Effects Of Enzyme And Bacteria Preparations On Its Ruminal Degradation And Microstructure Of Corn Stover

The objective of this study was to investigate the effects of enzyme and bacteria preparations on ruminal degradation and microstructure of corn stover,in order to provide a theoretical basis and data support for the application of corn stover.Firstly,we investigated the effects of enzyme and bacteria preparations on nutrient composition,fermentation quality and microstructure of corn stover.Secondly,we assessed the effects of enzyme and bacteria preparations on fermentation characteristics and microstructure of corn stover in vitro.We also determined rumen degradation rates and microstructure by in situ.The details are as follows:Experiment 1 Effects of enzyme and bacteria preparations on nutrients,fermentation quality and microstructure of corn stoverThis study was conducted to investigate the effects of corn stover fermented by enzyme andenzyme-bacteria compound preparations on its fermentation quality,nutrition composition and microstructure.And aimed to explore its mechanism of improving corn stovers utilization by breaking the cellulose microstructure.Five treatments were designed in the present study:corn stover group?CS?,silage control group?CK?,the corn stover fermented by compound enzyme group?CPL?,the corn stover fermented by compound enzyme and single bacteria group?CPLP?,and the corn stover fermented by compound enzyme and double bacteria group?CPLB?.Samples were prepared by vacuum packager in polyethylene bags.After storing at room temperature for 45 d,the chemical composition and fermentation quality of corn stover were measured by laboratory testing methods.Additionally,microstructure was analyzed by phenol-sulfuric acid colorimetry,2,2?-Bicinchoninic acid method,fourier transform infared spectroscopy and X-ray diffraction analyses.The results are showed as follows:1)Compared with the CK group,the pH,ratio of ammonia nitrogen to total nitrogen and ratio of acetic acid to lactic acid in the CPL group were significantly decreased?P<0.05?,the content of lactic acid,NDF,ADF,cellulose and hemicellulose in the compound enzyme group?CPL?did not affect?P>0.05?.The CPLP and CPLB group significantly increased the content of lactic acid?P<0.05?compared with the CK group.However,the pH,ratio of ammonia nitrogen to total nitrogen,ratio of acetic acid to lactic acid,NDF,ADF,cellulose and hemicellulose were significantly decreased?P<0.05?.2)Compared with the CK group,the crystallinity of tertiary structure in the CPL group was significantly increased?P<0.05?and the degree of polymerization of primary structure,the intermolecular hydrogen bonding force of secondary structure and the specific surface area of quaternary structure in the compound enzyme group did not change?P>0.05?.The degrees of polymerization of primary structure in the CPLP group and the CPLB group were significantly decreased?P<0.05?,which were lower by 38.92%and 35.64%,respectively.The specific surface area of quaternary structure was significantly increased?P<0.05?.The intermolecular hydrogen bonding force secondary structure was weakened.Furthermore,the crystallinity of tertiary structure did not change?P<0.05?.In conclusion,the CPLP and CPLB group significantly improved the chemical composition of corn stover.It can enhance the utilization rate of corn stover by reducing the degree of polymerization of primary structure and the amorphous area of tertiary structure,weakening the intermolecular hydrogen bonding force of secondary structure and increasing the specific surface area of quaternary structure from cellulose of corn stover.Experiment 2 Effects of enzyme and bacteria preparations on fermentation characteristics and microstructure of corn stover in vitroThis study aimed to investigate the effects of enzyme and bacteria preparations on fermentation characteristics and microstructure of corn stover in vitro.Gas production?0,6,12,24,48,72 h?,gas production parameters,dry matter degradation rate?DMD?,the total volatile fatty acid?TVFA?,ammonia nitrogen?NH₃-N?,pH after 24 h fermentation and microstructure?0,6,12,24,48,72 h?were measured.The results showed that:1)The CPLP group and CPLB group gas production after 72 h fermentation and theoretical gas production were significantly higher than those in CK group?P<0.05?,while TVFA,acetic acid,propionic acid and butyric acid concentrations were also significantly higher than those in the CK group?P<0.05?.There was no difference in gas production,theoretical gas production,TVFA,propionic acid,butyric acid in CPL group and control group at 72 h among treatments.2)The degree of polymerization of each treatment group gradually decreased with fermentation in vitro and degree of polymerization after 72 h fermentation was the lowest in CPLP group?61.29?.At the same time,the hydrogen bonding force of each group was weakened with fermentation in vitro.The characteristic absorption peaks of the functional groups of the CPLP group and the CPLB group after 72h fermentation were significantly lower than that in the CK group.The crystallinity and specific surface area of each group fluctuate.In summary,compound enzyme and bacteria preparations?CPLP,CPLB?can increase the gas production,dry matter degradation rate of corn stover,TVFA concentration and provide a large amount of carbohydrates for rumen fermentation.Experiment 3 Effects of enzyme and bacteria preparations on rumen degradation rate and microstructure of corn stover in situThe present study was conducted to determine the effects of enzyme and bacteria preparations on rumen degradation rate and microstructure of corn stover in situ.The rumen degradation rate of the dry matter?Dry Matter,DM?,crude protein?Crude Protein,CP?,NDF,ADF,cellulose and hemicellulose were measured and determined microstructure of corn stover at 0 h,6 h,12 h,24 h,48 h and 72 h.The results showed that:1)The rumen degradation rates of the DM,CP,NDF,ADF,cellulose,and hemicellulose in the CS group were lower than those in the CK group,and rumen degradation rates in the CPLP group and the CPLB group were significantly higher than that in the CK group?P<0.05?.2)With fermentation in situ,the degree of polymerizationin in CS group was significantly higher than that in the CK group?P<0.05?.The hydrogen bond interaction was higher than that in the CK group.The crystallinity and specific surface area showed a tendency of fluctuating change with time.The degree of polymerization of the CPLP group and the CPLB group was significantly lower than that in CK group?P<0.05?and the hydrogen bond strength was lower than that in the CK group?P<0.05?.In summary,the compound enzyme and bacterial preparation group?CPLP,CPLB?can destroied the fiber structure in the stover and improve rumen degradation rate of corn stover.