100(2)_str18

 

ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 100, No. 2 (2013), p. 143–150
DOI  10.13080/z-a.2013.100.018

Evaluation of fermentation parameters, microbiological composition and aerobic stability of grass and whole crop maize silages treated with microbial inoculants

Jonas JATKAUSKAS, Vilma VROTNIAKIENE

Abstract

Two experiments were conducted in 2011–2012 to evaluate the fermentation parameters, microbiological composition and aerobic stability of grass and whole crop maize silages treated with microbial inoculants, different blends of the selected bacterial strains and blend of the selected bacterial strains in combination with sodium benzoate. Wilted ryegrass:timothy and whole crop maize with 265 and 276 g kg-1 dry matter (DM) content were ensiled in 3 litre laboratory silos. The mean water soluble carbohydrate (WSC) concentration, buffer capacity and nitrate concentration in ryegrass:timothy and whole crop maize were 101.8 and 98.9 g kg-1 DM, 355 and 217 mEq kg-1 DM, and 153.2 and 841.1 mg kg-1 DM, respectively. Silages treated with the tested inoculants were characterized by higher concentrations of DM compared with the untreated silage. Ryegrass:timothy and maize herbage inoculant treatments before ensiling significantly decreased (P < 0.05) pH, significantly reduced butyric acid, ammonia-N concentrations and DM loss compared with control silage. Ryegrass:timothy and maize silages inoculated with homofermentative bacteria blends produce higher (P < 0.05) lactic acid compared with that of the control silage. Butyric acid, alcohols and N-NH3 fraction concentrations were significantly (P < 0.05) decreased by inoculation. When compared with control silage, increased (P < 0.05) acetic acid concentration and decreased lactic acid concentration were observed in ryegrass:timothy silages and maize silages inoculated with heterofermentative lactic acid bacteria (LAB) strain Lactobacillus buchnery. The LAB blends used in our experiment significantly suppressed yeast and moulds growth reflected in the lower concentration of alcohols, generally correlated to yeast activity in silages. Inoculation increased the aerobic stability of ryegrass:timothy and maize silages, compared with control silage. The aerobic stability of inoculated ryegrass:timothy and maize silages was improved by 66–312 hours compared to control silage.

Key words: aerobic stability, fermentation, maize, microbial inoculant, ryegrass, silage, timothy.

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