| In this study,three investigations were conducted that the effects of mixed storage ratio and additives on the quality of oat grass and rice straw mixed wrapped silage,and analyzed and evaluated the feed value of oat grass and rice straw mixed wrapped silage through in vitro gas production method and in vitro fermentation test.On this basis,the prepared oat grass and rice straw mixed wrapped silage was used as coarse fodder to feed the Hu sheep.By comparing the different combinations of oat grass and rice straw wrapped silage on the sheep’s internal digestion,rumen fermentation,growth performance,meat quality and other indicators,Determine the best feeding plan of oat grass and rice straw mixed wrapped silage,and provide reference for the reasonable use of oat grass and rice straw in the production of mutton sheep.The research content mainly includes the following three parts:Trial 1.Selection of the raw material ratio and production process of oat grass and rice straw mixed wrapped silageThis experiment uses oat grass and rice straw as raw materials and adopts a completely randomized experimental design.The experiment is divided into 7 treatment groups,namely control rice straw silage(RS),treatment 1:oat grass+rice straw(3:7)conventional mixed storage(OR30),treatment 2:oat grass+rice straw(4:6)conventional mixed storage(OR40),treatment3:oat grass+rice straw(5:5)conventional mixed storage(OR50),treatment 4:oat grass+rice straw(3:7)mixed storage with formic acid,lactic acid bacteria,cellulase(T30),Treatment 5:oat grass+straw(6:4)added formic acid,lactic acid bacteria,cellulase mixed storage(T40),treatment 6:oat grass+rice straw(5:5)added formic acid,lactic acid bacteria,cellulase mixed storage(T50).The silage was opened 45 days later,and sensory evaluation and nutrient composition analysis were performed on each group of silage.The results showed that:1)the visible sensory evaluation of oat grass and rice straw mixed silage was better than that of rice straw silage(RS group).2)compared with the rice straw silage group,the pH,acetic acid,propionic acid and butyric acid content of other groups of silage significantly reduced(P<0.05),the content of lactic acid in the OR30,OR40,and OR50 groups increased significantly(P<0.05);the content of lactic acid,acetic acid,TSCFA and the ethylene-propylene ratio in the T30,T40,and T50 groups treated with additives were significantly lower than the same ratio OR30,OR40 and OR50 groups(P<0.05),and the pH of the T50 group was significantly lower than that of the other treatment groups(P<0.05);compared with the OR30,OR40 groups,the NH3-N/TN in the T30,T40 and T50 groups were significant decrease(P<0.05).Compared with the additive silage group,the content of propionic acid in the T50 group was significantly higher than that in the T40 group(P<0.05).3)In terms of nutritional components,the WSC content in the T30,T40,and T50 groups were significantly higher in the OR30,OR40,and OR50 groups(P<0.05),the content of DM,CP,EE and NDF was not significantly different(P>0.05).Compared with the additive silage group,the content of DM and NDF in the T30 group was significantly higher than that in the T50 group(P<0.05),while the content of CP and WSC in the T50 group was significantly higher than that of the T30 and T40 groups.There was no significant difference in EE and Ash among the 3 treatment groups(P>0.05).And there was no significant difference in ADF content in each treatment group(P>0.05).It can be seen that the nutritional value and fermentation quality of oat grass and rice straw mixed silage is better than that of rice straw directly wrapped silage,and the silage effect of additives used in oat grass and rice straw mixed silage is better.When the mixing ratio of oat grass and rice straw is 4:6,the silage effect is best after adding formic acid,lactic acid bacteria and cellulase.Trial 2:Production of oat grass and rice straw mixed-wrapped silage and analysis and evaluation of its feeding valueIn vitro gas production method and in vitro fermentation test were used to evaluate the feeding value of oat grass and rice straw mixed wrapped silage.Oat grass silage(OS group),oat grass:rice straw 4:6 mixed silage(OR group),rice straw silage(RS group)and rice straw preserved in its natural state(RH group)as fermentation substrates for continuous 72 h in vitro gas production test and in vitro fermentation culture test.The results showed that:1)The gas production in the OS group was the largest at each time point;the gas production in the OS and OR groups was significantly higher than that in the RH group at each time point(P<0.05),and the cumulative gas production at 72 hours was significantly higher than that in the RS and RH groups(P<0.05).However,there was no significant difference between the OS group and the OR group at other time points except 12 h(P>0.05).2)At 12 h,24 h,48 h and 72 h,the pH of the OS,OR and RS groups were significantly lower than the RH group(P<0.05).At 12 h,24 h,and 48 h,the pH of the OS group was significantly lower than that of the RS group(P<0.05).3)The concentration of TVFA in culture medium of each group increased with the increase of time.At 12 h,the concentration of TVFA in the culture broth of the OS group was significantly higher than that of the other groups(P<0.05),at 6 h,48 h and 72 h,the TVFA concentration in the culture medium of the OS,OR,RS and RH groups was significantly higher than that of the control group(P<0.05);At 3 h,6 h,12 h,24 h and 72 h,there were significant differences in the concentrations of acetic acid,propionic acid and butyric acid in culture medium among all groups(P<0.05),the butyric acid concentration in all treatment groups was significantly lower than that in control group(P<0.05),and the acetic acid concentration in all treatment groups was significantly lower than that in control group(P<0.05),at 3 h,6 h,12 h and 24 h,the concentration of propionic acid in all treatment groups was significantly higher than that in control group(P<0.05).At 48 h,the concentrations of propionic acid and butyric acid in culture medium were significantly different among all groups(P<0.05),but the concentration of acetic acid was not significantly different among all groups(P>0.05).The ratio of acetic acid to propionic acid in culture medium of all treatment groups at all time points was significantly lower than that of control group(P<0.05).4)At 3h,24 h,the NH3-N concentration in the culture medium of the OS group significantly higher than the RH group(P<0.05).At 48 h,there was no significant difference in the NH3-N concentration in the culture medium between the OS group and the OR group(P>0.05),but both were significantly higher than the RS group and the RH group(P<0.05)5)The IVDOM of mixed silage of oat grass and rice straw in different proportions increased continuously with the increase of time.At 3 h,6 h,24 h,48 h and 72 h,the IVDOM of OS and OR group was significantly higher than that of RS group and RH group(P<0.05).Among them,at 3 h,6 h and 72 h,OS group IVDOM was significantly higher than the OR group(P<0.05).In summary,oat grass silage and 4:6 mixed wrapped silage of oat grass and rice straw can improve the characteristics of rumen fermentation in vitro,and the effect of oat grass silage is better.Trial 3.The effects of different combinations of oat straw and rice straw wrapped silage on rumen fermentation,growth performance and meat quality of Hu sheepIn the trial,48 Hu sheep with an average weight of 27±1.3 kg and good health conditions were randomly divided into 4 treatment groups,each with 4 replicates,and each replicate with 3 sheep.Treatment group 1 is the OS group fed with oat grass silage,and treatment 2 is the OR group fed with oats and rice straw mixed silage at a ratio of 4:6,treatment 3 is the RS group fed with rice straw silage,and treatment 4 is the RH group fed with rice straw.The test period was 47 days,the test pre-feeding period was 7 days,and the normal feeding period was 40 days.Rumen fluid was collected on the first day,the 20th day,and the 40th day.The results showed that:1)The net weight gain and average daily gain of the OS group were significantly higher than those of the RS group and the RH group(P<0.05),but there was no significant difference from the OR group(P>0.05);the average daily feed intake of the OS group was significant higher than the RH group(P<0.05),and not significantly different from the OR and RS groups(P>0.05).2)The apparent digestibility of DM in the OS group was significantly higher than the RH group(P<0.05);the apparent digestibility of EE in OS group and OR group was significantly higher than RS group and RH group(P<0.05);the apparent digestibility of NDF and ADF in RS group was significantly higher than that in OS group(P<0.05),and there was no significant difference from OR group and RH group(P>0.05).3)The NH3-N content in RS group was significantly higher than that in RH group on day 1(P<0.05);On day 20,the acetic acid content of rumen fluid in RH group was significantly higher than that in other groups(P<0.05),the propionic acid content in OS group was significantly higher than that in other groups(P<0.05),the propionic acid content in OR group and RS group was significantly higher than that in RH group(P<0.05),and the ratio of acetic acid to propionic acid in OS group and OR group was significantly lower than that in RH group,with the smallest value of 2.92 in the OS group;There were no significant differences in rumen fluid pH,NH3-N,MCP,TVFA,acetic acid,and butyric acid contents among all groups(P>0.05).TVFA content of rumen fluid in OS group was significantly higher than that in RH group on day 40(P<0.05),but there were no significant differences in other indexes(P>0.05).4)The level of alanine aminotransferase in the blood of the OS group was significantly higher than that of the other groups(P<0.05),while the content of creatinine was significantly lower than that of the RS group and the RH group(P<0.05);there was no significant difference in blood urea nitrogen between the OS group and the OR group(P>0.05),but all were significantly lower than the RH group(P<0.05).5)The longest back muscle color H of the OS group was significantly higher than that of the other groups(P<0.05),and the water loss rate and shear force of the longissimus dorsi in the RS group were significantly higher than those in the RH group(P<0.05),but it was not significantly different from the OR group of the OS group(P>0.05);the cooking loss of the foreleg muscle of the OS group was significantly lower than that of the RH group(P<0.05),there was no significant difference from OR group and RS group(P>0.05);the pH45 min of retreat muscles in OR group was significantly higher than that of OS group and RS group(P<0.05);the differences in pH24 h,flesh color L and flesh color C of different muscles in each group were all not significant(P>0.05).6)The C14:0,C15:0,C16:0,C18:0 and C18:ln9c contents of the longissimus dorsi in the OS group were significantly higher than those in the RS group(P<0.05).The difference between the two groups was not significant(P>0.05).The content of C17:0 and C18:3n3 in the OS group was significantly higher than the other groups(P<0.05),but the content of C22:6n3 was significantly lower than the other groups(P>0.05),there was no significant difference in the other muscle fatty acid indexes of each group(P>0.05). |
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