Browsing by Person "Rubio-Cervantes, Ismael"

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Impact of added phytase and different dietary InsP6 levels on the structure and core microbiota of the digestive tract in broiler chickens
(2025) Rubio-Cervantes, Ismael; Wolfrum, Stephanie; Rodehutscord, Markus; Camarinha-Silva, Amélia
The main objective of this research was to investigate the composition and shifts of the gut microbiota of broiler chickens in response to varying exogenous phytase combined with increasing levels of myo-inositol (1,2,3,4,5,6) hexakis (dihydrogen phosphate) (InsP6) in the feed. The InsP6 level was adjusted with the addition of oilseed meals (OSM) at the expense of maize starch. A secondary objective was to assess the existence of a core microbiota across the feed, litter and gastrointestinal tract (GIT). A total of 840 Ross 308 broiler chickens were raised in 84 elevated pens in groups of 10. The treatments consisted of four feed mixtures (FM) designed to achieve 1.4 (FM1.4), 1.9 (FM1.9), 2.4 (FM2.4), and, 3.0 (FM3.0) g InsP6-P/kg, each combined with 500, 1500 or 3000 FTU phytase/kg. In the crop and the ileum, Lactobacillus relative abundance decreased when OSM and phytase increased (p < 0.05), while FM2.4 and FM3.0 were associated with increased Ligilactobacillus abundance across the GIT (p < 0.05). No interaction effects were found across the studied sections (p = 0.22). Four amplicon sequence variants (ASV), identified within the genera Lactobacillus, Ligilactobacillus, and Limosilactobacillus were consistently found across the intestine sections. These four ASVs represented 58.9 % of the relative abundance in the crop, 72.9 % in the ileum and 29.7 % in the ceca. The results demonstrated that higher levels of OSM in the feed and exogenous phytase significantly affected these bacterial populations, decreasing Lactobacillus while increasing Ligilactobacillus, indicating independent effects of FM and phytase supplementation.
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