Isolation, in vitro probiotic characterization of Lactobacillus plantarum and its role on Italian ryegrass silage quality enhancement

Abstract

Italian ryegrass (IRG) is an important forage type for feeding ruminants. IRG has difficult to ensile with good quality. Hence the inoculation IRG with lactic acid producing bacterial strains (LAB) gives an alternate solution to produce quality silage. Accordingly new Lactobacillus sp. KCC-32 was isolated from fermented animal manure. Biochemical and physiological studies showed that the strain belonged to Gram positive, produced gas from glucose and catalase-negative. The 16S rRNA sequence analysis revealed that KCC-32 showed 99% similarity towards Lactobacillus plantarum sp. Further, KCC-32 displayed potential probiotic characteristics including resistant to low pH, bile salt tolerance, auto-aggregation and hydrophobicity. The homo fermentative activity of KCC-32 resulted in the enhancement of Italian ryegrass silage quality. In addition, KCC-32 added silage group showed significantly (P=0.05) increased lactic acid production (4.891 DM%) and the nutrient profile resulted with high crude protein content with less acid detergent fiber (ADF) and neutral detergent fiber (NDF) percentage when compared to control group. Further, the microbial count of KCC-32 silage group displayed significantly (P=0.05) high LAB count (24.3×107 cfu/g) and no fungal as well as yeast growth. Hence, this study suggests that KCC-32 has potential probiotic characteristics and the addition of KCC-32 to the IRG silage can improve the fermentation quality for the production of high-quality silage.