Currently, a growing industrial poultry sphere in many countries is quail farming. Quails have a complex of unique economic-productive advantages, as compared with other poultry, – high body temperature, intensive metabolism, small size, fast maturation, and high egg productivity. In the study, we examined the specifics of microscopic structure of morphometry of the spleen of the control and experimental birds as characteristics sensitive to the action of supplements. The proposed methods are intended for studying effects of protein-vitamin mineral supplements on poultry farming. Therefore, for 21 days, with the main diet, the quails were given mineral supplements produced by the Multilife trade mark (crude protein, amino acids (lysine, threonine, methionine, cysteine), calcium, available phosphorus, sodium, chlorine, vitamins (A, D3, E)), by the Missi trademark (protein, vitamins, minerals), and by the Standard Agro trademark (soybean press cake, vitamins А, D3, Е, В1, В2, В6, В12), multi-enzyme complex, salt, ground limestone, phosphate monocalcium, amino acids (lysine, threonine, methionine with cysteine). This is the first study of the ultrastructural organization of the spleen of Japanese quail (Coturnix japonica) fed with protein-vitamin mineral supplements. The tested supplements were beneficial for the productivity of the quails, as evidenced by increase in the body and spleen weight. Body weight of the quails increased by 5.8% in the group that was fed additionally with the Multilife supplement, and by 12.5% in the group that consumed the Missi supplement added to the fodder, and by 8.1% in the group that consumed the Standard Agro supplement with the diet. At the same time, the spleen weight increased by 7.2%, 16.0%, and 10.5%, respectively. However, the relative weight (0.1%) underwent no changes, which characterizes this parameter as permanent for age and species of animals. Analysis of the data of our morphological studies revealed that the splenic microscopic structure of the quails was characterized by presence of support-contractile apparatus (capsule and trabeculae) with the relative area of 4.6 ± 0.8% and single radial trabecula. The parenchyma was formed by white and red pulps without distinct boundaries. In the white pulp, there were designated lymphoid nodes with no light centers, and also periarterial lymphoid sheaths and ellipsoids. In the reticular stroma of the white pulp of the spleen, we found blood cells of various maturity, in particular, lymphocytes, which were clearly divided into large, average, and small; mononuclear and multinuclear macrophages, which contained hemosiderin and melanin, leukocytes, mostly eosinophilous. The ultrastructural organization of the spleen of the quails had the following peculiarities: nuclei of leukocytes contained large nuclei, endotheliocytes of the central artery of lymphoid follicle performed phagocyte function by accumulating autophagosomes in its cytoplasm. In the quails that had consumed the diet containing supplements, the macroscopic, microscopic, and ultramicroscopic structures underwent no changes. At the same time, there was seen a tendency towards increase in the relative area of white pulp and the support-contractile apparatus. The relative area of white pulp of the spleen increased by 0.5% in the group of quails that had received the diet with the Multilife supplement, by 1% in the group that had consumed the diet with the Missi supplement, and by 0.6% in the group that had consumed the diet with the Standard Agro supplement. The relative area of the red pulp in the spleen of the quails was observed to have the tendency towards decrease: by 0.4% in the group that received the Multilife supplement, by 1% in the group that consumed the Missi supplement, and by 0.5% in the group that consumed the Standard Agro supplement. The relative area of the support-contractile apparatus of the spleen increased by 0.4% in the group of quails that consumed the Multilife supplement, by 1% in the group that consumed the Missi supplement, and 0.5% in the group that consumed the Standard Agro supplement. Taking into account the data we obtained, we may conclude that our studies confirm the benefits of using modern protein-vitamin supplements in poultry farming for stimulation of growth and development. Especially valuable is the absence of negative effect on the morphofunctional parameters of the spleen, which we used as biomarkers.
