| Sweet clover is a legume forage with high protein content,which is not easy to succeed in silage due to low wsc content and high buffer energy value when silage alone.In this study,the Mixed Silage of sweet clover with green corn,corn straw and wheat straw was carried out.In the process of silage,conventional nutrient,gas chromatography,liquid chromatography and high-throughput sequencing were used to determine the nutritional components,fermentation products,microbial species and diversity,and rumen degradation characteristics of forage after silage,The quality of Mixed Silage of sweet clover was evaluated comprehensively to provide basis for the utilization of mixed Silage.The experiment is based on the minimum WSC required for silage（3%of the fresh silage weight）.The ratio of sweet clover to green corn is 8:2,7:3,6:4,5:5;recorded as Q8,Q7,Q6 And Q5.The mixing ratio of sweet clover and corn stalks is 9:1,8:2,7:3,6:4;recorded as H9,H8,H7 and H6.The ratio of sweet clover to winter wheat straw is 9:1,8:2;recorded as M9,M8.Silage in bags,and samples were taken from the silage on the 1d,3d,7d,15d,30d and 60d.The specific research results are as follows:The sweet clover silage with green corn,corn stalks and wheat stalks respectively,the pH value of Q6and H7 were decreased to 3.68 and 3.77 respectively in the silage 60d,which was significantly lower than others（P<0.05）.The WSC content was significantly different before and after silage.The Q5 WSC was reduced from 9.32%to 3.54%,and H6 was reduced from 8.94%to 3.71%.DM,NDF,ADF and EE was increased with the decrease of the amount of sweet clover,and the treatments were significant（P<0.05）.The content of NH3-N in H6 and Q5 were less to 0.66g/kg FM and 0.76g/kg FM respectively.The LA and AA contents of H6 were 4.57%FM and 1.63%FM respectively,which were significantly higher than others（P<0.05）.In the 15th day,PA was not detected,and in the 7th day,BA was not detected.During the silage,the number of LAB was reached the highest at 15d,and Q6 was the best to 11.35 Lg cfu/g,which was significantly higher than others（P<0.05）.The number of yeasts was increased first and then decreased.The number of yeasts was reached the Peak on the 7th day.The number of molds showed a decreasing trend,and no mold could be detected after the 30th day.Through high-throughput sequencing,the kinds and microbial flora were different in sweet clover silage with green corn,corn stalks and wheat stalks respectively.At the phylum level,the Predominant flora was phylum Firmicutes;at the genus level,the dominant was Weissella in silage with corn stalk,the ratio from 33.69%to 42.56%.The dominant was Lactobacillus Plantarum mixed silage with green corn,the ratio from 24.24%to 44.61%.On the Alpha diversity index,the silage with wheat stalks,M9 Shannon index was 2.84,Simpson index was 0.10,the community richness and species uniformity were higher than M8.Q6 Shannon index was 2.39,Simpson index was 0.20,community richness and species uniformity were higher than Q5,Q7,and Q8.The shannon index of H9 treatment was 2.33,Simpson index was 0.18,and species diversity were higher than H6,H7 and H8.The evaluation of mixed silage at 72 hours by in vitro,H8,H9,Q7,Q8,M8 and M9 Produced gas quickly from 0 to 10 hours.The gas Production from Q5 at 72 h was the highest to 103.57 ml.DMD wad increased rapidly from 0 to 36h,and DMD did not change significantly after 36h.DMD of H6 was the highest to 63.75%.Through comprehensive evaluation,the recommended addition amount was about 70%sweet clover silage with corn stalk.the recommended addition amount was about 60%when the silage of sweet clover and green corn. |
