THE EFFECT OF THE EXPERIMENTAL INVASION OF T. PSEUDOSPIRALIS ON THE MORPHOLOGY OF THE SPLEEN OF LAYING HENS (GALLUS DOMESTICUS)
Authors: Zhdanova Olga B. , Chassоkikh Olga V. , Uspensky Aleksandr V. 
Published: September 2024

Background. Еhe study of the reaction of the organs of the immune system of birds with nematodes is relevant for the development of treatment regimens. Numerous models have been developed for laboratory animals (mice and rats), carnivores (hori, etc.) and birds (quails, chickens). In the latter, a capsule-free type of trichinella parasitizes, which has a number of reproduction features. In this study, a model of experimental invasion of T. pseudospiralis was used. The role of the spleen in the formation of anti-nematodosis immunity and its reaction to the introduction of the parasite in chicken (Gallus domesticus) has been studied.
The purpose of this study was to investigate morphological changes in the structure of the spleen in trichinellosis caused by T. pseudospiralis in chickens in the muscular stage of the invasive process.
Materials and methods. By the method of analogues, 2 groups of 6 heads were formed. The birds of the experimental group were weighed and T. pseudospiralis larvae isolate was injected into the goiter at a dose of 2 lich. / g of body weight (3200-3600 thousand larvae per bird). T. pseudospiralis larvae used for experimental infection of poultry were previously isolated from the muscles of birds, and were maintained on laboratory animals. All chickens were kept and fed under identical conditions. In order to determine the distribution of larvae in the muscles of T. pseudospiralis poultry, 6 chickens of the experimental group were euthanized 3.5 months after experimental infection. The birds were removed from the experiment in accordance with the "Rules for carrying out work using experimental animals" and in accordance with the principles of the Declaration of Helsinki, and approved by the Institutional Review Board. The intensity of invasion (AI, lich./g) for each chicken and the average for the group and AI by the distribution of larvae in the slice were determined. Histological preparations of the spleen were prepared according to the classical method and stained with hematoxylin – eosin.
Results. After digestion of muscle mass in artificial gastric juice, the number of larvae was 2570+640 l./g of muscles (average AI from muscle samples of the studied groups), no trichinella larvae were found in the control group. By CT, the largest AI was found in the muscles of the head (5.5+1.5 larvae in the section). The parenchyma of the organ of the spleen is represented by red and white pulp, in healthy birds the area of the red pulp was 10 + 5% of the area of the organ, and the white pulp 76.5 + 5% of the mass of the organ. In chickens infected with trichinella larvae, the area of the white pulp increased dramatically to 90% of the organ area and more.
Conclusion. The chicken spleen is actively involved in the pathogenesis of helminthiasis of birds. The follicles of the white pulp, as in the trichinosis of white mice, grow, merging into large conglomerates. In birds, as well as in mammals, the number of large lymphocytes and plasmocytes increases, which indicates the similarity of intercellular interactions and the reaction of immunocompetent cells to the introduction of the parasite.