A model on biological flow of phosphorus in growing pigs

Lopes, João Batista; Moreira, José Aparecido; Kebreab, E.; Vitti, Dorinha Miriam Silber Schmidt; Abdalla, Adibe Luiz; Crompton, L.A.

doi:10.1590/s0102-09352009000300024

Cited by 10 publications

(12 citation statements)

References 14 publications

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“…An E value lower than E 95% also indicated that there was no bias in the simulations; as they did not consistently over-or under-estimate the predicted results compared with the observed values. The experiment of Lopes et al (2009) revealed that the P digested from the lumen of the small intestine into the bloodstream responded linearly to dicalcium phosphate supplementation and the response was in good agreement with the predicted results ( Figure 2). The correlation between observed and predicted results for P digested and excreted were high, with correlation coefficients of 0.90 and 0.98, respectively (Table 3).…”

Section: Sensitivity Analysessupporting

confidence: 76%

“…The model predicted very accurately the direction of response to inorganic P supplementation for digested, retained and total P excreted in the experiments of Ekpe et al (2002) and Lopes et al (2009). The agreement with the experiment of Lopes et al (2009) also gives some confidence in the value Figure 8 Comparison of experimental observations (■,•) by Poulsen et al (2010) to simulated predictions (□,○) of (a) retained P and (b) total P excreted.…”

Section: Comparison Of Model With Published Trialsmentioning

confidence: 55%

“…Studies that met the above criteria were used in the evaluation process to test for the effect of: (1) inclusion of inorganic P (Ekpe et al, 2002;Lopes et al, 2009); (2) different levels of phytate in the diet (Trujillo et al, 2010); (3) Aspergillus niger and Escherichia coli phytase supplementation (Akinmusire and Adeola, 2009;Jendza and Adeola, 2009;Poulsen et al, 2010;Trujillo et al, 2010;Almeida and Stein, 2012); (4) different levels of dietary Ca Stein et al, 2011). For detailed description of these studies, see Supplementary Material S2.…”

Section: Sensitivity Analysesmentioning

confidence: 99%

“…It can be seen from Figure 2 that there was an underestimation of the P digested and an over-estimation of the total P excreted; this was particularly the case for one of the treatments. Lopes et al (2009) did not provide standard errors of the observed results, therefore the RMSE 95% and E 95% could not be calculated.…”

Section: Sensitivity Analysesmentioning

confidence: 99%

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Modelling phosphorus intake, digestion, retention and excretion in growing and finishing pig: model evaluation

Symeou

Leinonen

Kyriazakis

2014

Animal

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A deterministic, dynamic model was developed, to enable predictions of phosphorus (P) digested, retained and excreted for different pig genotypes and under different dietary conditions. Before confidence can be placed on the predictions of the model, its evaluation was required. A sensitivity analysis of model predictions to ±20% changes in the model parameters was undertaken using a basal UK industry standard diet and a pig genotype characterized by British Society Animal Science as being of 'intermediate growth'. Model outputs were most sensitive to the values of the efficiency of digestible P utilization for growth and the non-phytate P absorption coefficient from the small intestine into the bloodstream; all other model parameters influenced model outputs by <10%, with the majority of the parameters influencing outputs by <5%. Independent data sets of published experiments were used to evaluate model performance based on graphical comparisons and statistical analysis. The literature studies were selected on the basis of the following criteria: they were within the BW range of 20 to 120 kg, pigs grew in a thermo-neutral environment; and they provided information on P intake, retention and excretion. In general, the model predicted satisfactorily the quantitative pig responses, in terms of P digested, retained and excreted, to variation in dietary inorganic P supply, Ca and phytase supplementation. The model performed well with 'conventional', European feed ingredients and poorly with 'less conventional' ones, such as dried distillers grains with solubles and canola meal. Explanations for these inconsistencies in the predictions are offered in the paper and they are expected to lead to further model development and improvement. The latter would include the characterization of the origin of phytate in pig diets. Keywords: mathematical model, phosphorus, phytate, pig, sensitivity analysis ImplicationsThe model developed in the companion paper (Symeou et al., 2014) and evaluated here predicts adequately the P digestion, retention and excretion of growing-finishing pigs for a wide range of dietary compositions and for pigs of different genotypes. Consequently, the model can be applied to develop feeding strategies to optimize phosphorus (P) utilization and minimize the different forms of P excreted to the environment. The model can be further improved, by considering 'reactive' as opposed to total phytate content of the diet, as well as experimentally establishing the net efficiency of digestible P utilization for growth and the non-phytate P absorption coefficient from the small intestine into the bloodstream, for pigs offered access to different diets.

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Section: Sensitivity Analysessupporting

confidence: 76%

Section: Comparison Of Model With Published Trialsmentioning

confidence: 55%

Section: Sensitivity Analysesmentioning

confidence: 99%

Section: Sensitivity Analysesmentioning

confidence: 99%

See 2 more Smart Citations

Modelling phosphorus intake, digestion, retention and excretion in growing and finishing pig: model evaluation

Symeou

Leinonen

Kyriazakis

2014

Animal

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“…It was assumed that the pig will attempt to consume an amount of feed that will satisfy its energy and protein requirements for potential daily gain and maintenance (Kyriazakis et al, 1990;Kyriazakis and Emmans, 1999). The same regulation does not seem to apply for P (Pomar et al, 2006;Lopes et al, 2009). The amount of feed that allows the pig to meet its energy and protein requirements to be achieved was calculated from the current protein and lipid contents of the pig, and the composition of the feed.…”

Section: Methodsmentioning

confidence: 99%

Quantifying the consequences of nutritional strategies aimed at decreasing phosphorus excretion from pig populations: a modeling approach

Symeou

Leinonen

Kyriazakis

2016

animal

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There is a global imperative to reduce phosphorous (P) excretion from pig systems. In this study, a previously validated deterministic model was modified to be stochastic, in order to investigate the consequences of different management strategies on P excretion by a group of growing pigs. The model predicts P digestion, retention and excretion from feed composition and growth parameters that describe a specified pig phenotype. Stochasticity was achieved by introducing random variation in the latter. The strategies investigated were: (1) changing feed composition frequently in order to match more closely pig digestible P (digP) requirements to feed composition (phase feeding) and (2) grouping pigs into light and heavy groups and feeding each group according to the requirements of their group average BW (sorting). Phase feeding reduced P excretion as the number of feeding phases increased. The effect was most pronounced as feeding phases increased from 1 to 2, with a 7.5% decrease achieved; the increase in phases from 2 to 3 was associated with a further 2.0% reduction. Similarly, the effect was more pronounced when the feed targeted the population requirements for digP at the average BW of the first third, rather than the average requirements at the mid-point BW of each feeding sequence plan. Increasing the number of feeding phases increased the percentage of pigs that met their digP requirements during the early stages of growth and reduced the percentage of pigs that were supplied <85% of their digP requirements at any stage of their growth; the latter may have welfare implications. Sorting of pigs reduced P excretion to a lesser extent; the reduction was greater as the percentage of pigs in the light group increased from 10% to 30% (from 1.5% to 3.0% reduction, respectively). This resulted from an increase in the P excreted by the light group, accompanied by a decrease in the P excreted by the remaining pigs. Sorting increased the percentage of light pigs that met their dig P requirements, but only slightly decreased the percentage of heavy pigs that met these requirements at any point of their growth. Exactly the converse was the case as far as the percentage of pigs that were supplied <85% of their digP requirements were concerned. The developed model is flexible and can be used to investigate the effectiveness of other management strategies in reducing P excretion from groups of pigs, including precision livestock feeding.

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Calcium and phosphorus digestibility in rock- and bone-derived calcium phosphates for pigs and poultry: A review

Woyengo

Nørgaard

Heide

et al. 2022

Animal Feed Science and Technology

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A model on biological flow of phosphorus in growing pigs

Cited by 10 publications

References 14 publications

Modelling phosphorus intake, digestion, retention and excretion in growing and finishing pig: model evaluation

Modelling phosphorus intake, digestion, retention and excretion in growing and finishing pig: model evaluation

Quantifying the consequences of nutritional strategies aimed at decreasing phosphorus excretion from pig populations: a modeling approach

Calcium and phosphorus digestibility in rock- and bone-derived calcium phosphates for pigs and poultry: A review

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