The effect of a lactic acid bacterial inoculant with enzymes on the fermentation dynamics, intake and digestibility of Digitaria eriantha silage

Abstract

The aim of this study was to determine the effect of applying a bacterial inoculant with enzymes to D. eriantha on the fermentation dynamics during ensiling, the aerobic stability, intake and digestibility of the silage. The grass was ensiled, with or without the addition of a lactic acid bacterial inoculant at 10 6colony forming units per gram of fresh material, in Cryovac barrier bags. The inoculant Sil-All (Supplied by Alltech Biotechnology) contained Lactobacillus plantarum, Steptococcus faecium and Pediococcus acidilactici together with the enzymes, cellulase, hemicellulase and amylase. To follow the fermentation dynamics during ensiling samples were taken on days 1, 2, 5, 9 and 44 of ensiling for chemical and microbiological analysis. The inoculant resulted in a more rapid drop in pH, a higher level of lactic acid and lactic acid bacteria, less protein breakdown and lower numbers of enterobacteria, clostridial spores, yeast and mould compared to control silage. Silage was made on a larger scale in two tower silos (1.5 t silage capacity) for each of the control and inoculated treatment. D. eriantha hay was also made at the same time. Silage and hay diets were fed to 24 Merino rams ( n = 8 per treatment), weighing 62 ± 2.7 kg to determine intake and digestibility. The intake of diets consisting of 90.9% D. eriantha hay, control silage or inoculated silage, differed significantly ( p < 0.05) at 1395, 1540 and 1848 g DM day −1, respectively. The in vivo organic matter digestibility (g kg −1) of D. eriantha hay, untreated silage and inoculated silage diets was 561, 546, 574, respectively. The addition of the bacterial inoculant when ensiling D. eriantha resulted in better preservation, improved aerobic stability, as well as a higher in vivo organic matter digestibility and intake of D. eriantha silage.