Application of LDH enzyme and viable LDH-producing bacteria to prevent lactate accumulation during in vitro rumen fermentation

This experiment was conducted to study effects of added lactate dehydrogenase (LDH), and viable LDH-producing bacteria, on rumen lactic acidosis in vitro. Lactic acidosis was induced by in vitro fermentation at 39 °C for 20 h with a 25 g/l test diet. The rumen fluid incubated with LDH enzymes isolated from bacterial strains of Streptococcus and Lactobacillus tended to reduce lactate concentrations and, among the three viable LDH-producing bacteria, strain F48 and strain FFy111-1 alleviated lactate accumulation in rumen fluid. Efficiency of LDH-producing bacteria to reduce lactate accumulation was proportional to their LDH activity. Although further investigation of a relationship between lactate metabolism and LDH activity during in vivo rumen fermentation is needed, the current findings suggest that some LDH enzymes, and LDH-producing bacteria, can alleviate lactate accumulation during rumen fermentation.