No description available.

Past literature has supported the supplementation of 25-OHD3 into poultry diets to reduce leg issues and improve muscle accretion. In addition, exogenous feed enzymes are included into poultry diets to increase nutrient utilization. The first objective of this thesis was to determine the effects of different sources and levels 25-OHD3 supplementation on D0-53 Ross x Ross 708 male broiler performance, processing yield, tibia ash, serum Ca and 25-OHD3 status. Data demonstrated that 25-OHD3 supplementation into diets with Low VitD3 (165 IU/kg) can improve broiler performance compared to High VitD3 (2756 IU/kg). The second objective was to investigate the effects of varying phytase inclusion with different xylanase levels on D0-56 Ross x Ross 708 male broiler performance, processing yield and tibia ash. Data exhibited some performance benefit (D46 and D56) when utilizing phytase (1000 and 1500 FTU/kg) with 1500 EPU/kg xylanase and phytase (250 and 1500 FTU/kg) with 3000 EPU/kg xylanase.

No description available.

The effects of parathyroid hormone (PTH), prostaglandins (PGE1, PGE2, PGF2a), cAMP, cAMP-analogues, phosphodiesterase (PDE) inhibitors and la (OH) D3 on bone resorption and associated cellular process have been studied in a bone organ culture system using half- calvaria from 6-7 day-old mice. Bone resorption was assessed by determining the release of calcium (Ca2+), inorganic phosphate (Pi) and 45Ca from the calvarial bones to the culture media. The release of lysosomal enzymes was studied by analysing the activities of β-glucuronidase, β-N-acetyl- glucosaminidase, β-galactosidase and p-nitrophenyl phosphatase in bone expiants and culture media. The release of non-lysosomal enzymes was followed by assaying the activities of lactate dehydrogenase (LDH), aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) in the expiants as well as the media. In addition glucose consumption and lactate production was registered. The findings may be summarized as follows: 1. cAMP and PDE-inhibitors have the capacity to inhibit the initial stages of spontaneous as well as PTH- PGE1- and PGE2-stimulated bone resorption. 2. cAMP and PDE-inhibitors produce after a lag period, or a period of reduced bone resorption, a stimulatory effect on bone resorption. 3. There is a significant correlation between bone resorption and lysosomal enzyme release both as regards the inhibitory and stimulatory effect of cAMP. 4. PGE2 and la (OH) D3 increase the release of lysosomal enzymes in parallel with bone resorption. 5. Bone resorption stimulated by cAMP and PGE2 is associated with increased glucose consumption and lactate production, while la (OH) D3 promotes bone resorption without any change with regard to these parameters of glucose metabolism. It is concluded that the initial stages of bone resorption stimulated by PTH, PGE1 and PGE2 is medited by cAMP-independent mechanisms, but that this nucleotide may be an intracellular mediator of these hormones of later stages of bone resorption. It is suggested that the role played by cAMP may be related to the capacity of PTH and PGE2 to develop new osteoclasts. The observations further support the concept that lysosomal enzyme release is intimately associated with bone resorption. Finally it is concluded that increased lactate production seems to be related to bone resorption stimulated by agents which increase the level of cAMP (PTH, PGE2, dbcAMP), but that it is not an indispensible part of the mechanism by which the osteoclasts solubilize bone mineral. / digitalisering@umu.se