添加不同生物益生菌对木薯块根青贮品质和微生物菌群多样性的影响

Effect of different biological probiotics on the quality of cassava root silage and the impact on microbial flora diversity

以华南9号鲜木薯(Manihot esculenta)块根为材料,设4个处理组,试验组分别添加微生物发酵菌剂(C_(1))、高效复合菌酶制剂(C_(2))和生物饲料发酵剂(C_(3)),对照组(CK)添加等体积蒸馏水,充分混合后密闭发酵30 d开封测定其营养成分、发酵品质及微生物群落结构,旨在探究添加不同生物益生菌对木薯块根的青贮品质和微生物多样性的影响。结果表明,添加生物益生菌后,各处理组的干物质和乳酸含量显著提升(P<0.05),可溶性糖、中性洗涤纤维含量和乳酸/乙酸无显著差异(P>0.05);C_(2)组粗蛋白含量显著低于CK组(P<0.05);C_(1)和C_(3)组的酸性洗涤纤维显著低于CK组(P<0.05),C_(1)组乙酸显著高于CK组(P<0.05);4个处理组的pH均在4.2以下,检测到少量丙酸,未检测到丁酸,且氨态氮/全氮均低于10%,属优良品质饲料。从微生物菌群结构看,菌群的丰度、多样性和分配的均匀程度均有所降低。在门水平上,添加生物益生菌后各处理组厚壁菌门(Firmicutes)丰度显著增加(P<0.05),蓝藻细菌门(Cyanophyta)、未分类细菌和其他细菌丰度均显著降低(P<0.05),C_(3)组变形菌门(Proteobacteria)显著降低(P<0.05);在属水平上,添加菌剂后乳杆菌属(Lactobacillus)和乳球菌属(Lactococcus)等有益菌属作为优势菌属丰度增高,未分类肠杆菌属和沙雷菌属(Serratia)等杂菌和有害菌属丰度则降低。综合分析可知,不同生物益生菌处理下的木薯块根青贮效果表现为C_(3)>C_(1)>C_(2)。

We performed an experiment using fresh cassava root(South China No.9)tubers under four different treatments:microbial fermenting agent(C_(1)),high efficiency complex bacterial enzyme preparation(C_(2)),biological feed fermenting agent(C_(3)),and the control group(CK),with equal volumes of distilled water.The nutrient composition,fermentation quality,and microbial community structure were measured after 30 days of closed fermentation after the tuber material and bacterial agent were thoroughly mixed.The objective was to discover the effect of adding different biological probiotics on silage quality and microbial diversity of cassava tubers.The results showed that the dry matter and lactic acid content were significantly elevated in each treatment group after the addition of bio-probiotics(P<0.05),and there were no significant differences in soluble sugars,neutral detergent fiber content,and lactic acid/acetic acid(P>0.05).The crude protein content of the C_(2) group was significantly lower than that of the CK group(P<0.05).The acid detergent fiber content was significantly lower in the C_(1) and C_(3) groups than in the CK group(P<0.05).The level of acetic acid in the C_(1) group was significantly higher than that in the CK group(P<0.05).The pH of all four treatment groups was below 4.2;a small amount of propionic acid was detected,but no butyric acid was detected,and ammoniacal nitrogen/whole nitrogen was below 10%in all the treatment groups.It shows that the four treatment groups are of excellent quality.The microflora structure was then analyzed and we found that the abundance,diversity,and uniformity of distribution of the flora were reduced.At the phylum level,the addition of bioprobiotics resulted in a significant increase in the abundance of the thick-walled phylum(P<0.05),and a significant decrease in the abundance of the cyanobacterial phylum,unclassified bacteria,and other bacteria(P<0.05).Among them,the phylum Proteobacteria was significantly reduced in group C_(3)(P<0.05).At the genus level,the addition of bio-probiotics increased the abundance of dominant genera,such as Lactobacillus and Lactococcus and decreased the abundance of miscellaneous bacteria,such as unclassified Enterobacter and Serratia.The combined analysis showed that the effect of adding different biological probiotics to cassava tubers was C_(3)>C_(1)>C_(2).