Effects Of Lactic Acid Bacteria On Fermentation Quality Of Apple Residue Silage And Fermentation Characteristics In Vitro

The paper mainly determined the effect of different levels of lactic acid bacteria and the addition of rice bran meal on the fermentation quality of apple pomace silage.And the effect of apple pomace silage and apple pomace plus rice bran meal silage on the rumen fermentation characteristics in vitro of Holstein dairy cows was investigated by the method of gas production in vitro to comprehensively evaluate the nutritional value of silage apple pomace,which provided a theoretical basis for the practical application of apple pomace silage in ruminants.Experiment 1:Effect of lactic acid bacteria on fermentation quality of apple pomace silageThe experiment adopts 2×4 design.The lactic acid bacteria preparation with 0（group A）,1.0×10⁶ cfu/g（group B）,3.0×10⁶ cfu/g（group C）and 5.0×10⁶ cfu/g（group D）was added to apple pomace（Group I）with a moisture content of 65%～75%after drying and a mixture of apple pomace+rice bran meal powder（7:3）（Group II）with a total of 8 treatment groups,and each treatment was repeated 4 times.After 40 days of silage,the fermentation index of each treatment group was measured.The results show that the addition of lactic acid bacteria preparation can effectively improve the fermentation quality of apple pomace silage.The addition of lactic acid bacteria lowered the value of p H and NH₃-N/TN in the silage,and increased the content of organic acid,and the increase of lactic acid content was the most obvious.The lactic acid content of each experimental group was significantly higher than that of the control group（P<0.05）,and it was the highest in group I-C and the II-C.Compared with the control group,the addition of lactic acid bacteria increased the content of CP（P<0.05）and ADF in apple pomace silage compared with the control group.The content of CP in the I-C group was the highest at 4.84%,which was higher than that of I-A group and increased by 14.15%;group II-D had the highest content of CP（16.24%）,which was11.08%higher than that in the II-A group;and NDF content was significantly reduced compared to the control group（P<0.05）,but there was no significant differences（P>0.05）between the experimental groups.There were differences in the quality of silage between group I and II.The results showed that there was no significant difference in the content of p H and lactic acid between the two silages.The ratio of NH₃-N and TN value of group II was significantly lower than that of group I,and the contents of CP,NDF,and Ash in group II were significantly higher than those of group I.The quality of silage in group II was better than that in group I.Experiment 2:Effects of lactic acid bacteria and apple pomace silage on the characteristics of rumen fermentation in vitroThe lactic acid bacteria with 0（group A）,1.0×10⁶ cfu/g（group B）,3.0×10⁶ cfu/g（group C）,and 5.0×10⁶cfu/g（group D）was added to the apple pomace silage and apple pomace+rice bran meal（7:3）silage（group II）as fermentation substrate,with 3 replicates per treatment.And the rumen fluid of healthy Holstein cows was taken for rumen fermentation test in vitro.During the test,the gas production of each treatment group was recorded at 2,4,8,12,24,36,and 48 h,and the fermentation broth of each treatment group was collected at 24 and 48 h respectively.And the fermentation index was measured after the ending of experiment.The results show that the gas production of silage added with lactic acid bacteria after in vitro fermentation is significantly higher than that of the control group,and there is a gradual upward trend with the increase of the lactic acid bacteria addition level.At 24 h of fermentation,the DMD of group I-C was the highest at50.21%,which was 28.05%higher than that of the control group;the DMD of group II-B and II-C were significantly higher than that of the control group;the highest was 46.86%in group B,and it increased by 18.03%compared with the control group.At 48 h of fermentation,the DMD of group I-B,I-C and I-D were significantly higher than control of group A（P<0.05）,which were 9.83%,11.00%and 6.04%higher than group A,respectively.The DMD was highest in group II-B and II-C,which was significantly higher than that in control group A（P<0.05）.The DMD in group B was the highest at 65.21%,which was an increase of 9.89%compared with group A.During the two fermentation periods of 24 h and 48 h,the p H and NH₃-N concentrations of group I and group II were within the normal range of rumen changes.At 48 h of fermentation,the concentrations of MCP in group I-B and II-D were the highest;the concentrations of AA,PA,BA,and TVFA in group I-B and II-C were higher than those in other group,which were significantly different from the control group（P<0.05）.Conclusion:（1）Compared with single apple pomace silage and the mixed silage with apple pomace+rice bran meal（7:3）,the silage quality of the mixture is better and more conducive to preserve than single apple pomace.（2）From the perspective of the silage effect,lactic acid bacteria can improve the quality of silage fermentation,and the added levels of 3.0×10⁶ cfu/g and 5.0×10⁶ cfu/g have better silage quality.（3）From the results of in vitro fermentation test of apple pomace silage,the addition of 3.0×10⁶ cfu/g lactic acid bacteria preparation in single-storage apple pomace had the best in vitro fermentation effect,and mixed silage apple pomace+rice bran meal added 5.0×10⁶ cfu/g lactic acid bacteria preparation had the best in vitro fermentation effect.