| Vitro fermentation experiments in our laboratory found isolated from cow rumen fluid facultative anaerobic cellulolytic bacteria(L5)and Azotobacter(C1)in accordance with the 4:1 ratio is added to promote the rumen fermentation,and improved fiber pigment degradation rate.Our hypothesis is that feeding L5 and C1 may have a role in promoting rumen fermentation in dairy cows,and this effect will be reflected in nutrient digestion and lactation performance of dairy cows.Therefore,this article is intended to test our hypothesis by cows feeding trials,and further understanding of the cow rumen L5 and C1.Determination of bacteria required for bacterial activation and field trials(1)First,the facultative anaerobic cellulose decomposing bacteria L5 and nitrogen fixing bacteria C1 were removed in the-20? refrigerator.After thawing at room temperature,the treatment of the strain was carried out.The two strains were activated by liquid LB medium,and the strain was treated two times.The concentration of live bacteria in culture medium was about 109 CFU·mL-1 and above,and the number of live bacteria in culture medium was determined by dilution coating plate method.(2)The rumen volume of dairy cows was 56.9 L,and the outflow rate of rumen contents was 6%of the total volume per hour.The total number of live bacteria needed for feeding 1 times per cow was 3.368 × 1011 CFU.The two agents,L5 and C1,are mixed according to the ratio of 4:1,so L5 contains 2.694×1011 CFU and C1 is 0.674 × 1011 CFU.Finally,because the broth and 30%glycerol for a ratio of 1:1 is stored in 1.5 mL EP tube.Therefore,to ensure that each cow fed twice per 2.694 × 1011 CFU of L5 and C1 0.674 × 1011 CFU based on,LB liquid medium to use the inactivated culture L5 concentration adjusted solution was 5.388×1011 CFU·mL-1 and a concentration C1 culture was adjusted to 1.348 × 1011 CFU·mL-1.That is,each fungus absorbs 0.5 mL and mixes with 0.5 mL 30%glycerin.Then it is stored in the refrigerator at-20?.Field feeding testThis test preclude the use of single-factor experimental design,the 18 weight(550 ± 50 kg)are similar,lactation(160 ± 20 d)are similar and lactation(31.72 ± 3.01 kg·d-1)days are similar Holstein cows were randomly divided into two control groups and test groups.Cows in the control group were fed the daily diet of dairy farm with inactivated L5 + C1(L5:C1=4:1)mixed bacteria,and the experimental group was fed with daily diet plus L5 + C1 mixed microbial inoculum.Test included 16 back-grounding of the day and 4-day sampling period,observation and familiarity with dairy cow feed intake during feeding,lying horizontal and individual behavior such as defecation;sampling period,feces and milk samples and blood samples are collected.The results showed that the apparent digestibility of dietary NDF,ADF and Ash was not significantly affected(P>0.5),but it could significantly increase the apparent digestibility of dietary EE(P=0.01);In addition,mixed bacteria tended to increase the utilization efficiency of dietary CP(P=0.06).In addition,the mixed strains of lactose in milk,milk fat,milk protein,total solid and conventional indicators of somatic cell count in milk and other effects of serum urea nitrogen,glucose,cholesterol,alanine aminotransferase and aspartate aminotransferase were not significant,but it has increased the number of serum albumin(P=0.0585).In summary,a mixed inoculum of facultative cellulose decomposing bacteria and nitrogen fixing bacteria was added to dairy cows to influence dietary fat digestion and protein metabolism.It could not only increase the apparent digestibility of crude fat in diet,but also increase the apparent digestibility of dietary crude protein and the content of serum albumin. |
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