2007 Volume 44 Issue 3 Pages 297-304
The effects of two phytogenic feed additives (PFA) on growth performance, carcass parameters, nutrient utilization, and efficiency of dietary threonine utilization were investigated in male growing chickens (ROSS 308), using threonine limiting corn-wheat-soybean diets. PFA 1 (XTRACTTM), containing 5% carvacrol, 3% cinnamaldehyde and 2% Capsicum oleoresin, was added in graded supply. B: 50ppm, C: 100ppm, D: 200ppm, E: 500ppm). PFA 2 (Sangrovit®), containing the alkaloids sanguinarin and chelerythrin, was given at 30ppm (F). All treatments were compared to a control diet (A). Growth studies utilized 480 male chickens (Ross 308) and eight floor pens per diet (10 chickens per pen). Simultaneously, two N-balance studies were conducted (I: 16-20d; II: 30-34d) to evaluate N-utilization parameters and dietary threonine efficiency depending on PFA addition. The results of growth study and N-balance experiments in both age periods provided no significant effect of the examined PFA on nutrient utilization and dietary threonine efficiency. The observed threonine efficiency data were utilized for further modeling of threonine requirements. The established threonine requirement data (at 0.4kg BW: 336, 468 and 646mg per day for 6, 7.5 and 9g daily protein deposition; at 1.6kg BW: 574, 712 and 883mg per day for 12, 14 and 16g daily protein deposition) are discussed in line with actual recommendations.
