摘要
为研究绵羊日粮添加不同水平甜菊糖苷对养分降解和绵羊瘤胃发酵的影响,共设8个处理,即绵羊日粮中甜菊糖苷添加水平分别为0(CK组)、0.01％、0.04％、0.07％、0.10％、0.15％、0.20％和0.30％(占日粮风干物质重),利用体外产气法评估不同添加水平甜菊糖苷对绵羊瘤胃发酵及48h养分降解的影响.结果表明:各处理组产气量(GP)、干物质降解率(DMD)、挥发性脂肪酸(VFA)和甲烷(CH4)产量均随瘤胃降解时间的延长而增加,且在48h时达到最大,pH随瘤胃降解时间的延长而降低.12h后,0.10％组GP显著高于CK组(P＜0.05).24h时,添加较低浓度甜菊糖苷的绵羊日粮DMD与CK组差异不显著(P＞0.05),而较高浓度0.20％和0.30％组的日粮DMD则较CK组分别降低了 9.71％和5.80％(P＜0.05).降解48 h时,各处理日粮的DMD和粗蛋白降解率(CPD)与CK组差异不显著(P＞0.05).随着发酵时间增加,各处理瘤胃液氨态氮(NH3-N)浓度介于7.05～13.97 mg·dL-1,在瘤胃微生物活动的适宜浓度范围内.0.07％组和0.10％组能够维持乙酸和总挥发性脂肪酸浓度于较高水平.综上,绵羊日粮中最适宜的甜菊糖苷浓度为0.07％～0.10％.
Abstract
We studied the effect of varying supplemental dietary stevioside levels on nutrient degradation and rumen fermentation in sheep.In this study,eight experimental sheep treatments were set up,with stevioside supplements at 0(CK group),0.01％,0.04％,0.07％,0.10％,0.15％,0.20％,and 0.30％(based on the air-dried matter in the diet),and the rumen fermentation and nutrient degradation rates were evaluated for 48 h by an in vitro gas production method.The results showed that the gas production(GP),dry matter degradation rate(DMD),volatile fatty acid,and methane yields,in all treatments,increased with prolonged rumen degradation time,peaking at 48 h.However,pH decreased with prolonged rumen degradation time.After 12 h,the GP of the 0.10％group showed a significant increase compared to the CK group(P＜0.05).At 24 h,the DMD in the 0.20％and 0.30％groups was significantly lower than in the CK group(P＜0.05),with reductions of 9.71％and 5.80％(P＜0.05),respectively.Compared with the CK group,there were no significant differences in DMD and crude protein degradation rate of all other groups at 48 h(P＞0.05).With an increase in fermentation time,the content of ammonium nitrogen(NH3-N)in the rumen fluid of each treatment ranged from 7.05～13.97 mg·dL-1,which was within the appropriate concentration range for rumen microbial activity.The 0.07％and 0.10％groups maintained elevated levels of acetic acid and total volatile fatty acids.In conclusion,the optimal concentration range of stevioside in sheep diet was observed to be 0.07％～0.10％.These results provide a theoretical basis for adopting the appropriate stevioside supplementation levels in sheep production practices.
基金项目
甘肃省高校创新基金项目(2022B-096)
甘肃省科技计划(项目技术传销引导计划-鲁甘科技协作专题)项目(22CX2NA005)
南疆重点产业创新发展支撑计划项目(2022DB017)
甘肃省教育厅研究生"创新之星"项目(2023CXZX-665)
国家科技期刊平台
NSTL
万方数据