TY - JOUR
T1 - Proteolysis During Ensilage of Forages Varying in Soluble Sugar Content
AU - Davies, D. R.
AU - Merry, R. J.
AU - Williams, A. P.
AU - Bakewell, Eleanor Lydia
AU - Leemans, David
AU - Tweed, John
PY - 1998/2
Y1 - 1998/2
N2 - The effect of contrasting concentrations of water-soluble carbohydrates of herbage on silage fermentation and composition was examined using grass with high [250 g/kg of dry matter (DM)] concentrations of water-soluble carbohydrates and grass and clover with low (66 g/kg of DM) concentrations of water-soluble carbohydrates. Herbages were ensiled untreated, after inoculation with lactic acid bacteria, or after treatment with formic acid. Good quality silages were produced from herbage with high concentrations of water-soluble carbohydrates, regardless of treatment, and all pH values were below 3.7 after 90 d of ensilage. However, the silage formed from inoculated herbage had a significantly lower concentration of ammonia N and a significantly higher proportion of residual ribulose-1,5-bisphosphate carboxylase compared with the other two silages. Fast protein liquid chromatography® (Pharmacia, Uppsala, Sweden) was used to measure ribulose-1,5-bisphosphate carboxylase, and measurement of true plant protein fractions in herbage and silage showed benefits over traditional measurements such as the measurement of N and ammonia N. Herbages with low concentrations of water-soluble carbohydrates produced inferior quality silages that had lower ribulose-1,5- bisphosphate carboxylase contents and higher ammonia N contents, regardless of treatment; few significant differences were observed among treatments. Under good ensiling conditions, when available water-soluble carbohydrate is adequate, the use of inoculants can improve fermentation characteristics and increase the ribulose-1,5-bisphosphate carboxylase content of silages. However, when the herbage has low concentrations of water-soluble carbohydrates, even in inoculated herbages, lactic acid bacteria may follow a heterofermentative pathway instead of a homofermentative pathway, which can result in a decrease in silage quality and a reduction in intact ribulose-1,5-bisphosphate carboxylase.
AB - The effect of contrasting concentrations of water-soluble carbohydrates of herbage on silage fermentation and composition was examined using grass with high [250 g/kg of dry matter (DM)] concentrations of water-soluble carbohydrates and grass and clover with low (66 g/kg of DM) concentrations of water-soluble carbohydrates. Herbages were ensiled untreated, after inoculation with lactic acid bacteria, or after treatment with formic acid. Good quality silages were produced from herbage with high concentrations of water-soluble carbohydrates, regardless of treatment, and all pH values were below 3.7 after 90 d of ensilage. However, the silage formed from inoculated herbage had a significantly lower concentration of ammonia N and a significantly higher proportion of residual ribulose-1,5-bisphosphate carboxylase compared with the other two silages. Fast protein liquid chromatography® (Pharmacia, Uppsala, Sweden) was used to measure ribulose-1,5-bisphosphate carboxylase, and measurement of true plant protein fractions in herbage and silage showed benefits over traditional measurements such as the measurement of N and ammonia N. Herbages with low concentrations of water-soluble carbohydrates produced inferior quality silages that had lower ribulose-1,5- bisphosphate carboxylase contents and higher ammonia N contents, regardless of treatment; few significant differences were observed among treatments. Under good ensiling conditions, when available water-soluble carbohydrate is adequate, the use of inoculants can improve fermentation characteristics and increase the ribulose-1,5-bisphosphate carboxylase content of silages. However, when the herbage has low concentrations of water-soluble carbohydrates, even in inoculated herbages, lactic acid bacteria may follow a heterofermentative pathway instead of a homofermentative pathway, which can result in a decrease in silage quality and a reduction in intact ribulose-1,5-bisphosphate carboxylase.
KW - silage
KW - proteolysis
KW - ribulose-1,5-bisphosphate carboxylase
KW - soluble sugar
UR - http://hdl.handle.net/2160/43186
U2 - 10.3168/jds.S0022-0302(98)75596-1
DO - 10.3168/jds.S0022-0302(98)75596-1
M3 - Article
SN - 0022-0302
VL - 81
SP - 444
EP - 453
JO - Journal of Dairy Science
JF - Journal of Dairy Science
IS - 2
ER -