THE EFFECT OF MANNAN-OLIGOSACCHARIDES IN FEED MIXTURES ON THE PERFORMANCE OF CHICKEN BROILERS

The effect of different concentrations of mannan-oligosaccharides (0 g , 50 g, 100 g, 150 g, 200 g, 250 g and 300 g in form of BIO-MOS prepar ation per 100 kg feed) applied in starters BR1 and production mixtures BR2 was examined in a comparative feeding and metabolic trial on sexe d broiler chickens of ROSS hybrid in relation to chicken growth, feed intake per 1 kg weight gain and nutrient digestibility (N x 6.25, fat, fiber, nitrogen-free extract). Mannan-oligosaccharides had highly sig nificant positive effects (P < 0.01) on chicken weight starting from t he concentration of 50 g BIO-MOS per 100 kg feed at the 21st day of ag e. The weight of chickens receiving the concentration of 150 g BIO-MOS per 100 kg feed was higher by 17.2% in this period in comparison with the control (P < 0.01). Live weight was highest in groups (a(3)) to ( a(6)) at the 42nd day of age (doses of 150 to 300 g of BIO-MOS prepara tion per 100 kg feed). Different concentrations of BIO-MOS preparation had significantly positive effects (P < 0.05) on the consumption of B R1 and BR2 mixtures in all groups while the lowest consumption of BR1 mixture was observed in group (a(4)) - 200 g BIO-MOS per 100 kg feed ( -11.1%). The lowest total feed consumption (-4.30%) was recorded in ch ickens of group a(3) that received BIO-MOS preparation applied in feed mixtures at a dose of 150 g per 100 kg. There was no significant diff erence between the groups a(3), a(4), a(5), a(6). The coefficients of fat, nitrogen-free extract and crude protein (N x 6.25) digestibility did not change as a result of different concentrations of mannan-oligo saccharides. The coefficient of fiber digestibility was higher by 61.5 -147.7% against the control in the groups of chickens that received di fferent doses of BIO-MOS preparation. There was a significant differen ce between the group ao and group a(4) (P < 0.05). A conclusion can be drawn from the results obtained that the BIO-MOS preparation concentr ation of 50 g per 100 kg feed was effective starting from this dose, t he upper boundary of effectiveness is defined by inflection points of second-degree polynomials calculated for BR1 and BR2 mixtures. The val ues of inflection points show that the effective upper boundary of BIO -MOS preparation dosing is at the concentration of 200 g per 100 kg.