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草业学报 ›› 2016, Vol. 25 ›› Issue (1): 187-198.DOI: 10.11686/cyxb2015065

• 研究论文 • 上一篇    下一篇

灌浆期弱光胁迫对“扬麦15”小麦秸营养价值和体外降解率的影响

李袁飞, 何香玉, 成艳芬*, 朱伟云   

  1. 南京农业大学动物科技学院消化道微生物研究室,江苏 南京210095
  • 收稿日期:2015-01-29 出版日期:2016-01-20 发布日期:2016-01-20
  • 通讯作者: *通信作者Corresponding author. E-mail: yanfencheng@njau.edu.cn
  • 作者简介:李袁飞(1988-),男,湖南郴州人,在读博士。E-mail:2012105077@njau.edu.cn
  • 基金资助:
    公益性行业(农业)科研专项(200903003)资助

Effects of shading during grain filling on nutritive value and in vitro digestibility of “Yangmai 15” wheat straw

LI Yuan-Fei, HE Xiang-Yu, CHENG Yan-Fen*, ZHU Wei-Yun   

  1. Laboratory of Gastrointestinal Microbiology, Nanjing Agricultural University, Nanjing 210095, China
  • Received:2015-01-29 Online:2016-01-20 Published:2016-01-20

摘要: 本试验采用瘤胃体外降解技术研究了弱光胁迫对小麦秸营养价值及畜禽消化率的影响。试验以弱筋小麦“扬麦15”为材料,在灌浆期进行3个遮阴水平(0%,50%,66%)和3个遮阴时间(2,4,8 d)的处理,成熟后统一收取小麦秸,进行营养成分分析并利用体外降解技术评定其体外降解率。营养成分分析结果表明,遮阴水平与遮阴时间均显著影响小麦秸粗蛋白(CP)、中性洗涤纤维(NDF)及中性洗涤可溶物(NDS)含量(P<0.05),但遮阴水平与遮阴时间没有交互作用;遮阴水平由0%增加至66%,小麦秸CP及NDS含量分别由3.06%,23.97%降至2.35%,20.46%,差异显著(P<0.05);而小麦秸NDF含量则由76.03%显著升高至79.54%(P<0.05);遮阴时间由2 d增至8 d时,小麦秸CP及NDS含量分别由3.11%,23.09%显著降低至2.51%,21.43%(P<0.05),而NDF含量则由76.91%显著升高至78.57%(P<0.05)。体外试验以4头装有永久性瘤胃瘘管的波尔山羊为瘤胃液供体,称量1 g小麦秸样品于含有10 mL瘤胃液和50 mL培养基的39℃发酵瓶内体外发酵,培养72 h冰浴终止发酵,测定产气量、pH、体外降解率和发酵液中挥发性脂肪酸。体外降解率结果显示,遮阴水平与遮阴时间均显著影响小麦秸中性洗涤纤维消失率(NDFD),且遮阴水平与遮阴时间没有交互作用,随着遮阴水平增加,小麦秸干物质消失率(DMD)、NDFD及酸性洗涤纤维消失率(ADFD)分别由40.33%,40.82%及36.56%显著降低至35.20%,36.03%及33.36%(P<0.05);随遮阴时间增加NDFD由38.88%显著降低至36.94%(P<0.05)。小麦秸体外降解结果显示,遮阴水平与遮阴时间均显著影响累积产气量(P<0.05),并且存在交互效应;遮阴水平显著影响总挥发性脂肪酸(TVFA)、丁酸产量及乙丙比(P<0.05),遮阴时间对挥发性脂肪酸(VFA)产量及组成没有影响,且遮阴水平与遮阴时间没有交互作用。随遮阴水平增加,小麦秸体外降解累积产气量、TVFA、丁酸产量分别由131.64 mL、57.04 mmol/L及5.18 mmol/L显著降低至120.96 mL、51.25 mmol/L及4.32 mmol/L(P<0.05),而乙丙比则由2.47显著增加至2.60(P<0.05);随遮阴时间增加,累积产气量由130.46 mL显著降低至121.22 mL(P<0.05)。结果表明,遮阴处理显著增加了“扬麦15”小麦秸NDF含量,降低了小麦秸粗蛋白、体外降解率及发酵累积产气量与挥发性脂肪酸产量,但对挥发性脂肪酸组成没有影响;不同遮阴水平对其影响更为明显。

Abstract: This study was conducted to investigate the effects of shading during the grain filling stage on the nutritive value and in vitro digestibility of “Yangmai 15” wheat straw. Three shading levels (0%, 50% and 66%) and three shade duration periods (2, 4 and 8 days) were compared. At harvest, the wheat straw was collected and stored for analysis of chemical composition and in vitro digestibility and fermentation characteristics. For in vitro fermentation, rumen fluid was collected from 4 Boer goats with permanent rumen fistulas. Bottles containing 10 mL rumen fluid and 50 mL media with 1 g wheat straw as substrate were incubated at 39℃ for 72 h. Gas production was measured throughout the fermentation and samples were collected for analysis of pH, in vitro digestibility and volatile fatty acids (VFA) at the end of fermentation. The results showed that shading level and period significantly affected the crude protein (CP) content, neutral detergent soluble (NDS) and neutral detergent fiber (NDF) (P<0.05) with no interaction between shade level and shade period. When the shade level increased from 0% to 66%, CP and NDS decreased significantly from 3.06% to 2.35%, and 23.97% to 20.46%, respectively (P<0.05), while NDF increased significantly from 76.03% to 79.54% (P<0.05). Increasing the shading period from 2 to 8 days decreased CP and NDS significantly; 3.11% to 2.51%, and 23.09% to 21.43%, respectively (P<0.05), while NDF increased significantly from 76.9% to 78.6% (P<0.05).Shade level and shade period significantly affected the neutral detergent fiber digestibility (NDFD) (P<0.05) but no interaction was observed. With increasing shade level dry matter digestibility (DMD), NDFD and acid detergent fiber digestibility (ADFD) decreased significantly from 40.33%, 40.82% and 36.56% to 35.20%, 36.03% and 33.36%, respectively (P<0.05). With increasing shade duration NDFD decreased significantly from 38.88% to 36.94% (P<0.05). Both shade level and shade duration significantly affected gas production (P<0.05) and an interaction between them was observed (P<0.05); gas production decreased significantly from 131.64 mL to 120.96 mL, and 130.46 mL to 121.22 mL with increasing shade level and duration, respectively (P<0.05). The concentration of VFA in the cultures showed that shade level significantly affected TVFA concentrations, butyrate and the acetate/propionate ratio (A/P) (P<0.05), but shade duration had no effect on these traits. With increasing shade level the concentrations of TVFA and butyrate decreased significantly from 57.04 mmol/L to 51.25 mmol/L and 5.18 mmol/L to 4.32 mmol/L, respectively (P<0.05), while the A/P ratio increased significantly from 2.47 to 2.60 (P<0.05). In conclusion, shade significantly increased the NDF, resulting in decreased CP, in vitro digestibility, gas production and VFA concentration. The impacts of shading increased increasing shade level and duration.