) Особенности гистоструктуры кожи и шерстной продуктивности дегересских овец, полученных от различных вариантов подбора по тонине шерсти (Features Histostructure Skin and Wool Sheep Productivity Degeress Obtained from Different Variants of Selection on the Fineness of Wool). Автореферат на соискание кандидатской диссертаци, Алма-Ата, АЗВИ, 23. c. (in Russian). 10. Plohinskiyi N. (1969) Руководство по биометрии для зоотехников (Guide to Biometrics for Livestock). Moscow, 423. c. (in Russian). 11. Trukhachev V. (2007) Influence of combination of sheep breeds on formation of skin intergument of gimmers Animal science, 30 p. Research for Rural Development 2014, volume 1 123