日粮纤维水平对绵羊消化道不同部位固相食糜流通速率和纤维消化的影响

Effects of dietary fiber level on passage rate and digestibilitiy of fibre at different sites of digestive tract in sheep

【目的】研究日粮纤维水平对绵羊消化道不同部位固相食糜流通速率和纤维类物质流通量及消化率的影响。【方法】选择9只体质量为(52.46±1.75)kg、装有瘤胃和十二指肠T型瘘管的苏尼特绵羊,随机均分为Ⅰ、Ⅱ和Ⅲ3组,3组绵羊分别饲喂NDF含量为64.38%,54.59%和42.71%的日粮;试验以铬标记纤维作为固相食糜标记物,通过分析不同时间瘤胃、十二指肠和直肠样品中的铬浓度以及不同时间混合样品中的NDF、ADF、HC、CEL和DM含量,计算不同消化部位固相食糜的流通速率、纤维物质流通量及消化率。【结果】各处理组间绵羊消化道相同部位的固相食糜流通速率、纤维物质流通量及消化率差异均不显著(P>0.05)。处理Ⅲ组各消化部位的流通速率以及瘤胃和全消化道营养物质的消化率均较低,但在后肠部位纤维类物质(NDF、ADF、CEL和HC)的消化力增强。【结论】在进食能氮总量相似的情况下,日粮纤维水平对纤维类物质的消化无显著影响。

[Objective] The present study was conducted to investigate the effects of different levels of dietary fiber on the solid passage rate and passage flow, digestibilitiy of fibre at different sites of digestive tract in sheep. [Method] Nine ruminally and duodenally cannulated Sunite sheep were randomly allocated into three groups. The dietary fiber levels of each group were 64. 38% ,54. 59% and 42.71% respectively. The solid phase digesta markers were Cr-mordanted fibre. The solid passage rate and nutrients passage flow and digestibilitiy in different digestive tract sites were calculated, based on the chromium concentration of single sample and NDF,ADF, HC, CEL and DM content of mixed sample,in the rumen, duodenum and rectum of sheep at different sampling time. The experiment lasted for four weeks. [Result] The results indicated that there were no significant differences among the three groups in solid phase passage rate and passage flow and digestibilitiy of nutrients at the same sites of digestive tract （P〉0.05）. However,group III was the lowest for solid phase passage rate, and fiber digestibility in rumen and whole digestive tract, but the fiber digestion was enhanced in the hindgut of sheep. [Conclusion] These results suggested that under the condition of similar energy and nitrogen offered, fiber digestibility was not significantly affected by the level of dietary fiber.