Effects Of Bacillus Subtilis And Bacillus Licheniformis On Growth Performance And Goat Manure Aerobic Composting Of Fattening Goats

Bacillus subtilis and Bacillus licheniformis belong to the Bacillus genus.Bacillus sub-tilis and Bacillus licheniformis are beneficial bacteria in the intestinal tract of animals,which can promote animal growth and regulate the intestinal flora.The enzyme is a new type of feed additive in recent years,which can improve the utilization rate of feed and the digesti-bility of nutrients.Therefore,this experiment explores the effects of individual feeding,com-bined feeding of two probiotics,and probiotics and enzyme compound feeding on the growth performance of weaned goats,serum biochemical immune and antioxidant indicators,rumen and fecal flora,and different ratios of Bacillus subtilis and Bacillus licheniformis on carbon,nitrogen,humus and bacterial communities during aerobic composting of goat manure.Ba-cillus subtilis and Bacillus licheniformis have a wide range of application and are multifunc-tional microorganisms.In recent years,Bacillus subtilis and Bacillus licheniformis have be-come more and more common in aerobic composting.Aerobic composting has a short fer-mentation time and is the first choice for composting.Bacillus subtilis and Bacillus licheni-formis can secrete various enzymes during the composting process.Therefore,the addition of Bacillus subtilis and Bacillus licheniformis in the aerobic composting process has benefi-cial effects.This research could provide theoretical and practical references for the applica-tion of Bacillus subtilis and Bacillus licheniformis.The main results are as follows:Experiment 1:Effects of probiotics on growth performance,serum biochemical indexes and fecal microflora of fattening goatsThe purpose of this study was to explore the effects of different probiotics on growth performance,serum biochemical indexes and fecal microflora of fattening goats.Sixty 3-month-old goats were selected and divided into four groups,fed with based diet（C group）,based diet and Bacillus subtilis（BS group）,based diet and Bacillus licheniformis（BL group）,based diet and Bacillus subtilis and Bacillus licheniformis（BS＿BL group）for 30d.Measured relevant indicators at different periods of experiment.The results showed that there was no significant difference among the weight,ADG and F/G of the fattening goats in the C,BS,BL and BS＿BL groups（P>0.05）;ADFI of the BS＿BL group was significantly higher than that of the C group,BS group and BL group（P<0.05）;Compared with C group,the diarrhea rate of BS＿BL group significantly reduced（P<0.05）.Compared with C group,on 30th,the contents of ALP,GLU and LDH in BS group were significantly reduced（P<0.05）,the contents of AST and ALB were extremely significantly reduced（P<0.01）,the content of UN in the BL group was significantly increased（P<0.05）,and the contents of AST and GLU in the BS＿BL group were significantly reduced（P<0.05）.The 16S r DNA sequencing of feces found that BS＿BL group had high diversity.The dominant phylum and genus were different in different groups.Conclusion:The combined feeding of Bacillus subtilis and Ba-cillus licheniformis can significantly improve the growth performance of fattening goats,re-duce the rate of diarrhea,improve serum biochemical indexes,and change the species com-position,diversity and abundance of fecal microflora.Experiment 2:Effects of combination feeding of enzymes and probiotics on growth performance,serum biochemical immune and antioxidant indexes,slaughter perfor-mance,meat quality and rumen microflora of fattening goatsThis experiment aimed at exploring the effects of combination feeding of enzymes and probiotics on the growth performance,serum biochemical immune and antioxidant indexes,slaughter performance,meat quality and rumen microflora of fattening goats.Thirty-six 3-month-old Yangtze River Delta White Goats were selected and divided into three groups,which had similar weight and fed with based diet（CON group）,based diet and Bacillus sub-tilis and Bacillus licheniformis（PRO group）,based diet and enzymes and Bacillus subtilis and Bacillus licheniformis（COM group）for 80d.The compound enzyme preparation was composed ofβ-mannase,β-glucanase,xylanase,protease,amylase and cellulase.Relevant indicators were measured at different periods of experiment.The results showed that the weight of goats in the COM group was significantly higher than that in the CON group（P<0.05）;ADG of goats in the COM group and PRO group were significantly higher than that in the CON group（P<0.05）;ADFI of goats in the COM group was significantly higher than that in the CON group and PRO group（P<0.01）.There was no significant difference in F/G among CON group,PRO group and COM group（P>0.05）.On the 80th,there was no sig-nificant difference in each serum biochemical indicators among CON group,PRO group and COM group（P>0.05）.Compared with CON group,the serum TNF-αcontent in PRO group and COM group were significantly increased（P<0.05）,the serum IL-10 content in PRO group and COM group were significantly increased（P<0.01）,but there was no significant difference in serum antioxidant among CON group,PRO group and COM group（P>0.05）.The heart weights of PRO group and COM group were significantly higher than that of CON group（P<0.05）,and the lung weight of PRO group and COM group were significantly higher than CON group（P<0.01）.Compared with CON group,the weight of digestive tract in PRO group and COM group was significantly increased（P<0.01）,and the proportion of live weight before slaughter was significantly increased（P<0.05）.The relative abundance of Proteobacteria（P<0.05）significantly increased,but the relative abundance of Actino-bacteria（P<0.05）significantly decreased in COM group.Conclusion:Combined feeding probiotics and enezmy can improve the average daily feed intake,average daily gain,body weight and growth performance of goats,and also can improve the immunity and slaughter performance of goats,and promote the development of internal organs and intestines of goats,and maintain the normal function of goat rumen by changing the structure of rumen micro-flora and increasing the number of anaerobic microorganisms.Experiment 3:Effects of microbial agents on the effect and bacterial community of goat manure aerobic compostingThe purpose of this experiment was to explore the effects of different addition ratios on the content of carbon,nitrogen,humus,and bacterial communities during the goat manure aerobic composting.The experimental materials were goat manure and rape straw.The mi-crobial agent was composed of Bacillus subtilis,Bacillus licheniformis,Trichoderma viride,Aspergillus niger and yeast.Three different inoculum ratios were treated,which were B1treatment group（1:1:1:1:2）,B2 treatment group（2:2:1:1:2）and B3 treatment group（3:3:1:1:2）.Regularly check the physical and chemical indicators,such as temperature,mois-ture content,p H,EC,GI,C/N,TOC,TN,TP,TK,NH₄⁺-N,NO₃^--N,cellulose and humus and bacterial communities during the composting process.Redundancy analysis（RDA）of the correlations between physicochemical parameters,bacterial communities and carbon com-ponents.The results showed that the highest temperature during the composting were B2（73.4℃）>B1（72.6℃）>B3（71.0℃）,the days with temperature reaching above 50℃were 11 d,15 d and 10 d,respectively.The moisture,EC,TN and HS-C content of B1treatment group were significantly lower than the other two treatment groups（P<0.05）.The NO₃^--N content,TOC content and HA-C content were significantly higher under B1 than under the other two treatment groups after composting（P<0.05）.The C/N ratio of each treatment was 15,14 and 14,respectively,when the composting process ended.16S r DNA high-throughput sequencing found that Bacteroides and Muribaculaceae＿unclassified were the main bacteria in the thermophilic stage of composting.Bacteroides and Bilophila were the main bacteria during the cooling phase of composting.During the maturity phase of com-posting,Fodinicurvataceae＿unclassified and Muribaculaceae＿unclassified were the main bacteria.The dominant phyla were Bacteroidetes,Firmicutes and Proteobacteria during composting.RDA showed that the variation of carbon components in NO₃^--N（19.2%）was the highest,Bacteroides had the highest correlation with carbon components in all bacteria.Conclusion:The proportion of microbial inoculum with Bacillus subtilis,Bacillus licheni-formis,Trichoderma viride,Aspergillus niger and yeast at 1:1:1:1:2 not only greatly added the preservation of total nitrogen but also reduced the loss of TOC in compost,the carbon fractions were mainly affected by NO₃^--N and positively correlated with Bacteroides.