Yeast is considered to be a valuable raw protein, having high nutritional value. However, data about yeast use in poultry feeding are inconsistent and depend on a number of factors, such as yeast origin, substrates and technological parameters. The purpose of the study was to define nutritional yeast value, analyze the influence of yeast addition to diet on broiler chicken productivity and feed consumption, determine the effect of feeding yeast on broiler chicken digestibility and meat quality. While achieving the purpose of the study nutritional value of the yeast was established (quantity of protein, fat, calcium, phosphorus, organic substance, fat acids). The data of the study show that yeast has a relatively high protein level from 42,44 to 46,79%. Quantity of crude fat varied from 5,30 to 6,50%. Analysis of mineral materials indicated calcium amount of 2,11-2,24% and phosphorus amount of 0,80-0,88%. Linoleic acid and linolenic acid made 60,32-60,81% and 3,80-4,17% respectively, of all fat acids. The main amino acids compiled 0,22-0,27% of lyzine, 0,49-0,55% of metionine, 0,56-0,62% of treonine. After experiments on meat quality, muscle maturation and chemical composition have been performed and chicken broilers’ breasts and thighs anlysed it was estimated that these indices did not vary to a higher quantity of yeast addition. Data of the sensory evaluation show that in presence of more than 6% of yeast, broiler breast muscles were of a sour taste. While assessing other... [to full text]