Avaliação do microbioma, fermentação, composição química, estabilidade aeróbia de silagens de sorgo e de ração total aditivadas com aditivos químico e microbianos

Abstract

The climatic variability poses challenges for pasture growth in Brazil, directly impacting livestock feeding, and silage stands out as an effective strategy for conserving forages, maintaining their nutritional value and ensuring the availability of food during periods of scarcity. The first experiment aimed to investigate the effects of inoculation with Lentilactobacillus buchneri (Lb) alone or in combination with Lentilactobacillus hilgardii (Lh) on the fermentation profile, bacterial and fungal succession, chemical composition, dry matter losses, and aerobic stability of whole-plant sorghum silages ensiled for 20, 60 and 100 days. The experimental design was fully randomized, arranged in a 3×3 factorial scheme, with three microbial additives (Control, non inoculated; commercial Lb-based inoculant; and another commercial inoculant composed of Lh with Lb), with five repetitions per treatment. The evaluated variables were fermentation profile, chemical composition, microbial population quantification, organic acids, and dry matter losses. Aerobic stability was monitored using data loggers, while microbial diversity was characterized by 16S rRNA gene sequencing, using the QIIME2 platform. Significant interaction (P<0,05) was observed between the additives and the fermentation period for the variables pH, soluble carbohydrates, ammoniacal nitrogen, dry matter, crude protein, lactic acid bacteria, acids, and aerobic stability. Beta diversity showed higher aerobic stability in the bacterial communities of the inoculated groups, while the control group exhibited greater dispersion and an increase in undesirable taxa. Lentilactobacillus dominated the inoculated groups, and Kazachstania was the main fungal taxon. Inoculation with Lb alone and in combination with Lh promoted greater development of lactic acid bacteria and produced antifungal compounds. Therefore, inoculation with Lb or Lb+Lh and a fermentation period of 60 to 100 days are recommended to optimize aerobic stability. In the second experiment, the aim was to evaluate the fermentation profile, dry matter losses, chemical composition, and aerobic stability of total mixed ration silages based on forage sorghum, treated with doses of FreshCUT Plus™ at 40- and 80-days post-ensiling. The experimental design was fully randomized, using two fermentation periods, three additives, and five repetitions per treatment, organized in a 2×3 factorial scheme. The additives used were: control total mixed ration, without additive; total mixed ration with 1 kg FreshCUT Plus™/Mg of dry matter. A significant interaction (P<0,05) was observed between the additive and fermentation period for ether extract, pH, soluble carbohydrates, organic acids, and aerobic stability. At 80 days, the silages with 2 kg FreshCUT Plus™ eliminated undesirable microbial populations, presenting higher concentrations of lactic and acetic acids, better aerobic stability, and lower temperatures, without significant changes in dry matter. Based on the results, it is recommended to add 2 kg FreshCUT Plus™/Mg and a fermentation period of 80 days to optimize silage quality.