282 Effect of formulating diets based on a ratio between STTD Ca and STTD P and the inclusion of phytase on the calcium and phosphorus balance of growing pigs. (30th November 2020)

• Record Type: Journal Article
• Authors: Lagos, Vanessa; Bedford, Mike R; Stein, Hans H
• Is Part Of: Journal of animal science. Volume 98(2020)Supplement 3
• Page Start: 103
• Page End: 104
• Publication Date: 2020-11-30
• Subjects: calcium and phosphorus balance -- digestible calcium -- requirements for pigs; Livestock -- Periodicals; Livestock; Electronic journals; Periodicals; 636.005
• DOI: 10.1093/jas/skaa054.177
• Languages: English
• ISSNs: 0021-8812

Abstract

Abstract: An experiment was conducted to test the hypothesis that formulating diets for pigs based on a ratio between standardized total tract digestible (STTD) Ca and STTD P instead of total Ca and STTD P increases the efficiency of Ca and P utilization. Forty barrows (59.4 ± 3.8 kg) were individually housed in metabolism crates and allotted to 4 corn-soybean meal diets and 2 periods of 11 d in a randomized complete block design. Diets were formulated using a 2 × 2 factorial design with 2 Ca requirement estimates (total Ca or STTD Ca) and 2 inclusion levels of microbial phytase (0 or 500 units/kg). Phytase was assumed to release 0.11% STTD P and 0.16% total Ca. Diets were formulated based on requirements for total Ca and STTD P and the ratio between STTD Ca and STTD P was 1.25:1 in diets formulated based on STTD Ca. Fecal and urine samples were collected from feed provided from d 6 to 9. Data for Ca and P balance were analyzed using a model that included the main effects of diet formulation and phytase level, the interaction between main effects, and the random effect of period. Interactions (P < 0.05) between diet formulation and phytase level were observed for Ca intake, Ca in feces, Ca digestibility, Ca retained as a percentage of intake, P digestibility, P absorbed, and P in urine (Table 1). Despite being provided less (P < 0.05) Ca, pigs fed diets formulated based on STTD Ca did not absorb or retain less Ca than pigs fed total Ca diets, but they absorbed more (P < 0.05) P than pigs fed diets formulated based on total Ca. In conclusion, by formulating diets based on values for STTD Ca, P absorption was increased confirming detrimental effects of oversupplying Ca.