Immunotropic Effect of Bursal Peptides on Mice with Experimental Immunodeficiency

Peptides are biologically active. This quality depends on the technological modes of protein hydrolysis. The research objective was to isolate peptides from the bursa fabricii and evaluate their immunotropic effect on mice of various lines with experimental immunodeficiency and the morphofunctional state of their immunopoiesis organs, i.e., thymus and spleen. The research featured bursa fabricii hydrolysate and peptides, as well as thymus and spleen of male mice. Amine nitrogen was determined according to State Standard R 55479-2013; molecular weight of peptides was determined by gel electrophoresis. The morphometry of the thymus and spleen was calculated using VideoTesT-Morphology 5.0. The research revealed the rational modes of enzymatic hydrolysis of the bursa fabricii protein by papain with subsequent isolation of peptides by ultrafiltration. According to the content of amine nitrogen in the bursa fabricii hydrolysate, the rational concentration of the papain enzyme was 0.15%. The molecular weight of peptides after ultrafiltration of bursa fabricii hydrolysate through membranes with a 43 kDa permeability had different values and depended on the concentration of papain, hydrolysis time, and temperature. The maximal amount of 27–18 kDa peptides was isolated at 36°C (85%) when the concentration of papain was 0.15% (73%), the hydromodule was 1:3 (78%), and the hydrolysis time of the raw material was 6 h (82%). The rational technological parameters of the hydrolysis of the bursa fabricii protein were as follows: concentration of papain – 0.15%, temperature – 36°C, hydromodule – 1:3, and hydrolysis time – 6 h. In immunodeficient mice, bursal peptides prevented a decrease in total cellularity in the thymus, sustained the content of CD3+ cells, activated the maturation of T-lymphocytes and proliferation of B-lymphocytes, and reduced the immunocytotoxic effects of cyclophosphamide. The article offers a new technology for obtaining peptides with a pronounced immunotropic effect that can be used in functional food production.