Effect of phytase on intestinal phytate breakdown, plasma inositol concentrations, and glucose transporter type 4 abundance in muscle membranes of weanling pigs1

Abstract

The objective of this present study was to determine the effects of phytase dosing on growth performance, mineral digestibility, phytate breakdown, and the level of glucose transporter type 4 (GLUT4) in muscle plasma membranes of weanling pigs. A total of 160 barrows were used in a randomized completely block design and assigned to 4 treatments for a 7-wk study. Depending on the feeding phase, diets differed in dietary calcium (Ca) and phosphorus (P) levels (positive control [PC]: 8 to 6.8g/kg Ca; 7.3 to 6.3 g/kg P; negative control [NC]: 5.5 to 5.2 g/kg Ca; 5.4 to 4.7 g/kg P). NC diets were supplemented with phytase at 0 (NC); 500 (NC + 500 FTU); or 2,000 FTU/kg (NC + 2,000 FTU) phytase units/kg. Blood was collected after fasting (day 48) or feeding (day 49) for measurement of plasma inositol concentrations. On day 49, 2 pigs per pen were euthanized, and duodenal and ileal digesta samples were collected to determine inositol phosphates (InsP6-2) concentrations. High phytase supplementation increased BW on days 21, 35, and 49 (P < 0.05). Over the entire feeding period, ADG, ADFI, and feed efficiency were increased by NC + 2,000 FTU compared with the other treatments (P < 0.05). Postprandial plasma inositol concentration was increased in NC + 2,000 (P < 0.01), but there was only a tendency (P = 0.06) of a higher fasting plasma inositol concentration in this group. Inositol concentrations in the portal vein plasma (day 49) were not different among treatments. Duodenal digesta InsP5 and InsP6 concentrations were similar in PC and NC, but higher in these 2 treatments (P < 0.05) than those supplemented with phytase. Phytase supplementation decreased InsP6-4, resulting in increased InsP3-2 and myo-inositol concentrations. Similar effects were found in ileal contents. Compared with NC, phytase supplementation resulted in greater cumulative InsP6-2 disappearance (93.6% vs. 72.8% vs. 25.0%, for NC + 2,000 FTU, NC + 500 FTU and NC, respectively, P < 0.01) till the distal ileum. Longissimus dorsi muscle plasma membrane GLUT4 concentration was increased by NC + 2,000 FTU (P < 0.01) compared with NC. In summary, high phytase supplementation increased growth performance of nursery pigs. The higher myo-inositol release from phytate could contribute to the increased expression of GLUT4 in muscle plasma membranes. Further investigation is needed to determine whether this is associated with enhanced cellular glucose uptake and utilization.

Supplemental Effects of Phytase on Modulation of Mucosa-Associated Microbiota in the Jejunum and the Impacts on Nutrient Digestibility, Intestinal Morphology, and Bone Parameters in Broiler Chickens

“…Phytase supplementation for broiler diets has been associated with improvements in growth performance, nutrient digestibility, bone parameters, and its efficacy has been established with a large number of studies over time [ 8 , 22 , 34 , 35 ]. Recently, the study of the mucosa-associated microbiota in the jejunum has gained more attention due to the relevance for the metabolism of nutrients, stimulation of immune response, protection from pathogens, and stimulation of epithelium cell proliferation of the animals [ 25 , 36 ].…”

“…However, monogastric animals do not produce endogenous phytase and, consequently, the P content in the phytic acid form is not available for utilization by poultry [ 4 , 5 ]. Furthermore, phytic acid can also bind to proteins and enzymes like trypsin and α-amylase, inhibiting their activity and lowering protein and carbohydrate digestibility [ 6 , 7 , 8 ]. The undigested nutrients would be eliminated via excreta by the animals, raising an environmental concern [ 9 ].…”

Application of Creep Feed and Phytase Super-Dosing as Tools to Support Digestive Adaption and Feed Efficiency in Piglets at Weaning

“…These performance responses were matched or exceeded with appropriate phytase supplementation. In addition, recent studies have reported a dose-dependent increase in phytate disappearance and myo-inositol concentrations in intestinal digesta of piglets with phytase [14,15,55,56]. Free myo-inositol is absorbed and can be detected in both portal and peripheral blood of pigs [15,52,56,57].…”

“…Typically phytases have been added to diets at a standard rate of 500 FTU/kg to target a moderate release of available P [12]. However, it has been demonstrated that using super-doses of phytase, at 3 to 5 times higher than the standard phytase dose, can lead to growth responses beyond what would be expected from the additional release of P [13][14][15]. A study in broilers suggested that 30 to 35% of the super-dosing response could be attributed to the generation of myo-inositol from the complete dephosphorylation of phytate [16].…”

Phytase dosing affects phytate degradation and Muc2 transporter gene expression in broiler starters

“…The relative composition of the membrane phospholipids phosphatidylserine, phosphatidylinositol, phosphatidylcholine, and phosphatidylethanolamine affects membrane properties such as fluidity and receptor expression ( Fajardo et al., 2011 ). Indeed, our study in pigs ( Lu et al., 2019 ) showed that phytase supplementation increased the expression of GLUT4 in the longissimus dorsi muscle. Others have shown that phytase supplementation increased expression of sodium-dependent MI transporter, SMIT2, in the jejunum of chickens ( Walk et al., 2018 ).…”