Growth, nutrient utilization and threonine requirement of growing chicken fed threonine limiting diets with commercial blends of phytogenic feed additives

Abstract

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 (XTRACT™), containing 5% carvacrol, 3% cinnamaldehyde and 2% Capsicum oleoresin, was added in graded supply. B: 50 ppm, C: 100 ppm, D: 200 ppm, E: 500 ppm). PFA 2 (Sangrovit®), containing the alkaloids sanguinarin and chelerythrin, was given at 30 ppm (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: 16-20 d; II: 30-34 d) 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 0.4 kg BW: 336, 468 and 646 mg per day for 6, 7.5 and 9 g daily protein deposition; at 1.6 kg BW: 574, 712 and 883 mg per day for 12, 14 and 16 g daily protein deposition) are discussed in line with actual recommendations.