Morpho-functional changes in the blood of laying hens in experimental trichinosis caused by T. pseudospiralis

Abstract

Background. Experimental trichinosis based on a model of invasion in birds has been repeatedly reproduced by domestic and foreign researchers when infected with Trichinella pseudospiralis larvae, however, there are very contradictory data on the reaction of red and white blood to invasion.

The purpose of the study was to study the state of oxidative metabolism using Fe–induced biochemiluminescence and changes in the morphological parameters of peripheral blood and spleen smears of laying hens during experimental infection with T.pseudospiralis.

Materials and methods. Birds of the experimental group (6 heads) were weighed and T. pseudospiralis larval isolate was injected into the goiter at a dose of 2 larvae per g of body weight. T. pseudospiralis larvae used for experimental infection of poultry were initially isolated from poultry muscle tissue and kept on laboratory animals. Blood sampling was carried out dynamically, smears were prepared, which were fixed, stained and examined at 800-fold magnification with morphometry on a VisionBio (Epi) light microscope with automatic display on the screen. 3.5-4 months after infection, the birds were euthanized, and muscle mass was collected for computed tomography and peptolysis studies. The number of erythrocytes, leukocytes and hemoglobin was determined, the state of oxidative metabolism in blood plasma and erythrocytes of chickens was assessed by Fe-induced biochemiluminescence on a BHL-06 apparatus (Nizhny Novgorod, Russia). The data obtained was processed using standard MS Excel and Statgraphics software packages. The nonparametric Mann-Whitney U-test (Sokal and Rohlf, 1981) was used to assess the homogeneity of groups and the significance of differences in averages between groups. The level of statistical significance of the differences obtained between the compared samples was assumed to be p<0.05.

Results. All birds of the experimental groups tolerated the invasion well, despite the high intensity of invasion (2940±490 larvae/g of muscle mass during artificial digestion of muscle mass). The content of erythrocytes and hemoglobin in infected laying hens decreased during migration and in the early stages of muscle mass development. The number of leukocytes in infected chickens was increased at the migration and early muscle stages (42.5±5.3 x 109/l, 40.5±7.3 x 109/l), at the late muscle stage it decreased sharply and practically did not differ from the control (33.3±4.3 x 109/l, 29.5±3.3 x 109/l respectively). Biochemiluminescent analysis of changes in the oxidative metabolism of erythrocytes and blood plasma in invaded birds also showed the highest levels of indicators at the migratory stage of helminthiasis.

Conclusion. Thus, the experimental invasion of laying hens by Trichinella pseudospiralis larvae has a pronounced effect on hematological and metabolic parameters of blood, causing their pronounced restructuring depending on the stage of helminthiasis. It has been established that the most serious shifts in the main hematological parameters (in particular, the number of red blood cells and the level of hemoglobin), as well as free radical processes in blood plasma and red blood cells are observed at the migrating stage of parasitosis and partially smoothed out during the migration of parasites. Interestingly, the blood plasma of birds reacts more actively to changes at the stage of experimental invasion than the cellular blood pool.