| The stress reaction caused by early weaning of calves will lead to diarrhea and other diseases,which will seriously affect the health of calves.Antibiotics have been gradually banned because of their harmful residues,and Clostridium buyricum,as an anaerobic bacillus,has been gradually used in livestock and poultry production because of its high temperature resistance,acid and alkali resistance,good stability,strong adhesion and so on.Studies have shown that Clostridium buyricum can regulate the intestinal microecological balance,promote the healthy growth of livestock and poultry,and improve its disease resistance.At present,most of the studies on Clostridium buyricum focus on monogastric animals,so it is necessary to explore in ruminants.The purpose of this study was to investigate the effects of Clostridium buyricum as feed additive on growth performance,serum biochemical indexes,antioxidant capacity,immune function and rumen related indexes of weaned calves and bred cattle,as well as the effects of different feeding methods of Clostridium buyricum were studied.This study provides a theoretical basis for the application of Clostridium buyricum to reduce weaning stress,promote rumen development,improve rumen fermentation and better breed dairy cows.Experiment 1: Effects of Clostridium buyricum on growth performance,blood Indexes and rumen fermentation of weaning calvesTwelve Holstein bull calves aged about 50 days with similar body weight and health condition were randomly assigned to 2 groups with 6 replicates per group and 1 calf per replicate.The calves in control group(CON group)were fed a basal diet,and those in Clostridium buyricum group(CB group)were fed the basal diet supplemented with 2.0×108 CFU/kg Clostridium buyricum.The trial lasted for 20 days including 10 days before weaning and 10 days after weaning.The body weight and feed intake of calves were recorded during the trial period.Blood samples were collected on the 10 th day(weaning day)and 20 th day(10th day after weaning),and rumen juice samples were collected on the 20 th day for the determination of related indexes.The results showed as follows:1)During the whole trial,the average daily gain(ADG)of calves in CB group was significantly increased compared with CON group(P<0.05);the feed efficiency(FE)of CB group had an increase trend compared with CON group(P=0.09)and the diarrhea rate of calves in CB group was 3.62 percentage point lower than that in CON group.2)The contents of serum cholesterol(CHOL)and high-density lipoprotein(HDL)in CB group decreased significantly(P<0.05)and the content of serum low density lipoprotein(LDL)tended to be lower than that in CON group(P=0.07)at the 20 th day of trial.3)At the 10 th day of trial,the content of serum glutathione(GSH)in CB group tended to be higher than that of CON group(P=0.06);at the 20 th day of trial,the content of serum malondialdehyde(MDA)in CB group was extremely significantly decreased compared with CON group(P<0.01).4)At the 20 th day of trial,the contents of immunoglobulin A and M and G(Ig A,Ig M,Ig G)in serum of calves in CB group were extremely significantly increased compared with CON group(P<0.01).5)At the 20 th day of trial,the content of propionic acid in rumen was significantly increased in CB group(P<0.05),and the content of butyric acid tended to increase compared with CON group(P<0.05).6)At the 20 th day of trial,the content of rumen microbial protein(MCP)and the activity of ?-glucosidase in CB group were significantly higher than CON group(P<0.05).It is concluded that adding 2.0×108 CFU/kg Clostridium buyricum into the diet for weaning calves can improve the growth performance,reduce the diarrhea rate,decrease the serum MDA content,improve the immune function,increase the concentration of propionic acid and butyric acid in rumen,the activity of ?-glucosidase and the concentration of microbial protein(MCP).It effectively alleviated the weaning stress of calves and improved rumen fermentation of calves.Therefore Clostridium buyricum can be used as a new probiotic preparation in calf production.Experiment 2: Effects of Clostridium buyricum on growth performance,blood index and rumen fermentation of bred cattleThirty Holstein bred cattles aged about 26 weeks old with similar body weight and health condition were randomly assigned to 3 groups with 10 replicates per group and 1 calf per replicate.The cattles in control group A(CON group A)were fed a basal diet,those in Clostridium buyricum group B(CB group B)and Clostridium buyricum group C(CB group C)were fed the basal diet supplemented with 2.0×108 CFU/kg Clostridium buyricum every day and every three days.The trial lasted for 6 weeks.The body weight and feed intake of bred cattle were recorded during the trial period.Blood and rumen fluid samples were collected at 29 and 32 weeks of age for the determination of related indexes.The results showed as follows:1)At 29~32 w,the ADG in CB group B was higher than that in CB group C(P<0.05)and CON group A(P>0.05);At 26~32 w,compared with the CON group A,the dry matter intake(DMI)of CB group B was significantly higher(P<0.05).2)At 32 w,the content of blood glucose(GLU)in CB group B was higher than that in CON group A(P=0.08);At 29 w,compared with the CON group A,the content of serum total cholesterol(TC)in CB group B was significantly higher(P<0.05)and had an increasing trend compared with CB group C(P=0.08).And during the whole trial period,there was an increasing trend in the CB group B compared with the CON group A(P=0.06).3)At 26~32 w,the total antioxidant capacity(T-AOC)in CB group B had an increasing trend compared with CON group A(P=0.08)and the content of GSH in CB group C was significantly higher(P<0.05);At 29 w,The content of MDA in CB group C was significantly lower than that in others(P<0.05);4)Clostridium butyricum treatment had no significant effect on Ig A,Ig M,Ig G,tumor necrosis factor-?(TNF-?),interleukin-1?(IL-1?),interleukin-4(IL-4)and interleukin-6(IL-6)of bred cattle(P>0.05).5)At 29 w,the content of butyric acid in CB group B was extremely significantly higher than others(P<0.05)and from the point of view of the whole period of the trial,the content of butyric acid was group B,group C and group A respectively from the high to the end.6)At 26~32 w,compared with the CON group,CB group B could significantly increase the number of B.fibrisolvens(P<0.05)and had the trend of increasing R.flavefaciens(P=0.06).the value of B.fibrisolvens and R.flavefaciens in CB group C were higher than that in CON group A,but the difference was not significant(P>0.05);The number of S.bovis in CB group B were extremely significantly increased compared with CON group A(P<0.01)and the number of S.bovis in CON group C was also higher than that in CON group A(P=0.08).It is concluded that adding 2.0×108 CFU/kg Clostridium buyricum into the diet for bred cattles can improve the growth performance,improve the antioxidant capacity and blood metabolism of the body,regulate the rumen microecosystem,promote the growth of dominant microorganisms in the rumen,and improve the rumen fermentation of bred cattle.Generally speaking,the effect of daily feeding Clostridium buyricum is better than that of feeding every three days.Therefore,the amount of bacterial agent and feeding conditions all affect the effect of Clostridium butyricum.In summary,Clostridium buyricum can promote the growth and development of calves and bred cattle,improve the antioxidant and immune function,regulate rumen microecosystem,promote rumen fermentation and alleviate weaning stress.Therefore,Clostridium butyricum can be used as a new feed additive in cattle production,and has great potential in the field of antibiotic substitution. |
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