Abstract
The purpose of the study was to verify the hypothesis that there are doses of silver nanoparticles (Ag-NPs) that improve immune defence in chickens without compromising their health. To verify this hypothesis, an attempt was made to determine which doses of Ag-NPs (5 nm) consumed by chickens as a result of administration of hydrocolloids during varying time periods at a concentration of 5 or 10 mg Ag/l stimulate immune defence. The experiment was performed on 296 chickens assigned to 3 treatments. Chickens from the control treatment received drinking water without experimental additives. Chickens from the T-5 and T-10 treatments received a hydrocolloid of Ag-NPs at a concentration of 5 mg/l (treatment T-5) or 10 mg/l (treatment T-10) from their second week of life. Blood for analysis was collected at the age of 42 days from 8 birds per treatment. Ceruloplasmin (Cp), leukocyte count (WBC), erythrocyte sedimentation rate (ESR), interleukin IL-6, immunoglobulins IgA, IgY, phagocytic cells (% PC), phagocytic index (PI), nitroblue tetrazolium reduction (NBT), and lysozyme content in the blood was determined. Application of Ag-NPs at a concentration of 5 mg/l or 10 mg/l in the dose range of 2.87-12.25 mg/bird (administration of Ag-NPs in concentration 5 mg/l in weeks: 2; 2 and 3; 2 and 4; 2 and 5; 2 and 6 or concentration 10 mg/l in week 2) resulted in an immunostimulatory effect expressed as an increase in heterophil respiratory burst and an increased concentration of lysozyme. Higher doses of Ag-NPs exerted a pro-inflammatory effect, as indicated by elevated levels of IL-6 and ceruloplasmin, as well as a high ESR. They also stimulated B lymphocytes to produce IgA and IgA immunoglobulins.