构树与茅台酒糟不同混合比例对其青贮品质及微生物组成的影响

Effects of Different Mixing Ratios of Broussonetia papyrifera L.and Moutai Distillers’Grains on Quality and Microbial Composition of Their Silage

本试验旨在探究构树与茅台酒糟不同混合比例对其青贮品质及微生物组成的影响。试验共设置6个不同的构树与茅台酒糟混合比例,分别为:100%构树(GCK组)、80%构树和20%茅台酒糟(Ⅰ组)、60%构树和40%茅台酒糟(Ⅱ组)、40%构树和60%茅台酒糟(Ⅲ组)、20%构树和80%茅台酒糟(Ⅳ组)以及100%茅台酒糟(JCK组),每个处理3个重复。青贮60 d后,测定青贮样品的养分含量、发酵品质及微生物组成。结果表明:1)Ⅱ组青贮饲料粗蛋白质(CP)含量显著高于GCK组和Ⅰ组(P<0.05),中性洗涤纤维(NDF)含量显著低于GCK组(P<0.05),酸性洗涤纤维(ADF)含量显著低于GCK组和Ⅰ组(P<0.05)。所有混合青贮组(Ⅰ组~Ⅳ组)青贮饲料可溶性碳水化合物(WSC)和干物质(DM)含量均显著低于JCK组(P<0.05),NDF和ADF含量均显著低于GCK组(P<0.05)。2)Ⅱ组青贮饲料pH显著低于GCK组和Ⅰ组(P<0.05),乳酸(LA)含量显著高于Ⅲ组和JCK组(P<0.05)。各组青贮饲料均未检测出丁酸存在。3)GCK组、Ⅳ组和JCK组青贮饲料细菌的优势菌门为变形菌门(Proteobacteria),其余组的优势菌门为厚壁菌门(Firmicutes);Ⅱ组青贮饲料的优势菌属为乳杆菌属(Lactobacillus),相对丰度为41.75%。各组青贮饲料真菌的优势菌门为子囊菌门(Ascomycota);随着茅台酒糟混合比例的提高,青贮饲料的毕赤酵母属(Pichia)相对丰度呈现先降低后升高的趋势,Ⅱ组青贮饲料的毕赤酵母属相对丰度低于JCK组和GCK组,Ⅰ组青贮饲料的毕赤酵母属相对丰度高于JCK组和GCK组。综合考虑营养价值、发酵品质和微生物组成等因素,60%构树与40%茅台酒糟混合青贮发酵品质较好。

This experiment was conducted to investigate the effects of different mixing ratio of Broussonetia papyrifera L.and Moutai distillers’grains on quality and microbial composition of their silage.A total of 6 different mixing ratios of Broussonetia papyrifera L.and Moutai distillers’grains were set in the experiment as follows:100% Broussonetia papyrifera L.(GCK group),80% Broussonetia papyrifera L.and 20% Moutai distillers’grains(group Ⅰ),60% Broussonetia papyrifera L.and 40% Moutai distillers’grains(group Ⅱ),40% Broussonetia papyrifera L.and 60% Moutai distillers’grains(group Ⅲ),20% Broussonetia papyrifera L.and 80% Moutai distillers’grains(group Ⅳ)and 100% Moutai distillers’grains(JCK group),and there were 3 replicates in each treatment.After silage for 60 days,the nutrient contents,fermentation quality and microbial composition of the silage samples were determined.The results showed as follows:1)the crude protein(CP)content of silage in group Ⅱ was significantly higher than that in groups GCK and Ⅰ(P<0.05),the neutral detergent fiber(NDF)content was significantly lower than that in GCK group(P<0.05),and the acid detergent fiber(ADF)content was significantly lower than that in groups GCK and Ⅰ(P<0.05).The contents of water soluble carbohydrate(WSC)and dry matter(DM)in mixed silage groups(groups Ⅰ to Ⅳ)were significantly lower than those in JCK group(P<0.05),and the contents of NDF and ADF were significantly lower than those in GCK group(P<0.05).2)The pH of silage in groupⅡwas significantly lower than that in groups GCK and Ⅰ(P<0.05),and the lactic acid(LA)content was significantly higher than that in groups Ⅲ and JCK(P<0.05).No butyric acid was detected in silage in all groups.3)Proteobacteria was the dominant bacterium of silage in groups GCK,Ⅳ and JCK,while Firmicutes was the dominant bacterium in the other groups.The dominant bacterium of silage in group Ⅱ was Lactobacillus,with a relative abundance of 41.75%.The dominant fungus of silage in each group was Ascomycota;with the increase of mixing ratios of Moutai distillers’grains,the relative abundance of Pichia of silage in group Ⅱ was lower than that in groups JCK and GCK,and which in groupⅠwas higher than that in groups JCK and GCK.Considering the nutritional value,fermentation quality and microbial composition,the fermentation quality of silage mixed with 60% Broussonetia papyrifera L.and 40% Moutai distillers’grains is better.