The aim of this study was to determine the effect of supplement «Press-Acid» on some parameters of mineral and protein metabolism and resistance of piglets. The study was done in condition «Meta» on two groups of piglets of the F-1 (BWхL) genotype. There were determined indexes of bacterial and lysocim activity of blood serum, calcium and phosphorus in piglets at the age of 21–30–45–75 days. Effect of supplement on the growth rate, morbidity and safety of pigs were revealed. We used hygienic, zootechnical, hematological, biochemical, immunological and statistical methods of analysis. The influence of «Press-Acid», which consist of formic, lactic, citric and fumaric acids, was established for the first time. The concentration of calcium in blood serum of experimental group of piglets were lower than in animals of control group. The level of phosphorus increased in blood serum of experimental animals on 11.83% (30 day), on 3.74% (45%), on 17.65% (75 day) respectively. Concentration of hemoglobin and the amount of erythrocytes increased on 11.8% and on 1.82% (30 day) in animals that feed the supplement. There were established the increase of viability of the pigs with gastro-intestinal diseases which were given the supplement in comparison with that, who did not feed it. Severity of diseases was determined using the Melenberg coefficient which did not higher than 1.2–2.4 score, it was lower on 6,0–9,3 unit than in control group. Using the supplement allowed to increase the intensity of growth of piglets by 3.7% (45 day) and 9.4% (75 day) respectively. Concentration of total protein, albumines and globulins increased on 8.66%, 9.90%, 7.3% respectively. The activity of alaninaminotransphaerasae in the blood serum of experimental animals were lower on 3.45% than in control piglets. Lysocym and bacterial activity of blood serum were higher in experimental group of piglets. Feeding piglets with addition supplement Press Acid promotes higher grow rates in experimental animals, that can be explained increases of oxidative-reducing processes in them organism. Feeding piglets with acidifier «Press-Acid», «Nifulin», zinc oxide, probiotics «Lactisan Complex» promotes growth energy, increase of morphological, biochemical and immunological parameters which indicates a higher level of oxidative reaction in the body. A low coefficient of Melenberg is recorded in the piglets at the age of 1 day. Safety was within 92.1–97.0%. That indicates a more successful elimination of complexes of protein, mineral substances, humoral protection in blood of experimental group of animals.