Effect of glucoamylase, particle size, and duration of silage storage on dry matter loss and digestibility of ground corn rehydrated and ensiled

• Published in: Journal of animal science 2016-10, Vol.94, p.671-671
• Main Authors: Lopes, N M, Cardoso, P C, Pereira, M N
• Format: Article
• Language: English
• Subjects: Coarsening; Corn; Cytotoxicity; Degradation; Digestibility; Dry matter; Effects; Endosperm; Feeds; Frozen ground; Glucoamylase; Grain; Grain silos; Grinding; Lymphocytes T; Particle size; pH effects; Polyethylene; Polyethylenes; Rehydration; Silage; Starch; Storage; Studies; Vacuum
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/jam2016-1388

Storing mature corn grain by rehydration and ensiling can improve digestibility by prolamin degradation in the silo. Particle size (PS) can determine the rate of grinding during ensiling and the duration of silage storage (D) determines farm cash flow. We evaluated the digestibility and DM loss of rehydrated and ensiled corn (REH) in response to PS, D, and glucoamylase addition at ensiling (G). Treatments were formed by a 2 x 2 x 2 factorial combination of PS (584 vs. 844 ...x|Ê|/x|m geometrical mean PS), D (30 vs. 250 d), and G (CTL vs. GAM. Sanferm Yield, 120 AGU/g, Novozymes. 0.35 mL/kg of corn). Particle distribution of fine and coarse corn were (% above screen): 2360 μm: 0.2 and 9.9. 2000 μm: 0.5 and 10.6. 1180 μm: 2.2 and 14.4. 850 μm: 21.3 and 21.8. 425 μm: 57.9 and 24.8. 300 μm: 4.7 and 3.9. Bottom pan: 13.1 and 14.5. Mature corn (86.8% DM, 49.2% vitreous endosperm, 4.3% prolamin/starch) was hydrated to a targeted DM concentration of 65%. Approximately 1 kg of corn DM was ensiled in heat sealed, nylon-polyethylene vacuum pouches, 5 silos per treatment combination. At opening, silages were frozen, dried at 55°C for 72 h, and ground through a 1 mm mesh diameter screen for determination of ruminal in vitro DM degradation in 3, 7, and 18 h. Coarse corn had higher pH and DM loss and lower DM concentration than fine corn. There was no effect of PS on digestibility and prolamine concentration. Longer D reduced pH and prolamine concentration, increased DM concentration and degradation in 18 h, and had no effect on DM loss. Glucoamylase reduced pH and DM concentration and increased DM loss and degradation in 3 h, and also induced greater decrease in silage pH and greater increase in DM loss when added to coarse (4.20 vs. 4.71 and 5.65 vs. 2.25% of ensiled) than to fine corn (3.98 vs. 4.19 and 3.09 vs.2.34% of incubated). The increase in DM loss induced by GAM was smaller when D was 30 d (4.21 vs. 2.25% of ensiled) than 250 d (4.52 vs. 2.35% of ensiled). Glucoamylase increased the proportion of rapidly degradable fraction in corn grain, but at the expense of increased DM loss, especially with coarse grinding. Longer storage increased prolamin degradation and the potentially degradable grain fraction.