Tempo de armazenamento e ação de enzimas amilolíticas em silagem de grão úmido de milho reidratado: atividade enzimática, população microbiana e estabilidade aeróbia

Abstract

The aim of this work was to evaluate the influence of amylolytic enzymes in association with bacterial inoculant on the microbiota and aerobic stability of damp grain corn silage. The following treatments have been applied the damp grain corn silage: 1) Control (CON) without amyliatic enzymes; 2) Glucoamylase (GLU), with 300 mL/ton fresh matter 35.563 IU/ml (Kerazyme 4560, Kera Animal Nutrition, Bento Gonçalves, RS); 3) Alpha-amylase (α-AMI), with 300 mL/ton fresh matter 49.473 IU/mL (Kerazyme 4577, Kera Animal Nutrition). All treatments were also inoculated with KeraSIL damp grain® (Kera Animal Nutrition, Bento Gonçalves, Brazil) constituted of Lactobacillus plantarum (4x1010UFC/g) and Propionibacterium acidipropionici (2.6 x1010 cfu/g), added in a proportion of 4 g/ton of ground corn hydrated. After 35 days the silos were opened, collected samples of 200 g of silage, which were used for identification and quantification of the present microbiota (lactic, anaerobic, aerobic, filamentous fungi and yeasts) and determination of the aerobic stability in different times. The α-AMI treatment showed the highest count of lactic acid bacteria (LAB), as anaerobic and aerobic, then compared with GLU and CON. Treatment the GLU did not show difference in the count of anaerobic bacteria in relation to CON. GLU and α-AMI showed low count of filamentous fungi and yeasts did not differ amongst them, while CON presented high count. The α-AMI treatment did not differ from CON in the count of filamentous fungi and yeasts at all times tested for aerobic stability. While GLU until 72 hours after the opening of the silos remained with low fungal counts in relation to α-AMI and CON. After 96 hours the treatments did not differ among themselves for quantity of fungi. Adding α-AMI in damp grain silage improved microbiological profile. The addition of GLU increased aerobic stability until 72 hours after opening times the silos.