Effect Of Some Additives On Fermentation Quality And Aerobic Stability Of Italian Ryegrass Siliages

The purpose of this study is to evaluate the effect of adding propionic acid and caproic acid on the fermentation quality and aerobic stability of Italian ryegrass silage, and the proper rate of adding propionic acid and caproic acid on the fermentation quality and aerobic stability of Italian Ryegrass (Lolium multiflorum Lam.) silages were determined. In the further, the effect of proper rate of adding propionic acid and caproic acid alone or with lactic acid bacteria on the fermentation quality and aerobic stability were estimated on 30th days or during aerobic stages. The pH, dry matter, lactic acid and water soluble carbohryate were analysed, and the proper adding rate was seleckted. the dynamic changes in fermentation were in further studied with the selected adding rate with lactic acid bacteria treatments during aerobic stages.The fresh Italian ryegrass was harvested at the heading stages, and then chopped and packed into small scale experiment silos (100 ml) immediately. The all silos were opened on the 30th day after ensiling and were analyzed the fermentation quality. The dynamic change of fermentation quality of adding propionic acid (0.3%, 0.4%, 0.5%) and caproic acid (0.1%, 0.15%, 0.2%, 0.25%) were analyzed on 0, 2, 4, 6, 8 days of aerobic exposure. Forthemore, the proper rate levels (Propionic acid-0.5%; Caproic acid-0.2%) and tow comparative levels (Propionic acid-0.4%; Caproic acid-0.15%) to alone or combined with lactic acid inoculation, and compared with Control and LAB-treaded. After 30 days of ensiling, opened the silos and three silos per treatment were adopted in different times during exposure days to study aerobic stability.The study result showed: (1) When compared with Control-treaded silage, the silages alonelv treated with Propionic acid and Caproic acid at each level all had no effects on fermentation of silages after 30 days of ensiling(P>0.05), but by the rate was higher, the quality was tend to become better. Propionic acid-treated silages had better aerobic stability than Control-treaded silage, because the Control-treaded silage showed a higher pH, DM, Ammonia-N (P<0.05), and lower content of lactic acid and WSC(P<0.05) in different times during aerobic exposure days. ( 2 ) Caproic acid -treaded silages had better aerobic stability than Control-treaded silage in whole aerobic detected period, but the feremetation quality were't improved, even became worse. (3 ) Regardless of Propionic acid alonely or jointly accession and all Caproic acid combined treated silages had lower content of acetic acid, butiryc acid and Ammonia-N(.P<0.05), higher content of lactic acid and WSC(P<0.05), they were preferably ameliorating the quality of silages. The change of depressed extent on lactic acid and WSC in all Propionic acid and Caproic acid-treated silages were notability slower compared with control silage, and there were only a few butiryc acid or no. Because of higher content of propionic acid and caproic acid, the total VFAs were also higher in them, but these tow acids could improve aerobic stability. ( 4 ) Compared with Control-treaded silage, the quality of LAB-treaded silage was worse, although the lactic acid content of it was markedly improved, but the rate of lactic acid : acetic acid was far lower than 3:1, and the content of propionic acid and caproic acid were increased 96.6 %, 169.4%. The tend of changes of all detected nutrition components in Control and LAB-treaded silages were almost identical(P>0.05), up to 8th day, the rate of lactic acid : acetic acid were under 2:1; WSC reduced 46.1% and 46.8%; Ammonia-N increased 88.2% and 92.6%.By the above analysis, we can see that, appending propionic acid and caproic acid can recede the aerobic loss, delay second fermentation, enhance aerobic stability, and the higher accession level, the better effect. If the condition was well, condign and high level propionic acid could improve fermentation quality. From improving fermentation quality and enhancing aerobic stability to see, when propionic acid and caproic acid combined with microbial inoculation, the geminate effect remarkable better than witch were alone accession.