The coating formation technique for artificial knee ligaments was proposed, which provided tight fixation of ligaments of polyethylene terephthalate (PET) fibers as a result of the healing of the bone channel in the short-term period after implantation. The coating is a frame structure of single-walled carbon nanotubes (SWCNT) in a collagen matrix, which is formed by layer-by-layer solidification of an aqueous dispersion of SWCNT with collagen during spin coating and controlled irradiation with IR radiation. Quantum mechanical method SCC DFTB, with a self-consistent charge, was used. It is based on the density functional theory and the tight-binding approximation. The method established the optimal temperature and time for the formation of the equilibrium configurations of the SWCNT/collagen type II complexes to ensure maximum binding energies between the nanotube and the collagen. The highest binding energies were observed in complexes with SWCNT nanometer diameter in comparison with subnanometer SWCNT. The coating had a porous structure—pore size was 0.5—6 μm. The process of reducing the mass and volume of the coating with the initial biodegradation of collagen after contact with blood plasma was demonstrated. This is proved by exceeding the intensity of the SWCNT peaks G and D after contact with the blood serum in the Raman spectrum and by decreasing the intensity of the main collagen bands in the SWCNT/collagen complex frame coating. The number of pores and their size increased to 20 μm. The modification of the PET tape with the SWCNT/collagen coating allowed to increase its hydrophilicity by 1.7 times compared to the original PET fibers and by 1.3 times compared to the collagen coating. A reduced hemolysis level of the PET tape coated with SWCNT/collagen was achieved. The SWCNT/collagen coating provided 2.2 times less hemolysis than an uncoated PET implant. MicroCT showed the effective formation of new bone and dense connective tissue around the implant. A decrease in channel diameter from 2.5 to 1.7 mm was detected at three and, especially, six months after implantation of a PET tape with SWCNT/collagen coating. MicroCT allowed us to identify areas for histological sections, which demonstrated the favorable interaction of the PET tape with the surrounding tissues. In the case of using the PET tape coated with SWCNT/collagen, more active growth of connective tissue with mature collagen fibers in the area of implantation was observed than in the case of only collagen coating. The stimulating effect of SWCNT/collagen on the formation of bone trabeculae around and inside the PET tape was evident in three and six months after implantation. Thus, a PET tape with SWCNT/collagen coating has osteoconductivity as well as a high level of hydrophilicity and hemocompatibility.

The authors have studied the influence of a probiotic and a gastrointestinal adsorbent on the histostructure of the digestive tract of broilers. Day-old broilers were divided into groups of 50 heads each by the method of analog pairs in terms of live weight. Control broilers received a basic diet. Broilers of the 1st experimental group during the first three days of the experiment received probiotic Vetom-1.1 (0.006%) containing spores of Bacillus subtilis with the basic diet, and broilers of the 2nd experimental group received gastrointestinal adsorbent Enterosgel (0.008%). For histological studies, three heads of broilers were selected at day 1 of age, day 4 of age, and at the end of the experiment (after the end of feeding the preparation and before the transition to the basic diet) from the average weight of each group. Samples were excised from the middle of the crop, the glandular part of the stomach, the duodenum, the jejunum, and the proximal part of the cecum of birds. At the end of the experiment, the positive aftereffect of the preparation persisted in the crop and duodenum. At the same time, in the experimental group, the thickness of the submucous membrane of the stomach decreased, and in the cecum, the layer of villi increased.

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Purpose of research was to study the effect of enzyme supplements and humic substances on the histostructure of the glandular part of the stomach of broiler chickens.Materials and methods. The experiment lasted 49 days. In the first 4 weeks, the level of metabolic energy in the diet was 10 kcal per 100 g of feed below the recommended level, then until the end of the experiment it was 5 kcal lower. Group 1 received the main diet, balanced in all respects. Group 2 received the enzyme preparation «Kemzaym» 1 g/kg feed. It contained beta-gluconase, cellulase, pentosanase, protease, lipase and alpha-amylase. Group 3 received sodium humate 1 g/kg of feed. Group 4 received both «Kemzyme» (1 g/kg) and sodium humate (1 g/kg) at the same time. Slaughter of chickens was at 28 days and 49 days of age. Samples of the glandular part of the stomach were taken from 5 chickens from the group.Results. The study of the histological picture showed that up to 49 days of age, the development and formation of the structures of the wall of the glandular stomach occurs. This is expressed in an increase in the thickness of the organ wall, mainly due to the submucosal layer. The use of «Kemzaym» continuously during the entire cultivation leads to a decrease in the thickness of the entire wall of the organ and inhibition of the development of the submucosa. There is also an irritating effect of the drug on the mucous membrane. In the first period, this is expressed in a decrease in the height of the mucosa, foci of violation of the integrity of the epithelium, atrophy of the glands of the mucosa and lymphocytic infiltration of the lamina propria are observed. In the second period, this is expressed in an increase in the thickness of the mucosa in the absence of destructive changes in its histological picture. Such a reaction of the structures can be considered as an adaptation of the stomach wall. The use of sodium humate in the first period leads to an increase in the thickness of the submucosa. No negative effect on the structures of the mucosa was found during this period. In the second period, this additive causes a decrease in the thickness of the submucosa. During this period, an increase in the layer of the mucous membrane is observed without destructive changes in its structure. The combined use of sodium humate and the enzyme complex does not have a positive effect on the wall of the glandular stomach.Conclusion. Studies have shown that long-term continuous use of enzyme supplements leads to a decrease in the production of the stomach's own enzymes. The use of sodium humate has a positive effect only in the first period, which indicates that the body is getting used to this additive.

The purpose of this work was to identify the features of the location and distribution of GCs with neutral and acidic secretions in the duodenum, jejunum, and proximal part of the caecum. The paper presents the results of a study of the development of goblet intestinal cells and the influence of Bacillus subtilis spores on this process. The study was carried out at the educational and experimental poultry house of the Russian State Agrarian University, Moscow Agricultural Academy named after K.A. Timiryazev. Broilers of the Konkurent cross were used, from which two groups of 50 heads were formed by the method of pairs of analogs in live weight. In the first three days of life, chickens of the experimental group apart from the basic diet received the Vetom-1.1 probiotic containing Bacillus subtilis spores (0.006%). From the age of four days, all chickens received the basic diet. The duration of the experiment was 42 days. The density of the location of goblet cells with acid secret decreases in all parts of the intestine, except for the crypts of the caecum in broilers of the experimental group. In the broilers of the experimental group, immediately after feeding the preparation, there was a significant increase in the density of goblet cells with a neutral secret in the villi of the duodenum by 22.2% (P<0.01), the crypts of the jejunum by 30.8% (P<0.001) and a decrease in the villi of the jejunum by 13.8% (P<0.01). By the end of the experiment, the density of GCs in the villi of the duodenum had increased slightly, and in the crypts of the jejunum and caecum, the number of cells with acid secret had increased.