Efeitos de novos inoculantes na fermentação de silagens de milho

Abstract

This present work had as objective to evaluate the inoculation effects of eight strains of lactic acid bacteria (LAB), pre-selected and isolated from sugar cane, and a commercial strain of LAB (Lalsil Cane) on different parameters that influence the quality of corn silage. Inoculation of forage for silage consisted of two doses (5 and 6 log UFC g-1) for each strain of LAB tested. The work was conducted in silos of PVC, for 3 months, and at 30 and 90 days of fermentation, the silos were opened for removal of silage samples intended for evaluations as chemical-bromatologic and microbiological characteristics to profile of fermentations metabolites (volatile fatty acids and alcohols) and aerobic stability. The results showed that the inoculants dosages did not promote significant differences on characteristics evaluated for silage samples, except for NDF, pH and filamentous fungi. No significant influence of the treatments reported in the following variables: MS, CHO, concentrations of lactic acid, ethanol, except for acetic acid, 1,2-propanediol, and pH value. The fermentation time affected significantly, favoring an increase of DM losses, the acetic acid content, 1,2-propanediol, ethanol, pH to 90 days of fermentation. About to microbiological analyzes was verified the significant influence of the treatments on the LAB population, filamentous fungi. The fermentation time also exercised significant influence over the population of microorganisms in silage, occurring, decreasing in the LAB number, filamentous fungi, and the increase of yeasts over the fermentation process. Regarding variables Tm, TTMAX and Aerobic stability (AS) has not been reported influence of the treatments, but in 90 days of fermentation was observed decrease in Tm, and TTMAX and AS increased, showing the inoculation advantage with LAB strains along the fermentation process. The inoculated with different LAB strains changed similarly the bromatologic characteristics without showing, however, differences in nutritional value of corn silage evaluated after the fermentation period. Different effects on LAB populations and filamentous fungi were provided by the treatments inoculated in corn silage, which is not observed for yeast population. It was determined that the tested treatments for the indicated dose inoculation is 6 log UFC g-1 of forage for providing the greatest reduction of the fungi filamentous in corn silage, thus, reducing the aerobic deterioration by these microorganisms.