| In this study,the nutritional value of hedysarum scoparium of shrub plants was evaluated by pretreatment,combined with in vitro gas production test,to investigate the effect of different chemical pretreatments on the nutritional value of hedysarum scoparium.In this experiment,4%,6%and 8%levels of urea and calcium hydroxide were selected to treat the hedysarum scoparium,the effects of different chemical treatments on the nutritional value of hedysarum scoparium,cellulose enzymatic sugar production were investigated,and finally,the effects of chemical treatment on rumen fermentation parameters of hedysarum scoparium were assessed by in vitro gas production method.The experimental results were as follows:Experiment 1:Effect of chemical treatment on the nutritional value of hedysarum scoparium.All of the chemical treatments could improve the sensory value of the hedysarum scoparium;the phytoelectron micrographs showed that the control hedysarum scoparium showed an intact fiber structure,and the cell wall fiber structure was basically not destroyed.According to the different treatments,the cell wall fiber structure of the hedysarum scoparium was destroyed in the following order from the largest to the smallest:8%calcium hydroxide>6%calcium hydroxide>4%calcium hydroxide>8%urea>6%urea>4%urea>control group.In terms of neutral detergent fiber(NDF)and acid detergent fiber(ADF)contents,both ammoniated and alkalized groups were significantly(P<0.05)reduced.In terms of ash content,all treatment groups were significantly(P<0.05)higher than the control group,except for the ammoniation group with 6%addition level which was not significantly(P>0.05)different.In terms of calcium content,the alkalinized group was significantly(P<0.05)higher than the control and ammoniation groups.In terms of tannin,phytoanthocyanin and total phenol content,the ammoniated group with 4%and 6%addition levels and the alkalinized group with 6%and 8%addition levels were significantly(P<0.05)lower than the control group,with the lowest tannin content in the alkalinized group with 6%addition level.The relative values of feed in the alkalinized group were significantly(P<0.05)higher than those in the control group,with the alkalinized group having the highest 8%addition level.Experiment 2:Study of changes in lignin and cellulose enzymatic sugar production from chemically treated hedysarum scoparium.In terms of hemicellulose and cellulose content,the alkalinized group and ammoniation group with 6%addition level were significantly(P<0.05)lower than the control and ammonized groups,with the lowest hemicellulose content in the alkalinized group at 6%addition level and the lowest cellulose content in the alkalinized group at 8%addition level.In terms of lignin content,the differences were not significant(P>0.05)in both the ammoniated and alkalinized groups compared to the control group.Both the ammoniated and alkalinized groups significantly(P<0.05)increased the enzymatic reducing sugar yield of the hedysarum scoparium,with the 6%and 8%addition levels of the alkalinized group having significantly higher enzymatic reducing sugar yield than the ammoniated and control groups.Experiment 3:In vitro study of changes in ruminal degradation characteristics of chemically treated hedysarum scoparium.The dynamic trends of gas production in different treatment groups were more or less the same,and gas production increased with time,with the highest gas production rate in the alkalinized group was 24 h at 6%addition level;at 72 h,the highest gas production was in the alkalinized group at 6%addition level.Compared with the control group,the rapid gas production fraction was significantly(P<0.05)lower in the alkalinization group at 6%and 8%addition levels;the slow gas production in the alkalinization group at 4%and 6%addition levels was significantly(P<0.05)higher than that in the control group and the ammoniation group,with the alkalinization group at 6%addition level being the highest.The 6%and 8%addition levels of the alkalinization group significantly(P<0.05)improved the organic matter digestibility and metabolic energy;at 48 h and 72 h of in vitro incubation,compared with the control group,the microbial protein concentration of fermentation broth was significantly(P<0.05)increased in all treatment groups,except for the 4%addition level of the alkalinization group,which was not significantly(P>0.05)different from the control group;at 48 h and 72 h of in vitro incubation,compared with the control group of in vitro incubation,the acetic acid was significantly(P<0.05)higher in the 4%and 6%addition levels of fermentation broth acetic acid in the alkalinization group compared with the control group,but the differences were not significant(P>0.05)in the remaining groups;at 48 h and 72 h of in vitro incubation,the total VFA was significantly(P<0.05)higher in the 4%and 6%addition levels of alkalinization group compared with the control group.In conclusion,all chemical treatments could improve the nutritional value of hedysarum scoparium,reduce phyto-phenols and improve the fermentation state of the rumen,with the 6%alkalinization group having the best treatment effect. |
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