Effects of amylase and glucoamylase on rehydrated corn ensiled for an extended period: nutritive value, fermentation profile, and amylolytic activity

ABSTRACT

This study evaluated the effects of amylolytic enzymes on the nutritive value, fermentation losses, fermentation profile, and amylolytic activity of rehydrated corn that had been stored for 30, 60, 90, 120, 150, 180, 210, or 240 d. Corn kernels were harvested, ground in a knife mill using a 4-mm screen, rehydrated to 625 g/kg of dry matter (DM). These experimental silos were then randomly assigned to the following treatments (n = 40 each): 1) CON (control) – rehydrated corn silage with no exogenous enzymes incorporated during the ensiling process; 2) AMY – rehydrated corn silage with exogenous alpha-amylase incorporated at 90 U/kg of fresh matter; and 3) GLU – rehydrated corn silage with exogenous glucoamylase incorporated at 90 U/kg of fresh matter. It was found that enzyme incorporation decreased the DM, starch, and non-fibre carbohydrate and increased the total losses and contents of crude protein, ether extract. Enzyme incorporation also reduced the silage pH, while increasing the lactate concentration. silages in the GLU treatment had higher aerobic bacteria counts and acetate and propionate concentrations. Amylolytic enzymes increased fermentation losses and the lactate and ethanol contents and decreased the nutritive value of rehydrated corn silage, reducing the starch content and DM degradation.

KEYWORDS:

• Cereals
• digestibility
• feed quality
• grain starch
• maize silage

Acknowledgements

The authors thank Kera Nutrição Animal by inoculants donation.

Disclosure statement

No potential conflict of interest was reported by the author(s).