Effects Of Acarbose Addition On Rumen Fermentation In Dairy Cattle

Acidosis is a very common metabolic disease in ruminants,which causes huge economic losses in dairy industry.Therefore,it is very important to explore strategies to prevent rumen acidosis.The objectives of this study was to investigate the effects of acarbose addition on ruminal fermentation and bacterial composition of dairy cattle fed high concentrate diet.1 Effects of acarbose addition on rumen fermentation with high concentrate as substrate in vitroThis study investigated the effects of acarbose addition on ruminal fermentation characteristics and ruminal bacterial composition in vitro with high concentrate as substrate.The batch cultures consisted of 8 mL strained rumen fluid in 40 mL anaerobic buffer and contained 0.49 g com grain,0.21 g soybean meal,0.15 g alfalfa and 0.15 g Leymus chinensis.Acarbose was added to incubation bottles to achieve final concentrations of 0.1,0.2,and 0.4 mg/mL.After incubation of 24 h,the addition of acarbose linearly decreased(P<0.05)the concentrations of acetate,propionate,butyrate,total volatile fatty acids,lactate and lipopolysaccharide(LPS).It also linearly increased(P<0.05)the ratio of acetate to propionate,the concentrations of isovalerate,valerate and ammonia-nitrogen and the pH value compared with the control.Pyrosequencing of the 16S rRNA gene showed that the addition of acarbose decreased(P<0.05)the proportion of Firmicutes and Proteobacteria and increased(P<0.05)the percentage of Bacteroidetes,Fibrobacteres,and Synergistetes compared with the control.A principal coordinates analysis plot based on unweighted UniFrac values and molecular variance analysis revealed that the structure of the ruminal bacterial communities in the control was different from that of the ruminal microbiota in the acarbose group.In conclusion,acarbose addition can significantly increase the pH value,and decrease the concentrate of lactate in the rumen.The results showed that acarbose may be potentially useful for preventing the occurrence of ruminal acidosis.2 Effects of acarbose addition on rumen fermentation and ruminal bacterial composition with different substrate in vitroThis study investigated the effects of acarbose addition on ruminal fermentation characteristics and ruminal bacterial composition in the three experiment in vitro.In the first and second experiment,the effect of acarbose addition on subacute ruminal acidosis was studied.In the third experiment,the effect of acarbose addition on acute ruminal acidosis was studied.Acarbose was added to incubation bottles to achieve final concentrations of 0.1,0.2 and 0.4 mg/mL,respectively.There were four replicate bottles in both the acarbose treatment group and the control group.With 1.0 g wheat as substrate,after incubation of 24 h,as compared with control,the addition of acarbose linearly decreased(P<0.05)the concentrations of acetate,propionate,butyrate,total volatile fatty acids and lactate.It also linearly increased(P<0.05)the ratio of acetate to propionate and ammonia-nitrogen and the pH value,when compared with the control group.Pyrosequencing of the 16S rRNA gene showed that the addition of acarbose increased(P<0.05)the proportion of Firmicutes and Bacteroidetes and increased(P<0.05)the Ace value,Chao value,Shannon index,and decreased(P<0.05)the percentage of Tenericutes and Proteobacteria compared with the control.In second experiment,with 1.0 g beet pulp as substrate,the addition of acarbose increased(P<0.05)the concentrations of isovalerate,valerate,ammonia-nitrogen and decreased(P<0.05)the concentrations of isobutyrate compared with the control.Pyrosequencing of the 16S rRNA gene showed that the addition of acarbose had no significant on(P>0.05)the Ace value,Chao value,Shannon index and the proportion of Firmicutes and Bacteroidetes compared with the control.In third experiment,the substrate consisted of 1.0g corn.As compared with control,the addition of acarbose linearly decreased(P<0.05)the concentrations of acetate,propionate,butyrate,valerate,total volatile fatty acids,lactate and linearly increased(P<0.05)the ratio of acetate to propionate and isovalerate,isobutyrate,ammonia-nitrogen and the pH value.Pyrosequencing of the 16S rRNA gene showed that the addition of acarbose decreased(P<0.05)the proportion of Firmicutes and Bacteroidetes,and decreased(P<0.05)the percentage of Proteobacteria and Fusobacteria compared with the control,and decreased(P<0.05)the Ace value and Chao value.In conclusion,with corn,wheat,beet pulp as substrate,acarbose addition had different effect on ruminal fermentation and bacterial composition;With corn and wheat as substrate,acarbose addition had significant effect on inhibition of ruminal fermentation,but with beet pulp as substrate,acarbose addition had no significant effect on ruminal fermentation in vitro.3 Effects of acarbose addition on the rumen fermentation in dairy cattleThis study investigated the effects of acarbose addition on ruminal fermentation characteristics.Three cannulated Holstein cows(590 ± 48 kg)were used in a 3 x 3 Latin square design to investigate the effect of acarbose addition(0,0.5 and 1.0 g/d)on the fermentation of ruminal.The results showed that acarbose addition decreased the ruminal propionate concentration(P<0.05),and increased the ratio of acetate to propionate(P<0.05),but no significant on concentrations of ruminal acetate,isobutyrate,butyrate,isovalerate,valerate,total volatile fatty acid and amonia-nitrogen,pH value and lactate level compared with the control(P>0.05).The results indicated that acarbose addition may reduce the effect on preventing the occurrence of ruminal acidosis in the long term.Therefore,it is suggested that acarbose can not be used as additive for preventing the occurrence of ruminal acidosis in the long term in ruminants.