Effect of glucoamylase enzyme extract on in vitro gas production and degradability of two diets with 25% of corn or sorghum grains

Abstract

The objective of this study was to evaluate the effect of glucoamylase enzyme (GEZ) extract on the in vitro ruminal gas production (GP) and degradability of 2 total mixed rations (TMR) of 25% of corn and other of 25% of sorghum grains. The 2 diets were treated with 0, 1.5 and 3 g of GEZ protein (65% of protein) per kg of grain in diet. Diets GP were measured at 2, 4, 6, 8, 10, 12, 24, 48 and 72 h of incubation. Incubations were stopped after 72 h where pH was measured and supernatant was filtered to determine in vitro dry matter (DMD), neutral detergent fiber (NDFD), and acid detergent fiber (ADFD) degradabilities. Addition of GEZ to corn diet had no effect on kinetics of GP, whereas GEZ added to sorghum diet, at the high dose of the enzyme (3 g/kg DM), was traduced by an increase of the rhythm of GP (c) and the volume of GP at 2, 4 and 6 h of incubation. Likewise, effect of GEZ was not affected either on the DMD or cell wall (NDFD and ADFD) of both diets (sorghum or corn). Irrespective to enzyme supply, kinetics of GP and pattern of degradation of corn were generally higher than those of sorghum. A net effect of the diet and the interactions between diet and enzyme were recorded for the volume of GP at different incubation times. The use of high doses of GEZ should be tested on the pattern rumen fermentation.