| In order to develop silage technique of high moisture materials in eastern China,effects of wilting and mixed materials on nutritional and fermenting quality of silage were explored using the method of mini-silo bags with sweet sorghum(Sorghum bicolor L.Moench)and Italian ryegrass(Lolium multiflorum L.).Furthermore,the effect of mixed silage on nutrient recovery was analyzed by determining changes of nutritional components during the ensiling process.1.Effects of wilting on the fermenting and nutritional quality of silageIn the wilting silage experiment,sweet sorghum and Italian ryegrass were wilted,keeping the moisture content at 75%,65%and 55%,respectively,under laboratory conditions.Ensiling without wilting was set as control(CK),and the experiment was carried out in three replications.Effects of wilting and mixed ensiling on nutritional and fermenting quality of silage were investigated using the method of mini-silo bags.The results were as follows:the wilting treatment of materials reduced silage pH and the rate of ammonia nitrogen/total nitrogen(NH3-N/TN).However,the content of lactic acid(LA),acetic acid(AA),and fileg' s score were increased by the wilting treatment.Wilting treatment significantly increased the dry matter(DM)of silage,and had little effect on the contents of neutral detergent fiber(NDF),acid detergent fiber(ADF)and hemicellulose.With the increasing of the withering degree,the residual water soluble carbohydrates(WSC)content of the silage and the in vitro dry matter digestibility(IVDMD)increased,and the fermenting and nutritional quality of silage were also improved by wilting.These results indicated that the optimum moisture content of sweet sorghum and Italian ryegrass as silage materials were 75?65%and 65?55%,respectively,under laboratory condition.2.Effects of forages mixing with straws on the fermenting and nutritional quality of silageIn mixed silage experiment,sweet sorghum and Itlian ryegrass mixed with soybean straw,rice straw,wheat straw and corn stalk,keeping the moisture content at 75%,65%and 55%,respectively.Ensiling with single sweet sorghum or Italian ryegrass was set as control(CK),and the experiment was carried out in three replications.Effects of forages mixing with straws on the fermenting and nutritional quality of silage were studied.The results were as follows:forages mixing with straws decreased pH value and butyric acid(BA)content of silage,while increased the content of LA and AA.The best and worst fermenting quality of silage were found when the moisture content of mixed materials was at 65%and 55%,respectively.The NDF,ADF and cellulose contents of silage mixing sweet sorghum with corn stalk induced,with the decreasing of moisture content.However,mixing sweet sorghum with other straws had no significant affect on NDF,ADF,cellulose and hemicellulose contents of the mixed silage.Mixing Italian ryegrass with straws significantly increased cellulose content of the mixed silage of which CP content decreased with the decreasing of moisture content.In addition,forages mixing with straws could improve the IVDMD to some extent,and IVDMD decreased with the decreasing of moisture content(as the proportion of straw added).These results indicated that good quality of silage with materials of sweet sorghum mixing with soybean straw and corn stalk or Italian ryegrass mixing with wheat and corn stalks were observed under laboratory condition.3.Effect of forages mixing with straws on nutrient recovery of forageAccording to the results as mentioned above,the materials with 65%moisture content were used to ensile,and the nutrient recovery of mixed silage was estimated by determining changes of nutritional components during the ensiling process.Ensiling with single forage(CK)and forage air dried to 65%moisture content(SD)were set as control.The results were as follows:dry matter recovery(DMR)and crude protein recovery(CPR)of forage in mixed silage were higher than that of the CK.The DMR and CPR of the most mixed silage with sweet sorghum and straws were higher than that of the SD.However,the DMR of the mixed silage with Italian ryegrass and straws were lower than that of the SD.Furthermore,The efficiency of WSC conversion to LA in Mixed Silage was significantly higher than that in CK and SD.Under the fixed moisture condition,the loss rate of cellulose of most mixed silage with sorghum and straws were lower than that of the SD,while the loss rate of celluloses of the mixed silage with Italian ryegrass and straws had great difference.The changes of hemicellulose loss rate were similar to that of cellulose.In addition,the hemicellulose loss rate of mixed silage with sweet sorghum and straws was lower than that of the SD,the hemicellulose loss rate in mixed silage with Italian ryegrass and straws had great difference,and the parameter in some treatment was lower than that of the SD.In conclusion,the silage fermenting quality of sweet sorghum and Italian ryegrass can be improved by wilting or mixing with straws.The optimum moisture content of sweet sorghum and Italian ryegrass were 65%,and the quality of mixed silage with corn stalk was better than that with others.Mixture of sweet sorghum or Italian ryegrass with straws can improve the silage nutrient recovery,especially,enhance hemicellulose recovery,but have little effect on cellulose decomposition. |
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