СТРУКТУРНАЯ ОРГАНИЗАЦИЯ ТИРЕОИДНОЙ ЖЕЛЕЗЫ СВИНЕЙ ПРИ СКАРМЛИВАНИИ ХЛОРЕЛЛЫ

Гаева В.А.¹, Минченко В.Н.²

¹Аспирант; ²Кандидат биологических наук, ФГБОУ ВО «Брянский  государственный аграрный университет»

СТРУКТУРНАЯ ОРГАНИЗАЦИЯ ТИРЕОИДНОЙ ЖЕЛЕЗЫ СВИНЕЙ ПРИ СКАРМЛИВАНИИ  ХЛОРЕЛЛЫ

Аннотация

В статье изучено влияние различных вариантов скармливания суспензии планктонного штамма ИФР № С-111 на морфологическое строение щитовидной железы (ЩЖ) свиней на откорме. При изучении структурной организации щитовидной железы у свиней, получавших с кормом суспензию хлореллы, установлено, что её структурная организация и функциональная активность зависит от массы органа и кратности применения препарата.

Ключевые слова: щитовидная железа, свиньи, хлорелла, фолликулы.

Gaeva V.A.¹, Minchenko V.N.²

¹Postgraduate stuent; ²PhD in Biology; FSBEE HPE Bryansk State Agricultural University

STRUCTURAL ORGANIZATION OF THYROID GLAND OF PIGS AT FEEDING CHLORELLA

Abstract

The influence of different feeding options plankton suspension strain IGF number C-111 on the morphological structure of the thyroid gland (TG) of fattening pigs was examined in the article. In studying of structural organization the thyroid gland of pigs, getting the suspension of chlorella with fodder, showed that its structural organization and functional activity depends on the mass of organs and multiplicity of the drug.

Keywords: thyroid, pigs, chlorella, follicles.

Deficiency of protein and its high cost is reflected in the cost of production, making use of non-conventional feed additives of current interest.

Use of chlorella in animal diets related to the fact that its dry biomass contains 40-50% protein, 35% carbohydrates, 5-10% lipids and 10% of mineral substances.

Today highly effective chlorella experiments on different animals (weight gain, development of quality marketable products, physiological condition, disease resistance) [1, 2] is proved. Although algae are a safe component of human food and animal feed, the effects of algae, except as a source of protein, are not clear. Some authors have expressed the view of the negative impact on the body of chlorella by detecting lipopolysaccharide (LPS) in the cell wall of chlorella. [3] Morphological characteristics and adaptive capabilities of the organism of fattening pigs when giving BAS were largely determined by functional activity of endocrine glands [4].

The purpose of the work is to study the influence of different options of feeding the suspension of the new strain plankton FMI number C-111 on the morphological structure of the thyroid gland (TG) of fattening pigs. It is known that the thyroid gland plays an important role in the regulation of primary metabolism, protein synthesis, tissue differentiation, development and growth of the organism, and can significantly alter the structure under the influence of various environmental factors. It was found that the weight of the thyroid gland of pigs, as well as its functional activity dependent on age [5], physiological condition, body weight and the influence of external factors [6], the most important among them is feeding [7]. Thereby it is of interest to study TG after using microalgae suspension, as it can have a definite impact on the functional activity of the body, due to the presence of biologically active substances.

 Scientific and economic experiment was conducted on young pigs of large white breed in fattening period with diets adopted in the economy. Its duration was 150 days. Alimentation and feeding animals matched zootechnical regulations. The difference in the feeding of pigs of compared groups of control animals was the following:

• the first group got the basic diet;

in the experimental groups in addition to the basic diet they got a suspension of microalgae at a dose of 125 ml per 1 kg of dry matter of the diet with the following frequency:

• the second group - experimental pigs, daily;
• the third group - experimental pigs with an interval of 15 days;
• and the fourth group - experimental pigs with an interval of 30 days.

Feeding was carried out in a mixture of concentrates once a day – in the morning.

To evaluate the morphological structure of thyroid we slaughtered three animals in each group. Thyroid was inspected, dissected, measured and weight. The microstructure of the glands was studied in a series of histological sections stained with hematoxylin and eosin, with the thickness of 5-10 microns. We carried gistometrical measurement of structural components of glands. The digital results of research were analyzed and subjected to statistical analysis with the usage of the Student's criteria.

The live weight of the control animals and experimental animals increased by 2.45, 2.57 (p <0.01), 2.54 (p <0.01) and 2.59 (p> 0.05) times respectively for the accounting period.

Visual examination of thyroid of animals of the first, the second, the third and the fourth groups set no differences in their appearance. The results of the organometrical measurement of thyroid are presented in Table 1.

 Table 1 - Linear measures of the thyroid gland of pigs in feeding a suspension of Chlorella

Data analysis of Table 1 shows a decrease prostate weight of the experimental animals in groups respectively: absolute 1.12, 1.02, 1.04 times, relative to 1.27, 1.27, and 1.16 times in comparison with control animals. The length of gland of animals in the first and third test groups was over 1.04 more than of control animals, and in second group was over 1.12 times respectively. The width of the body in the first and second experimental groups was over 1.06 and 1.10 times than in the control ones, and in the third it was identical to the glands of control animals. The gland was thicker in the second and the third groups -1.18 and - 1.05 times accordingly and in 1.05 times lesser in the first experimental group compared with the control animals bodies. Changes in weight and linear parameters were not reliable.

A number of researchers found that the functional activity of the thyroid gland due to the synthesis and secretion of hormones is directly related to its morphometric parameters. These indicators include: the diameter of the follicles, the follicular epithelium height and volume of its nuclei, and the index of the state of colloid Brown. Accordingly to that we carried out morphometric measurement of corresponding structures in histological sections of the organ. The results are shown in  Table 3.

Analysis mikromorfometrical indicators of thyroid showed that the drug had affected both the structure of the body and its functional activity. The second indicator shown in Table 3 is not decisive in regard to the functional activity of the body. But others indirectly indicates a change in the functional activity of the glands of animals getting drug.

Table 3 - Mikromorfometrical measures of thyroid

** P <0.01; *** P <0.001;

The study found that thyroid parenchyma and stroma presented all the structural elements, which are typical for this body of both the control and experimental animals. There were all groups of follicles (large, medium, small) filled with dense, homogeneous, colloid oxyphilic in the thyroid of the control animals. In individual follicles we observed edge and central colloid vacuolation. Most follicles had flat thyrocytes, elongated-oval nuclei and were arranged parallel to the basal pole of the cell. Next to the crowded functionally inactive follicles there were small "daughter" follicles filled with colloid having a vacuolization. In these glands large and cystic (having an area of 283,326.5 mkm²) follicles were dominated. The observed histological situation was most defined at the thyroid by the increased absolute weight. In the thyroid of control animals with lower absolute mass there were an increasing number of small follicles. Colloid resorptions were edge and central, thyrocytes were of cubic form. In the interfollicular connective tissue interlayers the capillaries were expanded with form elements of blood. All the structural composition of the body indicated the hypersecretion of thyroid with less weight. There were single and interfollicular intraepithelial C-cells with pale-colored cytoplasm.

In the first experimental group all kinds of follicles are found in the thyroid - large, medium and small, as well as single cystic (with an area of 148,095.41 mkm²) follicles. Colloid of follicles was unevenly painted with almost no resorption. Thyrocytes had a cubic shape, large round nucleus, contained euchromatin, indicating active participation of epithelial cells in the process of protein synthesis. Microvascular of thyroid are full of blood that indicated the allocation and secretion of colloid. This histology situation was inherent to glands with greater absolute weight. In the thyroid gland with a smaller mass the follicles of polygonal shape with a predominance of small and medium were also found. Cystic follicles were completely or half filled with colloid. Colloid in most cases was located in the center of the follicles or eccentrically with enlightened portions. The epithelium was of cylindrical and cubic forms. Interfollicular connective layer were almost absent in these glands. There were areas, in follicles of witch colloid had a uniform resorption of the periphery, epithelium was of cubic shape, capillaries were dilated. The areas of interfollicular connective tissue were well defined.

In the second group the thyroid contained all kinds of follicles, including cystic (having an area of 110,325.4 mkm²). Large follicles were arranged in groups. Colloid in them was dense, occupied the entire follicle, epithelium was flattened. Interfollicular connective tissue more expressed closer to the central vessels. In these areas the morphological status of the follicles could be viewed as the functional activity. A number of follicles had colloid resorption of vacuoles on the edge, and in some cases in the center. Thyrocyte was of cubic form. The follicles of thyroid with a smaller mass were smaller, some were large, filled with colloid. In most of them there were almost no colloid or observed residues of polygonal shapes. Connective layer contained significant concentrations of group C-cells. They had a light cytoplasm. Some of them had large nucleus. At nucleus chromatin was eccentric.

In the fourth test group of animals thyroid had all kinds of follicles including cystic (having an area of 90,923.7 mkm²). The glands were of more weight, many large follicles filled with colloid, almost had no vacuoles, epithelium was flat, nucleus were small. In single follicles colloid had a frothy appearance and cubic epithelium. The glands were of less weight, colloid also filled the whole follicle. The epithelium was flattened. The capillaries were expanded and filled with blood. In individual follicles we observed resorption which thyrocytes had a cubic shape.

Thus, experimental animals had an increase in number of follicles in a field of view of the microscope. An increasing number of follicles in the second, third and fourth groups were 31.6, 42.6 (p <0.001) and 8.8%. With the increase in the number of follicles, their diameter reduced, so the second by 49.6% (p <0.01) in the third 39.4 (p <0.01) and fourth by 7% (p> 0.5). This fact indirectly indicated the increased functional activity of the thyroid gland of these animals.

Increased functional activity of the glands of animals of the second group getting the drug lead to hyperfunctioning of body. This was confirmed by the presence in the colloid follicles typical zones of resorption and large vacuoles. In the thyroid follicles of control animal and the fourth group there were signs of hipofunctional changes: the phenomenon of stagnation colloid, the emergence of "sleeping follicles" colloid dense, homogeneous, oxyphilic painted. In the control group there was an increased follicles (cystic transformation). It should be noted that at the same time there were areas of hypofunction thyroid tissue, morphological state of which could be viewed as the functional activity.

On the fact of enhance the functional activity of the glands of pigs treated with a suspension of Chlorella also indicated a lower value of the index Brown. Brown Index is the ratio of diameter of follicle to height of follicular epithelium, and is used for the comparative determination of the functional activity of the thyroid gland. Its smaller values indicate greater functional activity of the body.

Thus, our studies had shown that the multiplicity of application microalgae suspension affected thyroid function of pigs of the second and the third groups. Observable signs of hyperfunction were not strumal for thyroid.

Data analysis of the productivity of animals in fattening period showed that the multiplicity of application chlorella with an interval of 15 days of application was the most effective.

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