| Autor: |
R. S. Dias, T. Silva, R. M. P. Pardo, J. C. Silva Filho, D. M. S. S. Vitti, E. Kebreab, S. López, J. France |
| Rok vydání: |
2011 |
| Předmět: |
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| Zdroj: |
Modelling nutrient digestion and utilisation in farm animals ISBN: 9789086867127 |
| DOI: |
10.3920/978-90-8686-712-7_30 |
| Popis: |
A compartmental model was developed to provide information on P metabolism in ruminants. The model is an extension of that proposed by Vitti et al. (2000) and amended by Dias et al. (2006). Compartments representing saliva and rumen were added to the original model. The data used to develop the extended model were generated in an experiment using 24 male sheep, initial live weight 34.5 kg, aged 8 mo, fed 0.14; 0.31; 0.49 and 0.65% P in DM. Animals received a single dose of 7.4 MBq of 32P injected into the jugular vein and subsequently samples of plasma and faeces were collected daily for one week. Mixed saliva samples and rumen fluid samples were taken only at 4 and 6 d after injection to prevent animal stress. Specifc activities and inorganic P measurements from bone, soft tissues, plasma, rumen, saliva and faeces were used to calculate fows between compartments. Increased dietary P levels affected positively total P and endogenous P excretion in faeces and P fow from rumen to lower gastrointestinal tract (GIT). The latter fow was also related to both total and endogenous P excreted in faeces. Phosphorus fow from GIT to plasma was correlated with endogenous P excretion and P recycled to GIT. Phosphorus fow from saliva to rumen was related to P fow from rumen to GIT. Phosphorus mobilized from bone was addressed to soft tissues as shown in the correlations between P fow from bone to plasma and net P fow in soft tissue, and P fow from plasma to soft tissue and net P fow in bone. The fows from the model resulted in appropriate biological description of P metabolism in ruminants. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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