Sampling duration and freezing temperature influence the analysed gastric inositol phosphate composition of pigs fed diets with different levels of phytase

作     者：Steven Laird Imke Kühn Michael R.Bedford Hayley Whitfield Helen M.Miller 

作者机构：Faculty of Biological SciencesUniversity of Leeds AB Vista School of Biological SciencesUniversity of East Anglia 

出 版 物：《Animal Nutrition》 (动物营养（英文版）)

年 卷 期：2019年第5卷第2期

页      面：196-201页

核心收录：

学科分类：090502[农学-动物营养与饲料科学] 0905[农学-畜牧学] 09[农学] 

基　　金：funded by AB Vista (a division of AB Agri Ltd.  Marlborough  UK) 

主　　题：Pig Inositol phosphate Phytase Sampling time Freezing temperature 

摘      要：This experiment was conducted to determine the effects of time and freezing temperature during sampling on gastric phytate(myo-inositol [MYO] hexakisphosphate [InsP6]), lower inositol phosphates(InsP2-5) and MYO concentrations in pigs fed diets containing different levels of phytase. Forty pigs were fed 1 of 4 wheat-barley diets on an ad libitum basis for 28 d. The diets comprised a nutritionally adequate positive control(PC), a similar diet but with Ca and P reduced by 1.6 and 1.24 g/kg, respectively(NC), and the NC supplemented with 500(NC + 500) or 2,000(NC + 2000) FTU phytase/kg. At the end of the experiment, chyme were collected from the stomach, thoroughly mixed and 2 subsamples(30 mL) were frozen immediately: one snap-frozen at-79 ℃ and the other at-20 0 C. The remaining chyme were left to sit at room temperature(20 ℃) and further subsamples were collected and frozen as above at 5,10 and15 min from the point of mixing. There were linear reductions in gastric InsP6 concentration over time during sampling(P 0.001), irrespective of diet or freezing temperature. Moreover, InsP6 concentration was influenced by a diet × freezing temperature interaction(P 0.05), with less InsP6 measured in chyme frozen at-20 ℃ than at-79 ℃;however,this difference was greater in the control diets than the phytase supplemented diets. Freezing chyme at-79 ℃ recovered more ∑InsP2-5 + MYO than freezing at-20 ℃ in pigs fed phytase supplemented diets;however, this difference was not apparent in the diets without phytase(diet × freezing temperature, P 0.01), It can be concluded that significant phytate hydrolysis occurs in the gastric chyme of pigs during sampling and processing, irrespective of supplementary phytase activity. Therefore, to minimise post-slaughter phytate degradation and changes in the gastric inositol phosphate profile, chyme should be snap-frozen immediately after collection.