Animal Nutrition Group, Wageningen University & Research, Wageningen, The Netherlands.
J Anim Physiol Anim Nutr (Berl). 2020 Jan;104(1):12-21. doi: 10.1111/jpn.13221. Epub 2019 Oct 3.
This study investigated the chemical composition (proximate and Van Soest analysis) and in vitro gas production parameters of maize leaves and stems separately, and related the in vitro gas production parameters with the chemical composition, of thirteen maize cultivars. After harvest in September 2016, all plants were separated into two morphological fractions: leaves and stems. The crude protein (CP) content was greater, and the ratio of acid detergent lignin (ADL) to potentially rumen degradable fibre (calculated as the difference between neutral detergent fibre and ADL; ADL:pRDF) was lower in the leaves than in the stems in all 13 cultivars. For the leaves, the cumulative gas production between 3 and 20 hr (A2), representing cell wall fermentation in the rumen fluid, and the cumulative 72-hr gas production (GP72), representing total organic matter (OM) degradation, were moderately to weakly correlated with the chemical composition, including hemicellulose, cellulose, ADL and CP content (R < 0.40), whilst the best relationship between the half-time value (B2), representing the rate of cell wall degradation, and chemical composition had an R of 0.63. For the stems, the best relationship between A2, B2 and GP72 with chemical composition was greater (R ≥ 0.74) and the best relationship included hemicellulose (A2 only), cellulose and ADL (GP72 and A2 only) contents. In conclusion, maize leaves and stems differed in chemical composition, in particular CP content and ADL:pRDF. The A2 and GP72 of the stems, but not of the leaves, were highly correlated with the chemical composition, indicating that the cell wall and OM degradation of maize stems can be better predicted by its chemical composition.
本研究分别研究了玉米叶片和茎的化学成分（近似分析和范索斯特分析）和体外产气参数，并将体外产气参数与 13 个玉米品种的化学成分相关联。2016 年 9 月收获后，所有植物均分为两个形态部分：叶片和茎。在所有 13 个品种中，叶片中的粗蛋白（CP）含量较高，且酸性洗涤木质素（ADL）与潜在瘤胃可降解纤维（计算为中性洗涤纤维与 ADL 的差值；ADL：pRDF）的比例低于茎。对于叶片，3 至 20 小时（A2）之间的累积产气量（代表瘤胃液中细胞壁发酵）和 72 小时（GP72）的累积产气量（代表总有机物（OM）降解）与化学成分（包括半纤维素、纤维素、ADL 和 CP 含量）呈中度至弱相关（R < 0.40），而 B2（代表细胞壁降解速率）与化学组成之间的最佳关系的 R 值为 0.63。对于茎，A2、B2 和 GP72 与化学成分之间的最佳关系更大（R ≥ 0.74），最佳关系包括半纤维素（仅 A2）、纤维素和 ADL（仅 GP72 和 A2）含量。总之，玉米叶片和茎在化学成分上存在差异，特别是 CP 含量和 ADL：pRDF。茎的 A2 和 GP72 与化学成分高度相关，但叶片的 A2 和 GP72 与化学成分不相关，这表明玉米茎的细胞壁和 OM 降解可以通过其化学成分更好地预测。
