REPLACEMENT OF SOYBEAN-MEAL IN CHICKEN BROILER DIETS BY RAPESEED AND PEA

The aim of the study was to propose and test formulae of feeding mixtures for the grower period of broilers, in which traditional components as extracted soybean meal, fish meal, maize and fat were fully or partially replaced by rapeseed (RS), rapeseed meal (RSM), peas (P), meat-bone meal, tallow and wheat. Four mixtures (crude protein 19.5 - 19.6 %, metabolisable energy 11.8 - 12.9 MJ) differing mainly in the content of rape and peas (diet 1: 20 % RS, 7 % RSM; diet 2: 20 % RS; diet 3: 15 % RS; diet 4: 5 % RS, 10 % P) were tested. The experiment was carried out on 3,750 chickens (both sexes) of HYBRO genotype and the same number of chickens of HBX-3 genotype. They were housed in a windowless house with controlled environment according to the standard technological procedure of the International Poultry Random Sample Testing Station at Ustrasice and tested for a period of 42 days. Within each genotype the chickens were divided into five groups: each group was placed iii three boxes with 250 birds in each (15 birds/m2) . From the 1st to the 20th day of age all chickens were fed ad libitum with the starter mash BR1 IT, from the 21st to the 42nd day with grower diets differing in their composition (Tab. I). The mixture BR2 IT was used as standard. Live weight at the age of 42 days, mortality, total feed consumption per box, carcass weight, abdominal fat, the weight of breast and leg muscles and palatability traits were recorded. Traits measured on individuals were analysed according to model (1), traits measured on box basis were analyzed according to model (2), where y(ijklm) is the value of the m-th individual of the k-th sex housed in the 1-th box receiving the j-th diet and belonging to the i-th genotype, y(ijl) is the value of the l-th box where birds from the i-th genotype are housed receiving the j-th diet, mu is the general mean, g(i) is the effect of the i-th genotype, v(j) is the effect of the j-th diet, pk is the effect of the k-th sex, (gv)ij, (gp)ik, (gvp)ijk are the appropriate interaction effects, e(ijkbm) and e(ijl) are the residual effects for models (1) and (2), resp. All calculations were carried out using the procedure GLM of SAS(R). For all diets the meat performance of the broilers was at a high level at the end of the experiment (live weight 1.80 - 1.93 kg, feed conversion 2.14 - 2.26, carcass percentage 64.4 - 66.0 %, abdominal fat content 2.7 - 4.1 %). The mortality, percentage of breast and leg muscles and meat quality were not influenced by the diet. Live weight, carcass percentage and percentage of abdominal fat were significantly decreased when increasing the RS percentage above 15 %. The feed conversion was significantly worse when the percentage of RS rose to 20 %. Using native sources of nutrients may considerably reduce the production costs for broiler growing.