Humic acids are characterized by chelating properties due to which they are able to influence the mineral metabolism in animals. Rabbits have species-specific characteristics of mineral metabolism, which distinguishes them from most species of mammals. For the experiment, 16 rabbits of 45-day-old of Hyplus breed were divided into the experimental and control group of 8 rabbits in each. The animals were 15 days in the preparatory period. The rabbits of the experimental group received humic acid additive individually with water in the amount of 5 mg/kg, the rabbits of the control group received pure water in the same amount. The ability of humic acid additive to increase the content of calcium, ionized calcium, iron, to correct the content of copper and zinc, and also to increase the activity of alkaline phosphatase in the blood serum of rabbits of the experimental group has been proved. We observed the early effect of the humic acid additive on increasing the content of iron and calcium ionized and a later effect on the activity of alkaline phosphatase and an increase in the content of copper in the blood serum. The influence of humic acid additive on the distribution of calcium, phosphorus, manganese, copper and zinc in bone tissue is determined. According to a histological study, there was a significant increase in the number of layers of osteons and osteoblasts in the bone tissue of the femur, an increase in the number of osteons and osteoblasts in the bone tissue of the sternum and an increase in the number of columns of chondrocytes and an increase in the number of chondrocytes in the column in the cartilaginous tissue of the sternum. The results of a histological study of bone tissue, together with an increase in structural macroelements in it and redistribution of osteotropic trace elements in the blood and bone tissue suggest the possibility of using a humic acid additive to intensify the growth and mineralization of bone tissue, which can improve the state of bone tissue of rabbits in the postnatal period ontogenesis.

Morphofunctional state of blood cells of rabbits against the background of feed additive humic nature.

PLA-based implants are characterized by high biocompatibility with body tissues, and are also distinguished by their biodegradable and osseointegrative properties. The regulation of bone tissue growth and development is inextricably linked with the blood system, which is a source of plastic substances and hormones of calcium homeostasis. When PLA implants were inserted into the parietal bone of rabbits, changes occurred in their bodies that were typical for the period after orthopedic and traumatological operations. Metabolism dysregulation of macro- and microelements and disturbances of erythropoiesis, which can occur in the postoperative period, have a negative effect on the bone tissue growth in the young rabbits’ body. It has been proven that humic substances were able to influence the activity of osteoblasts and regulate mineral metabolism. For the experiment, 32 rabbits were divided into four groups, 8 rabbits in each group; sixteen rabbits underwent surgery using PLA implants, which were placed bilaterally in the parietal bone. Eight of the 16 operated rabbits were given Humilid together with water, the rest of them received pure water. Eight of 16 rabbits, intact before surgery, received Humilid together with water, the non-surgical control group did not receive Humilid. The influence of humic substances on physiological osteogenesis and hematological parameters during the use of PLA implants was determined. On the 14th day of the experiment, the rabbits of the surgical group receiving Humilid did not show a decrease in erythrocytes, hemoglobin, and an increase in leukocytes, in contrast to the rabbits of the surgical control group. An increase in the number of osteons and osteoblasts layers was recorded in the femur of the young rabbits that were receiving Humilid, and in the sternum – the number of osteons and layers of osteoblasts. There was also an increase in the number of erythrocytes and hemoglobin in the non-surgical group rabbits that were receiving Humilid to compare the rabbits of the non-surgical control group. ln rabbits that received Humilid, there was an intensification of bone tissue growth against the background of physiological and reparative osteogenesis.