Meta-analysis of the influence of dietary @entity8959 and @entity563 , with consideration of @entity1853 and XXXX , on growth and feed conversion of broilers.

@entity3534 @entity8959 @entity462 @entity4508 @entity2569 @entity4022 @entity1853 @entity563 @entity60448 @entity15 @entity2723
The existing literature is inconsistent with respect to optimal dietary concentrations of @entity8959 ( @entity4022 ) and @entity563 ( @entity60448 ) in broiler feed. Therefore, we conducted a meta-analysis to investigate the response of broilers to dietary levels of @entity4022 using a full quadratic model based on mixed model methodology. Response was measured as ADG (g/d), ADFI (g/d), and G:F (g/g). In addition, the influence of other dietary constituents was evaluated. This meta-analysis was based on a data set comprising a total of 9,626 broilers in 10 peer-reviewed papers that investigated the response of broilers to different dietary concentrations of @entity4022 , achieved by addition of free @entity4022 . The fitted quadratic model, with either @entity4022 + @entity60448 or the calculated @entity8959 equivalent (Glyequi) of both @entity3534 as the independent variable, revealed that all model terms were significant (P  <= 0.05), and hence proved a curvilinear relationship between these independent variables and response traits. The R(2) value and root @entity15 error confirmed a strong relationship between observed and predicted traits. A comparison of the influence of @entity4022 + @entity60448 and Glyequi on response traits revealed that both approaches produced similar results. Because Glyequi should meet the physiological values of a diet better than @entity4022 + @entity60448 , models with 2 independent variables were conducted using Glyequi. The second independent variables were @entity1853 ( @entity4508 ):TSAA ratio and the concentrations of @entity462 ( @entity2569 ) and @entity2723 . In models with one or 2 independent variables, the impact of dietary @entity4022 on ADFI was low. By contrast, G:F was markedly influenced by dietary @entity4022 ; this effect intensified at lower @entity4508 :TSAA ratios and higher @entity2569 and @entity2723 levels. ADG was also a function of Glyequi and the second independent variables. For ADG, an optimal @entity4508 :TSAA ratio of 0.655 and @entity2569 concentration of 0.302% was calculated. Following the nonlinear nature of relationship, generally applicable replacement values could not be calculated. However, it was concluded that consideration of dietary @entity2569 can diminish the requirement for Glyequi, and therefore, enable a reduction in the @entity2723 of broiler diets without limiting growth performance.
