Effect of lactic acid bacteria inoculants, formic acid, potassium sorbate and sodium benzoate on fermentation quality and aerobic stability of wilted grass silage

Abstract

The efficiency of a novel strain of lactic acid bacteria inoculant (Lactobacillus plantarum VTT E-78076, E76) on the fermentation quality of wilted silage was studied. Furthermore, the possibility to improve aerobic stability of silages by combining an inoculant and chemical preservatives was investigated. Two experiments were conducted with wilted timothy-meadow fescue herbage (dry matter 429 and 344 g kg -1 ) using six treatments. In experiment I, E76 (10 6 cfu g -1 fresh matter (FM)) was applied alone and in combination with sodium benzoate (0.3 g kg -1 grass FM) or low rate of formic acid (0.4 l t -1 FM). In experiment II, E76 and a commercial inoculant were applied alone and in combination with sodium benzoate. Untreated silage and formic acid (4 l t -1 FM) treated silage served as negative and positive controls in both experiments. The effect of sodium benzoate and potassium sorbate in experiment I, on aerobic stability was tested by treating silages prior to aerobic stability measurements. The novel lactic acid bacteria inoculant was equally effective in improving fermentation quality as the commercial inoculant. However, the aerobic stability of both inoculated silages was poorer than that of formic acid treated or the untreated one in one of the experiments. The results suggested that antimicrobial properties of E76 were not effective enough to improve aerobic instability. One option to overcome this problem is to use chemical additives in combination with the inoculants.

Improvement on the Nutritive Quality of Napier Grass Silage through Inoculation of Lactobacillus plantarum and Formic Acid

“…This result is in agreement with that of Saarisalo et al (2006). Formic acid is effective in inhibiting amino acid breakdown during ensilage process as reflected by the lowest level of N-NH 3 in the silage supplemented with formic acid especially at the level of 7.5% FA.…”

“…Formic acid was able to restrict fermentation indirectly by limiting the activity of LAB to produce lactic acid. The result was consistent with that reported by Saarisalo et al (2006), but different from that reported by Aksu et al (2006) that formic acid supplementation did not alter lactid acid concentration. These results suggest that the effects of formic acid on lactid acid concentration are inconsistent.…”

“…This result is supported by the data reported by Aksu et al (2006) that acid treatment reduced the apparent digestibility of crude protein in the rumen through its effect on preventing the conversion of protein to ammonia that eventually increased the proportion of by-pass protein entering the duodenum. This result indicated that the application of formic acid was an important factor in determining the effect of formic acid on the fermentation,the synthesis of microbial protein in the rumen, and the supply of nutrients to the ruminants (Jaakola et al, 2006). On the other hand, the addition of L. plantarum bacteria increased ammonia concentration in the rumen compared to control and acid treatments.…”

“…This was evident from the low content of ADF in the treatment of acid based (Table 2). It appears that during the ensilage process, the most easily degradable fiber fractions are hydrolysed, whereas the remaining fractions are less digestible in the rumen (Jaakola et al, 2006).…”

The effects of three silage inoculants on aerobic stability in grass, clover-grass, lucerne and maize silages

“…Jaakkola et al (2010) observed that the combination of L. plantarum with sodium benzoate was more efficient than the combination of L. plantarum and L. buchneri. In the experiment of Saarisalo et al (2006b) the aerobic stability of silages was increased by inoculation with L. plantarum and was distinctly increased by treatment with L. plantarum in combination with sodium benzoate compared with untreated silage. Some inoculant lactic acid bacteria strains produce anti-microbial compounds that inhibit mould growth or undesirable bacterial species like Salmonella sp., Listeria sp.…”