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 .
Particle size of calcium carbonate does not affect apparent and standardized total tract digestibility of calcium, retention of calcium, or growth performance of growing pigs.
Two experiments were conducted to evaluate particle size of calcium carbonate used in diets fed to growing pigs . Experiment 1 was conducted to determine apparent total tract digestibility ( ATTD ) , st and ardized total tract digestibility ( STTD ) , and retention of Ca among diets containing calcium carbonate produced to different particle sizes , and Exp . 2 was conducted to determine if growth performance of weanling pigs is affected by particle size of calcium carbonate . In Exp . 1 , 4 diets based on corn and potato protein isolate were formulated to contain 0.70 % Ca and 0.33 % st and ardized total tract digestible P , but the calcium carbonate used in the diets was ground to 4 different particle sizes ( 200 , 500 , 700 , or 1,125 μm ) . A Ca-free diet was formulated to determine basal endogenous losses of Ca . In Exp . 2 , 4 diets were based on corn and soybean meal and the only difference among diets was that each diet contained calcium carbonate ground to the 4 particle sizes used in Exp . 1 . In Exp . 1 , 40 barrows ( 15.42 ± 0.70 kg initial BW ) were allotted to the 5 diets with 8 replicate pigs per diet using a r and omized complete block design , and in Exp . 2 , 128 pigs with an initial BW of 9.61 ± 0.09 kg were r and omly allotted to 4 experimental diets . Results of Exp . 1 indicated that basal endogenous losses of Ca were 0.329 g/kg DMI . The ATTD of Ca was 70.0 ± 3.2 , 74.3 ± 2.7 , 70.0 ± 2.9 , and 72.1 ± 2.7 and the STTD of Ca was 74.2 ± 3.2 , 78.5 ± 2.7 , 74.1 ± 2.9 , and 76.2 ± 2.7 for calcium carbonate ground to 200 , 500 , 700 , or 1,125 μm , respectively . Retention of Ca was 67.4 ± 3.1 , 70.4 ± 2.6 , 63.9 ± 2.8 , and 67.2 ± 2.2 for diets containing calcium carbonate ground to 200 , 500 , 700 , or 1,125 μm , respectively . There were no differences among diets for ATTD of Ca , STTD of Ca , or retention of Ca . The ATTD of P was 64.5 ± 1.7 , 66.8 ± 2.6 , 64.2 ± 3.0 , and 63.2 ± 1.7 % and retention of P was 61.4 ± 1.4 , 63.8 ± 2.8 , 61.9 ± 2.8 , and 60.9 ± 1.5 for diets containing calcium carbonate ground to 200 , 500 , 700 , or 1,125 μm , respectively . Neither ATTD of P nor retention of P was influenced by the particle size of calcium carbonate . Results of Exp . 2 indicated that ADG , ADFI , and G : F were not impacted by the particle size of calcium carbonate . In conclusion , particle size of calcium carbonate did not affect ATTD of Ca , STTD of Ca , or retention of Ca ; ATTD of P or retention of P ; or growth performance of pigs . Any particle size of calcium carbonate in the range from 200 to 1,125 μm can therefore be used in diets fed to pigs
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 .