Peculiarities of sheep pathogenesis at associative invasions of gastrointestinal tract.
In the Republic of Belarus, primarily in farms with imperfect technology, parasitic diseases of sheep are widespread, including: nematodes of gastrointestinal tract, strongyloidosis, eimeriosis, monieziosis, trichocephalosis, cryptosporidiosis, etc. Study of impact of associative parasitosis of sheep on the immunobiological reactivity of animal body has recently become more and more theoretical and practical for rational use of drugs in treatment of these diseases. The purpose of research is to study peculiarities of sheep pathogenesis at associative invasions of gastrointestinal tract. The study was carried out at farm "Villia-agro", Kobrin district, Brest region. Lambs of 2-4 months of age spontaneously infested with parasites of gastrointestinal tract have been selected. Parameters of cellular immunity were determined: number of leukocytes, monocytes, neutrophils, eosinophils, level of rosette-forming T- and B-lymphocytes and humoral immunity: circulating immune complexes, total protein, protein fractions, including proteins of C3 complement system and immunoglobulins, macro and microelements (calcium, phosphorus and iron) in blood serum. With spontaneous invasion of sheep by associations of parasites of gastrointestinal tract, the following changes have been determined: significant decrease in number of lymphocytes, T-lymphocytes, concentration of total protein, albumin, - β- and γ-globulins, calcium and phosphorus. Significant increase in leukocytes: Eosinophils and stab neutrophils, α1-globulins, circulating immune complexes. All this together indicates disturbance in functioning of body's immunity and requires immediate appropriate treatment aimed both at destroying associations of parasites of gastrointestinal tract and restoring immune system of animal's body. These studies will form basis for development of rational system for therapeutic and preventive measures for associative parasitosis of sheep in the Republic of Belarus, which will reduce economic damage from these diseases and improve quality of livestock products. Acknowledgments. The research was carried out as part of the state research and technical program of scientific research "Quality and Efficiency of Agroindustrial Production for 2016-2020", subprogram "Animal breeding and pedigree work".