本试验旨在通过体外发酵法研究不同水平沙葱粉对牦牛瘤胃体外发酵参数、营养物质降解率和微生物区系的影响.采用体外发酵法,在发酵罐中分别加入1 g全混合日粮(TMR,发酵底物)(YZA 组)、1 g TMR+1.2％沙葱粉(YLA 组)、1 g TMR+2.4％沙葱粉(YMA 组)、1 g TMR+3.6％沙葱粉(YHA组),在发酵时间分别到达4、8、16、24、48和72 h时采集发酵液及底物残渣,测定发酵参数、营养物质降解率及微生物区系.结果表明:1)与YZA组相比,发酵从16h开始,YMA组和YHA组氨态氮(NH3-N)含量均极显著降低(P＜0.01),发酵16和72 h时,YMA组和YHA组菌体蛋白(MCP)含量极显著升高(P＜0.01);发酵4和16 h时,YLA组和YMA组pH均显著降低(P＜0.05),48 h时YMA组pH显著降低(P＜0.05),72 h时YMA组pH极显著降低(P＜0.01);除72 h外,其余各时间点YLA组和YMA组总挥发性脂肪酸(TVFA)和乙酸含量显著(P＜0.05)或极显著(P＜0.01)升高;各发酵时间点YLA组和YMA组丙酸含量显著(P＜0.05)或极显著(P＜0.01)升高.2)与YZA组相比,发酵时间4、24、72 h时,YMA组干物质降解率(DMD)显著升高(P＜0.05);发酵4、24、48和72 h时,YMA组和YHA组中性洗涤纤维降解率(NDFD)显著(P＜0.05)或极显著(P＜0.01)升高;各发酵时间点,YLA组和YMA组酸性洗涤纤维降解率(ADFD)显著(P＜0.05)或极显著(P＜0.01)升高.3)不同添加水平沙葱粉并未改变瘤胃主要微生物类群的占比,但可增加属水平普雷沃氏菌科UCG-001(YMA组)和F082(YMA组和YHA组)等有益微生物的相对丰度,提高底物营养物质降解率.4)毛螺菌科UCG-009相对丰度与丙酸含量呈极显著正相关(r=0.982;P＜0.01),与DMD呈极显著负相关(r=-0.990;P＜0.01),土圈菌DEV114相对丰度与异戊酸含量呈极显著正相关(r=0.998;P＜0.01),不动杆菌属相对丰度与丙酸含量呈极显著负相关(r=-0.994;P＜0.01),与DMD呈极显著正相关(r=0.984;P＜0.01).综上所述,在本试验条件下,饲粮中添加2.4％沙葱粉能改善牦牛瘤胃体外发酵参数和营养物质降解率,促进有益菌的增殖,且部分参数变化呈现剂量依赖效应.
Abstract
The purpose of this experiment was to study the effects of different levels of Allium mongolicum Re-gel powder on rumen in vitro fermentation parameters,nutrient degradation rate and microflora of yak by in vitro fermentation.In vitro fermentation method was used to add 1 g total mixed ration(TMR,fermentation substrate)(YZA group),1 g TMR+1.2％Allium mongolicum Regel powder(YLA group),1 g TMR+2.4％Allium mongolicum Regel powder(YMA group),1 g TMR+3.6％Allium mongolicum Regel powder(YHA group)to the fermentation tank.When the fermentation time reached 4,8,16,24,48 and 72 h,the fermen-tation broth and substrate residue were collected,and the fermentation parameters,nutrient degradation rate and microflora were determined.The results showed as follows:1)compared with the YZA group,the content of ammonia nitrogen(NH3-N)in the YMA group and the YHA group decreased significantly(P＜0.01)from 16 h of fermentation,and the content of mycoprotein(MCP)increased significantly(P＜0.01)at 16 and 72 h of fermentation.The pH in YLA group and YMA group decreased significantly at 4 and 16 h(P＜0.05),the pH in YMA group decreased significantly at 48 h(P＜0.05),and the pH in YMA group decreased significant-ly at 72 h(P＜0.01).Except for 72 h,the contents of total volatile fatty acids(TVFA)and acetic acid in YLA group and YMA group were significantly(P＜0.05)or extremely significantly(P＜0.01)increased at other time points.The propionic acid content in YLA group and YMA group increased significantly(P＜0.05)or extremely significantly(P＜0.01)at each fermentation time point.2)Compared with YZA group,the dry matter degradation rate(DMD)in YMA group significantly increased at 4,24 and 72 h of fermentation time(P＜0.05).The neutral detergent fiber degradation rate(NDFD)in YMA group and YHA group increased significantly(P＜0.05)or extremely significantly(P＜0.01)at4,24,48 and 72 h of fermentation.At each fer-mentation time point,the acid detergent fiber degradation rate(ADFD)in YLA group and YMA group in-creased significantly(P＜0.05)or extremely significantly(P＜0.01).3)Different addition levels of Allium mongolicum Regel powder did not change the proportion of main microbial groups in rumen fluid,but in-creased the relative abundance of beneficial microorganisms such as Prevotellaceae_UCG-001(YMA group)and F082(YMA group and YHA group)at the genus level,and increased the degradation rate of substrate nu-trients.4)The relative abundance of Lachnospiraceae_UCG-009 was significantly positively correlated with propionic acid content(r=0.982;P＜0.01),and there was a significant negative correlation with DMD(r=-0.990;P＜0.01).The relative abundance of DEV114 was significantly positively correlated with isovaleric acid content(r=0.998;P＜0.01).The relative abundance of Agathobacter was significantly negatively corre-lated with propionic acid content(r=-0.994;P＜0.01),which was positively correlated with DMD(r=0.984;P＜0.01).In summary,within the scope of this experiment,the addition of 2.4％Allium mongolicum Regel powder to the diet of yak can improve the in vitro fermentation parameters and nutrient degradation rate of rumen fluid of yak,promote the value-added of beneficial bacteria,and some parameter changes show a dose-dependent effect.[Chinese Journal of Animal Nutrition,2024,36(6):3739-3755]
关键词
沙葱粉/牦牛/营养物质降解率/发酵参数/微生物区系
Key words
Allium mongolicum Regel powder/yak/nutrient degradation rate/fermentation parameters/microflora
维普
万方数据