Effect of Different Kefir Source on Fermentation, Aerobic Stability, and Microbial Community of Alfalfa Silage

Abstract

The present study has been one of the first attempts to thoroughly examine the effects of different kefir sources on fermentation characteristics, aerobic stability, and microbial communities of alfalfa silages. The effects of commercial kefir (CK) and homemade kefir culture (HK) applied with untreated a common control (CON) and three different application doses (5.0, 5.7, and 6.0 log cfu g−1) on wilted alfalfa and stored at an ambient temperature of 25–30 °C are studied. After 45 days of ensiling, fermentation characteristics and aerobic stability of silages were measured, and bacterial diversity was investigated by 16S ribosomal RNA gene sequencing using the GenomeLab™ GeXP platform. Both CK and HK accelerate more lactic acid production and reduced ammonia nitrogen concentration. Factor analysis of kefir sources suggests that the addition of kefir improves the aerobic stability of silages, even the initial water-soluble carbohydrate (WSC) content is inadequate via its antimicrobial effect on yeast and mold formation. Enterococcus faecium, Pediococcus pentosaceous, and Lactobacillus brevis were dominant bacterial species among the treated groups at silo opening, while Lactobacillus plantarum and Lactobacillus brevis became dominant bacterial species after 7 days of aerobic exposure. In conclusion, the application of kefir on alfalfa silages improves fermentation quality and aerobic stability even with low WSC content.

Infrared Thermography Assessment of Aerobic Stability of a Total Mixed Ration: An Innovative Approach to Evaluating Dairy Cow Feed

“…The moisture level and chemical composition of the TMR were the other categories that contributed the most. These results are similar to those obtained by Koç et al [44], who reported that the moisture level, the type of ensiled plant, and its parts are more important than biological treatments for adequate forage conservation.…”

Lentilactobacillus buchneri Preactivation Affects the Mitigation of Methane Emission in Corn Silage Treated with or without Urea

“…The restraining activity of urea on spoilage microorganisms, including yeast and mold, was also stated by Fang et al [19]. Furthermore Koç et al [27] stated that such factors could affect the aerobic stability of silage, such as the initial epiphytic LAB population and its abundance, additive types, organic acid, and WSC content of ensiled material. These results mirror previous studies examining LB and urea on silages' aerobic stability.…”

“…The WSC (water-soluble carbohydrate) content of the silages was determined using a 0.2% anthrone reagent [25]. The pH, ammonia nitrogen (NH 3 -N), and organic acid content of the silage samples was determined after extracting a representative 20 g of fresh silage in 180 mL of distilled water at room temperature for 1 h. A digital pH meter (inoLab ph 730, WTW, Weilheim, Germany) and a microdistillation apparatus were deployed for the determination of pH and NH 3 -N analysis [27]. After deproteinization of the silage extract with a mixture of metaphosphoric acid and formic acid (3:1, v:v), the organic acid content of the silages, i.e., acetic acid (AA), propionic acid (PA), butyric acid (BA), was determined using a gas chromatograph (Shimadzu GC-201, Kyoto, Japan) with a capillary column (Restek, Bellefonte, PA, USA; 30 m, id: 0.25 mm, f.t.…”