Comparative evaluation of the efficacy of cereal and microbial phytases in growing pigs fed diets with marginal phosphorus supply

Abstract

Two experiments with a total of 76 growing pigs (average initial body weight 16.6 kg) were conducted to compare the efficacy of cereal phytases (wheat and rye) and supplemented microbial phytase (Natuphos 1 ). Using the slope ratio technique, the dose-response relationship between five levels of phytase (0, 50, 100, 150 and 200 U kg À1 ) and the apparent absorption of phosphorus (P) within each source of phytase was calculated. Graded phytase levels in the diets were obtained by adding increasing amounts of microbial phytase or phytase-containing wheat (Exp 1) or rye (Exp 2) to phytase-inactivated basal diets at the expense of phytase-inactivated wheat (Exp 1) or rye (Exp 2). Except for wheat phytase, addition of phytase to the basal diets increased (P < 0.05) apparent P absorption, with microbial phytase being more efficient (P < 0.05) than cereal phytase. There were no significant differences in apparent P absorption between the wheat-or rye-based diets when either microbial or cereal phytases were supplemented from 0 to 200 U kg À1 . It could be derived from the results of this study, by means of regression analysis, that the efficacy of cereal phytases was 40% compared to microbial phytase.

Influence of feeding level and dietary oil supplementation on apparent ileal and total tract digestibilities of phosphorus and calcium in pigs fed low-phosphorus diets supplemented with microbial or wheat phytase

“…This observation is in general agreement with previous reports in which digestibilities were measured either over the total tract (Eeckhout and De Paepe 1992;Zimmermann et al 2002;Steiner et al 2004) or at the ileal level (Rapp et al 2001a). In contrast to these reports, the present study allows for a direct comparison of digestibility coefficients for P and Ca determined both at the ileal and total tract level.…”

“…The total P supply was below the actual requirement of the animals to exclude or at least to minimize the influence of homeostatic regulation (decreased absorption, increased urinary excretion of P) on P metabolism (Zimmermann et al 2002). The diets were formulated to contain 600 U kg -1 phytase, supplemented either as microbial (Natuphos ® 5000 G, Diet A) or native wheat phytase (Diet B).…”

“…Additionally, there are several reports that describe the potential of native plant phytases to hydrolyze phytate. However, in comparison with microbial phytase, plant phytase has proven to be less efficient in hydrolyzing phytate under in vivo conditions (e.g., Eeckhout and De Paepe 1992;Zimmermann et al 2002;Steiner et al 2004). The efficacy of microbial or plant phytase is affected by various factors.…”

Activity of phytate dephosphorylation in cereals, legumes and oilseeds determined by colourimetric and isotachophoretic method

“…by feeds with high phytase activity. In experiment of Zimmermann et al (2002), however, cereal phytases were less efficient in pigs than microbial Natuphos ® phytase as 2.5 U of cereal phytase from wheat or rye were needed to replace 1 U of microbial phytase. This was probably caused by a negative effect of low pH, pepsin and pancreatin in the gastrointestinal tract on the intrinsic activity of grains.…”

<b>Intestinal carbohydrase activity and sodium-glucose transporter expression in layers fed diets containing wheat and rice brans supplemented with phytase

“…Due to low content of available phosphorous in these ingredients and the low endogenous phytase activity in birds (Rapp, Lantzsch, & Drochner, 2001;Zimmermann et al, 2002), diets must be supplemented with enzyme phytase. Also, with their high phytate P content, wheat and rice brans are excellent candidates for phytase application in diets.…”