Preparation Of Fermented Feed With Composite Bacteria And Its Effect On Litter Performance And Fecal Microflora In Pregnant Sow

Fermented feed,as a new feed resource,is currently receiving widespread attention in the feed industry.However,the effect of fermented feeds is currently good or bad,and further optimization is needed.This study screened the compatibility of strains that can efficiently ferment feed,and explored the effect of fermented feed by mixed bacteria on the litter performance and fecal microflora of pregnant sows.The research content is mainly divided into three parts:1.Screen the optimum composite strains for fermented feedThis study is carried out to screen a combination of highly efficient fermented feed strains.The experiment used three different Lactobacillus salivarius(L1,L2 and L3)and Bacillus subtilis(B1,B2 and B3)and two strains of Saccharomyces cerevisiae(S1 and S2)for compatibility test.There were 6 groups of fermentation compatibility,3 replicates in each group.The corn,soybean meal and bran mixture were used as fermentation substrates,and the composite bacteria were inoculated at a ratio of 2%(L:B:S=2:2:1).The feed was incubated at 37℃ for 48 h.The number of probiotics,fermentation parameters and conventional nutrients in different compatibility groups were determined after the end of fermentation.The results showed that compared with the other groups,the dry matter loss rate and pH of group 5 were significantly decreased(P<0.05),and the lactic acid content was significantly increased(P<0.001).The crude protein content of group 5 was significantly lower than that of group 1(P=0.015)and group 4(P=0.048),and the crude fat content of group 5 was significantly lower than that of group 1(P=0.027)and group 2(P=0.047),which was not significantly different from other groups(P>0.05).The content of acetate and total volatile fatty acids in group 5 was significantly higher than that in the other groups(P<0.001).The number of lactic acid bacteria in groups 5 and 6 was significantly higher than that in the other groups(P<0.001).The number of Bacillus in group 5 was significantly higher than that in group 1(P=0.001)and 6(P=0.035),and the number of Saccharomycetes in group 5 was significantly higher than that in group 1(P<0.001)and group 2(P=0.02),which was not significantly different from the other groups(P>0.05).In summary,the group 5(L3+B2+S1)is most suitable for fermented feed production and can be used in subsequent fermented feed production.2.Effect of composite bacteria inoculation on small molecular compounds and microflora composition in fermented feeds based on metabolome and high-throughput sequencingIn this study,16S-rRNA highthrough sequencing and the liquid chromatography-mass spectrometry was applied to compare the differences between spontaneous fermentation(SF)and microbial fermentation(MF)feeds.The results showed that MF increased the acidity(P=0.006)and the lactate content(P<0.001),and decreased the level of acetate,propionate,isobutyrate and total volatile fatty acid(P<0.05)in feed compared with the SF.Microbial analysis revealed that composite bacteria inoculation did not affect the number of OTUs(P=0.248),the Chao value(P=0.564)and the Shannon index(P=0.772),while decreased the ACE index(P=0.021)and increased the Simpson index(P=0.037)compared with SF.The proportion of Enterococcus,Lactobacillus,and Bacteroides was higher(P<0.05)in MF;however,some potential pathogens,including Pediococcus,Weissella,Enterobacter,Escherichia-Shigella,Pantoea,and unclassified Enterobacteriaceae were lower(P<0.05).A metabolomics analysis showed the differentiated metabolites belonged to organic acids(included maleic acid,phenylacetic acid,etc.),lipids(included ethyl linoleate,dihomo-gamma-linolenic acid,etc.),amino acids(included 1-theanine,glutamine,glutamic acid,etc.),and nucleosides/nucleotides(included 2’-deoxyinosine,etc.).Correlation analysis revealed a significant correlation between some microorganisms and metabolites.This study revealed the inoculum with composite probiotic preparation positively influenced the fermentation process of the feed,which may beneficial for animal health.3.The effect of feeding a fermented feed diet on production performance,serum index and fecal microbial community in pregnant sowThe current study investigated the effects of fermented feed on litter performance,serum parameters and fecal microflora in pregnant sows.Sixteen sows were selected and randomly divided into two groups.The control group was fed with conventional feed and the treatment group was fed with fermented feed.The test was started from 85 days of gestation and ended in 21 days of weaning.At 105 days of gestation,sow feces were collected for fermentation parameter and high-throughput sequencing,serum was collected for serum index.The sow’s litter size,live litter size,and piglet’s birth weight were recorded.The results showed that feeding fermented feed did not affect the number and the weight of piglets(P>0.05).The results of serum index showed that feeding fermented feed had a tendency to decreased HDL content(P=0.092)and increase CAT levels(P=0.089).The results of fermentation parameters showed that feeding fermented feed significantly increased the content of acetate,butyrate,isobutyrate,isovalerate,valerate and total volatile fatty acid(VFA)in the feces(P<0.05).High-throughput sequencing results showed that the diversity and structure of the bacterial flora in the two groups were similar.Feeding fermented feed significantly reduced the relative abundance of Oscillospira(P=0.016)and Fibrobacter(P=0.016);Feeding fermented feed had a tendency to increase the percentage of Blautia(P=0.074)and Bacteroides(P=0.052).In summary,feeding fermented feed had a tendency to improve the antioxidant capacity of sows,can alter the composition of hindgut,stimulate the hindgut fermentation,improve the intestinal health of sows,and did not improve the production performance of sows.