Screening Of Lactic Acid Bacteria For Garlic Straw Fermentation And Its Application In Beef Cattle Production

In the process of seeking the development and utilization of unconventional feed raw materials,various agricultural and sideline products are the focus of attention.After garlic harvest,garlic straw is abandoned in the field or burned as waste,which has a negative impact on the environment.Microbial fermentation technology is an effective way to realize the rational utilization of garlic straw.The purpose of this study was to study the application of garlic straw in ruminant beef cattle,two strains of lactic acid bacteria with excellent performance were selected to carry out garlic silage fermentation test,based on biological characteristics,growth and acid production rate,acid resistance and antibacterial properties.The nutritional quality and fermentation characteristics of each group of silage were measured at 60 days of silage fermentation.The best silage method was selected for micro-storage processing to replace part of the roughage in the mixed diet of beef cattle.It affects the growth performance,slaughter performance,blood index,meat quality and rumen microorganisms of beef cattle were measured.The following experiments were carried out:1.Isolation,screening and performance determination of lactic acid bacteria from garlic straw.A total of 15 strains of lactic acid bacteria were screened from the surface of garlic straw by traditional microbial culture method,morphological identification,biochemical identification and 16 S r DNA sequence analysis.Among them,2 strains of Lactobacillus paracasei,7 strains of Pediococcus acidilactici,2 strains of Pediococcus pentosaceus,3 strains of Enterococcus faecium and 1 strain of Leuconostoc citreum,among which Pediococcus acidilactici was the dominant bacteria on the surface of garlic straw.By evaluating the biological characteristics and safety of the strains,the compound microbial inoculum of S3 and S8 was finally selected to carry out the fermentation experiment of garlic straw silage.2.Effect of garlic straw silage fermentation.The fermentation test was carried out for 60 days by natural fermentation,separately adding lactic acid bacteria,adding lactic acid bacteria with different proportions of jujube powde,and the conventional nutrients and fermentation indexes of the fermentation products were determined.The results showed that the addition of lactic acid bacteria alone was the best silage treatment group.3.Effect of feeding beef cattle with fermented garlic straw on production performance and rumen microflora of beef cattle.Thirty-six experimental cattle were randomly divided into 3groups with 12 cattle in each group.The control group was fed with the original diet of the cattle farm,the experimental group with 7.5% fermented garlic straw,and the Gs B group with 15%fermented garlic straw.After 6 weeks of experiment,the following results were obtained.(1)There was no apparent difference in beef cattle’s growth performance and slaughter performance when fermented garlic straw replaced part of roughage in the diet.(2)Feeding fermented garlic straw effected the apparent digestibility of beef cattle.The results showed that the apparent digestibility of dry matter,neutral detergent fiber and crude protein in Gs B group was significantly increased(P<0.05).(3)Effect of feeding fermented garlic straw on blood biochemical parameters.The content of alkaline phosphatase(ALP)decreased with the increase of substitution ratio(P>0.05).Alanine aminotransferase(ALT)and aspartate aminotransferase(AST)showed significant differences(P<0.01).The contents of serum urea nitrogen(BUN)and total cholesterol(TCHO)in the Gs A group were considerably higher than those in the other two groups(P<0.05).The total protein(TP)content in the Gs B group was significantly higher than that in the control group and Gs A group(P<0.01).(4)Effects of feeding fermented garlic straw on immune and antioxidant indices.The content of complement C3 was significantly different(P<0.05),and the range of the Gs A group was the lowest.Immunoglobulin A(Ig A)in the control group was significantly lower than that in Gs A and Gs B groups(P<0.05).The difference in TNF-α in blood was significant(P< 0.05),the control group was the highest,followed by the Gs A group,and the Gs B group was the lowest.The catalase(CAT)in the control group was significantly higher than that in the Gs A and Gs B groups(P<0.05).The contents of glutathione and glutathione peroxidase were quite different(P<0.05).The content of catalase(CAT)changed significantly(P<0.01),the highest in the control group,followed by the Gs A group,and the lowest in the Gs B group.(5)Effect of feeding fermented garlic straw on beef quality and beef nutrient content.The meat color,p H value,cooking loss,shear force and texture analyzer analysis of beef in each test group were not significant(P>0.05).The contents of Ash and CP in the Gs B group were significantly higher than those in the CON and Gs A group(P<0.05).(6)Effect of feeding fermented garlic straw on rumen microbiota.The community composition of the three groups of samples changed,and the Gs A group and the Gs B group were significantly different from the control group,which indicated that with the increase of the proportion of fermented garlic straw,the microbial community composition would be greatly different.Feeding 15% fermented garlic straw affected rumen bacterial richness and diversity.In a word,replacing part of the roughage of beef cattle with 15% fermented garlic straw not only didn’t affect the growth performance and slaughter performance of beef cattle but also improved the immune and antioxidant capacity of beef cattle and affected the diversity and richness of rumen bacteria in beef cattle.