Browsing by Person "Feuerstein, Dieter"

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Growth performance, phytate degradation, and tibia characteristics of broiler chickens fed pelleted diets with varying feed particle sizes and phytase levels
(2025) Wolfrum, Stephanie; Francesch, Maria; Jimenez-Moya, Beatriz; Feuerstein, Dieter; Rodehutscord, Markus
The objective was to investigate the effects of feed particle size and microbial phytase supplementation of pelleted diets on growth performance, myo-inositol hexakisphosphate (InsP6) degradation, and tibia characteristics in broiler chickens. Ross 308 broilers were housed in 56 floor pens in groups of 42, and seven pens were allocated to one of eight dietary treatments to measure the performance data on day 38 of age. From day 21 to 26, six birds from each floor pen were moved to metabolism units with the same distribution of treatments for digestibility and bone measurements. For the starter phase, two diets with fine or coarse particle size (429 or 657 µm mean particle size, determined after feed processing by wet sieving) were formulated and added with 500 FTU phytase/kg. For the grower and finisher phase, diets were arranged with two particle sizes (fine and coarse, 434 or 729 µm) and four phytase levels (0, 300, 600, and 1,200 FTU/kg). No significant interactions between particle size and phytase were determined. Prececal InsP6 disappearance and P digestibility were higher with fine than coarse particles, indicating that coarse grinding of rapeseed meal may not benefit birds. Increasing phytase supplementation increased ADG, ADFI, prececal InsP6 disappearance and P digestibility, tibia ash, and tibia breaking strength. Under the conditions of this study, birds were sufficiently supplied with P at a total P level of 4.0 g/kg and phytase supplementation of 1,200 FTU/kg. Renouncement of feed phosphate in the grower and finisher phase was possible without impaired performance.
Interactions between dietary phytate concentration and phytase level on phytate degradation and amino acid digestibility in broiler chickens
(2025) Wolfrum, Stephanie; Siegert, Wolfgang; Rubio-Cervantes, Ismael; Liebhold, Tina Marie; Feuerstein, Dieter; Camarinha-Silva, Amélia; Rodehutscord, Markus
The objective of the present study was to investigate the effects of dietary myo-inositol hexakisphosphate (InsP6) concentration and added phytase on gastrointestinal InsP6 degradation, prececal digestibility of P, Ca, and amino acids (AA), and MEN in broiler chickens. Dietary InsP6 was increased by graded substitution of corn starch with a mixture of 50 % soybean meal, 20 % rapeseed meal, 20 % sunflower meal, and 10 % rice bran (oilseed meal-rice bran level (ORL)). The experiment was arranged in a 4 × 3-factorial design with 4 ORL (leading to 1.4, 1.9, 2.4, and 3.0 g InsP6-P/kg) and 3 phytase levels (500, 1,500, and 3,000 FTU/kg). Male Ross 308 broilers were allocated to 84 metabolism units in groups of 10 and assigned to 1 of the 12 diets. InsP6 disappearance in the crop decreased with increasing ORL (45 to 24 %; P = 0.001). Prececal InsP6 disappearance and P digestibility linearly decreased with increasing ORL at 500 FTU/kg (83 to 56 % and 80 to 62 %; P < 0.001). Minor differences were determined for prececal InsP6 disappearance and P digestibility among ORL at 1,500 and 3,000 FTU/kg, but values decreased with increasing ORL (91 to 83 % and 87 to 81 %, respectively; P < 0.001). When prececal InsP6 disappearance relative to FTU was regressed against dietary InsP6, the relationship was non-linear at 500 FTU/kg but linear at 1,500 and 3,000 FTU/kg. Cecal InsP6 concentration increased with ORL and decreased with phytase (P < 0.001). Except for cysteine, prececal digestibility of all AA and MEN decreased with increasing ORL. The data indicated that phytase supplemented at or above 1,500 FTU/kg did not limit gastrointestinal InsP6 degradation and AA digestibility at high InsP6 concentrations of the fee