The effect of an exogenous protease on the fermentation and nutritive value of high-moisture corn

Abstract

The objective of this study was to determine if treating high-moisture corn at harvest with an exogenous protease could accelerate the increase in in vitro ruminal starch degradation that is normally found with advancing times of ensiling. Ground high-moisture corn (HMC; 73% dry matter) was untreated or treated with an exogenous protease to achieve a final concentration of 2,000 mg of protease/kg of fresh corn. Corn was ensiled in laboratory-scale bags (approximately 500 g) that were evacuated of air, heat-sealed, and stored at 22 to 23°C for 70 and 140 d. Samples of freshly treated corn samples were collected to represent d 0 samples. Treatment of HMC with protease did not affect the gross populations of lactic acid bacteria or yeasts throughout the ensiling period. Treatment of HMC with protease resulted in higher concentrations of lactic acid and ethanol after 70 but not 140 d of ensiling. Concentrations of crude protein, water-soluble carbohydrates, and starch were unaffected by treatment with protease within each sampling day. After 70 or 140 d of ensiling, HMC that was treated with protease had higher concentrations of soluble protein (as a % of crude protein) and NH3-N, and had lower concentrations of prolamin protein, compared with untreated corn. In vitro rumen degradability (7-h incubation) of starch was greater in protease-treated versus untreated corn at all sampling days but the difference was more pronounced after 70 and 140 d compared with d 0. Concentrations of soluble protein and NH3-N were positively correlated with in vitro starch degradation. Conversely, the concentrations of prolamin protein in HMC were negatively correlated with in vitro starch degradation. Treating HMC with an exogenous protease could be a method to obtain greater potential for ruminal starch fermentation after a relatively short period of ensiling.

Effect of substituting dry corn with rehydrated ensiled corn on dairy cow milk yield and nutrient digestibility

“…The increase of soluble protein content over the time of ensiling has been also reported for rehydrated corn (Ferraretto et al, 2015) and HMC (Kung et al, 2014). Moreover, the soluble protein content was highly associated with increased in vitro digestibility of starch (Kung et al, 2014;Ferraretto et al, 2014), indicating that the solubilization of the protein corn matrix may increase the access of ruminal bacteria on the starch granules.…”

“…Therefore, protein matrix solubilization may occur in REC (Ferraretto et al, 2015) and, consequently, it may increase starch granule surface area for bacterial attachment in the rumen (Huntington et al, 2006). In addition, increased corn starch digestibility in high-moisture corn may be accelerated by the inclusion of proteases during the ensiling process, which also indicates the inhibitory role of zein on corn starch digestibility (Kung et al, 2014). Additionally, a recent study described that addition of exogenous protease, increased in vitro digestibility of starch in REC (Ferraretto et al, 2015).…”

“…The ensiling process of corn grain reduced the integrity of the protein matrix that surrounds the corn starch granule, which increased the availability of starch to bacterial enzymatic activity, and, consequently, the in vitro starch digestibility (ivSD) (Hoffman et al, 2011;Ferraretto et al, 2015). Recent studies suggested that an extended ensiling period increases ruminal ivSD, which indicated that maximum starch digestibility occurs only after several months of storage Kung et al, 2014).…”

Influence of ensiling, exogenous protease addition, and bacterial inoculation on fermentation profile, nitrogen fractions, and ruminal in vitro starch digestibility in rehydrated and high-moisture corn

“…Recent reports indicate that an extended ensiling period increases ruminal in vitro starch digestibility (ivSD; Ferraretto et al, 2014;Kung et al, 2014), underscoring that maximum starch digestibility occurs only after several months of storage. To help overcome this lag, 2 options may merit consideration.…”

A fermentação de grãos de milho reidratados influenciada pela aplicação de aditivos: aspectos da conservação e do valor nutritivo para vacas leiteiras

“…Para elucidar o efeito da aplicação dos aditivos em silagens de grãos de milho foi realizado um estudo meta-analítico a partir de 24 artigos publicados na íntegra (BIRO et al, 2006(BIRO et al, , 2009CANIBE et al, 2014;Da SILVA, T. et al, 2015;DAWSON;RUST;YOKOYAMA, 1998;DOLEZAL;ZEMAN, 2005;DUTTON;OTTERBY, 1971;FERRARETTO;FREDIN;SHAVER, 2015;FLORES-GALARZA et al, 1985;GÁLIK et al, 2007GÁLIK et al, , 2008ÍTAVO et al, 2006ÍTAVO et al, , 2009JOBIM et al, 2008;KUNG Jr. et al, 2004, 2007WINDLE;WALKER, 2014;LOUCKA, 2010;MORAIS et al, 2012;PRIGGE et al, 1976;PYŚ et al, 2009;REIS et al, 2008;TAYLOR;KUNG, 2002;WARDYNSKI; RUST; YOKOYAMA, 1993) uma nota científica (BASSO et al, 2012) e 10 resumos publicados nos principais simpósios internacionais sobre silagens e não publicados como artigos até o momento (AUERBACH et al, 2015;COUDURE et al, 2012;DA SILVA, N. et al, 2015;DAVIES et al, 2009 …”