TY - JOUR
T1 - Wheat and barley increase phytate degradation and phosphorus digestibility in corn fed to pigs
AU - Poulsen, H. D.
AU - Voergaard, A. L.
AU - Strathe, A. B.
AU - Blaabjerg, K.
PY - 2019/2
Y1 - 2019/2
N2 - Two experiments evaluated the additivity of phytate content and coefficient of total tract apparent digestibility (CTTAD) of phosphorus (P) in wheat-barley (WB) and corn (C) when soaked (exp. 1) or fed dry to pigs (exp. 2) in combination with or without microbial phytase (1250 FTU/kg as-fed). In exp. 1, WB (1:1, w/w) and C were soaked separately or together (W:B:C = 1:1:2, w/w/w) without (WBC) or with microbial phytase (WBC+phy). Phytate content was affected by the interaction between diet and soaking time (P<0.0001) as phytate decreased with time. The decrease was greatest for WBC+phy followed by WBC, WB and C resulting in a half-life of phytate (K) of 8.7, 15.8, 24.4 and 303.4 h, respectively. Soaking of WB and C together showed non-additive effects as the estimated (assuming additivity) phytate content at 2, 4, 8 and 24 h of soaking was 0.17, 0.34, 0.42 and 0.5 g/kg DM higher (P<0.001) than the experimentally determined phytate content in WBC. Actually, phytate degradation in C was estimated to be 0.15, 0.30, 0.42 and 0.49 higher at 2, 4, 8 and 24 h, respectively, when soaked together with WB than when soaked alone. Accordingly, the estimated (assuming additivity) K-value for WBC was 148 h longer (P=0.08) than the K-value derived from the experimentally determined phytate degradation in WBC. Exp. 2 comprised 24 pigs of 47 ± 2 kg from 6 litters. Pigs were housed in metabolism crates and fed one of four diets (WB, C, WBC or WBC + phy) for 12 days; 5 days adaptation and 7 days total collection of feces and urine. The CTTAD of P was greatest for WBC + phy followed by WB, WBC and C (P<0.0001). Feeding WB and C in combination tended to show non-additive effects as the estimated (assuming additivity) CTTAD of P in WBC was 7.7 percentage units lower (P=0.09) than the experimentally determined CTTAD of P in WBC. In fact, CTTAD of P in C was estimated to be 14.6 percentage units higher when fed together with WB than alone. In conclusion, phytases present in W and B are non-specific and catalyze the degradation of phytate in C when soaked or fed dry together (ratio 1:1:2). Thus, when phytate rich cereals very different in plant phytase activity, are mixed, additivity cannot be assumed.
AB - Two experiments evaluated the additivity of phytate content and coefficient of total tract apparent digestibility (CTTAD) of phosphorus (P) in wheat-barley (WB) and corn (C) when soaked (exp. 1) or fed dry to pigs (exp. 2) in combination with or without microbial phytase (1250 FTU/kg as-fed). In exp. 1, WB (1:1, w/w) and C were soaked separately or together (W:B:C = 1:1:2, w/w/w) without (WBC) or with microbial phytase (WBC+phy). Phytate content was affected by the interaction between diet and soaking time (P<0.0001) as phytate decreased with time. The decrease was greatest for WBC+phy followed by WBC, WB and C resulting in a half-life of phytate (K) of 8.7, 15.8, 24.4 and 303.4 h, respectively. Soaking of WB and C together showed non-additive effects as the estimated (assuming additivity) phytate content at 2, 4, 8 and 24 h of soaking was 0.17, 0.34, 0.42 and 0.5 g/kg DM higher (P<0.001) than the experimentally determined phytate content in WBC. Actually, phytate degradation in C was estimated to be 0.15, 0.30, 0.42 and 0.49 higher at 2, 4, 8 and 24 h, respectively, when soaked together with WB than when soaked alone. Accordingly, the estimated (assuming additivity) K-value for WBC was 148 h longer (P=0.08) than the K-value derived from the experimentally determined phytate degradation in WBC. Exp. 2 comprised 24 pigs of 47 ± 2 kg from 6 litters. Pigs were housed in metabolism crates and fed one of four diets (WB, C, WBC or WBC + phy) for 12 days; 5 days adaptation and 7 days total collection of feces and urine. The CTTAD of P was greatest for WBC + phy followed by WB, WBC and C (P<0.0001). Feeding WB and C in combination tended to show non-additive effects as the estimated (assuming additivity) CTTAD of P in WBC was 7.7 percentage units lower (P=0.09) than the experimentally determined CTTAD of P in WBC. In fact, CTTAD of P in C was estimated to be 14.6 percentage units higher when fed together with WB than alone. In conclusion, phytases present in W and B are non-specific and catalyze the degradation of phytate in C when soaked or fed dry together (ratio 1:1:2). Thus, when phytate rich cereals very different in plant phytase activity, are mixed, additivity cannot be assumed.
KW - Additivity
KW - Liquid feeding
KW - Phosphorus
KW - Phytase
KW - Phytate
KW - Pig
KW - PLANT
KW - ACID
KW - RAPID-DETERMINATION
KW - MICROBIAL PHYTASE
KW - TIME
KW - SOYBEAN-MEAL
KW - CALCIUM
KW - PH
KW - FEED
UR - http://www.scopus.com/inward/record.url?scp=85059681293&partnerID=8YFLogxK
U2 - 10.1016/j.anifeedsci.2018.12.006
DO - 10.1016/j.anifeedsci.2018.12.006
M3 - Journal article
AN - SCOPUS:85059681293
SN - 0377-8401
VL - 248
SP - 77
EP - 84
JO - Animal Feed Science and Technology
JF - Animal Feed Science and Technology
ER -