Efeitos da associação de diferentes microrganismos sobre a degradação do amido de silagens de espigas e de grãos úmidos de milho

Abstract

The objective of this study was to evaluate the association of different microorganisms and inoculation rates on the fermentation profile, aerobic stability and in situ degradation of starch from snaplage for 30, 60 and 120 days of ensilage and wet grain silage for 30, 60, 120 and 150 days. In experiment 1, the treatments consisted of: control and silage inoculated with L. buchneri (LB) NCIMB 40788 (1k20757) + L. hilgardii (LH) CNCM I-4785 (1.5 x 10-5 /g for both bacteria). In experiment 2, the treatments consisted of: treatment 1 (CON) without additive, treatment 2 (LB) addition of L. buchneri NCIMB 40788 (1k20739) (6.0 x 10-5CFU/g), treatment 3 (LBLH) addition of L. buchneri NCIMB 40788 (1k20757) + L. hilgardii CNCM I-4785 (6.0 x 10-5 CFU/g for both bacteria), treatment 4 (LBLHP) addition of L. buchneri NCIMB 40788 (1k20757) + L. hilgardii CNCM I-4785 (4.0 x 10-5 CFU/g for both bacteria) + Pediococus pentosaceus NCIMB 12455 (1k2106) (2.0 x 10-5 CFU/g), treatment 5 (LBLHPE) addition of L. buchneri NCIM 40788 (1k20757) + L. hilgardii CNCM I-4785 (6.0 x 10-5 CFU/g for both bacteria), Pediococus pentosaceus NCIMB 12455 (1k2106) (≥ 2.0 x 10-6 CFU/g) + Xylanase (EC3.2.1.8) MUCL 39203 (1k) ( ≥ 1.2 x 10-1 IU/g) + Beta-glucanase (EC 3.2.1.6) MUCL 39199 (1k) (≥ 2.3 x 10-2 IU/g). The experiments were carried out in a completely randomized design. Experiment 1, in a 2 x 3 factorial scheme (two treatments and 3 storage times), totaling 30 experimental units. Experiment 2 was conducted in a 5 x 4 factorial scheme (five treatments and four storage times), totaling 100 experimental units. Data were analyzed using PROC MIXED of the SAS statistical program. Treatment means were estimated by “LSMEANS” and comparison was performed by Tukey’s test at 5% probability. In Experiment 1, the use of inoculant and different storage times affected aerobic stability in snaplage (P < 0.001). In the starch degradability (7 h), interactions were observed between the use of inoculant x storage time (P = 0.023). Storage time affected fraction B2 (P = 0.012), fraction B3 (P < 0.001), and fraction C (P < 0.001), longer storage times reduced the respective protein fractions. In Experiment 2 inoculants and storage times affected the acetic acid concentrations (P < 0.001 and P < 0.001), as well as the 1,2-propanediol concentrations (P < 0.002 and P = 0.002), respectively. The use of inoculant and storage times altered the A1 fraction of the protein (P < 0.001 and P = 0.023, respectively). Wet grain silages inoculated with LBLH, LBLHP and LB presented higher values of the A fraction of the protein (0.10%; 0.13% and 0.10%, respectively). Starch degradability was altered only by storage time (P < 0.001). The use of inoculants and different storage times modify the fermentation profile of snaplage and wet grain silage and also positively affect protein fractionation.