EN
The objective of this study was to evaluate the effect of a varied content of sodium in diets for broiler chickens on serum levels of macroelements and on the percentage of CD4⁺, CD8⁺, and CD4⁺CD8⁺ T-lymphocyte subpopulations in blood. The study was conducted on 432 one-day-old cockerels representing six experimental groups (eight replications, each with nine birds). The chickens were administered for 5 weeks feed mixtures in which the content of Na was differentiated by the addition of NaCl in the following amounts (%): group 1 - 0, group 2 - 0.127, group 3 - 0.254, group 4 - 0.382, group 5 - 0.509, and group 6 - 0.636. Potassium content and electrolyte balance (expressed as the total molar mass of Na⁺ and K⁺ minus molar mass of Cl⁻) were kept at a similar level. On day 35 of age, their body weight was measured and eight birds from each treatment were selected from blood analysis. Serum concentrations of Na, K, Cl, Ca, P, and Mg and the percentage of CD4⁺, CD8⁺, and CD4⁺CD8⁺ T-lymphocyte subpopulations were measured. The administration of the NaCl-free feed mixture caused a decrease in the levels of Na and chlorides and an increase in concentrations of K, Ca, and Mg, as compared to the cockerels from groups fed the mixtures with an addition of Na. Differentiated addition of NaCl to the feed mixtures had no significant effect on the percentage of the analysed subpopulations of CD4⁺, CD8⁺, and CD4⁺CD8⁺ T-lymphocytes. Sodium deficiency in the diet was found to affect a decrease in the body weight of the chickens examined.