Community of natural lactic acid bacteria and silage fermentation of corn stover and sugarcane tops in Africa

Abstract

Objective: To effectively utilize crop by-product resources to address the shortage of animal feed during the dry season in Africa, the community of natural lactic acid bacteria (LAB) of corn stover and sugarcane tops and fermentation characteristics of silage were studied in Mozambique.

Methods: Corn stover and sugarcane tops were obtained from agricultural field in Mozambique. Silage was prepared with LAB inoculant and cellulase enzyme and their fermentation quality and microbial population were analyzed.

Results: Aerobic bacteria were the dominant population with 107 colony-forming unit/g of fresh matter in both crops prior to ensiling, while 104 to 107 LAB became the dominant bacteria during ensiling. Lactobacillus plantarum was more than 76.30% of total isolates which dominated silage fermentation in the LAB-treated sugarcane top silages or all corn stover silages. Fresh corn stover and sugarcane tops contain 65.05% to 76.10% neutral detergent fiber (NDF) and 6.52% to 6.77% crude protein (CP) on a dry matter basis, and these nutrients did not change greatly during ensiling. Corn stover exhibits higher LAB counts and watersoluble carbohydrates content than sugarcane top, which are naturally suited for ensiling. Meanwhile, sugarcane tops require LAB or cellulase additives for high quality of silage making.

Conclusion: This study confirms that both crop by-products contain certain nutrients of CP and NDF that could be well-preserved in silage, and that they are potential roughage resources that could cover livestock feed shortages during the dry season in Africa.

Keywords: Corn Stover; Lactic Acid Bacteria; Microbial Population; Silage Fermentation; Sugarcane Top.

Figure 1

Phylogenetic tree showing the relationship between the 16S rDNA sequences of rod-shaped LAB strains obtained in this study. Numbers at nodes are bootstrap values based on a neighbor-joining bootstrap analysis with 1,000 replications. Bacillus subtilis is used as the outgroup. The bar indicates 1% sequence divergence. Knuc, nucleotide substitution rates; LAB, lactic acid bacteria.

Figure 2

Phylogenetic tree showing the relationship between the 16S rDNA sequences of cocci-shaped LAB strains obtained in this study. Numbers at nodes are bootstrap values based on a neighbor-joining bootstrap analysis with 1,000 replications. Baccillus subtilis is used as the outgroup. The bar indicates 1% sequence divergence. Knuc, nucleotide substitution rates; LAB, lactic acid bacteria.

Figure 3

Community of lactic acid bacteria of corn stover, sugarcane top and silage. LAB, lactic acid bacteria inoculant FG; Cellulase, Acremonium cellulase.