305 Effects of Super-Dosing Phytase and Inositol Supplementation on Growth Performance and Blood Metabolites of Weaned Pigs Housed Under Commercial Conditions. (10th April 2018)

• Record Type: Journal Article
• Authors: Moran, K; Boyd, R D; Zier-Rush, C E; Elsbernd, A J; Wilcock, P; van Heugten, E
• Is Part Of: Journal of animal science. Volume 96(2018)Supplement 2
• Page Start: 164
• Page End: 164
• Publication Date: 2018-04-10
• Subjects: phytase -- inositol -- plasma inositol; Livestock -- Periodicals; Livestock; Electronic journals; Periodicals; 636.005
• DOI: 10.1093/jas/sky073.302
• Languages: English
• ISSNs: 0021-8812

Abstract

Abstract: This study was designed to evaluate if improvements in growth performance associated with super-dosing phytase can be explained by the liberation of inositol through the near complete dephosphorylation of phytate. A total of 2, 156 barrows and gilts (BW 6.75 ± 0.11 kg) were used in a 42 d study. Two phytase doses (0 and 2, 500 FTU/kg; Quantum Blue, AB Vista) and 3 inositol levels (0, 0.15 and 0.30%) were arranged to create 6 dietary treatments. Pigs were placed in a total of 98 pens (22 pigs per pen: 16 to 17 pens per treatment) and fed a 3-phase feeding program, with each period being 10, 10 and 22 d, respectively. Blood samples were collected on d 0, 21 and 42 from a subset of 48 pigs (8 pigs per treatment) to determine serum concentrations of P, K, Ca, Mg, Zn, Fe, S and Cu and plasma concentrations of inositol. Data were analyzed as a RCBD in a 2 × 3 factorial arrangement of treatments. During phase 1, increasing inositol in diets without supplemental phytase linearly (P<0.001) improved the G:F ratio (1022, 1040, and 1089 g/kg for 0, 0.15 and 0.30% inositol, respectively), but not in pigs supplemented with phytase (1102, 1087, and 1076, g/kg for 0, 0.15 and 0.30% inositol, respectively; P=0.015, interaction). During phase 2, increasing dietary inositol increased ADFI in diets without supplemental phytase only (interaction, P=0.01; 589, 600, and 612 g/d and 627, 626 and 607 g/d for 0, 0.15 and 0.30% inositol, respectively). Super-dosing phytase to diets without inositol improved (P<0.001) G:F (1102 vs. 1022 g/kg) during phase 1 and improved (P < 0.001) ADG (479 vs. 461 g/d) during phase 2. Phytase increased serum Zn on d 21, but not on d 42 (interaction, P=0.008). Phytase increased serum Cu (2.06 vs. 1.82 mg/L) and reduced serum Fe (0.72 vs. 1.15 mg/L), regardless of day of measurement (P<0.05). Dietary inositol linearly increased plasma inositol concentrations (66.9, 97.1 and 113.2 nmol/mL, respectively; P<0.001), regardless of phytase supplementation. Super-dosing phytase to diets without inositol tended to increase (P=0.064) plasma inositol concentrations (81.4 vs. 56.5 nmol/mL) on d 42. Results suggest that the improvement in performance when applying super-dosing levels of phytase may be partially linked to inositol production and that inositol (supplemented or liberated by phytase) had a greater metabolic impact in piglets immediately after weaning. This suggests that inositol may be conditionally essential for young pigs during the stress of weaning.