不同分级指数苜蓿干草–小麦秸秆组合对牦牛瘤胃体外发酵的影响  

Effects of different graded index alfalfa hay and wheat straw on yak rumen fermentation characteristics in vitro

作　　者：夏洪泽 郝文君 崔占鸿[1] 刘书杰[1] XIA Hongze;HAO Wenjun;CUI Zhanhong;LIU Shujie(Qinghai University Academy of Animal Husbandry and Veterinary Sciences/Yak Engineering Technology Research Center of Qinghai Province/Key Laboratory of Plateau Grazing Animal Nutrition and Feed Science of Qinghai Province,Xining 810016,Qinghai,China)

机构地区：[1]青海大学畜牧兽医科学院/青海省牦牛工程技术研究中心/青海省高原放牧家畜动物营养与饲料科学重点实验室,青海西宁810016

出　　处：《草业科学》2021年第1期171-182,共12页Pratacultural Science

基　　金：西宁市科技计划项目(2018-Y-58);国家重点研发计划子课题“放牧牦牛冷季营养平衡调控技术研究(2018YFD0502403)”;青海省科技厅项目(2020-ZJ-911);中国科学院“西部之光”西部青年学者A类(3-4)。

摘　　要：本试验旨在通过饲草分级指数(GI)优化牦牛日粮粗饲料营养组合。选取5种不同GI(7.03、6.21、5.38、4.55、3.72)的苜蓿(Medicago)干草–小麦(Triticum aestivum)秸秆组合进行牦牛瘤胃体外发酵试验,每个样本设3个重复,共发酵48 h。结果表明:发酵3~48 h,GI为6.21组合的累积产气量显著高于其他GI组合(P<0.05);发酵3、48 h的干物质消失率(IVDMD)随着GI减小呈现降低趋势;发酵3、12、48 h时,GI为7.03组合的中性洗涤纤维降解率(IVNDFD)与GI为6.21组合的差异不显著(P>0.05),但显著高于其他GI组合(P<0.05);发酵6 h时,GI为7.03组合的IVNDFD显著高于其他GI组合(P<0.05);发酵3~48 h,氨态氮(NH3-N)浓度整体随着GI减小呈现出先小幅增加后降低的趋势;发酵48 h,微生物蛋白(MCP)浓度整体随着GI减小呈现出先小幅增加后降低的趋势;发酵48 h的乙酸、丙酸和总挥发性脂肪酸随着GI减小呈现先小幅增加后降低的趋势;发酵3~24 h时,GI为6.21组合的甲烷(CH4)、消化能(DE)显著高于其他组合(P<0.05);GI为7.03、6.21、5.38组合在各时间段均产生了正组合效应,GI为4.55、3.72组合在48 h产生了正组合效应,但在3~48 h的综合组合效应指数(MFAEI)均随着GI减小呈现先增大后减小的趋势,且各时间段GI为6.21组合的MFAEI均高于其他GI组合。根据各项瘤胃发酵指标以及组合效应综合得出,GI为6.21苜蓿干草–小麦秸秆组合体外发酵效果优于其他GI组合。The purpose of this study was to optimize the forage nutritional combination of yak diet with the grading index(GI).Five combinations of alfalfa hay and wheat straw with different GI(7.03,6.21,5.38,4.55,and 3.72)were selected to study yak rumen fermentation in vitro.The fermentation time was 48 h and 3 replicates were performed for each sample.At3~48 h of fermentation,the gas production(GP)of the GI=6.21 combination was significantly higher than that using the other GI values(P<0.05).At 3 h and 48 h of fermentation,the dry matter degradation in vitro(IVDMD)showed a decreasing trend with a decrease in GI.At 3,12,and 48 h of fermentation,the difference between the neutral detergent fiber in vitro(IVNDFD)of GI=7.03 and GI=6.21 is not significant,but they were higher than other GI combinations(P<0.05).At 3~48 h of fermentation,the concentration of ammonia nitrogen(NH3-N)showed an initial increasing trend followed by a decrease as the GI decreased.At 48 h of fermentation,the microbial protein(MCP)showed a trend of an initial increase followed by a decrease as the GI decreased.At 48 h of fermentation,the concentrations of acetic acid,propionic acid,and total volatile fatty acids(TVFAs)showed an initial trend of increase followed by a decrease as the GI decreased.At 3~24 h of fermentation,the concentration of CH4 and DE showed an initial trend of increase followed by a decrease as the GI decreased.The GIs of 7.03,6.21,5.38 showed a positive combination effect from 3~48 h of fermentation,whereas GI=4.55 and 3.72 showed a positive combination effect beyond 48 h of fermentation.The results of multiple factor associative effects index(MFAEI)were first increased and then showed a decreasing trend as the GI decreased.The GI=6.21 combination of MFAEI was higher than other GI combinations.Overall,in vitro fermentation of yak rumen with GI=6.21 alfalfa hay and wheat straw combination were found to be optimal.

关 键 词：分级指数 苜蓿干草 小麦秸秆 瘤胃发酵 组合效应 

分 类 号：S823.5[农业科学—畜牧学]