The effect of different doses of -galactoside (RFOs) preparations from Pisum sativum L. cv. Opal, injected into eggs during embryogenesis, on maintaining a high number of bifidobacteria, selected chicken broiler traits and the lipoprotein level of blood were studied. Two independent experiments were conducted. In the first, Ringer water solution containing 1.763 mg/egg of fructooligosaccharides (FOS) (I group), 2.1158 mg of pea RFO preparation containing 20% sucrose (II group) and 0.4232 mg of sucrose (III group) were injected into Hubbard broiler breeder eggs containing 12-day old embryos. Only Ringer water solution was applied to the eggs of the control group (IV group). The number of bifidobacteria determined in faeces of two-day old chicken of groups I and II was significantly higher in comparison with the sucrose and control groups. The high level of bifidobacteria of groups I and II was maintained during 6 weeks. The dose of both preparations had no influence on the body weight, carcass, breast muscle, leg and abdominal fat ratio, total cholesterol, HDL and LDL serum concentrations. Broiler mortality and breast muscle cholesterol concentration was highest (P<0.05) for the control group. On the other hand, the European Production Index, as well as serum triglycerides, were the lowest for this group. The second experiment was performed on Hybro G chicken breeder eggs. 0.69, 3.43 and 6.87 mg/egg of pea RFO preparation doses containing 20% sucrose were injected into the experimental groups. The number of bifidobacteria in the caecum and selected meat traits of broilers were determined. The results of this experiment confirmed that RFO injection in ovo causes the long-time maintenance of a high level of bifidobacteria. The dose of the preparations does not have any effect on the selected broiler meat traits, except that the highest dose increases the percent of carcase in body weight. However, this dose reduced the hatchability of the treated embryos.