象草细胞壁成分与干物质体外消化率关系分析

以提高干物质体外消化率(IVDMD)为目标,在保持一定干物质产量的同时,通过研究象草细胞壁成分与消化率之间的关系,确定影响干物质体外消化率的细胞壁成分,为筛选高消化率象草育种材料和选育品种提供依据.结果表明:矮生多蘖、较高中蘖、较高少蘖以及高大少蘖型于物质体外消化率依次增加,细胞壁成分NDF、ADF、ADL、HEM、CEL含量则依次降低；第一次刈割时的叶片、茎鞘干物质体外消化率均明显高于第二次刈割,同一刈割时期的茎鞘干物质体外消化率显著高于叶片.叶片干物质体外消化率与NDF、CEL含量表现为显著或极显著负相关,茎鞘干物质体外消化率与NDF、ADF、CEL、ADL含量以及ADL/HEM、ADL/CEL、ADL/(HEM+CEL)比值之间表现为显著或极显著负相关.对IVDMD与细胞壁成分进行主成分分析可得两个较为稳定的主成分,一为ADL含量及ADL/CEL、ADL/(HEM+CEL)比值,二为HEM含量及HEM/CEL比值,因此认为ADL、HEM含量为象草细胞壁成分中影响干物质体外消化率的的主要因素.

Correlation of Cell Wall Constituents to in vitro Dry Matter Digestibility in Elephant Grass

The objective of the experiment was to improve elephant grass(Pennisetum purpureum) digestibility,to identify and evaluate selection criteria that have effective and stable effects on elephant grass digestibility while maintaining DM yields.Cell wall constituents and their ratios and in vitro dry matter digestibility(IVDMD) were investigated with 16 lines of selfed-progeny of elephant grass N51,one purple elephant grass and hybrid pennisetum(pearl millet × elephant grass) in a field experiment.The results showed that the IVDMD of elephant grass increased from dwarf type with numerous tillers,to semi-dwarf types with plentiful tillers,to intermediate height types with moderate tillers and to tall types with limited tillers,and NDF,ADF,ADL,HEM,CEL content decreased in sequence.IVDMD of leaf and stem of first harvest was significantly higher than that of second harvest,and IVDMD of stem was higher than leaf in the same harvest stage.IVDMD of leaf was negatively and significantly correlated with NDF(P<0.05) and CEL(P<0.01) concentration,respectively.IVDMD of stem was positively and significantly correlated with NDF,ADF,CEL,ADL,ADL/HEM,ADL/CEL and ADL/(HEM+CEL)(P<0.01),respectively.Principal components analysis showed that three principal component factors reflected traits of cell wall constituents and their ratios.The first principal component was a factor of ADL concentration and its ratios,the second principle component was HEM and its ratio.So ADL and HEM concentration were two important factors of fiber component concentration affecting IVDMD.