2种决明属牧草不同生育期营养成分在肉牛瘤胃降解动态研究

摘要

The degradability dynamics of dry matter (DM) , neutral detergent fiber (NDF) and crude protein (CP) of C. Rotundi folia cv. Wynn and C. Nictitans cv. Minyin were studied by using the nylon bag technique. The Chamaecrist forages were collected in two different growth stages, which were early-blooming stage and bearing pod stage. The rumen degradation model parameters were also researched. Results showed that the rumen degradability dynamics of nutrient components were different in different stages. The 72 h degradability of DM, NDF and CP in early-blooming stage was higher than that in bearing pod stage, respectively. The fraction disappeared at a measurable rate (b) of DM and NDF decreased with maturity.There was no significant difference between early-blooming stage and bearing pod stage. The NDF degradability of C . Nictitans cv . Minyin in early-blooming stage (20. 31%) was significant higher than bearing pod stage (13.01%) (P<0. 05). The NDF degradability of C. Rotundifolia cv. Wynn in early-blooming stage (11. 84%) was 29. 82% higher than that in bearing pod stage (9.12%)(P<0. 05), but there was no significant difference. The CP contents of immediately soluble fraction (a) and the fraction disappeared at a measurable rate (b) of C. Nictitans cv. Minyin were significant higher in early-blooming stage than that in bearing pod stage (P< 0. 05). The Eds of two stages were 65. 99% and 58. 76%, respectively. The CP a, b and ED of C. Rotundifolia cv. Wynn were not significantly different between early-blooming stage and bearing pod stage. The Eds of NDF were all lower than the ED of the DM, CP in different maturity of two rotundifolias. The degradability of different nutrition of C. Nictitans cv. Minyin was better than that of C. Rotundifolia cv. Wynn.%采用瘤胃尼龙袋法,研究威恩圆叶决明(Chamaecrista rotundi folia cv.Wynn)和闽引羽叶决明(C.nictitans cv.Minyin)2个豆科牧草初花期和结荚期干物质(DM)、中性洗涤纤维(NDF)、粗蛋白质(CP)等养分在肉牛瘤胃内0～72 h降解动态变化,并建立瘤胃降解模型参数.结果表明:不同生育期决明属牧草各营养成分的瘤胃降解特性有着不同差异,牧草初花期的DM,NDF和CP在肉牛瘤胃72 h的有效降解率均高于结荚期.2个牧草品种的DM和NDF的慢速降解部分b值均随着生育期的延长而逐渐降低,但牧草DM的有效降解率差异并不显著.闽引羽叶决明初花期NDF的有效降解率(20.31％)显著高于结荚期(13.01％)(P＜0.05)；威恩圆叶决明初花期NDF的有效降解率(11.84％)比结荚期(9.12％)高出29.82％,但差异不显著.闽引羽叶决明初花期的CP快速降解部分a值和慢速降解部分b值均显著大于结荚期(P＜0.05),有效降解率分别达到65.99％和58.76％；威恩圆叶决明初花期和结荚期CP的快速降解部分a值、慢速降解部分b值及有效降解率均无显著差异.不同品种、不同生育期DM和CP的有效降解率均要高于NDF的有效降解率.此外,从品种间营养成分的瘤胃降解特性综合比较,闽引羽叶决明在瘤胃的降解效果要优于威恩圆叶决明.