Effect of microbial inoculation and particle size on fermentation profile, aerobic stability, and ruminal in situ starch degradation of high-moisture corn ensiled for a short period

Abstract

Dairy farmers are often challenged with the need to feed high-moisture corn (HMC) after less than 30 d of fermentation. The objective this study was to assess the effects of microbial inoculation and particle size on fermentation profile, aerobic stability, and ruminal in situ starch degradation of HMC ensiled for a short period. High-moisture corn was harvested, coarsely ground (3,798 ± 40 µm, on average) or finely ground (984 ± 42 µm, on average), then ensiled in quadruplicate vacuum pouches untreated (CON) or with the following treatments: Lactobacillus plantarum CH6072 at 5 × 10 4 cfu/g and Enterococcus faecium CH212 at 5 × 10 4 cfu/g of fresh forage (LPEF); or Lactobacillus buchneri LB1819 at 7.5 × 10 4 cfu/g and Lactococcus lactis O224 at 7.5 × 10 4 cfu/g (LBLL). Silos were allowed to ferment for 14 or 28 d. Ruminal in situ starch degradation increased when HMC was finely ground. In addition, in situ starch degradation was greater and aerobic stability increased approximately 5-fold with LBLL compared with CON and LPEF. An interaction between microbial inoculation and storage length occurred for lactic acid. At 14 d, concentrations of lactic acid were greatest in LPEF and lowest in LBLL. Lactic acid concentrations increased from 14 to 28 d with CON and LPEF, but decreased with LBLL. At 28 d, concentrations of lactic acid were lower in LBLL compared with CON and LPEF. An interaction between particle size, microbial inoculation, and storage length occurred for acetic acid and ammonia-N. At 14 and 28 d, acetic acid concentrations were greatest in finely ground LBLL followed by coarsely ground LBLL. Ammonia-N concentrations increased across all treatments from 0 to 28 d. At 14 and 28 d, concentrations of ammonia-N were greatest in finely ground LBLL and lowest in coarsely ground CON and coarsely ground LPEF. Results from this study suggest that L. buchneri LB1819 can produce acetic acid in as little as 14 d, and that by 28 d, it has the potential to improve the aerobic stability of HMC. Additionally, results indicate that L. buchneri LB1819 has the potential to improve ruminal degradation of starch by 28 d of storage. Finally, results confirm enhanced fermentation and improved ruminal starch degradation with finely ground HMC by 28 d of storage.

Effect of kernel breakage on the fermentation profile, nitrogen fractions, and in vitro starch digestibility of whole-plant corn silage and ensiled corn grain

“…At least within the first 30 d of storage, our results indicate that protein solubilization and degradation by microorganisms, plant enzymes, and organic acids may be insufficient to improve starch digestibility when the endosperm is protected by an intact pericarp. Saylor et al (2020) reported greater in situ starch degradation after 28 d of ensiling for finely ground compared with coarsely ground HMC and attributed this effect to physical (based on mean particle size) and chemical (based on soluble CP and ammonia N concentrations) characteristics of HMC. Greater proteolytic activity and concomitant improvements in soluble CP and ammonia N were associated with a more pronounced fermentation pattern (Saylor et al, 2020).…”

“…Mechanical processing of corn kernels breaks the pericarp and disrupts the starch-protein matrix, thereby facilitating this proteolytic activity and enhancing starch digestibility (Ferraretto et al, 2018). Saylor et al (2020) reported greater ruminal in situ starch degradation for finely ground compared with coarsely ground HMC; this effect was related to a reduction in particle size and increased proteolysis during storage as indicated by greater soluble CP and ammonia N concentrations. These findings suggest that the degree of proteolysis is partially dependent on the physical form of ensiled kernels.…”

Effect of particle size on storage time of hydrated corn grain

“…Rehydration and ensilage, through the fermentation process of the material inside the silo, reduce the concentration of prolamines due to proteolytic activity, increasing the soluble protein content over time (Kung, Windle, & Walker, 2014). Similarly, Saylor et al (2019) observed that high-moisture corn silage with fine grinding showed higher concentrations of soluble protein than produced by coarse grinding, as well as a positive effect of the storage time for this same component, another positive effect of which was increased in situ degradability of starch from these silages. (14, 28, and 56 days).…”

“…To reduce labor, time, and energy costs, many farms use whole grain or coarse grind, rather than grinding into fine particles to create moist or rehydrated corn silage. Doing this can compromise digestibility ruminal starch, because smaller particles maximize the available surface area for microbial fixation and subsequent degradation (Saylor, Casale, Sultana, & Ferraretto, 2019); however, compensation occurs in the form of starch digestibility in the small intestine. According to these authors, there is usually a need to start using silage to feed animals in periods not exceeding 30 days of storage, and this also compromises the availability of starch.…”

Estabilidade aeróbia em silagens de gramíneas tropicais tratadas com Lactobacillus buchneri

“…Research, Society and Development, v. 9, n. 11, e75991110530, 2020(CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i11.10530 Ferraretto et al (2015, observaram um aumento na proteína solúvel de silagem de grão úmido inoculadas, entretanto, esse aumento da proteína solúvel não promoveu diferenças significativas sobre a digestibilidade do amido. Em contrapartida, Saylor et al (2020), observaram um aumento da proteína solúvel acompanhado do aumento da digestibilidade do amido quando a silagem de grão úmido foi inoculada com L. buchneri e Lactococcus lactis (39,5% proteína bruta e 57,5% amido), em relação a silagem controle (34,8% proteína bruta e 50,8% amido) e inoculada com L. plantarum e Enterococcus faecium (34,7% proteína bruta e 52,2% do amido).…”