| Probiotics are a kind of beneficial active microorganisms,which colonizate in host's intestine,help the host to improve the microecological balance of the body.With the advent of post antibiotic era,probiotics are widely used in animal husbandry,as one of the best alternatives to antibiotics.In this paper,the screening of bacterial strains,the preparation technology of the compound probiotics and application in ruminant production were studied.1.Screening of enterococcus faecium and preparation process of the compound probioticsThe strains that screened from rumen of goats were identified as enterococcus faecium through these methods,for example,agar plate was used for separation,morphological observation,biochemical identification and 16S rDNA gene sequence analysis.The results showed that the strains had good growth characteristics,they were well tolerated to pH2.5-3.5 artificial gastric juice and 0.2%-0.3%bile salt artificial intestinal fluid,inhibitury effect of strains on escherichia coli,salmonella and staphylococcus aureus were obviousEnterococcus faecium and lactobacillus plantarum were co cultured,the results showed that the best culture time of the compound probiotics seed solution was 12 hours.The optimum fermentation parameters of the compound probiotics were as follows:The fermentation time was 15 hours,fermentation medium of seed solution was 10%,inoculation amount also 10%.This showed that the fermentation process is stable and industrial production is feasible.The survival rate of total viable bacteria in the compound probiotics showed a downward trend with the extension of storage time in different quarters,the extent of decline were significant various in different quarters.The extent of decline was the most serious in the third quarter,the fourth quarter and the second quarter were a little better,the survival rate of total viable bacteria was the best in the first quarter.2.Effects of the compound probiotics on production performance and blood physicochemical indexes of cowsThis experiment has been carried out with 24 healthy holstein cows,whose age,parity,milk production,days in milk(112±8.5d)were all similar.The experimental design was divided into four groups randomly,they were control group and experimental group 1,2 and 3,6 cows in each group.The control group was fed with basal diet,5,10 and 15 g/(head·day)of the compound probiotics were added to the basal diet in all the experimental groups.The pre-test period was 7 days and the trial period was 35 days.The results showed that the compound probiotics could significantly improve milk yield(p<0.05),improve milk quality,and the number of somatic cells in milk was significantly reduced(p<0.05),increase blood GLO content(p<0.05),enhance immune function of cows.The best dosage of the compound probiotics is 10g/(d·head),considering the comprehensive input-output ratio.3.Effects of the compound probiotics on intestinal defense function of goatsThis experiment has been carried out with 18 healthy adult female goats whose weights were about 20±3kg in order to study the effect of compound probiotics on prevention and therapeutic of intestinal infection of E.coli in goats.The preventive trial was divided into three groups,the goats were randomly divided into control group,E.coli group and probiotics prevention group,with 3 goats in each group.On the 1 st to 4th day of the experiment,goats in control group and E.coli group were given 30mL normal saline every day,while goats in probiotics prevention group were given 30mLcompound probiotics every day.On the 5th to 6th day,30mL normal saline was given to the goats in the control group,and 30mL of E.coli was given to the other two groups every day.The treatment trial was divided into 3 groups:control group,E.coli group and probiotic treatment group,3 goats/group.On the first and second days of the experiment,the goats in the control group were fed with 30mL normal saline every day,and the other groups were given 30mL of E.coli every day.On the 3th to 6th day,goats in control group and E.coli group were given 30mL normal saline every day,while the goats in probiotics treatment group were given 30mL compound probiotics to treat goats every day.The experiment lasted for 11 days.The body temperature,respiratory rate,heart rate and blood leukocyte count of goats in each group were measured on the days of 1st,3rd,5th,7th,9th and 11th.The pathological changes of intestinal tract were observed and the number of intestinal flora and the gene expression of inflammatory factors IL-1? IL-8 and TNF-? in intestinal mucosa were measured in both preventive trial and treatment trial in different days.The prevention trial was conducted on the days of 7th and 11th,and the treatment trial on days of 3th and 9th separately,The results are as follows:(1).Changes of vital signs and the number of white blood cells of goatsPrevention trial:Compared with the control group,the vital signs and the number of white blood cells in E.coli group all increased from 7th to 11th days(p<0.01 orp<0.05),the indexes in probiotics prevention group increased on the 7th day(p<0.05),and then returned to normal,and body temperature,respiratory rate and white blood cell count were all lower than those in E,coli group(p<0.05).Treatment trial:Compared with the control group,the vital signs and the number of white blood cells in E.coli group all increased from 3rd to 9th days(p<0.01 or p<0.05),but they only increased on the 3rd to 5th day in the probiotics treatment group,then returned to normal and were significantly lower than those in E.coli group from 5th to 9th days(p<0.05).(2).Histopathological changes of intestinal tract in goatsPrevention trial:Compared with the control group,the jejunum wall became thinner and the cecum was congested,the length of jejunum villi,crypt depth,V/C ratio and cecal mucosa thickness decreased in E.coli group(p<0.01 or p<0.05).Compared with the E.coli group,jejunum and cecum lesions improved significantly,the length of jejunum villi,crypt depth,V/C ratio and cecal mucosa thickness increased in probiotics prevention group(p<0.01 or p<0.05).Treatment trial:Compared with the control group,the contents of the caecum were congested and watery in E.coli group,the length of jejunum villi,crypt depth,V/C ratio and cecal mucosa thickness decreased in E.coli group(p<0.01 or p<0.05).Compared with the E.coli group,they all increased in probiotics treatment group(p<0.01 or p<0.05),and the clinical symptoms were obviously relieved.(3).Changes of intestinal microflora in goatsPrevention trial:Compared with the control group,the number of lactic acid bacteria in jejunum and cecum decreased(p<0.05),the number of E.coli increased(p<0.01)in E.coli group on the 7th and 11th day of the experiment.Compared with the E.coli group,the number of E.coli in jejunum and cecum decreased(p<0.05)in probiotics prevention group.Treatment trial:The number of lactic acid bacteria in jejunum and cecum decreased(p<0.01 or p<0.05)and the number of E.coli increased(p<0.01)in E.coli group on the 3th and 9th day.Compared with the E.coli group,the number of lactic acid bacteria in jejunum and cecum increased(p<0.05),the number of E.coli increased(p<0.01)in probiotics treatment group on the 9th day of the experiment.(4).Changes of inflammatory factor gene expression in intestinal mucosa of goatsPrevention trial:Compared with the control group,the expression of inflammatory factors in jejunum and cecum mucosa increased(p<0.01)in E.coli group on the 7th and 11th day.Compared with the E.coli group,the expression of inflammatory factors in jejunum and cecum mucosa decreased(p<0.01 or p<0.05)in probiotics prevention group.Treatment trial:Compared with the control group,the expression of inflammatory factors in jejunum and cecum mucosa all increased(p<0.01 or p<0.05)in E.coli group and probiotics treatment group on the 3th and 9th day.Compared with E.coli group,the expression of intestinal mucosa inflammatory factors was lower(p<0.01 or p<0.05)in probiotics treatment group. |
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