Cultivation of Lactobacillus sp. and Production of Probiotic Powder as Animal Feed Additive

Abstract

The objectives of this study were to develop culture medium and fillers with appropriate growth conditions and to evaluate stability of selected Lactobacillus salivarius L61 and commercial probiotic (L. plantarum Fr-B). Both strains were cultured in full-fat Soybean, Skim Milk, Dextrose (SSMD) and K2HPO4 with 1, 5 or 10 g/L yeast extract compared to de Man, Rogosa and Sharpe (MRS) medium. Stabilities of powdered Lactobacillus cultures were examined using Ground Rice Husk (GRH) or Rice Bran (RB) fillers with 25% (w/w) CaCO3. Lactobacillus counts were determined using ten-fold serial dilution of a pour plate method on MRS agar and incubated in anaerobic jar at 37°C for 48 h. The results showed that Lactobacilli populations in MRS broth were higher than those in SSMD but had lower stability. Lactobacillus salivarius L61 and L. plantarum Fr-B population growth at optimal incubation time (24 h) and optimal growth medium were 2.63 x 10¹⁰ CFU/ml and 1 x 10⁹ CFU/ml. The optimal growth media (w/v) was 1% full-fat soybean, 1% skim milk, 0.5% yeast extract, 0.5% dextrose and 0.05% K₂HPO₄. The stability of Lactobacillus L61 in GRH was higher than in RB and the stability under refrigeration temperature (RFT, 4-6°C) in both fillers were higher those in room temperature (RMT, 28-30°C). The GRH filler could maintain 10⁹ CFU/g of Lactobacillus L61 cells at RFT and at RMT for 35 and 21 d, respectively while RB could maintain 10⁹ CFU/g of Lactobacillus L61 cells at RFT for 14 d.