الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 95 |  |  |
| | | from | 95 | | |
Abstract
The aim of the study was the present experiment was carried out to investigate the effects of feeding diets containing graded levels of urea (0.345, 0.69, 1.035 and 1.38%) on the performance, carcass traits, nutrient digestibility and some blood parameters of broiler chicks during the grower period (from 3 to 6 weeks of age). Methods and results: During the starter period (0-3 weeks of age), unsexed Cobb-500 broiler chicks were kept in brooding batteries and given a commercial starter diet. At three weeks of age, 360 broiler chicks were randomly divided into 5 treatments, with 6 replicates each (12 chicks) and fed 5 experimental diets of similar crude protein (18.9%) and energy (3136 kcal ME/kg) contents having five graded levels of urea (0.00, 0.345, 0.69, 1.035 and 1.38%) were formulated and used from 3 to 6 weeks of age. The obtained results could be summarized as follows: During the entire experimental period (3 to 6 weeks of age), birds fed urea-containing diets exhibited significantly (P<0.01) lower FI compared with their control and counterparts birds fed urea-containing diets exhibited significantly (P<0.01) lower BWG as opposed to their control counterparts and there were no significant differences in FC values among all the experimental groups of broiler chicks, although no significant differences were observed in EEG of broiler chicks fed the different experimental diets from 3 to 6 weeks of age birds fed the urea-containing diets, with an exception of significant reductions in CP digestibility and rate of nitrogen retention in birds fed the 1.38% urea in their diet (Diet 5), with the exception of a significant increase in blood plasma urea concentrations of broilers fed the diets containing urea at levels of 0.69, 1.035 and 1.38% (Diets 3, 4 and 5, respectively). Conclusion : Because of the depressed growth performance and poor economic efficiency of growth resulting from feeding urea-containing diets, it can be concluded that urea addition as a source of non-protein nitrogen in broiler chick diets is nutritionally invaluable and not recommended.