Institute of Animal Science, University of Hohenheim, Stuttgart 70599, Germany.
BASF SE, Lampertheim 68623, Germany.
Poult Sci. 2020 Jun;99(6):3251-3265. doi: 10.1016/j.psj.2020.03.010. Epub 2020 Apr 8.
The objective was to determine phytase effects on prececal amino acid (AA) digestibility and phytate (InsP) breakdown when different oilseed meals were used in broiler chicken diets. The study included 14 diets: a corn-soybean meal (SBM) basal diet and 6 diets that contained SBM, rapeseed meal (RSM), and sunflower meal (SFM) with 2 inclusion levels at the expense of corn starch (150 and 300 g/kg SBM or SFM, or 100 and 200 g/kg RSM). Each diet was mixed with or without a phytase supplement of 1,500 FTU/kg. Diets were provided to broilers for 5 D. Digesta from the posterior half of the ileum were collected on day 21. The average essential AA digestibility, calculated by a regression approach, without and with phytase was 84 and 85% (SBM), 74 and 77% (SFM), and 66 and 73% (RSM), respectively. In the diets, phytase effects on AA digestibility were lower owing to other protein sources also present in the diet, but significant. Prececal InsP disappearance was significantly affected by interactions between oilseed meal, inclusion level, and phytase supplementation. Overall, prececal InsP disappearance was higher in SBM diets (52%) than in SFM diets (38%) and intermediate in RSM diets (43%). Across diets, phytase supplementation effects on prececal InsP degradation linearly increased with the InsP concentration of the diet up to 12 g/kg DM. The only exception from linearity was the diet with the high inclusion of SFM, which contained 15.9 g InsP/kg DM. In the ileal content, the concentration of myo-inositol was significantly increased by phytase supplementation, and this effect was highest in the diets that contained SBM as the only oilseed meal. Concentrations of lower inositol phosphates were increased by phytase supplementation, and this effect was most remarkable for Ins(1,2,3,4)P and inositol tetrakisphosphates. The study showed that phytase effects on AA digestibility varied among the 3 tested oilseed meals, but these differences were not detectable in the diets containing these meals. Although phytase effects on ileal content of InsP and its degradation products were substantial, they were not related to the effects on AA digestibility.
本研究旨在确定植酸酶对不同油籽粕在肉鸡饲粮中的回肠前段氨基酸（AA）消化率和植酸（InsP）降解的影响。研究包括 14 种饲粮：玉米-豆粕（SBM）基础饲粮和 6 种饲粮，其中 SBM 分别用油菜籽粕（RSM）和葵花籽粕（SFM）替代 150 和 300 g/kg SBM 或 SFM，或 100 和 200 g/kg RSM，同时用或不用 1500 FTU/kg 的植酸酶进行补充。饲粮连续喂养肉鸡 5 d，于第 21 天收集回肠后段食糜。通过回归分析计算出平均必需 AA 消化率，不用和用植酸酶时分别为 84%和 85%（SBM）、74%和 77%（SFM）和 66%和 73%（RSM）。在饲粮中，由于饲粮中还存在其他蛋白质来源，植酸酶对 AA 消化率的影响较低，但仍有显著作用。回肠前段 InsP 消失率显著受油籽粕、添加水平和植酸酶补充的互作影响。总体而言，SBM 饲粮的回肠前段 InsP 消失率（52%）高于 SFM 饲粮（38%），而处于 RSM 饲粮（43%）之间。在所有饲粮中，随着饲粮中 InsP 浓度的增加，植酸酶对回肠前段 InsP 降解的线性影响逐渐增加，最高可达 12 g/kg DM。唯一的例外是高添加 SFM 饲粮，其中含有 15.9 g InsP/kg DM。在回肠内容物中，植酸酶补充显著增加了肌醇的浓度，且这种作用在仅含有 SBM 的饲粮中最为明显。植酸酶补充还增加了低磷酸肌醇的浓度，这种作用在 Ins(1,2,3,4)P 和肌醇四磷酸中最为显著。本研究表明，植酸酶对 3 种测试油籽粕的 AA 消化率的影响存在差异，但在含有这些油籽粕的饲粮中这些差异无法检测到。尽管植酸酶对回肠内容物中 InsP 及其降解产物的影响较大，但与 AA 消化率的影响无关。
