| In this study,the effects of six plant extracts added at different levels on rumen fermentation characteristics,methane production,total gas production,respiration entropy and digestion performance of mutton sheep were studied by in vitro gas production test and feeding test.Experiment one:This experiment adopts the rumen liquid fermentation gas simulation method,selection of single-factor completely random design of experiment,gastric juice in vitro tumor(from northeast fine wool sheep X Du Bo sheep cross ram),respectively,in the add oregano oil(8,24,40,and 56 mL/L),coconut oil(15,30,45 and 60 g/kg),condensed tannin(20,40,60 and 80 g/kg),silk LanZao glycosides(2.5,5,7.5 and 10 g/kg),tea saponin(10,20,30 and 40 g/kg)and the free gossypol(0.1,0.2,0.3,and 0.4 g/kg),The effects of six plant extracts on total gas production,methane(CH4)production and pH of gastric juice in vitro were studied.The results show that:1)when in vitro fermentation time is 6 h,56 mL/L oregano oil group of in vitro gas production rate decreased significantly,adding high dose(40,56 mL/L)oregano oil group of CH4 production decreased significantly,in vitro fermentation time of 12 h,adding high dose(40,56 mL/L)of the pH value of the oregano oil group significantly increased(P<0.05),and low dose group(8 and 24 mL/L)compared with significant difference(P<0.05),24,40,56 mL/L total volume of test group and CH,production decreased significantly(P<0.05),Fermentation time of 24 h,56 mL/L oregano oil of pH and low dose group(8 and 24 mL/L)compared with signi ficant difference(P<0.05),the total volume of the test group and CH,production were significantly lower than control group(P<0.05),high dose group(40,56 mL/L)and 8 mL/L oregano oil group compared to the total volume and CH4 production significant difference(P<0.05);2)compared with the control group,when the fermentation time was 6 h,the pH of the 60g/kg coconut oil group was significantly lower than that of the control group(P<0.05),while the pH,total gas yield and CH4 yield of other coconut oil were not significantly different.3)compared with control group,in vitro fermentation to add condensed tannins to 6 h groups of CH4 production were significantly decreased(P<0.05),while in vitro fermentation time of 12 h,80 g/kg of condensed tannins pH group decreased significantly(P<0.05),and 20 g/kg significant difference between groups(P<0.05),in vitro fermentation more than 12 h,high dose(60,80 g/kg)of condensed tannins group total volume and CH4 yield significant difference compared with control group(P<0.05);4)compared with the control group,there were no significant differences in the pH and total gas production of yucca saponins.The CH4 production of group 5 g/kg increased significantly(P<0.05),and the difference between groups was significant(P<0.05).5),20 g/kg of tea saponin,12 h in vitro fermentation of total volume significantly reduced(P<0.05),30 g/kg of tea saponin group pH increased significantly(P<0.05),in vitro fermentation 24 h,20,30,40 g/kg of tea saponin of CH4 production decreased significantly(P<0.05),40 g/kg group with significant difference between the experimental group(P<0.05),30 g/kg difference between experimental group and 10 g/kg group significantly(P<0.05);6)in vitro fermentation time is 6 h,add 0.2,0.4 g/kg free gossypol made pH decreased significantly(P<0.05),and significant difference between groups(P<0.05),add 0.3 g/kg free gossypol made pH increase significantly(P<0.05),and 0.1 g/kg free gossypol group difference was not significant,and the difference between groups was significant(P<0.05),no significant difference in CH4 production and total volume.Based on the results of rumen liquid external fermentation,the best CH4 emission inhibition effect was obtained by adding oreganum oil(24,40,56 mL/L),condensed tannin(40,60,80 g/kg)and tea saponin(20,30,40 g/kg)in vitro culture.Experiment two:In this study,16 22-month-old Dubo sheep X small-tailed Han sheep hybrid sheep with a body weight of 45.83±4.11 kg were randomly divided into 2 groups,8 in each group and 2 in each level.According to the results of the experiment one outside fermentation chose 20 is added in the mutton sheep diet,35,50 ml/kg oregano oil,40,60,80 g/kg of condensed tannins and 20,25,30 g/kg of tea saponin,each group of 8 d of the trial period,the feeding stage 5 d,in the hot breath test device was developed for the determination of the sheep digestion performance,total volume,CH4 gas production rate and breathing entropy,a total of 3 d.The results showed that:1)compared with the control group,the addition of 20 ml/kg of oregano oil could significantly inhibit the yield of CH4(P<0.05),while the difference between the other treatment groups was not significant.2)compared with the control group,the addition of 60,80 g/kg condensation tannin group could significantly inhibit the total gas production and CH4 production of mutton sheep(P<0.05),and the difference between treatment groups was not significant.3)adding 20,25 and 30 g/kg tea saponin group into the diet of mutton sheep can significantly reduce the total gas production and CH4 production of mutton sheep(P<0.05).4)no significant effect was observed on apparent digestibility of crude protein(CP),neutral washing fiber(NDF)and acid washing fiber(ADF)of mutton sheep in each test group added oreganum oil,condensed tannin and tea saponin.The above results showed that the addition of 24,40 and 56 mL/L oreganum oil,40,60 and 80 g/kg condensed tannin and 20,30 and 40g/kg tea saponin could significantly inhibit the yield of CH4 in the simulated rumen fermentation test in vitro.Considering the factors of rumen fermentation,digestive performance,in vitro gas production and price of the three additives,the effect of adding 30 g/kg tea saponin into the diet in the actual feeding was the best. |
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