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Dietary phytate (inositol hexaphosphate) regulates the activity of intestinal mucosa phytase
Author(s) -
Onyango E. M.,
Adeola O.
Publication year - 2009
Publication title -
journal of animal physiology and animal nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.651
H-Index - 56
eISSN - 1439-0396
pISSN - 0931-2439
DOI - 10.1111/j.1439-0396.2008.00850.x
Subject(s) - phytase , casein , food science , sucrase , intestinal mucosa , bone ash , calcium , phytic acid , chemistry , composition (language) , alkaline phosphatase , biology , biochemistry , enzyme , medicine , linguistics , philosophy , organic chemistry
Summary The role of dietary phytate (inositol hexaphosphate) in the regulation of intestinal mucosa phytase was investigated in chicks. Seven‐day‐old chicks were grouped by weight into six blocks of three cages with six birds per cage. Three purified diets [a chemically defined casein diet, a chemically defined casein diet plus sodium phytate (20 g/kg diet) and a chemically defined casein diet plus sodium phytate (20 g/kg diet) and microbial phytase (1000 units/kg diet)] were randomly assigned to cages within each block. Chicks were fed experimental diets from 8 to 22 days of age then killed, and duodenal mucosa and left tibia removed. Phytase activity in duodenal mucosa, growth performance and bone ash content were determined. Addition of phytate to the chemically defined casein diet reduced (p < 0.05) the V max of the duodenal brush border phytase, but the K m of the enzyme was not affected. Addition of phytate also reduced (p < 0.05) weight gain, feed intake, feed efficiency and percentage ash. Addition of microbial phytase fully restored the feed efficiency (p < 0.05), but V max and body weight gain were only partially restored (p < 0.05). In conclusion, it would seem that dietary phytates non‐competitively inhibit intestinal mucosa phytase.