Nowadays there is an ample quantity of different additives which might be the alternatives to feed antibiotics when it comes to regulation of microbiological processes in the digestive tract and stimulation of animals’ productivity: probiotics, prebiotics, acidifying agents, ferments, phytobiotics, essential oil etc. But recently one of the most widespread feed additives in poultry industry became acidifying agents, which contain different organic acids and their salts.

The higher acidity level in the stomach improves ooze of sap and ferments of pancreas which is the main factor of further optimal digestion and consumption of nutrients.

Experiments in creation of new preparations on the basis of organic acids continue so as there is some kind of synergism in their actions, when several acids in complex amplify capabilities of each other, working at different acidity levels in different parts of digestive tract. Also hydrolysis of nutrients of diets is closely tied to physiological condition of poultry (age, gender, direction and period of productivity).

Thus, the essential task is to determine balanced levels of acidifiers and their impact on postnatal ontogenetic regularity of digestive processes in the organism of quail at different periods of their growth and evolution in order to increase transformation of nutrient rich and biologically active solutions of the feed into production of quail farming.

Having carried out the research we established the changes in the live weight of quails under the impact of different levels of acidifier in the combined feed. The highest dynamics of growth was observed in quails of the third study group, which were fed by combined feed that contained 0,3 % of acidifier. Quails of this group probably (p<0,01) dominated quails of other groups by live weight in the period of 14-19 days. The difference by this index in reference to the age mates of control group fluctuated from 6,1 to 9,4 %.

Also the highest daily average and relative increase of live weight during research were noticed in quails which consumed combined feed with moderate content of acidifier (0,3 %) and exceeded poultry of study group correspondingly by 9,0; 2,8 %.

Different intensity of quails’ growth under the influence of the investigated factor had an impact on expenditure of feed by 1 kg of live weight increase. One should mention that according to the size of daily feed consummation per one unit any significant discrepancy was observed.

Quails, which were fed by combined feed supplemented with acidifier, consumed less feed over 1 kg of live weight increase than those quails which were fed by combined feed with acidifier. At that poultry which consumed combined feed supplemented by 0,3 % acidifier during the whole investigation period (1–49 days) were characterized by the lowest feed expenditures by 1 kg of live weight increase which is less by 3,3–9,3 % than in control group.

Safety of quails in all study groups was quite high and estimated 97–98 %.

In order to establish correlation between level of acidifier and productivity of quails we carried out graphic and correlational analysis. Among that we established nonlinear dependence between content of acidifier in combined feed and daily average live weight increases in of growing quails. Graphic analysis of indexes which characterize the correlation between given values states that the best way to describe it is to use polynomial curve with the value of approximation trustworthiness (R2) which equals 1.

According to the results of investigation we approved the practicability of using the acidifier during feeding of growing quails of pharaoh breed. In particular feeding combined food to the of growing quails supplemented by acidifier (0,3 %) in the period from 1^st to 49^th day of the research increases live weight by 6,1–9,4 %, improves daily average and relative increases approximately by 9,0; 2,8% and decreases the expenditures of feed by 1kg of live weight increase by 3,3–9,3 %.

Key words: quails, mixed fodder, live weight, feed costs, acidificator.