Effects of chemical and microbial additives on clostridium development in sugarcane (Saccharum officinarum L.) ensiled with lime

Abstract

The aim of this study was to compare strategies to prevent clostridium growth in sugarcane silages added with lime. In Experiment 1, treatments were (as fed basis): no additives (Control), 15 g lime kg−1 (L), 15 g lime kg−1 + 1.5 g sodium benzoate kg−1 (L+B), 15 g lime kg−1 + 0.7 g sodium nitrite kg−1 (L+N), 15 g lime kg−1 + Lactobacillus buchneri (5 × 105 cfu g−1) (L+LB) and 15 g lime kg−1 + Lactobacillus plantarum (5 × 105 cfu g−1) (L+LP). Plastic buckets (20 L) were used as experimental silos. Silage fermentative losses and aerobic stability were also evaluated. Lime treatment was not effective in decreasing dry matter (DM) losses compared with control silage (121 and 158 g kg−1, respectively). On the other hand, L+LB, L+B, L+LP and L+N treatments significantly decreased DM losses (70, 73, 87 and 98 g kg−1, respectively). The aerobic stability of silages L (172 h), L+B (155 h) and L+N (223 h) was substantially higher compared to those treated with L+LB (49 h), L+LP (48 h) and control (52 h). Control silages had low counts of clostridia (log 3.3 cfu g−1) whereas L and L+LB treated silages reached very high clostridium counts (log 6.7 and log 6.0 cfu g−1, respectively). The remaining treatments resulted in intermediate values. In Experiment 2, sugarcane treated with lime (15 g kg−1) received the following doses of sodium nitrite prior to ensiling: 0, 0.5, 1.0 and 1.5 g kg−1 as fed. Treatments did not affect clostridium counts but decreased butyric acid and 2,3‐butanediol. The silage with the highest nitrite dose decreased the butyric acid content substantially compared to other treatments but the final level (5.9 g kg−1 DM) was above the target value for well‐fermented silage. None of additives combined with lime were able to provide completely butyric acid free silages.

Silage review: Recent advances and future uses of silage additives

“…Calcium oxide (lime) has been tested as an additive to sugarcane silage, as it is converted to calcium hydroxide upon reaction with water. Compared with untreated sugarcane silage, studies have shown decreased ethanol content and increased aerobic stability from calcium oxide treatment, but it increased concentrations of NH 3 -N and butyric acid, making it less desirable as a silage additive (Custódio et al, 2016;Jacovaci et al, 2017).…”

Effects of Obligate Heterofermentative Lactic Acid Bacteria Alone or in Combination on the Conservation of Sugarcane Silage

“…It may suggest that lactic acid may have been produced in a lesser extent at the onset of fermentation in control silage whereas in treated silages lactic acid was partially converted to acetic acid and 1,2-propanediol. In fact, control silage had a higher pH value compared with inoculated silages and, although acetic acid has a greater pka than lactic acid (4.8 vs. 3.8), the greater concentration of acetic acid in treated silages might have contributed to pH drop, particularly due to the low buffering capacity in sugarcane crop ( Custódio et al, 2016 ).…”

Natamycin as a potential silage additive: A lab trial using sugarcane to assess greenhouse gas emissions

“…In our trial, the average pH was 3.9, an unfavorable condition for natamycin action (Stark and Tan, 2003;Delves-Broughton et al, 2005;Hanušová et al, 2012). In addition, sugarcane presents high lactic acid production and a fast pH drop (Custódio et al, 2016), which also result in lowered natamycin effectiveness during fermentation. Shah et al (2020) reported lower yeast counts in Napier grass silage treated with natamycin for 60 days than in untreated silage.…”