The Study On Improving The Feed Value Of Corn Stalks By Biotechnology And Its Mechanism

The use of biotechnology to improve the utilization rate of straw feed can help solve the practical problems caused by straw burned and waste of feed resources.In this study,the effect of silage fermentation on the improvement of straw quality was screened,and the efficient biological agent was screened out.The mechanism of silage biological agent was explored and the effect was verified by in vitro,in situ and in vivo experiment.Test was divided into the following four steps:1.Effects of ensiling on quality and bacteria composition of corn stalks were investigated.The objective of the present study was to investigate the effect of ensiling process of corn stalks silage on its sensory indicators,fermentation quality,nutrition composition and bacteria composition and abundance;2.Ascertain the effects of microecological agents on fermentation quality,nutrition composition and in situ ruminal degradability of corn stalks silage;3.The effect of silage fermentation days,biological inoculant,and silage environmental variables on silage quality and both bacterial and fungal communities involved in corn stalks ensiling was investigated;4.Animal validation test was investigated in this study to elucidate the effect of corn stalks silage treated with biological inoculant on growth and slaughter performance of Dorper × small-tailed Han crossbred male lambs.Results showed that:1.the corn silage was yellow-green and had the good texture and smellafter ensiling 45 days.The pH value,lactic acidwere significantly increased(P<0.05),while the content ofneutral detergent fiber(NDF)and acid detergent fiber(ADF)had the downward trend(0.1<P<0.05);the numbers of Proteobacteria plylum,Gammaproteobacteria class,Enterobacterialesorder,Enterobacteriaceae family and Weissella genus were significantly decreased(P<0.05),while the numbers of Firmicutes phylum,Bacilli class,Lactobacillales order,Lactobacillaceae family,and Pediococcus andLactobacillus genus increased significantly(P<0.05)after ensiling 45 days;2.Mixture of cellulose and lactobacillus treatments(MCL1and MCL2)had the lowest pH value and the highest in situ degradation of NDF and cellulose compared with other treatments(P<0.05).In addition,in situ degradation of acid detergent lignin(ADL)was increased but did not reach significance(P>0.05).Compared with control,NDF,ADF and cellulose contents of mixture of cellulose and lactobacillus treatments decreased(P<0.05);3.The effect of ensiling time on crude protein(CP),NDF,ADF,water soluble sugar(WSC),pH value,ammonia nitrogen(NH3-N),lactic acid(LA),acetic acid(AA),and propionic acid(PA)was observed(P<0.05);however,only the effect of the additive on NDF,pH value,LA,and PA was significant during ensiling(P<0.05).Significant effects(P<0.05)of ensiling time and the interaction between ensiling time and additive on bacterial and fungal community structurewere observed during ensiling.Significant effects(P<0.05)of additive on bacterial community structure were observed(P<0.05),but not observedon fungal community structure(P>0.05);4.The weight gain(WG),average daily weight gain(ADG),carcass weight,apparent digestibility of dry matter(DM)and ADF of corn stalks silage with biological agenttreatment,corn stalks silage without additive treatment and Leymus Chinensis treatment were significantly higher than those of blank control group(P<0.05).Dry matter and organic matterexcretion was lower than blank control and Leymus Chinensis group(P<0.05).Apparent digestibility of NDF of treatment I and II were higher than blank control and Leymus Chinensis group(P<0.05).But no significant differences were found inpercentage of LWBS and erum metabolite concentrations(EMC)in all the treatments(P>0.05).The results indicated that:1.Ensiling process could improve the sensory indicators,fermentation quality,nutrition composition with effectively reducing the amount of harmful bacteria and increasing the number of beneficial bacteria,which can reduce the potential risk to animal health pathogens exist;2.Application of mixture of celluloseand lactobacillus into fermentation of corn stalks contributed to the break down of lignin-cellulose-hemicellulose composite structure and improvement of fermentation quality,which consequently resulted into high nutrient digestibility and utilization efficiency,and the MCL2 treatment had the best effect;3.Biologicalinoculant improves corn stalks utilization by affecting the fungal community structure;4.The corn stalks were improved by using biological agent,and its nutrient value is close to that of Leymus Chinensis;biological agent could significantly improve feeding effect.