Browsing by Subject "Mucosal phosphatase"

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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.
Endogenous mucosal phosphatases characterization in duodenum brush border membrane of laying hens
(2025) Hanauska, Anna; Sommerfeld, Vera; Schollenberger, Margit; Huber, Korinna; Rodehutscord, Markus
Chicken mucosal phosphatases can partially degrade phytate contained in the feed. Little is known about the characteristics and degradation products of such mucosal phosphatases and the effects of age and genetic strain of the chicken. The objective of this study was to characterize endogenous mucosal phosphatases of two laying hen strains fed diets with or without mineral phosphorus (P) before and after the onset of egg laying. Hens of the strains Lohmann Brown-classic (LB) and Lohmann LSL-classic (LSL) were sacrificed in weeks 19 and 24 of age after 4 weeks of feeding one of two diets with (P+) or without (P-) mineral P supplement. Mucosa of the duodenum was collected, and the brush border membrane (BBM) of enterocytes was enriched and used for phosphatase activity determination. Additionally, the BBM was used in a modified three-step in vitro assay to study the InsP6 degradation products. The results of both in vitro assays were not significantly affected by hen strain and diet. The activity of mucosal phosphatase in 19-week-old hens was, on average, 0.8 µmol Pi/g BBM protein/min lower than in 24-week-old hens (P < 0.002). Consistently, the InsP6 concentration in the incubation residue was significantly higher in 19-week-old hens than in 24-week-old hens (P < 0.001). In the incubation residue, the concentrations of Ins(1,2,3,4,5)P5, Ins(1,2,3,4,6)P5, and Ins(1,2,3,4)P4 were significantly lower (P ≤ 0.002), and those of InsP3 and InsP2 were significantly higher (P ≤ 0.027) when BBM of 24-week-old hens was used compared to 19-week-old hens. The InsP6 degradation products suggest the activity primarily of a 6- and secondarily of a 5-phytase in the duodenal mucosa. The consistent results from both in vitro assays provide a comprehensive characterization of these enzymes. Under the conditions of this study, small intestine calcium concentration appeared to influence mucosal enzyme activity more than dietary mineral P supplementation.