Temperature and microbial changes of corn silage during aerobic exposure

Abstract

Objective This study was conducted to estimate the temperature and microbial changes of corn silages during aerobic exposure. Methods Kwangpyeongok (KW) and Pioneer 1543 (PI) corn hybrids were harvested at 29.7% of dry matter and chopped to 3 to 5 cm lengths. Homo ( Lactobacillus plantarum ; LP) or hetero ( Lactobacillus buchneri ; LB) fermentative inoculants at 1.2×10 5 colony forming unit/g of fresh forage was applied to the chopped corn forage which was then ensiled in quadruplicate with a 2×2 (hybrid×inoculant) treatment arrangement for 100 days. After the silo was opened, silage was sub-sampled for analysis of chemical compositions, in vitro digestibility, and fermentation indices. The fresh silage was continued to determine aerobic exposure qualities by recorded temperature and microbial changes. Results The KW silages had higher (p<0.01) in vitro digestibilities of dry matter and neutral detergent fiber than those of PI silages. Silages applied with LB had higher (p<0.001) acetate concentration, but lower (p<0.01) lactate concentration and lactate to acetate ratio than those of LP silages. The interaction effect among hybrid and inoculant was detected in acetate production (p = 0.008), aerobic stability (p = 0.006), and lactic acid bacteria count (p = 0.048). The yeast was lower (p = 0.018) in LB silages than that in LP silages. During the aerobic exposure, PI silages showed higher (p<0.05) temperature and mold than KW silages, while LP silages had higher (p<0.05) lactic acid bacteria and yeast than LB silages. Conclusion The results indicated that the changes of silage temperature during aerobic exposure seems mainly affected by mold growth, while applied LB only enhanced aerobic stability of PI silages.

Dual-Purpose Inoculants and Their Effects on Corn Silage

“…The chemical compositions of corn forage used in the present study were in normal range for corn grown in South Korea [33]. After ensiling, the concentrations of DM, CP, and EE were not affected by inoculant application in the present study.…”

“…Moreover, the presence of acetate in silage could reduce aerobic deterioration after silo opening [3,6]. Molds were not detected in all silages on the day of silo opening because low pH in all silages were enough acid to inhibit its growth in the present study [5,33].…”

“…There was no increase of silage temperatures more than 2 • C over 7 d of aerobic exposure. In addition, Lee et al [33] explained that the increase of silage temperature during aerobic exposure is associated with mold and yeast growths. The mean room temperature in farm storage for 7 d of aerobic exposure was 10.7 • C, which inhibited yeasts or molds to grow optimally and to degrade the nutrient content in the silage [4].…”

Effects of Inoculants Producing Antifungal and Carboxylesterase Activities on Corn Silage and Its Shelf Life against Mold Contamination at Feed-Out Phase

“…In the present study, the chemical compositions of Kwangpyeongok corn forage were in a normal range according to Lee et al [ 24 ]. After ensiling, chemical compositions of corn silage were not influenced by inoculant application due to the good acidification in all silages.…”

“…Silage pH was measured using a pH meter (SevenEasy, Mettler Toledo, Greifensee, Switzerland), while ammonia-N was determined by the colorimetric method following the protocol of Chaney and Marbach [ 23 ]. Before analyzing lactate and volatile fatty acid (VFA), the centrifugation of silage extraction at 5645× g for 15 min was conducted to collect the supernatant [ 16 , 24 ]. The supernatant was used to measure the concentrations of lactate and VFA using HPLC (L-2200, Hitachi, Tokyo, Japan) fitted with a UV detector (L-2400, Hitachi, Tokyo, Japan) and a column (Metacarb 87H, Varian, Palo Alto, CA, USA) following the method of Muck and Dickerson [ 25 ].…”