College of Grassland Science, Gansu Agricultural University, Key Laboratory of Grassland Ecosystem, Gansu Agricultural University, Lanzhou, Gansu Province, China.
College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, Gansu Province, China.
PeerJ. 2023 Jan 25;11:e14689. doi: 10.7717/peerj.14689. eCollection 2023.
Stevia straw is a byproduct of sugar crop stevia. It is a good feed material because of richness in nutrients and active substances (steviosides and flavonoids). However, due to improper utilization such as piling, burning and so on, it became a large amount of wasted straw resources and lead to environmental pollution.
We added 0%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0% and 1.5% of stevia stalk to study the effects of different stevia stalk concentrations on nutrient utilization and rumen fermentation in sheep (based on sheep diet). fermentation method was used, with 17 repetitions for each treatment. All fermentation substrate based on sheep diet with different stevia stalk concentrations were fermented for 2 h, 6 h, 12 h, 24 h and 48 h, then the gas production, dry matter degradability (DMD), crude protein degradability (CPD), neutral detergent fiber degradability (NDFD), acid detergent fiber degradability (ADFD), pH, ammonia nitrogen (NH-N) and volatile fatty acids (VFAs) were determined.
The results showed that at different fermentation time, the change trend of gas production in each teatment was basically same, but the maximum occurred in 1.0% treatment at 48 h. The DMD, CPD, NDFD and ADFD of sheep diets increased with fermentation time increasing, especially the CPD, NDFD and ADFD of diets in 0.8%, 1.0% and 1.5% treatments were significantly higher than those in control ( < 0.05). The pH of fermentation substrate in each treatment remained within the normal range of 6.21∼7.25. NH-Nin 0.8%, 1.0% and 1.5% treatments were higher than that in control. At 6 h-12 h, the total acid content of 0.8% and 1.0% treatments were significantly higher than those of other treatments ( < 0.05), it reached the highest in 1.0% treatment. According to overall evaluation, effect ranking of stevia stalk on sheep nutrient utilization was as follows: 1.0% >0.8% >1.5% >0.4% >0.6% >0.2%. Overall, 1.0% stevia stalk could promote nutrient degradation and sheep rumen fermentation.
甜叶菊秸秆是甜叶菊糖作物的副产物。它是一种很好的饲料原料，因为它富含营养物质和活性物质（甜菊糖苷和类黄酮）。然而，由于堆放、燃烧等不当利用，大量甜叶菊秸秆资源浪费，造成环境污染。
我们在绵羊日粮中添加 0%、0.2%、0.4%、0.6%、0.8%、1.0%和 1.5%的甜叶菊秸秆，研究不同甜叶菊秸秆浓度对绵羊养分利用和瘤胃发酵的影响（基于绵羊日粮）。采用发酵法，每个处理重复 17 次。所有基于不同甜叶菊秸秆浓度的绵羊日粮发酵底物均发酵 2 h、6 h、12 h、24 h 和 48 h，然后测定产气量、干物质降解率（DMD）、粗蛋白降解率（CPD）、中性洗涤纤维降解率（NDFD）、酸性洗涤纤维降解率（ADFD）、pH 值、氨氮（NH-N）和挥发性脂肪酸（VFAs）。
结果表明，在不同发酵时间，各处理的产气量变化趋势基本相同，但在 48 h 时 1.0%处理的产气量最大。绵羊日粮的 DMD、CPD、NDFD 和 ADFD 随着发酵时间的增加而增加，尤其是 0.8%、1.0%和 1.5%处理的 CPD、NDFD 和 ADFD 显著高于对照组（<0.05）。各处理发酵底物的 pH 值均在 6.21∼7.25 的正常范围内。0.8%、1.0%和 1.5%处理的 NH-N 均高于对照组。在 6 h-12 h 时，0.8%和 1.0%处理的总酸含量显著高于其他处理（<0.05），在 1.0%处理时达到最高。综合评价，甜叶菊秸秆对绵羊养分利用率的影响排序为：1.0%>0.8%>1.5%>0.4%>0.6%>0.2%。总体而言，1.0%的甜叶菊秸秆能促进养分降解和绵羊瘤胃发酵。
