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Query: UMLS:C0020437 (hypercalcemia)
 10,293 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Some cereal by-products, such as bran, exhibit a high phytase activity that may enhance phytate P digestibility. This was studied in growing pigs fed a phytase-rich (1,200 IU/kg) diet containing 20% rye bran. The trial involved 12 animals; six were fed a control diet and six were fed a diet containing rye bran for 2 mo. Both diets contained the same levels of energy, protein, Ca (.7%) and total P (.4%). No inorganic P was added; thus, the dietary P was mainly phytic. Pigs fed the control diet, in contrast to those fed the diet containing rye bran, developed a P deficiency, as indicated by hypophosphatemia, hypophosphaturia, hyperhydroxyprolinuria, hypercalcemia, and hypercalciuria. Phosphorus from the rye bran diet was more completely absorbed (55 vs 36%) and retained (50 vs 36%) than that from the control diet. Calcium absorption was equal for the two diets, but Ca retention was higher in pigs fed rye bran than in controls. Pigs fed the rye bran diet showed greater bone density, ash content, and bending moments than controls. In conclusion, high dietary phytase levels or phytase-rich by-products increased phytate P availability and consequently improved bone scores.
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PMID:Enhancement of phosphorus utilization in growing pigs fed phytate-rich diets by using rye bran. 164 62

1. The effects of phosphorus deprivation on phytate digestibility, phosphorus utilization and intestinal phytase (EC 3.1.3.8) and alkaline phosphatase (EC 3.1.3.1) in rats were investigated. 2. P deprivation was achieved by giving rats a diet containing 3 g P/kg and resulted in hypophosphataemia, hypercalcaemia, hypercalciuria, and lower levels of P absorbed and retained, and calcium retained. 3. Rats adapted to P deprivation by increasing the digestion of total dietary-P and phytate-P. 4. Levels of intestinal alkaline phosphatase and alkaline phytase were not different between the two treatment groups. 5. P deprivation in the rats given the marginal-P diet may be a result of a lower absorption of total dietary-P or increased absorption of inositol phosphates formed during the enzymatic hydrolysis of phytate which are not readily utilized by the rat. 6. These results suggest that intestinal phytase and alkaline phosphatase do not play a role in the adaptive increase in phytate digestibility by rats given marginal-P diets. The adaptation may result from enhanced phytase or alkaline phosphatase synthesis by the gastrointestinal microflora stimulated by a lower level of P in the digesta.
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PMID:Adaptive increase in phytate digestibility by phosphorus-deprived rats and the relationship of intestinal phytase (EC 3.1.3.8) and alkaline phosphatase (EC 3.1.3.1) to phytate utilization. 629 37

Phosphorus (P) is an essential component of many organic and inorganic compounds in vertebrates such as pigs. Therefore, adequate dietary P supply is important to meet daily requirements in order to maintain P homeostasis. Under normal circumstances regulation of P homeostasis occurrs by controlling the absorption rate of inorganic phosphate (Pi) in the upper small intestines and by renal Pi excretion. These processes are mainly mediated by parathyroid hormone (PTH) and calcitriol (1,25-dihydroxycholecalciferol, 1,25-(OH)2D3). If, for example, the Pi level in plasma decreases, renal calcitriol production is stimulated and higher amounts of the hormone are released into the circulation. Calcitriol increases Pi absorption from the intestinal tract by stimulation of a secondary active, sodium-coupled Pi-cotransport system in the upper small intestines. In addition, calcitriol is involved in the mobilization of bone and soft tissue P. Simultaneously, hypercalcemia develops, which can be induced by either increased intestinal Ca absorption and/or Ca mobilization from bone. Hypophosphatemia and hypercalcemia suppress PTH release from the parathyroid glands and thus minimize urinary Pi losses. The concerted action of increased/decreased circulating calcitriol/PTH on the intestinal tract, bone and kidneys normalizes Pi levels in plasma. With respect to adequate P supply in animal nutrition, it must be considered that utilization of dietary P not only depends on absorption capacity of the pig intestinal tract but also on differences in availability of dietary P between ingredients. In feedstuffs of plant origin most of the P is bound as phytate-P and can only be absorbed after enzymatic breakdown of phytic acid by phytases. Intrinsic phytase activity differs between plant materials such as wheat, wheat bran, barley and triticale with higher activities than found in maize and legume seeds subjected to thermal treatments. Supplementation of microbial phytase increased P digestibility more pronounced in those feedstuffs which showed very limited intrinsic phytase activity. At present, a digestibility of about 70% seems to be the upper level for digestibility of P from plant material. From the environmental point of view, an increased digestibility resulting from phytase supplementation offers the possibility to reduce the supplementation of phosphates and the concentration of total P in the diet. Therefore, the amount of P being excreted by the pig can be remarkably reduced. However, the first step for minimizing faecal P excretion should be to supply P in accordance with the animal's requirement.
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PMID:Mechanisms of intestinal phosphorus absorption and availability of dietary phosphorus in pigs. 876 2

Phytic-phosphorus has a very low bioavailability for monogastric animals and the non-utilized mineral contributes to the phosphorus (P) pollution problems. Phytases may ameliorate phytic-P antinutritive properties. However, phytases are very sensitive to the pelleting temperature commonly used for compound feed production and thus the challenge to produce a more thermostable phytase is very important. Pure Aspergillus fumigatus phytase (AFP) has the ability to refold into a native-like fully active structure after heat denaturation (20 min at 90 degrees C). The aim of the present work was to evaluate in vitro (in feed) and in vivo in young and in growing-finishing pigs the effects of AFP included in the feed at a level of 500 U/kg. Feed supplementation with AFP resulted in an in vitro phosphorus release of about three times higher than that obtained from the basal diets, irrespective of the pH value used for the determination (5.5 or 7). When the supplemented feed was steam pelleted at about 84 degrees C, the free P obtained after incubation at pH 5.5 represented 53% on an average of that obtained from the corresponding mash diets. The phytic-P-rich diets systematically induced hypophosphataemia, hypercalcaemia and hyperphosphatasaemia. The normal blood levels of P, Ca and alkaline phosphatase were restored by AFP. P apparent digestibility was significantly higher for the AFP diet (52.8 versus 30.8%). The improvement in Ca digestibility was not statistically significant. In all three in vivo experiments, AFP significantly decreased the P concentration in faeces (between 13 and 33%) as well as increased the growth rate and decreased the feed conversion ratio. Bone strength was significantly higher in the growing-fattening pigs fed on the AFP diet.
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PMID:Effects of Aspergillus fumigatus phytase on phosphorus digestibility, phosphorus excretion, bone strength and performance in pigs. 979 86