Effect of lactic acid bacteria inoculant and beet pulp addition on fermentation characteristics and in vitro ruminal digestion of vegetable residue silage

Abstract

The objective of this study was to determine the effect of beet pulp (BP) and lactic acid bacteria (LAB) on silage fermentation quality and in vitro ruminal dry matter (DM) digestion of vegetable residues, including white cabbage, Chinese cabbage, red cabbage, and lettuce. Silage was prepared using a small-scale fermentation system, and treatments were designed as control silage without additive or with BP (30% fresh matter basis), LAB inoculant Chikuso-1 (Lactobacillus plantarum, 5mg/kg, fresh matter basis), and BP+LAB. In vitro incubation was performed using rumen fluid mixed with McDougall's artificial saliva (at a ratio of 1:4, vol/vol) at 39°C for 6h to determine the ruminal fermentability of the vegetable residue silages. These vegetable residues contained high levels of crude protein (20.6-22.8% of DM) and moderate levels of neutral detergent fiber (22.7-33.6% of DM). In all silages, the pH sharply decreased and lactic acid increased, and the growth of bacilli, coliform bacteria, molds, and yeasts was inhibited by the low pH at the early stage of ensiling. The silage treated with BP or LAB had a lower pH and a higher lactic acid content than the control silage. After 6h of incubation, all silages had relatively high DM digestibility (38.6-44.9%); in particular, the LAB-inoculated silage had the highest DM digestibility and the lowest methane production. The vegetable residues had high nutritional content and high in vitro DM digestibility. Also, both the addition of a LAB inoculant and moisture adjustment with BP improved the fermentation quality of the vegetable residue silages. In addition, LAB increased DM digestibility and decreased ruminal methane production.

Wasted cabbage (Brassica oleracea) silages treated with different levels of ground corn andsilage inoculant

“…The negative effect of fiber on digestibility is well known, and lignin is the component most negatively associated with fiber digestion by ruminants (Jung and Allen, 1995); this helps us to understand the obtained results. Our results are in agreement with those reported by Cao et al (2011), who found increases in DM digestibility of Chinese cabbage silages treated with beet pulp.…”

“…Moreover, the commercial processing of vegetables in the world results in many residues, which are a waste of resources that leads to possible environmental problems because of unsuitable disposal (Cao et al, 2011). Thus, considering that approximately 45% of the cabbage production is wasted or lost during cultivation in the field before human consumption (FAO, 2011), we investigated the possibility of ensiling cabbage treated with ground corn and a silage inoculant.…”

“…It is important to stress that the use of vegetable silages (e.g., cabbage) as animal feed has proven economically viable in regions where vegetables residues are the main food by-product resulting not only from a way of disposing of vegetables' residues but also as an alternative for livestock feed (Cao et al, 2011). Conversely, considering the profitability of the use of ground corn as an additive for cabbage silage, their use may be unviable initially, but ground corn is largely used in the nutrition of ruminants and monogastrics, and the use of the cabbage silages supplemented with ground corn could reduce or offset the costs associated with concentrate feedstuffs.…”

“…The ensiling of cabbage without additives leads to low production of lactic acid and pH reduction is not satisfactory to avoid the action of undesirable microorganisms for silage (Cao et al, 2011), which results in an inefficient fermentative process and low silage quality (Woolford, 1984). Thus, the use of absorbent material (e.g., ground corn) could increase the DM content of the silage and improve the fermentation, as suggested for mango, lemon, and banana (Aguilera et al, 1997;Khattab et al, 2000).…”

Effects of sucrose, formic acid and lactic acid bacteria inoculant on quality, <i>in vitro</i> rumen digestibility and fermentability of drooping wild ryegrass (<i>Elymus nutans</i> Griseb.) silage

“…Some researchers (Cao et al, 2011;Fang et al, 2012) found that LAB inoculants showed little effects on IVDMD, ruminal VFA concentration though they improved fermentation quality of napier grass (Pennisetum purpureum), rice straw and vegetable residue silages. Although IVDMD was not affected, in the present study, VFA production was increased in the treated silages in comparison to the untreated control, and such result implicate that nutrients of the drooping wild ryegrass were partially utilized during ensiling, and the fermentable organic matter left in the silages could be further metabolized by rumen microbes due to the application of additives during ensiling.…”