Cowieson A J, Ravindran V
Danisco Animal Nutrition, Marlborough, Wiltshire, SN8 1XN UK.
Br J Nutr. 2007 Oct;98(4):745-52. doi: 10.1017/S0007114507750894. Epub 2007 May 25.
The effects of phytic acid and microbial phytase on the flow and composition of endogenous protein at the terminal ileum of broiler chickens were investigated using the peptide alimentation method. Phytic acid (fed as the sodium salt) was included in a synthetic diet at 8.5, 11.5 and 14.5 g/kg (or 2.4, 3.2 and 4.0 g/kg phytate-phosphorus) and each diet was fed without or with an Escherichia coli-derived microbial phytase at 500 phytase units/kg diet. A control containing no phytate was fed as a comparison to estimate basal endogenous flows. Ingestion of phytic acid increased (P < 0.05) the flow of endogenous amino acids and N by an average of 47 % at the lowest phytic acid concentration and 87 % at the highest. The addition of microbial phytase reduced (P < 0.05) the inimical effects of phytic acid on endogenous amino acid flow at all dietary phytic acid levels. The composition of endogenous protein was also influenced (P < 0.10-0.001) by increasing phytic acid concentrations and phytase addition. The effects of phytic acid and phytase on endogenous flow and composition of endogenous protein, however, varied depending on the amino acid. It is concluded that the effects of phytase on amino acid digestibility may be mediated, in part, through a route of reduced endogenous loss.
采用肽营养法研究了植酸和微生物植酸酶对肉鸡回肠末端内源蛋白质流量和组成的影响。在合成日粮中分别添加8.5、11.5和14.5 g/kg（即2.4、3.2和4.0 g/kg植酸磷）的植酸钠，每种日粮分别不添加或添加500单位/kg日粮的大肠杆菌源微生物植酸酶。饲喂不含植酸盐的对照日粮以估计基础内源流量。摄入植酸使内源氨基酸和氮的流量增加（P<0.05），在最低植酸浓度下平均增加47%，在最高浓度下增加87%。添加微生物植酸酶降低了（P<0.05）所有日粮植酸水平下植酸对内源氨基酸流量的有害影响。植酸浓度的增加和植酸酶的添加也对内源蛋白质的组成产生了影响（P<0.10 - 0.001）。然而，植酸和植酸酶对内源流量和内源蛋白质组成的影响因氨基酸而异。得出的结论是，植酸酶对氨基酸消化率的影响可能部分通过减少内源损失的途径来介导。
