Lactic Acid Bacteria Strains Suitable for High Quality Silage Production in the Tropics

Cooperating agency for this topic:
Japan International Research Center for Agricultural Sciences
1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
Tel: (81 29) 838 6365
Fax: (81 29) 838 6653
E-mail: bupmomo@ruby.plala.or.jp, 2005-12-01

Silage feeding is an effective and easily adaptable technique despite its limited application in tropical regions. The use of high quality silage is a highly dependable means of increasing and stabilizing the quality of raw milk production. However, successful results are not always ensured if ensilage depends on natural fermentation. In order to address this problem, lactic acid bacteria (LAB) strains suitable for silage making in tropical regions were screened.

Screening Method

LAB strains having culture filtrate pH levels less than 4.0 at 45oC were isolated and their ability for silage fermentation were carefully evaluated. The evaluation was monitored by using the modified pouch method which was a kind of solid-mixed culture system consisting of three kinds of microorganism, yeast, coli-form bacteria and LAB, to simulate a tropical environment.

Ability of Selected Strain

The time course of lactic acid production in the cultures using the modified pouch method with various inoculum sizes were confirmed for selected strains, CS 1-8, CS 5-5, KS 1-9 and SP 1-3 (Fig. 1). The most important property of LAB strains in terms of silage making is their high ability to produce lactic acid during the silage fermentation process. Strain SP 1-3, Lactobacillus plantarum, exhibited an inherent tolerance for high incubation temperatures and lactic acid. Strains CS 5-5 and KS 1-9, Pediococcus sp., also exhibited similar properties to strain SP 1-3, but they showed weaker lactic acid tolerance than that of strain SP 1-3. Strain CS 1-8, Pediococcus sp., displayed steady growth during the early stages of silage fermentation, but did not accumulate much lactate by the end of the long-term fermentation. The amount of lactic acid in silage inoculated with strain SP 1-3 (Fig. 2 & Fig. 3) significantly increased to about 1.35 times and the number of coliform bacteria and yeast was obviously repressed.

Practice and Precaution

Practical inoculant powder of strain SP 1-3 developed in Thailand is pre-cultured before one day of use in the farm by using convenient medium easily prepared with commercial drinking water. With pre-culturing, only 50 g of inoculant powder is required to induce 50 tons of fresh material to have good quality fermentation.

Index of Images

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  Figure 1 Time Course of Lactic Acid Production by Selected Lab Strains in the Modified Pouch Method

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  Figure 2 Silage Preparation by Using Plastic Bag Sealed and Wrapped after Making Vacuuming

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  Figure 3 Silage after 2 Weeks of Fermentation

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