Browsing by Subject "Laying hen"

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Effects of feeding diets without mineral P supplement on intestinal phytate degradation, blood concentrations of Ca and P, and excretion of Ca and P in two laying hen strains before and after onset of laying activity
(2024) Sommerfeld, Vera; Bennewitz, Jörn; Camarinha-Silva, Amélia; Feger, Martina; Föller, Michael; Huber, Korinna; Oster, Michael; Ponsuksili, Siriluck; Schmucker, Sonja; Seifert, Jana; Stefanski, Volker; Wimmers, Klaus; Rodehutscord, Markus
The objective of this study was to characterize intestinal phytate degradation and mineral utilization by 2 laying hen strains before and after the onset of egg laying using diets without or with a mineral phosphorus (P) supplement. One offspring of 10 roosters per strain (Lohmann Brown-classic [LB] and Lohmann LSL-classic [LSL]) was sacrificed before (wk 19) and after (wk 24) the onset of egg-laying activity and following 4 wk placement in a metabolic unit. Diets were corn-soybean meal-based and without supplemented P (P-) or with 1 g/kg supplemented P (P+) from monocalcium phosphate. In wk 19 and 24, the blood plasma and digesta of duodenum+jejunum and distal ileum were collected. The concentration of P in blood plasma was higher in hens fed P+ than P- (P < 0.001). In duodenum + jejunum and ileum content, the concentrations of InsP6, Ins(1,2,4,5,6)P5 and Ins(1,2,3,4,5)P5 were lower in P- than in P+ (P ≤ 0.009). In duodenum+jejunum, the concentrations of InsP6, Ins(1,2,4,5,6)P5 and Ins(1,2,3,4,5)P5 were lower in wk 24 than 19 and lower in LSL than LB hens (P < 0.001). The concentration of myo-inositol (MI) in duodenum + jejunum content was lower in wk 19 than 24 (P < 0.001). Following a 4-d total excreta collection, the retained amount of P was higher in P+ than P- (P < 0.001). Phosphorus retention was lower in LB hens fed P- than in other treatments (P × strain: P = 0.039). In the jejunal tissue, some genes related to intracellular InsP metabolism were higher expressed in LB than LSL hens. The renunciation of mineral P increased endogenous phytate degradation, but more P was retained with supplemented P. Differences in endogenous phytate degradation between the periods before and after the onset of egg laying might be attributed to different Ca concentrations in intestinal digesta caused by different Ca needs in both periods.
Effects of myo-inositol supplementation in the diet on myo-inositol concentrations in the intestine, blood, eggs, and excreta of laying hens
(2025) Sommerfeld, Vera; Hanauska, Anna; Huber, Korinna; Bennewitz, Jörn; Camarinha-Silva, Amélia; Feger, Martina; Föller, Michael; Oster, Michael; Ponsuksili, Siriluck; Schmucker, Sonja; Seifert, Jana; Stefanski, Volker; Wimmers, Klaus; Rodehutscord, Markus
The objectives of this study were to investigate whether an increased dietary myo-inositol (MI) supply translates into changes in MI concentrations and endogenous mucosal phosphatase activities in the intestine of laying hens and whether different laying hen strains respond differently to MI supplementation. The diets were corn–soybean meal-based and supplemented without (MI0) or with 1 (MI1), 2 (MI2), or 3 (MI3) g MI/kg feed. Ten hens per strain (Lohmann Brown-classic (LB) and Lohmann LSL-classic (LSL)) and diet were sacrificed at the age of 30 wk following a 4-wk stay in a metabolic unit. The blood plasma, digesta of the duodenum+jejunum and distal ileum, mucosa of the duodenum, and eggs were collected at wk 30. The concentration of MI in the blood plasma was increased by MI supplementation (P < 0.001); however, that of MI3 did not further increase compared with MI2. The concentration of MI in the duodenum+jejunum and ileum increased steadily (P < 0.001). The MI concentration in the duodenum+jejunum was higher in LB than in LSL hens (P = 0.017). The MI concentration in egg yolk was increased by MI supplementation (P < 0.001) and was higher in LB than in LSL hens (P = 0.015). Strain or diet did not affect mucosal phosphatase activity. Myo-inositol flow at the terminal ileum and postileal disappearance increased with each increment in MI supplementation (P < 0.001) and was higher in LB than in LSL hens (P ≤ 0.041). Regression analysis indicated that, on average, 84% of supplemented MI was retained in the body or metabolized and excreted in a different form. Based on the measured MI concentrations in the blood and eggs, dietary MI was not completely absorbed in the small intestine and, to a different extent, in the two laying hen strains. A higher dietary MI supply was followed by higher intestinal absorption or metabolism by microorganisms. The fate of supplemented MI and its relevance to birds warrant further research.