Time-series responses of swine plasma metabolites to ingestion of diets containing myo-inositol or phytase.

The effect of the ingestion of diets containing either myo-inositol or exogenous phytase on plasma metabolites was examined using 29 kg barrows. The diets were: control (maize, soya, rapeseed, rice bran), control plus 2 g/kg myo-inositol, control plus 1000 phytase units (FYT)/kg or 3000 FYT/kg exogenous phytase. Pigs were housed in a PigTurn device and blood was collected, from jugular catheters, via an automated system at -30, (30 min before feeding), 0, 15, 30, 45, 60, 90, 120, 150, 180, 240, 300 and 360 min post-feeding. The addition of 2 g/kg myo-inositol to the basal diet resulted in an increase in plasma myo-inositol concentration that was evident 45-60 min after diet introduction and persisted to 360 min post-feeding. Similarly, supplementation of the basal diet with either 1000 or 3000 FYT/kg exogenous phytase resulted in an increase in plasma myo-inositol concentration that was still rising 360 min post-feeding. Plasma P concentration was increased over time by the addition of 1000 and 3000 FYT/kg phytase, but not by the addition of myo-inositol. Other plasma metabolites examined were not affected by dietary treatment. It can be concluded that oral delivery of myo-inositol results in rapid increase in plasma myo-inositol concentrations that peak approximately 45-60 min after feeding. Use of supplemental phytase achieves similar increases in myo-inositol concentration in plasma but the appearance is more gradual. Furthermore, supplementation of pig diets with exogenous phytase results in rapid appearance of P in plasma that may be sustained over time relative to diets with no added phytase.

Detection of transgenic and endogenous plant DNA fragments and proteins in the digesta, blood, tissues, and eggs of laying hens fed with phytase transgenic corn.

The trials were conducted to assess the effects of long-term feeding with phytase transgenic corn (PTC) to hens on laying performance and egg quality, and investigate the fate of transgenic DNA and protein in digesta, blood, tissues, and eggs. Fifty-week old laying hens (n = 144) were fed with a diet containing 62.4% PTC or non-transgenic isogenic control corn (CC) for 16 weeks. We observed that feeding PTC to laying hens had no adverse effect on laying performance or egg quality (P>0.05) except on yolk color (P<0.05). Transgenic phyA2 gene and protein were rapidly degraded in the digestive tract and were not detected in blood, heart, liver, spleen, kidney, breast muscle, and eggs of laying hens fed with diet containing PTC. It was concluded that performance of hens fed diets containing PTC, as measured by egg production and egg quality, was similar to that of hens fed diets formulated with CC. There was no evidence of phyA2 gene or protein translocation to the blood, tissues, and eggs of laying hens.

Synthesis and levels of organic phosphates in erythrocytes during avian development: specific formation of BPG and IP5 in two distinct populations from young chicks.

Two generations of red cells (embryonic and definitive), different types of haemoglobins, and special organic phosphates involved in the control of haemoglobin oxygenation (2:3-bisphosphoglycerate, BPG, and inositol-5-phosphate, IP5), have been found progressively during development of the chick. Levels of both organic phosphates, as well as activities of the enzymes involved in BPG synthesis (2:3-bisphosphoglycerate synthase, BPGM) and IP5 formation (phytase), were studied in the erythrocyte populations from embryo, young and adult chickens. Measurement of specific activities of BPGM and phytase in the two subpopulations present in young chickens showed that these phosphates could be specifically and predominantly formed in these two red cell populations.

Separation by counter-current distribution of rat and chicken erythrocytes of different age, and its application to the assay of enzyme activities.

The separation of cells with different ages from erythrocyte populations of adult rats and young or adult chickens have been achieved by counter-current distribution (CCD). A thin-layer CCD apparatus has been employed. Erythrocytes from blood samples taken at different times after 59Fe i.p. injection were separated by CCD. By compilation in a "composite curve" of the hemoglobin and radioactivity CCD profiles obtained for each erythrocyte population, the distribution of cells according to age can be inferred. Young erythrocytes of rats are located at the right part of the CCD curves, while older cells are distributed towards the left. An opposite distribution has been found for erythrocytes from adult or young chickens. As a first attempt for the application of the CCD procedure to the assay of enzyme activities, it was found a decrease in phytase activity as the age of chicken erythrocytes increases and an increase in phosphoglycerate kinase and phosphofructokinase as the age of rat erythrocytes increases.

Phytase activity in chicken erythrocytes and its control by organic phosphates (glycerate-2,3-P2 and inositol-P5) during avian development.

The activity and basic kinetic constants of phytase were studied in chicken erythrocytes during animal development. The regulatory inhibition of phytase by IHP and 2,3-BPG takes place at key stages of the development. As in mammals, there is a specific control of the levels of organic phosphate involved in the oxygenation process of haemoglobin, during animal development.