EN
Four diets (17.8% crude protein) with different salts (NaCl) content were subjected to analysis. Diet 1 contained no addition of NaCl; diet 2 contained 0.19% of NaCl - which corresponds to 50% of the standard concerning the sodium content per kg of diet for pigs; diet 3 contained 0.38% of NaCl - which corresponds to the standard; in diet 4 the salt content was increased by 50% in relation to the standard, and amounted to 0.57%. The research was conducted in an experimental pig farm on 32 crossbred weaned pigs (Polish Large White X Polish Landrace) aged 8-12 weeks. In the course of the 28-day experiment feed intake was controlled every day and the animals were weighed on the 1st, 14th and 28th day. Blood samples were taken on the 28th day of the experiment. The following indices were determined in the blood and blood sera of the experimental animals: the number of red blood cells (RBC) and white blood cells (WBC), haemoglobin concentration (HGB), haematocrit value (HTC), mean volume of red blood cells (MCV), mean haemoglobin content in a blood cell (MCH), mean haemoglobin concentration in a red blood cell (MCHC) and concentrations of glucose, urea, chlorides, sodium and potassium. Withholding salt from diets had a significant effect on a decrease in the growth rate of pigs, as well as on a drop in the feed intake and feed conversion ratio of weaned pigs. On the other hand, its addition equal to 0.57% caused a distinct improvement in growth results. However, it also affected certain blood changes, which may be connected with the initial stages of relative hypernatraemia in the pigs subjected to the experiment.