Impact of varying starter amino acid density and energy on 42 d male Cobb MV × Cobb 500 broiler performance and processing

Abstract

Summary Previous research has shown that feeding high amino acid density (AAD) diets or increased AME improved broiler performance, though the relationship between AAD and AME on performance needs to be further explored. Therefore, the objective of this study was to evaluate the impact of feeding 2 AAD and 4 AME levels from day 0 to 14 on performance and yield of 42-day-old Cobb MV × Cobb 500 males. Starter diets were formulated to medium or high AAD (HAA), and very low (VLE), low (LE), medium (ME), or high (HE) AME. Common diets were provided from day 15 to 41. A 2 × 4 factorial arrangement of treatments was used, with day 0 BW considered as a covariant. On day 0 to 14, birds receiving HAA had the lowest feed conversion ratio (FCR) corrected and uncorrected for mortality (uFCR). Birds receiving VLE diets had the highest day 0 to 14 FCR when compared to birds fed other AME levels. Feeding LE diets resulted in higher day 0 to 14 FCR when compared to ME and HE diets. An AAD × AME interaction for day 0 to 14 total Lys intake/bird found that Lys intake/bird decreased when increasing dietary AME for HAA diets. An AAD × AME interaction was observed for day 0 to 28 uFCR whereas increasing starter AAD in diets formulated to ME and HE increased day 0 to 28 uFCR; no change was observed for VLE and LE diets. However, overall performance and processing was not affected by varying starter AAD and AME levels. Further research should investigate similar feeding strategies, but in other feeding phases.