| The resources of rice straw are very abundant in Jiangsu and Zhejiang provinces,however,only a small part of them are used as roughage for feeding ruminants.Most of them are not used reasonably and efficiently.They are often discarded in the field,which causes resources wasting and environmental pollution.If we can utilize the rice straw rationally,it can not only solve the problem of feed shortage,but also protect the environment.The research is to evaluate the effect of adding different additives on the fermentation and carbohydrate of rice straw silage,and provided theoretical guidance for producing high quality of rice straw silage.1.Effect of adding different levels of cellulase on fermentation quality and carbohydrate of rice straw silageThis study was to evaluate the effects of different levels of cellulase on fermentation quality and carbohydrate of rice straw silage.The treatments were as follows:(1)control(no additives,CK);(2)0.35 g/kg cellulase(C1);(3)0.5 g/kg cellulase(C2);(4)0.6 g/kg cellulase(C3).Silos were opened on 3,6,9,15,30 and 60 d after ensiling,and then the fermentation quality and carbohydrate were analyzed.The result showed that addition of cellulase improved the fermentation quality of rice straw silage as indicated by higher(P<0.05)lactic acid content and lactic acid/acetic acid,and significantly(P<0.05)lower pH value and AN/TN.During the ensiling,cellulose and hemicellulose contents of the additive treatments were numerically(P>0.05)or significantly(P<0.05)lower than control.At the end of ensiling,the additive treatments had higher water soluble carbohydrate,glucose and fructose contents than control.In conclusion,0.35 g/kg treatment was the most appropriate.2.Effect of adding different levels of cellulase combined with lactiac acid bacteria on fermentation quality and carbohydrate of rice straw silageThe study aimed to evaluate the effect of different levels of cellulase combined with lactic acid bacteria on fermentation quality and carbohydrate of rice straw silage.The treatments were as follows:control(CK),lactic acid bacteria(L),0.35 g/kg cellulase+L(C1L),0.50 g/kg cellulase+L(C2L),0.65 g/kg cellulase+L(C3L).These silos were opened after 3,6,9,15,30 and 60 d of ensiling and the fermentation quality and carbohydrate were analyzed.Compared with control,the additive treatments had significantly(P<0.05)higher LA content and significantly(P<0.05)lower pH,AN/TN(<100 g/kg TN),AA and ethanol contents.Compared with L silage,CL treatment did not further improve the fermentation quality.During ensiling,the additive treatments significantly(P<0.05)decreased cellulose and hemicellulose contents,however significantly(P<0.05)increased glucose and fructose contents than control.With the cellulase level increased,there were no differences(P>0.05)in structural carbohydrate and water soluble carbohydrate contents ammong the additive treatments.In conclusion,it was suggested that 0.35 g/kg cellulase combined with LAB was appropriate.3.Effect of adding cellulase,complex enzyme and lactic acid bacteria on fermentation quality and carbohydrate of rice straw silageThis experiment was to determine the effect of adding cellulase,complex enzyme and lactic acid bacteria on fermentation quality and carbohydrate of rice straw silage.The treatments were as follows:(1)control(no additives,CK);(2)lactic acid bacteria(L);(3)cellulase(C);(4)cellulase+hemicellulase(CHC);(5)lactic acid bacteria+cellulase(CL);(6)lactic acid bacteria+cellulase+hemicellulase(CHCL).The silos from each treatment were opened on 3,6,9,15,30 and 60 d,and then the fermentation quality and carbohydrate were analyzed.The results showed that C and CHC somewhat improved the fermentation quality.L,CL and CHCL produced large amount of LA,and LA contents were up to 87.8～89.3 g/kg DM at d 30,resulting in lower pH,AN/TN and AA contents(P<0.05).After 6 d of ensiling,C,CHC,CL and CHCL had significantly(P<0.05)lower cellulose and hemicellulose contents than control,and CHCL treatment had the lowest(P<0.05)hemicellulose content.During the ensiling,the additive treatments had higher water soluble carbohydrate and monosaccharide contents than controls.In conclusion,CHCL not only improved fermentation quality,but also effectively degraded cellulose and hemicellulose and increased glucose and fructose contents.4.Effect of adding different levels of formic acid on fermentation quality and carbohydrate of rice straw silageThis study was to evaluate the effects of different levels of formic acid on fermentation quality and carbohydrate contents of rice straw silage.The treatments were as follows:control(CK),2%formic acid(F1),4%formic acid(F2)and 6%formic acid(F3).The sample was taken after 3,6,9,15,30 and 60 d of ensiling,and then the fermentation quality and carbohydrate were analyzed.The results indicated that formic acid addition significantly(P<0.05)decreased pH,AA and ethanol contents,however inhibited lactic acid fermentation during the early phase of fermentation,and the inhibitation was more obvious with the addition level increased.LA content of F1,F2 and F3 treatments increased rapidly after 3,9 and 30 d,respectively,and F1 and F2 showed significantly(P<0.05)higher LA contents than control at the end of ensiling.During ensiling,formic acid treatments had lower(P>0.05)cellulose and hemicellulose contents than control,and cellulose and hemicellulose contents in F3 treatment were significantly(P<0.05)lower than control.F2 and F3 treatments had higher water soluble carbohydrate and monosaccharide contents than control,and F3 treatment was numerically higher(P>0.05)than F2 treatment.In conclusion,6%formic acid improved the fermentation quality of rice straw silage and degradation of cellulose and hemicellulose.5.Effect of adding different levels of formic acid combined with lactic acid bacteria on fermentation quality and carbohydrate of rice straw silageThis study was to evaluate the effect of different levels of formic acid combined with lactic acid bacteria on fermentation quality and carbohydrate of rice straw silage.The treatments were as follows:control(CK),lactic acid bacteria(L),0.2%formic acid＋L(F1L),0.4%formic acid+L(F2L),0.6%formic acid+L(F3L).These silos were opened after 3,6,9,15,30 and 60 d of ensiling and the fermentation qulity and carbohydrate were analyzed.The result showed that formic acid combined with lactic acid bacteria had significantly(P<0.05)higher LA contents as compared with control at the end of ensiling,and LA content in FIL was significantly(P<0.05)higher than F2L and F3L.the additive treatments significantly(P<0.05)decreased ethanol content and AN/TN.Formic acid combined with lactic acid bacteria decreased cellulose and hemicellulose contents.Cellulose and hemicellulose contents gradually decreaed,and water soluble carbohydrate contents increased with the formic acid ratios increasing.In summary,0.6%formic acid combined with lactic acid bacteria was appropriate. 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