Protein and Amino Acid Supplementation Levels for Broilers in Pre-Starter Ration

Performance, ether extract, dry matter and protein digestibility and enzymatic activities of broilers fed different Crude Protein (CP) and amino acid levels in pre-starter ration were evaluated. 560 MPK male day-old chicks were raised until 21 days of age in heated brooders and allotted in a complete randomized design with eight treatments and five replicates each: A. 20% CP non-supplemented; B. 20% CP supplemented with Met, Lys and Thr; C. 20% CP supplemented with Met, Lys, Thr and Trp for 22% CP; D. 20% CP supplemented with Met, Lys, Thr and Trp for 24% CP; E. 22% CP non-supplemented; F. 22% CP supplemented with Met, Lys and Thr; G. 22% CP supplemented with Met, Lys, Thr and Trp for 24% CP; H. 22% CP supplemented with Met, Lys, Thr and Trp for 26% CP: All diets attended amino acid requirements of Rostagno et al. (2000) for corn-soybean rations with 2.900 Kcal/kg ME from 1-7 days. From 8-21 days, broilers received the same starter ration with 21.1% CP and 2900 Kcal/kg ME. The weight gain, feed intake and feed-to-gain ratio for total period and digestibility index and retention for Dry Matter (DM), CP (CP) and Ether Extract (EE) and digestibility parameters were measured from 4-7 days. In the 4th, 7th, 10th and 14th days of age, the pancreas of four birds was collected to amylase and tripsin analysis. The means were calculated and the Tukey test (p<0.05) was used to compare treatments. Low protein diets supplemented to attend 22 or 24% CP amino acid levels, were indicated for better results in performance, nutrient digestibility and retention. Amylase and Trypsin activities were affected with amino acid supplementation and reduced with birds age.