Details

Autor(en) / Beteiligte

• Moran, K
• Wilcock, P
• Elsbernd, A
• Zier-Rush, C
• Boyd, R D
• van Heugten, E

Titel

Effects of super-dosing phytase and inositol on growth performance and blood metabolites of weaned pigs housed under commercial conditions

Ist Teil von

• Journal of animal science, 2019-07

Ort / Verlag

United States

Erscheinungsjahr

2019

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• A total of 2,156 weaned pigs (6.75±0.11 kg BW) were used in a 42-d study to evaluate if improvements in growth performance associated with super-dosing phytase can be explained by the complete dephosphorylation of phytase and liberation of inositol. Two phytase doses (0 and 2,500 FTU/kg) and 3 inositol concentrations (0, 0.15 and 0.30%) were combined to create 6 dietary treatments in a 2 x 3 factorial arrangement. Pigs were fed a 3-phase feeding program, with periods being 10, 10 and 22 d, respectively. Blood samples were collected on d 0, 21 and 42 from a subset of 48 pigs to analyze mineral and myo-inositol concentrations. During Phase 1, super-dosing phytase tended to improve ADG compared to pigs fed diets without phytase (P=0.09). Increasing concentrations of inositol improved the efficiency of gain in pigs fed diets without phytase (1022.1, 1040.9, and 1089.2 g/kg), but not diets with phytase (1102.2, 1087.2, and 1076.2 g/kg) and this improvement was equivalent to that observed with super-dosing phytase in the absence of inositol (interaction, P=0.015). During Phase 2, super-dosing phytase improved ADG (P=0.001), resulting in heavier BW (P=0.007). During Phase 3 and overall, inositol supplementation increased ADG and ADFI in a quadratic manner (P<0.10), with the highest ADG and ADFI observed for pigs fed 0.15% of inositol. Super-dosing phytase increased serum Zn on d 21 but not on d 42 (interaction, P=0.008), increased serum Cu (P=0.01), but decreased serum Fe (P=0.02). Plasma myo-inositol increased linearly from 66.9, 97.1 to 113.2 nmol/ml with increasing inositol (P<0.001). When plasma myo-inositol was analyzed within the sub-group of pigs fed diets without added inositol, super-dosing phytase increased plasma myo-inositol from 57.81 to 76.05 nmol/ml (0 and 2,500 FTU/kg, respectively; P=0.05). Results demonstrate that exogenous inositol improved efficiency of gain in weaned pigs to the same level as that observed with super-dosing phytase, but this occurred only during the first 10 d of the nursery period. This suggest that the improvement in growth performance when applying super-dosing phytase could be linked, in part, to complete dephosphorylation of phytase and liberation of myo-inositol, and that myo-inositol had a greater metabolic impact in piglets immediately after weaning. Consequently, myo-inositol may be a conditionally essential nutrient for young pigs during weaning stress but further research is needed to prove this hypothesis.