Effects of Lactiplantibacillus plantarum LM1001 culture on fermentation characteristics and greenhouse gas emissions in the rumen

This study aimed to estimate the effects of <italic>Lactiplantibacillus plantarum</italic> LM1001 culture (LPC) on fermentation characteristics and greenhouse gas emissions in the rumen. Pure starch and cellulose were mixed at a 1:1 ratio, and used as the substrate for 12 h and 24 h of rumen incubations. Rumen fluid was collected from two cannulated Hanwoo cows just before morning feeding and mixed with <italic>Van Soest</italic> medium at a 1:2 ratio for the rumen buffer. The substrate (0.3 g) and rumen buffer (30 mL) were placed into the incubation bottles (n=4) with the additions of 0, 10, and 20% of LPC based on the rumen buffer (v/v). After the incubation times, total gas was measured and sub-sampled for CO₂ and CH₄ analyses. Then, the bottle content was centrifuged for <italic>in vitro</italic> digestibilities of dry matter (IVDMD) and organic matter (IVOMD), and rumen fermentation characteristics. By increases of LPC supplementation levels, acetate content decreased (Linear, p=0.027) at 12 h of incubation time and propionate content increased (Linear, p=0.015), resulting in a decrease of the acetate to propionate ratio (Linear, p=0.035). And, total gas emission (mL/g DM) in 20% LPC was higher (p&lt;0.05) than that in the control at 12 h incubation time, whereas CH₄ and CO₂ (mL/g DM, DMD and OMD) emissions were lower (p&lt;0.05) than those in the control. In contrast, both greenhouse gas emissions (mL/g DM, DMD, and OMD) in LPC supplemented treatments were higher (p&lt;0.05) than those in the control at 24 h incubation time. Therefore, this study concluded that LPC supplementation has benefits on greenhouse gas mitigation in the rumen at 12 h incubation time without adverse effects on nutrient digestibility.