Effect of Density of Protein and Time of Pre-Starter Feeding on Performance, Digestive System Development, Body Composition,Carcass Characteristics and Some Blood Parameters in Broiler Chicks

This study was conducted to investigate the effect of different levels of protein crude and pre-starter period feeding on performance, digestive system development, some blood parameters, body composition and carcass characteristics of broiler chicks. In this study, 276 one-day-old Ross 308 male broiler chicks was allocated to three treatments with 4 replicates and 23 chicks per replicate in a completely randomized design. Experimental treatments included treatment 1 (20.84 percent protein as basal diet), treatment 2 10% higher protein content than basal diet (22.92 percent) that was feeded for 5-day period and treatment 3 10% higher protein content than basal diet (22.92 percent) that was feeded for 7-day period. In all treatments, metabolizable energy content was similar (2900 kcal /kg). Results indicated that there was not significant differences among treatment for performance and carcass characteristics. Also there were not significant differences among treatments for liver, spleen and burs fabresius percentage. There were significant differences among treatments for glucose in 21, triglycerides concentration in 21 and 42 days and HDL concentration in 21 day, as treatments 2 and 3 had higher values for these traits (p<0.05). There was significant differences among treatments for small intestine length in 14 day, as small intestine length had higher value in treatment 3 in comparison to other treatments (p<0.05). There were significant difference among treatments for body protein and dry matter in 42 day, as treatment 3 had higher protein and lower dry matter percentage (p<0.05). Results of this investigation showed that small intestine length and blood HDL, TG and glucose concentration and body protein percent increased via enhencing protein level in broiler pre-starter diet.