Poultry Feeding Trial

To determine the efficacy of feed supplementation with phytase produced in transgenic soybeans, a three-week poultry feeding trial was conducted 38 . Graded levels of phytase were added to a basal poultry diet as either milled transgenic soybeans or as a commercially available enzyme supplement (Natuphos ). To generate transgenic soybean plants, Asgrow A5403 soybeans were transformed with expression vector pWR2787 by the method of McCabe et al. 39 at Agracetus (Middleton, WI). Plasmid pWR2787...

Phytates Introduction

Grain and legume crops have two main uses in human foods and in animal feeds. To be effective, estimations of the impacts of grain and legume phytic acid, and the development of strategies to deal with these impacts, probably need to take into consideration both of these major uses of staple crops. In the case of livestock production, the concerns over grain and legume phytic acid are relatively straightforward 1,2 . Nonruminants such as poultry, swine, and fish, excrete essentially all feed...

Phytic Acid Biosynthesis

INS(3)Pi AS THE FIRST STEP IN PHYTIC ACID BIOSYNTHESIS An important contribution regarding the first step in InsP6 biosynthesis was made by Yoshida et al. 64 , whose group isolated a cDNA clone, pRINO1, from rice (Oryza sativa L.) callus suspension cultures, that was highly homologous to Ins(3)Pi synthase from yeast and plants 38 . Its transcript appeared in the apical region of globular-stage embryos two days after anthesis, and strong signals were detected in the scutellum and aleurone...

Fermentation And Bread Making

Many cereals and legumes are extensively used in the preparation of a variety of fermented foods 13,14 . Microbes used in these fermentations may be natural microflora commonly found in the cereal legume that are fermented or specially cultivated cultures designed to bring about specific changes in the cereal legume that is being fermented. The type of microorganism, the fermentation conditions used, and the starting amount of phytate present in the raw material significantly affect the extent...

Degradation Of Phytate In The Stomach And Small Intestine

Few studies have been performed to determine hydrolysis of phytate in the stomach. It is likely that consumption of raw plant foods may lead to some hydrolysis in the stomach, as the enzyme phytase is present, and in particular, cereal phytase activity increases when the pH is lowered. Investigating hydrolysis of inositol phosphates in the stomach of slaughtered pigs showed that approximately 50 of the feed InsP6 was hydrolyzed 51 . This hydrolysis was probably a result of activity of the...

Conclusions

Through the mid 1980s, phytate was regarded strictly as a dietary inhibitor of mineral absorption. More recently, studies indicate that phytic acid is a natural antioxidant important for seed viability. Evidence also indicates that the inhibitory effects of phytate on mineral absorption are not seen in varied diets containing animal protein. Phytate may actually be beneficial as a dietary an-tioxidant in an animal protein diet. There may be nutritional advantages, or at least no disadvantage,...

Making A Global Estimate

Global estimates are very useful but not perfect. Oerke et al. 22 in discussing this point, concluded that because the data can always be improved, the only alternative to an imperfect estimate is no estimate at all. The global estimates of P and PA in crop grains seeds fruits 1 , parts of which are summarized here, made detailed notations of where data came from, what assumptions were used to fill in missing information, and what calculations were used to calculate phytic acid concentrations...

References

A resume of the literature on inosite phosphoric acid with special reference to the relation of that substance to plants. Biochem. Bull. 2 21-49. 2. Averill, H.P. and King, C.G. 1926. The phytin content of foodstuffs. J. Amer. Chem. Soc. 48 724-728. 3. Harland, B.F. and Oberleas, D. 1987. Phytate in foods. World Rev. Nutr. Diet. 52 235-259. 4. Reddy, N.R., Pierson, M.D., Sathe, S.K., and Salunkhe, D.K. 1989. Phytates in Cereals and Legumes. CRC Press, Inc., Boca Raton, FL. 5....

Phytatemineral Interactions

The effect of phytate on mineral bioavailability has been the focus of numerous research studies and the subject of extensive reviews 2-7 . Phytic acid has a potential for binding positively charged proteins, amino acids, and or multivalent cations or minerals in foods Figure 13.1 . The resulting complexes are insoluble, difficult for humans to hydrolyze during digestion, and thus, typically are nutritionally less available for absorption. Phytate forms chelating conjugates with nutritionally...