Effect Of Two Commercial Lactic Acid Bacteria Additives On Silage Quality Of Whole Plant Maize

Silage is an indispensable food source for ruminants,and with the development of the economy,the proportion of silage is increasing,and at the same time,silage is of great significance to the development of animal husbandry.The aim of this experiment was to investigate the effects of homo-and homo-heterotypic mixed lactic acid bacteria on the nutritional value,fermentation quality and microbial community of whole plant maize after silage and aerobic exposure,to further investigate the trends of microbial communities during whole plant maize silage and to provide insights for improving silage preservation.Experiment 1:Effect of two lactic acid bacteria additives on nutritional value,fermentation quality and microbiota of whole plant maize silageThree treatments were set up in this experiment:(1)control(CK);no treatment;(2)Lactobacillus plantarum(LP);2.5×10~8 CFU/kg;(3)Lactococcus lactis and Lactobacillus buchneri(LLLB;2.6×10~8 CFU/kg;Lactococcus lactis:Lactobacillus buchneri=1:1)After 1,2,3,5,7,15,30 and 45 days of silage,open samples were taken and used to determine fermentation indicators and microbiota;45-day samples were taken for nutrient determination.The results showed that the soluble protein and non-protein nitrogen of whole plant maize silage were significantly higher in the LP group than in the LLLB group(P<0.05),and there were no significant differences in crude protein,neutral detergent fiber,acid detergent fiber,soluble carbohydrate,and starch content among the three treatment groups(P>0.05).The PC fraction(unavailable nitrogen)of the CNCPS fraction was significantly lower in the LP group than in the CK group(P<0.05),and the CB1 fraction was significantly higher in the LP group than in the LLLB group of the CK combination(P<0.05).There was no significant effect of the three treatment groups on methane and energy value of whole plant maize silage(P>0.05).total digestible neutral detergent fiber was significantly higher in the LP group than in the CK and LLLB groups.There was no significant difference in p H and lactic acid between the three treatment groups after 30 days of silage(P>0.05).There was no significant difference in acetic acid between LP and LLLB groups on the 45th day of silage(P>0.05),and both were significantly higher than CK group(P<0.05).The ammoniacal nitrogen content of the LLB group was significantly higher than that of the LP group(P<0.05)during silage 5 to 45 days.The mold and yeast no longer appeared after 7 days of silage,and there was no significant difference in the number of lactic acid bacteria between the three treatment groups at 45 days of silage.At 30days of silage,the OUT index and Chao1 index of LP and LLLB groups were significantly lower than those of CK group(P<0.05),and at day 45 was no significant difference between the three treatment groups(P>0.05).During silage,both LP and LLLB groups increased the abundance of Lactobacillus and decreased the abundance of Weissella.Among them,Lactobacillus abundance increased from 30.50%to 77.85%in the LP group and from 32.84%to 77.23%in the LLLB group.the abundance of Weissella decreased from 33.34%to 5.68%in the LP group and from 25.15%to5.69%in the LLLB group.Experiment 2:Effect of two lactic acid bacteria additives on aerobic stability and microbiota of whole plant corn silage after aerobic exposureThe experimental design was the same as Experiment 1.The fermentation indexes were measured at 2 h,4 h,8 h,16 h,32 h,64 h and 128 h after opening the bags for 45 days of silage.The microbiota was determined by taking 4,8,16 and 32 h of silage.At 2 h of aerobic exposure,p H was significantly lower in the LP and LLLB groups than in the CK group(P<0.05),and there was no significant difference between the three treatment groups after 32 h of aerobic exposure(P>0.05).There was no significant difference in lactate content between the three treatment groups before 32 h of aerobic exposure(P>0.05).At 2 h of aerobic exposure,the acetic acid content in the LP group was significantly higher than that in the LLLB group(P<0.05),and at 128 h of aerobic exposure,there was no significant difference between the two(P>0.05),and it was significantly higher than that in the CK group(P<0.05).At 2 h of aerobic exposure,the number of lactic acid bacteria in the LP group was significantly higher than that in the CK and LLLB groups(P<0.05),and the number of lactic acid bacteria in the LP group was not significantly different from that in the LLLB group at 32 h of aerobic exposure(P>0.05),and lactic acid bacteria were no longer detected in the three treatment groups after 64 h.There was no significant difference in alpha diversity between treatment groups after aerobic exposure(P>0.05).Aerobic exposure for 128 h resulted in significantly lower numbers of mycobacteria and yeasts in the LLLB group than in the control and LP groups(P<0.05),and significantly lower numbers of Clostridium in the LP group than in the LLLB and CK groups(P<0.05).During 32 h of aerobic exposure,the dominance of Lactobacillus remained stable and dominated the microbial community.In the LP group,Lactobacillus abundance was maintained at 69.74%and 69.68%from 4 h to 32 h of aerobic exposure.Lactobacillus abundance in the LLLB group was maintained at 71.15%and 69.38%during the same period.Experiment 3:Effect of two lactic acid bacteria additives on ruminal degradation rate of whole plant maize silage and in vitro gas productionRuminal degradation rate and in vitro gas production test were performed by taking silage samples from 45 days CK group,LP group and LLLB group.The results showed that there was no significant difference(P>0.05)in the rumen degradation rate of whole plant silage maize treated with different lactic acid bacteria additives.During the 72 h in vitro gas production,the LP group produced significantly more gas than the CK and LLLB groups(P<0.05).In summary,the following conclusions were obtained from this study:1.Nutritional value of Lactobacillus plantarum additive to whole maize silage is better than the combination of Lactococcus lactis and Lactobacillus brucei treatment;2.The effect of Lactobacillus plantarum additive in whole maize silage on fermentation quality is better than the combination of Lactococcus lactis and Lactobacillus brucei treatment;3.The effect of Lactobacillus plantarum additive in whole maize silage on aerobic stability is better than the combined Lactococcus lactis and Lactobacillus brucei treatment.4.The effect of Lactobacillus plantarum additive in whole maize silage on in vitro gas production is better than the combined Lactococcus lactis and Lactobacillus brucei treatment.