Hydrolysis of phytic acid by intrinsic plant and supplemented microbial phytase (Aspergillus niger) in the stomach and small intestine of minipigs fitted with re‐entrant cannulas

Abstract

Hydrolysis of phytate in the stomach and the small intestine as influenced by intrinsic plant (wheat) and supplemented microbial phytase (A. niger) were investigated with six minipigs (40-50 kg initial BW) fitted with re-entrant cannulas in the duodenum, 30 cm posterior to the pylorus (animals 1, 4, 5, and 6) and ileocecal re-entrant cannulas, 5 cm prior the ileocecal junction (animals 1, 2, and 3), respectively. Dietary treatments were as follows: (1) diet 1, a corn-based diet (43 U phytase/kg DM); (2) diet 2, diet 1 supplemented with microbial phytase (818 U/kg DM) and (3) diet 3, a wheat-based diet (1192 U/kg DM). At 0730 and 1930 per animal 350 g diet mixed with 1050 ml de-ionized water were fed. Digesta were collected continuously and completely during 12 h after feeding. In the duodenal digesta, 70% of the microbial phytase (diet 2) and 45% of the wheat phytase (diet 3) were recovered within 12 h after ingestion of the phytases, whereas only negligible amounts were detected in the digesta of pigs fed the phytase-poor corn-based diet 1. Most phytase activity passed through the stomach within the first hour after feeding. Microbial phytase activity at pH 2.8 was less sensitive to acidic pHs, such as those found in the stomach, than phytase activity at pH 5.3. Phytase activities in the digesta of the distal ileum did not depend either on source or amount of dietary phytase activity.

Endosperm-Specific Co-Expression of Recombinant Soybean Ferritin and Aspergillus Phytase in Maize Results in Significant Increases in the Levels of Bioavailable Iron

“…When added to feed preparations at a final concentration of 1200 FTU/kg, this supplement can enhance iron uptake in pigs . Similarly, Aspergillus phytase at a concentration of 818 FTU/kg has been shown to hydrolyze phytate effectively in the stomach and intestines of miniature pigs (Rapp et al, 2001).…”

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

“…Furthermore, there is a reduction in wheat phytase activity of 30% in the presence of pepsin, whereas the activity of Aspergillus phytase decreases by 5% only (Phillippy 1999). In studies by Rapp et al (2001b) with minipigs, the recovery of microbial phytase in duodenal digesta was 70%, whereas that of wheat phytase amounted to 45% only.…”

“…In contrast, microbial phytase originating from Aspergillus remains almost completely active at pH 2.0 (Phillippy and Mullaney 1997). Thus, conditions in the stomach are more favorable for microbial rather than plant phytases (Rapp et al 2001b). Furthermore, there is a reduction in wheat phytase activity of 30% in the presence of pepsin, whereas the activity of Aspergillus phytase decreases by 5% only (Phillippy 1999).…”

Characterisation of European varieties of triticale with special emphasis on the ability of plant phytase to improve phytate phosphorus availability to chickens

“…The acidic pH of the gizzard inactivates plant phytase in contrast to protected microbial phytase and consequently plant phytase activity is limited to the crop (Frapin, 1996). Moreover, plant phytase may be more sensitive to the presence of pepsin than 3-phytase (Rapp et al, 2001).…”