The Study Of Adding Wet Brewer's Grains On Fermentation Quality Of Mixed Ensilages Of Corn Stalk And Agricultural Byproducts

This study was carried out to evaluate the fermentation quality of mixed silages by adding wet brewers' grains at different rates. Corn stalk and apple pomace were respectively mixed with carrot, sweet potato skins, sweet potato vine and orange peel. The silos were opened after 1,3,5,7,14 or 30 days of ensiling and the fermentation quality was analyzed. There are four experiments in this study.ExperimentⅠ:Effect of adding wet brewers' grains on fermentation quality of mixed silage of corn stalk, apple pomace and carrot. The rate of corn stalk, apple pomace and carrot was respectively 50%,40% and 10% of fresh weight. Wet brewers' grains was added at 0,10%,20%,30% of fresh weight. Based on the results, the pH value of silage at the later stages of ensiling were lower than 4.0. The pH value of the treatment was significantly (P<0.05) lower than control. Lactic acid content was significantly (P<0.05) higher than control. These showed that wet brewers' grains addition inhibited the action of aerobic microorganism and promote lactic acid fermentation. The WSC content of treatment at the later stages of ensiling was significantly (P<0.05) lower, while AN/TN value was significantly (P<0.05) higher than control. The content of butyric acid and proponic acid was less.These indicated wet brewers' grains addition increased the protein content, and it was hydrolyzed by perotease to produce more ammonia nitrogen. Except for the fifth day, the acetic acid content of treatment was significantly (P<0.05) higher than the control. This indicated that wet brewers' grains addition promoted the heterotypic fermentation of lactic acid bacteria. The DM content of treatment at the later stages of ensiling was significantly (P<0.05) higher than control. This showed that wet brewers' grains addition increased the loss of WSC content, but decreased the loss of DM content. The pH value of silage were lower than 4.0 after five days, so the silage can be well preserved. These results suggested that adding wet brewers' grains to the silage at a rate of 20% was the optimum for fermentation quality.ExperimentⅡ:Effect of adding wet brewers' grains on fermentation quality of mixed silage of corn stalk, apple pomace and sweet potato skins. The rate of corn stalk, apple pomace and sweet potato skins was respectively 50%,30% and 20% of fresh weight. Wet brewers' grains was added at 0,10%,20%,30%of fresh weight. Based on the results, between seven to fourteen days, the pH value of the treatment was significantly (P<0.05) lower than control. These indicated that wet brewers' grains addition reduced the pH value at early stage of fermentation. At the later stage of ensiling the acetic acid content and AN/TN value of treatment was significantly (P<0.05) higher, while WSC content was lower than the control. The content of butyric acid and proponic acid was less. These showed that wet brewers' grains addition promoted the fermentation of lactic acid bacteria and hydrolysis of protein. At the later stage of fermentation the pH value was stable, lactic acid and acetic acid content were higher, and the amount of wet brewers' grains had no significant (P<0.05) impacts on the results. The silage could be well preserved.ExperimentⅢ:Effect of adding wet brewers' grains on fermentation quality of mixed silage of corn stalk, apple pomace and sweet potato vine.The rate of corn stalk, apple pomace and sweet potato vine was respectively 50%,30% and 20% of fresh weight. Wet brewers' grains was added at 0,10%,15%,20% of fresh weight. Based on the results, lactic acid content of the treatments was higher than control. This showed that wet brewers' grains addition promoted the fermentation of lactic acid bacteria. The rate of wet brewers' grains has no effect significantly (P<0.05) on lactic acid content. At the later stage of fermentation the pH value and AN/TN value increased, while the WSC content of the treatments was significantly (P<0.05) lower than control. This may be the fermentation of clostridium. At the early stage of fermentation wet brewers' grains addition reduced the pH value and AN/TN value, and increased lactic acid content of silage. The amount of wet brewers' grains had no significant (P<0.05) impacts on the results. These results suggest that adding wet brewers' grains to the silage at a rate of 15% is the optimum for fermentation quality.ExperimentⅣ:Effect of adding wet brewers' grains on fermentation quality of mixed silage of corn stalk, apple pomace and orange peel.The rate of corn stalk, apple pomace and orange peel was respectively 50%,30% and 20% of fresh weight. Wet brewers' grains was added at 0,10%,15%,20% of fresh weight. Based on the results, wet brewers' grains addition promoted the fermentation of lactic acid bacteria and increased lactic acid content as compared with the controls, inhibited the action of aerobic microorganism, and decreased the content of butyric acid and proponic acid. The acetic acid content of treatment was significantly (P<0.05) increased, so the aerobic stability of silage was increased. This was benefit for the preservation of silage. For fourteen days' fermentation the pH value of treatment was the lowest than others, and the content of lactic acid and acetic acid was the highest than others. On this experimental conditions, the amount of wet brewers' grains had no significant (P<0.05) impacts on the results.