title: Natural lactic acid bacteria population of tropical grasses and their fermentation factor analysis of silage prepared with cellulase and inoculant.
abstract: Natural lactic acid bacteria (LAB) populations in tropical grasses and their fermentation characteristics on silage prepared with cellulase enzyme and LAB inoculants were studied. A commercial inoculant Lactobacillus plantarum Chikuso 1 (CH), a local selected strain Lactobacillus casei TH14 (TH14), and 2 cellulases, Acremonium cellulase (AC) and Maicelase (MC; Meiji Seika Pharma Co. Ltd., Tokyo, Japan), were used as additives to silage preparation with fresh and wilted (6 h) Guinea grass and Napier grass. Silage was prepared using a laboratory-scale fermentation system. Treatments were CH, TH14, AC at 0.01% fresh matter, AC 0.1%, MC 0.01%, MC 0.1%, CH+AC 0.01%, CH+AC 0.1%, CH+MC 0.01%, CH+MC 0.1%, TH14+AC 0.1%, TH14+AC 0.01%, TH14+MC 0.1%, and TH14+MC 0.01%. Microorganism counts of Guinea grass and Napier grass before ensiling were 102LAB and 106aerobic bacteria; these increased during wilting. Based on morphological and biochemical characteristics, and 16S rRNA gene sequence analysis, natural strains from both grasses were identified as L. plantarum, L. casei, Lactobacillus acidipiscis, Leuconostoc pseudomesenteroides, Leuconostoc garlicum, Weissella confusa, and Lactococcus lactis. Lactobacillus plantarum and L. casei are the dominant species and could grow at lower pH and produce more lactic acid than the other isolates. Crude protein and neutral detergent fiber were 5.8 and 83.7% of dry matter (DM) for Guinea grass, and 7.5 and 77.1% of DM for Napier grass. Guinea grass had a low level of water-soluble carbohydrates (0.39% of DM). Guinea grass silage treated with cellulase had a lower pH and higher lactic acid content than control and LAB treatments. The 0.1% AC and MC treatments had the best result for fermentation quality. All high water-soluble carbohydrate (2.38% DM) Napier grass silages showed good fermentation quality. Compared with control and LAB-inoculated silage, the cellulase-treated silages had significantly higher crude protein content and lower neutral detergent fiber and acid detergent fiber contents. The results confirmed that cellulase could improve tropical silage quality, inhibiting protein degradation and promoting fiber degradation.
authors.affiliation: Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Waroon
authors.initials: W
authors.lastname: Khota
authors.affiliation: Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand. Electronic address: surpho@kku.ac.th.
authors.forename: Suradej
authors.initials: S
authors.lastname: Pholsen
authors.affiliation: Department of Biological and Environmental Sciences, University of Hertfordshire, AL10 9AB, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Higgs
authors.affiliation: Institute of Livestock and Grassland Science, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-0901, Japan. Electronic address: cai@affrc.go.jp.
authors.forename: Yimin
authors.initials: Y
authors.lastname: Cai
mesh_terms: D000818:Animals; D002480:Cellulase / Q000378:metabolism; D005163:Factor Analysis, Statistical; D005285:Fermentation; D019344:Lactic Acid; D007778:Lactobacillus / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012820:Silage
chemical_list: D012336:RNA, Ribosomal, 16S; D019344:Lactic Acid; D002480:Cellulase
keywords: cellulase; fermentation factor; lactic acid bacteria; tropical silage