These outcomes advance the current underst and ing of Ca digestibility and utilisation , and should contribute towards establishing requirements for digestible Ca .
Consequently , pig diets will be more correctly formulated if digestible Ca values are used in estimating requirements for Ca
Ca digestibility and utilisation in growing pigs are not well understood , and are usually neglected in diet formulation .
This has implication s not only for the accurate determination of its requirements but also for its interactions with other nutrients .
A systematic review and meta- analysis ( meta-regression ) of published trials was carried out to quantify factors affecting Ca absorption and utilisation , and to derive an estimate of Ca endogenous excretion .
Estimation of true phosphorus digestibility and endogenous phosphorus loss in growing pigs fed conventional and low-phytate soybean meals.
This study reevaluated the method of regressing of total P output against dietary P intake to simultaneously estimate true P digestibility and endogenous P loss in growing pigs fed either conventional or low-phytate soybean meal ( SBM ) . Four isocaloric diets were formulated to contain increasing concentrations of each type of SBM ( 8 diets total ) , and therefore contained increasing concentrations of dietary P. Dietary P and Ca concentrations were deficient because they were supplied solely by SBM , and Ca : total P ratios were less than 1:1 . Sixteen barrows ( initial BW 17.7 + /- 1.8 kg ) were surgically fitted with a simple T-cannula at the distal ileum , r and omly assigned to metabolism crates , and fed the experimental diets in a replicated 8 x 8 Latin square design . Feed was provided at 90 g/kg of BW(0.75 ) and fed in 2 equally sized meals at 0800 and 2000 , with diets containing Cr sesquioxide ( 3 g/kg ) as an indigestible marker . As the P concentration increased from 0.9 to 3.9 g/kg of DM , the apparent prececal P digestibility increased for conventional SBM ( P < 0.05 ) , but no relationship was observed for low-phytate SBM . The output of total P [ mg/(kg of BW(0.75).d ) ] , either prececal or total tract , exhibited a linear relationship ( P < 0.01 ) with increasing P intake . However , a quadratic response ( P = 0.02 ) was also detected for total tract P output from pigs fed low-phytate SBM . True P digestibility was not different between prececal and total tract collection sites ( P > 0.10 ) , but was greater ( P < 0.01 ) for low-phytate SBM ( 62.6 % ) compared with conventional SBM ( 44.5 % ) . Endogenous P estimates were not different between the SBM varieties and averaged 4.83 mg/(kg of BW(0.75).d ) . However , endogenous P estimates were highly variable between individual animals and , therefore , were not significantly different from zero . In this study , estimates of endogenous P loss from pigs were relatively low compared with previously reported values , and evidence of nonlinearity in P output was observed . These results suggest that the difference in true P digestibility between conventional SBM and low-phytate SBM is influenced by dietary phytate content when growing pigs are fed P-deficient diets
These outcomes advance the current underst and ing of Ca digestibility and utilisation , and should contribute towards establishing requirements for digestible Ca .
Consequently , pig diets will be more correctly formulated if digestible Ca values are used in estimating requirements for Ca
Ca digestibility and utilisation in growing pigs are not well understood , and are usually neglected in diet formulation .
This has implication s not only for the accurate determination of its requirements but also for its interactions with other nutrients .
A systematic review and meta- analysis ( meta-regression ) of published trials was carried out to quantify factors affecting Ca absorption and utilisation , and to derive an estimate of Ca endogenous excretion .