INFLUENCE OF DIFFERENT ENERGY SUPPLY ON N UTRIENT-UTILIZATION AND ENERGY-UTILIZATION OF BROILERS

The aim of investigations was to estimate effects of stepwise reduced energy density (12,5-12-11,5 vs 13MJME) in broiler feed on growth, fee d efficiency, protein utilisation and energy utilisation. Further the influence of different feed treatment (Conditioning vs expansion) on a vailability of energy from wheat/soybean/fishmeal diet should be prove d. Male broiler chickens (Lohmann) were used in an metabolism trial (d ay 15-20, n = 5) as well as in a growth trial (day 8-28, n = 60) with estimation of body composition of representative animals (n = 11). In metabolism trial protein utilisation was not significantly related to step of energy density, but crude fat digestibility decreased with red uced percentage of sunflower oil. Growth trial showed no changes in we igth gain and feed efficiency which could be significantly related to energy density. Protein concentration in the dry matter of whole body was slightly higher after reduction of energy density but not signific antly related to the step of energy density. Energy utilisation for ma intenance and growth led to the same conclusion. In the range of energ y density under investigation no limitation of protein utilisation by energy supply was obtained. Relation protein: fat deposition was chang ed from 1,62 to 1,80 after reduction of energy density. Feed treatment had no effect on availability of energy from energy reduced chicken d iets.