直鏈支鏈淀粉比、膨化、儲存時間和酶制劑對斷奶仔豬玉米淀粉體內(nèi)、體外消化率的影響

畜牧編輯

　　2015. J. Anim. Sci. 93(7):3512-3520

　　直鏈支鏈淀粉比、膨化、儲存時間和酶制劑對斷奶仔豬玉米淀粉體內(nèi)、體外消化率的影響

　　Y. Li, A. R. Zhang, H. F. Luo, H. Wei, Z. Zhou, J. Peng 和 Y. J. Ru

　　本試驗的目的在于研究直鏈支鏈淀粉比、膨化、儲存時間和酶制劑對玉米淀粉消化率的影響。從74個玉米樣品中選取3個有代表性的樣品進(jìn)行體外、體外消化試驗，其直支鏈淀粉比分別為0.60（HA）、0.44（MA）、0.39（LA）。試驗一，玉米經(jīng)膨化后4周內(nèi)，3種玉米抗性淀粉含量每周都有顯著提高（P＜0.05），并且淀粉的體外消化率隨儲存時間的增加顯著降低（P＜0.05）。直支鏈淀粉比影響了抗性淀粉的形成（P＜0.01）。3個玉米樣品抗性淀粉的含量始終都是：LA＜MA＜HA（P＜0.05）。直支鏈淀粉比例和儲存時間與抗性淀粉含量顯著相關(guān)（P＜0.01）。并且，三個樣品的儲存時間和抗性淀粉含量之間存在顯著的二次線性相關(guān)關(guān)系，儲存時間和淀粉消化率之間也存在類似相關(guān)關(guān)系。淀粉消化率與抗性淀粉含量呈負(fù)相關(guān)關(guān)系（P＜0.001）。試驗二，采用回腸瘺管法測定樣品的消化率，豬只初始體重為13.2±0.94kg。與酶制劑組相比，膨化增加了HA和LA淀粉以及總能的回腸消化率（P＜0.001）。酶制劑不能改善淀粉和能量的回腸消化率。LA組淀粉和總能的回腸消化率顯著高于HA組（P＜0.05）。

試驗結(jié)果表明直支鏈淀粉比例和膨化后的儲存時間是抗性淀粉形成和淀粉消化率的決定性因素。此外，抗性淀粉含量是膨化玉米淀粉消化率的重要指標(biāo)。選用低直支鏈淀粉比玉米或者減少玉米膨化后的儲存時間能有助于減少抗性淀粉的形成，并改善小豬對玉米淀粉的利用率。

　　In vitro and in vivo digestibility of corn starch for weaned pigs: Effects of amylose:amylopectin ratio, extrusion, storage duration, and enzyme supplementation

　　Y. Li, A. R. Zhang, H. F. Luo, H. Wei, Z. Zhou, J. Peng and Y. J. Ru

　　The objective of this study was to investigate the effects of amylose (AM):amylopectin (AP) ratio, extrusion, storage duration, and enzyme supplementation on starch digestibility of corn. Three corn varieties with high (0.60; HA), medium (0.44; MA), and low (0.39; LA) AM:AP ratios, respectively, were selected from 74 corn samples to evaluate the in vitro and in vivo digestibility of starch. In Exp. 1, during wk 4 after extrusion, resistant starch (RS) content of the 3 selected corn varieties (LA, MA, and HA) increased (P < 0.05) each week and starch digestibility in vitro decreased as storage time increased (P < 0.05). The AM:AP ratio affected the formation of RS (P < 0.01). The RS content of the 3 corn varieties was ranked as LA < MA < HA in each week (P < 0.05). Correlation analysis showed that AM:AP ratio and storage duration were both positively correlated with RS content (P < 0.01). Furthermore, a significant quadratic relation was found between storage duration and RS content in each corn variety as well as storage duration and digestibility. Starch digestibility was negatively correlated with RS content (P < 0.001). In Exp. 2, digestion trials were performed on cannulated pigs with BW of 13.20 ± 0.94 kg. Extrusion increased ileal digestibility of GE and starch of either HA or LA compared with the enzyme-supplemented diets (P < 0.001). Enzyme supplementation did not improve ileal energy and starch digestibility. The ileal digestibility of starch and GE of LA varieties was greater than HA samples (P < 0.05). The results implied that AM:AP ratio and storage duration after extrusion may be important determinants of RS formation and digestibility of starch for corn. In addition, RS content could be an important indicator of digestibility of starch in extruded corn. Using a lower AM:AP ratio corn or reducing the storage duration of extruded corn would help to reduce the formation of RS and improve the starch bioavailability of corn for piglets。
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