Title: Effects of Class IIa Bacteriocin-Producing Lactobacillus Species on Fermentation Quality and Aerobic Stability of Alfalfa Silage

Authors: Fuhou Li, Zitong Ding, Adegbola T. Adesogan, Wencan Ke, Yun Jiang, Jie Bai, Shah Mudassar, Yixin Zhang, Wenkang Huang, Xusheng Guo

Journal: Animals

Impact Factor: IF2019=2.323 (农林科学2区)

Abstract: Effects of two strains of class IIa bacteriocin-producing lactic acid bacteria, Lactobacillus delbrueckii F17 and Lactobacillus plantarum (BNCC 336943) or a non-bacteriocin Lactobacillus plantarum MTD/1 (NCIMB 40027), on fermentation quality, microbial counts and aerobic stability of alfalfa silage were investigated. Alfalfa was harvested at the initial flowering stage, wilted to a dry matter concentration of approximately 32% and chopped into 1 to 2 cm length. Chopped samples were treated with nothing (control, CON), Lactobacillus delbrueckii F17 (F17), Lactobacillus plantarum (BNCC 336943) (LPB) or Lactobacillus plantarum MTD/1 (NCIMB 40027) (LPN), each at an application rate of 1 × 10⁶ colony-forming units/g of fresh weight. Each treatment was ensiled in quadruplicate in vacuum-sealed polyethylene bags packed with 500 g of fresh alfalfa per bag and ensiled at ambient temperature (25 ± 2°C) for 3, 7, 14, 30 and 60 d. The samples were then subjected to an aerobic stability test after 60 days of ensiling. Compared to the CON silage, the inoculants reduced the pH after 14 d of ensiling. After 60 d, pH was lowest in the LPB-treated silage, followed by the F17 and LPN-treated silages. Inoculation of F17 increased concentrations of lactic acid in silages fermented for 7, 14, 30 and 60 d relative to other treatments, except for the LPN-treated silages ensiled for 30 and 60 d, in which the lactic acid concentrations was similar to that of F17 silage. Application of F17 and LPB decreased the number of yeast and mold relative to CON and LPN-treated silages. Compared with the CON silage, inoculant-treated silages had greater aerobic stability, water-soluble carbohydrate and crude protein concentrations, and lower neutral detergent fiber, amino acid nitrogen, and ammonia nitrogen concentrations. The LPB-treated silage had the greatest aerobic stability followed by the F17-treated silage. Both class IIa bacteriocin producing inoculants improved alfalfa silage fermentation quality, reduced the growth of yeasts and molds, and improved the aerobic stability of the ensiled forage to a greater extent than the proven LPN inoculant. However, higher crude protein concentration and lower ammonia nitrogen concentration were observed in LPN treated silage relative to other treatments.

文章链接：https://doi.org/10.3390/ani10091575