Standardized total tract digestibility of calcium varies among sources of calcium carbonate, but not among sources of dicalcium phosphate, but microbial phytase increases calcium digestibility in calcium carbonate1

Abstract

Two experiments were conducted to test the hypothesis that standardized total tract digestibility (STTD) of Ca and the response to microbial phytase is constant among different sources of Ca carbonate and that the STTD of Ca is constant among different sources of dicalcium phosphate (DCP) when fed to growing pigs. In Exp. 1, 80 pigs (initial BW: 19.0 ± 1.9 kg) were randomly allotted to 10 diets and 2 blocks with 4 pigs per diet in each block. Four sources of Ca carbonate were used, and each source was included in a diet without microbial phytase and a diet with microbial phytase (500 units/kg diet). Two Ca-free diets without or with microbial phytase were also formulated. Feed allowance was 2.7 times the maintenance energy requirement for ME and daily feed allotments were divided into 2 equal meals. The initial 4 d of each period were considered the adaptation period to the diets followed by 4 d of fecal collection using the marker-to-marker procedure. Pigs fed diets containing exogenous phytase had lower (P < 0.05) basal endogenous loss of Ca compared with pigs fed diets containing no phytase. There were no interactions between phytase and source of Ca carbonate. Values for STTD of Ca were greater (P < 0.05) for diets containing microbial phytase (77.3% to 85.4%) compared with diets without exogenous phytase (70.6% to 75.2%), and values for STTD of Ca differed (P < 0.05) among the 4 sources of Ca carbonate. In Exp. 2, 40 pigs (initial BW: 14.9 ± 1.3 kg) were allotted to a completely randomized design with 5 diets and 8 replicate pigs per diet. A basal diet in which all Ca was supplied by Ca carbonate was formulated. Three diets were formulated by adding 3 sources of DCP to the basal diet and a Ca-free diet was also used. Feeding and collection methods were as described for Exp. 1. Results indicated that values for STTD of Ca and ATTD of P were not different among diets, indicating that under the conditions of this experiment, the digestibility of Ca and P in DCP appears to be constant regardless of origin of DCP. In conclusion, use of microbial phytase reduces the basal endogenous loss of Ca and increases Ca digestibility in Ca carbonate. The STTD of Ca varies among sources of Ca carbonate, regardless of phytase inclusion, but that appears not to be the case for the STTD of Ca in different sources of DCP.

— Invited Review — Mineral composition and phosphorus digestibility in feed phosphates fed to pigs and poultry

“…The STTD of Ca in feed ingredients has been determined because digestible Ca is more additive in mixed diets if values are corrected with endogenous losses [ 50 ]. Use of exogenous phytase may increase the STTD of Ca in calcium carbonate and some other feed ingredients, but that is not the case for the STTD of Ca in MCP and DCP [ 51 , 52 ]. However, the STTD of Ca in feed phosphates has been determined only in a few experiments.…”

“…However, because of the greater concentration of Ca in DCP than in MCP, the concentration of standardized total tract digestible Ca in DCP is close to that in MCP. Variations in the STTD of Ca among different sources of DCP and MCP appear to be low [ 52 ].…”

Addition of calcitic seaweed in the diet of sows positively affects the number of live-born piglets and milk parameters

“…This is likely due to greater demand in late gestation for the end of piglet formation and milk production (Mellagi et al, 2013). Moreover, calcium total tract digestibility is altered in late pregnancy, which interferes with plasma calcium concentration (Lagos et al, 2019;Lee et al, 2019).…”