| The present experiment was conducted to study the nutritional value of distillers grains of white spirit and to improve the utilization of it.First,the nutritional value of DG was analysed,and in vitro fermentation was carried out to study the associative effects of corn,soybean meal(SM)and DG..At last,the cellulolytic bacteria and ethnogeny were quantified by the method of real-time PCR,furthermore,the mechanisms of AE between DG and SM and corn were studied.In Trial 1,The nutritional values of DG,SM and corn was tested by the methods of AOAC(1990) and Van Soest(1991).The CF content of DG,SM and corn are 12.5%,1.7% and 4.3%as feed basis and 38.5%,2.0%and 4.8 as DM basis.The CP content of DG,SM and corn are 7.5%,44%and 8.7%as feed basis and 23.1%,49.4%and 10.1%as DM basis. The result showed that DG was a forage because of the content of CF,and it also was a concentrate as the content of CP.In Trial 2,The AE of SM and corn was learned.The corn was incubated together with soybean meal(SM) with a SM proportion of 0,20,40,60,80,and 100%(SM0,SM20, SM40,SM60,SM80,SM100),respectively.Syringe system was conducted to investigate the interactions between corn and soybean meal.The gas production was recorded at 2,4, 6,8,10,12,24,36,48h of incubation and the value of pH was recorded at 48h,and then the IVOMD was determined at 48h.Gas production was increased with the proprotion of corn increasing within 7 hours incubation;but Gas production was increased with the proprotion of soybean meal increasing after 7 hours incubation.Gas production differed significantly among treatments,pH value ranged from 6.42 to 6.9,meanwhile,when the concentration of the soybean meal increased,the value of the pH was increased from 6.42 to 6.90.There were positive associative effects of SM 40 at 12 and 24h of incubation,and it was 4.13 and 0.72 which was larger than other treatments(p＜0.001).In Trial 3,corn and soybean meal were used to constitute the mixted concentrate (corn:soybean meal=6:4 according to Trial 1 and 2) with DG at levels of 0,20,40,60,80 and 100%(DG0,DG20,DG40,DG60,DG80,DG100),respectively.The gas production was recorded at 2,4,6,8,10,12,24,36,48 and 96h of incubation in vitro fermentation. The fluid pH,microorganism-nitrogen,VFA,N-NH3,activities of cellulolytic enzymes and relative amount of cellulolytic microorganisms were determined.DG40 showed the greatest positive associative effects among treatments at 24 and 48h of incubation.The concentrations of N-NH3 were increased from 25.2 to 30.84 mg/dl when the DG level reduced(p=0.02).The MN production was increased from 2.61 to 6.82 mg/100ml along with the increasing level of MF(P＜0.001).The level of acetate, propionate,and butyrate were reduced along with the DG level(p＜0.001,p=0.002, p＜0.001).The level of acetate acid,prop ionic acid and butyric acid were increased from 0.143,0.084,0.028 to 0.250,0.149,0.034 mmol/L,respectively,along with the increasing level of SM and corn of all the treatments,but prop ionic acid of DG40 was higher than DG20,and then the level of acetate acid:prop ionic acid was lower than other treatment. The observed cellulose activity,quantities of cellulolytic bacteria from DG40 was higher than DG 20 and significant higher than other treatment(p=0.002).It is inferred that the increased activities of cellulolytic bacteria and cellulose activity are the reasons of the mechanism for the positive AE among the DG,SM and corn.It could be concluded that positive associative effects of in vitro fermentation was 22 when the proportion of corn,SM and DG was 3.6:2.4:4 at 96h of incubation,which was greater than other treatments(p＜0.001).The improving of energy utilization rate,activities of cellulolytic bacteria and cellulose activity may the main reasons of the AE among DG,SM and corn.
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