Introduction. The present research featured biochemical and microstructural features of thyroid glands obtained from lambs raised on various feeds enriched with essential elements. The article focuses on iodine as the most important physiologically active microelement. Iodine participates in the synthesis of thyroid hormones, namely thyroxine and triiodothyronine, which are known to regulate metabolic processes. Iodine deficiency may impair reproductive function and cause such diseases as endemic goiter. Study objects and methods. The study involved thyroid glands from lambs of the Edilbaev breed aged seven months. The lambs were divided into four experimental groups, ten animals in each. The lambs received several feed additives. Ioddar-Zn and DAFS-25 had a balanced protein and carbohydrate content, while the mineral feed of Coretron brand contained such trace elements and minerals as iodine, selenium, and silicon. Results and discussion. The experiment made it possible to describe the microstructural profile of the thyroid glands extracted from seven-month-old lambs raised on feeds enriched with iodine and selenium. Ioddar-Zn and DAFS-25 did not harm the structure of the thyroid tissue, while causing its functional activation in some cases. The morphological parameters of the thyroid glands indicated some breed differences. The iodine concentration in the thyroid glands obtained from the experimental animals was five or six times higher than that in the control group. The content of mono- and diiodotyrosine depended on the accumulation profile of organic iodine. Conclusion. Diets enforced with DAFS-25, Ioddar-Zn, silicon, and a protein-carbohydrate complex produced no negative effect on the structure of the thyroid tissue. It fact, the diet increased the organic iodine content in the thyroid glands in the form of iodotyrosines. The gland structure revealed some cubic epithelium or follicular cells. The mass spectrometric studies confirmed the presence of covalently bound iodine in the form of mono- and diiodotyrosine. Thus, the abovementioned feed additives can be recommended for industrial use.

The research featured the effect of a diet fortified with essential microelements on the ruminal microbiota of young rams. Ruminal microbiota is largely responsible for feed digestibility and body functioning of cattle. The study involved the contents of the rumens and jejuna of seven-month-old rams of the Edilbaev breed, which were subjected to a biofortified diet. The diet included the Russian feed additives Yoddar-Zn and DAFS-25 represent a protein-carbohydrate complex with plant silicon. The microflora of the digestive tract was tested using the molecular genetic method of terminal restriction fragment length polymorphism (T-RFLP) sequestration. The microstructural studies of the jejunum samples exploited light microscopy. The feed additives increased the population of cellulolytic and lactate-fermenting bacteria, as well as the Prevotella sp. microbiome and bifidobacteria in the rumen samples. The data obtained revealed the effect of essential microelements on the taxonomic pattern of microorganisms and the microflora profile. The research revealed the ratio of normal, opportunistic, pathogenic, nonculturable, and transit microflora. The jejunum wall samples obtained from the experimental group that fed on Yoddar-Zn and DAFS-25 had a more distinct micropicture of mucous membrane. Their rumen microflora balance had fewer pathogenic and opportunistic microorganisms, which was also confirmed by the jejunum morphology. The feed additives DAFS-25 and Yoddar-Zn proved beneficial for ram diet and inhibited the negative effect of pathogenic treponemas on the rumen. The additives improved digestion, absorption, and assimilation of food nutrients, as well as increased the livestock yield.

The article presents a study of the antioxidant properties of meat from lambs that received organic forms of iodine and selenium during growth. This meat was included in diets of laboratory animals using a model of acute toxic hepatitis. The experiments resulted in developing and testing a technique that was effective in enriching lamb with bioorganic elements of iodine and selenium and contributed to the activation metabolism in the bodies of animals consuming the meat. The purpose of the presented investigation was to compare the roles of bioorganic iodine and selenium and their combination as antioxidants in rat rations using a model of acute toxic hepatitis induced by carbon tetrachloride. The experimental studies have established a hepatoprotective effect of lamb meat enriched with selenium and iodine on rats suffering from toxic xenobiotic effects. This was confirmed by normalized hematological and biochemical measures in the blood of the experimental rats.

The paper describes an environmentally safe technology for biofortifying lamb with target components in required concentrations packed in biodegradable film. To address the problem of micronutrient deficiency, we developed a biologically safe method of enriching lamb with organic iodine and selenium supplements. Introducing selenium and iodine feed supplements to the animals’ diet increased the average daily growth of their live mass in experimental groups by 3.43, 6.72, and 14.92% in groups I (iodine), II (selenium), and III (iodine and selenium), respectively, compared to the control group (feed only). The analysis of immunephysiological status showed an increase in phagocytic number in experimental groups: by 5.1% (P > 0.95), 9.4%, and 14.5% in groups I, II, III, respectively. In addition, the highest phagocytic activity and phagocytic intensity were observed in animals of group II and group III, indicating their higher resistance to adverse environmental factors, compared to the control. There was an increase in iodine, selenium and zinc content in the lamb meat from the experimental groups grown on enriched diets. We recorded a higher concentration of the micronutrients in the lambs receiving “Yoddar-Zn” and “DAFS-25” supplements together (Zn – 980 μg/100 g; Se – 53.9 μg/100 g; I – 77.6 μg/100 g). We found that the contents of zinc, selenium, and iodine in 100 g of m. Longissimus dorsi were 8.2%, 77.0%, and 51.7%, respectively, of the required content in the daily diet. Thus, we can use this raw material to produce functional meat products. Packaging lamb in sodium alginate-based biodegradable film helped reduce moisture loss during storage.

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