TY - ABST

T1 - THE EFFECT OF DIRECT-FED MICROBIALS ON GRASS OR MAIZE SILAGE ON IN-INVITRO RUMEN FERMENTATION

AU - Dhakal, Rajan

AU - Hansen, Hanne Helene

AU - Milora, Nina

AU - Copani, Giuseppe

PY - 2021/11/16

Y1 - 2021/11/16

N2 - Direct-fed microbials (DFM) are used in ruminant production to increase productivity and improve health, they canbe used as a possible option to decrease methane emission. The objectives of this study was i) to validate thesame test in two laboratories and ii) to asses the effect oftwo DFM products in an in vitro rumen fermentation. Sixtreatments (n=3/treatment) were fermentated twice for48 hours using an automated gas pressure measurementsystem, simultaneously at University of Copenhagen andChr. Hansen. Maize silage (MS) and grass silage (GS) wasfermented with and without two DFM products (P1: Lactobacillus animalis, Propionibacterium freudenreichii 1.5*107total CFU/ml, P2: P1 + Bacillus subtilis, Bacillus licheniformis5.9*107 total CFU/ml). Rumen fluid was added to a buffersolution (2:1) and kept anaerobic at 39.5°C. The test unitswere kept in a thermoshaker with 40 rotations per minutefor 48h. Total gas production (TGP: ml at Standard Temperature and Pressure/gram organic matter), pH, organicmatter degradability (dOM), methane concentration (MC)and volatile fatty acids (VFA) were measured after fermentation. All the measured parameters were blank correctedbefore statistical analysis. No significant effect of laboratorywas detected for any of the response variables. Therefore,a mixed linear model with laboratory as a random variableand feed and additive was used. Significance was determined if p<0.05. The dOM of MS (78.3%) was significantlydifferent from GS (81.4%) regardless of the additives (P1and P2), however there were no significant differences ofthe effect of either probiotic within the feed type. Degradation of MS produced significantly more gas than GS after 48hours. Both probiotics increased TGP significantly in GS butnot in MS. There was no difference in total VFA production,however GS with and without probiotics produced signifincantly more propionic acid and less butyric acid then MSwith and without probiotics. The addition P2 numericallyreduced the total methane production per gOM between4-6% in both MS and GS. These results showed that i) thereis alignment between the two tested laboratories and ii)the P2 DFM shows potential to reduce methane productionwithout affecting organic matter degradation.

AB - Direct-fed microbials (DFM) are used in ruminant production to increase productivity and improve health, they canbe used as a possible option to decrease methane emission. The objectives of this study was i) to validate thesame test in two laboratories and ii) to asses the effect oftwo DFM products in an in vitro rumen fermentation. Sixtreatments (n=3/treatment) were fermentated twice for48 hours using an automated gas pressure measurementsystem, simultaneously at University of Copenhagen andChr. Hansen. Maize silage (MS) and grass silage (GS) wasfermented with and without two DFM products (P1: Lactobacillus animalis, Propionibacterium freudenreichii 1.5*107total CFU/ml, P2: P1 + Bacillus subtilis, Bacillus licheniformis5.9*107 total CFU/ml). Rumen fluid was added to a buffersolution (2:1) and kept anaerobic at 39.5°C. The test unitswere kept in a thermoshaker with 40 rotations per minutefor 48h. Total gas production (TGP: ml at Standard Temperature and Pressure/gram organic matter), pH, organicmatter degradability (dOM), methane concentration (MC)and volatile fatty acids (VFA) were measured after fermentation. All the measured parameters were blank correctedbefore statistical analysis. No significant effect of laboratorywas detected for any of the response variables. Therefore,a mixed linear model with laboratory as a random variableand feed and additive was used. Significance was determined if p<0.05. The dOM of MS (78.3%) was significantlydifferent from GS (81.4%) regardless of the additives (P1and P2), however there were no significant differences ofthe effect of either probiotic within the feed type. Degradation of MS produced significantly more gas than GS after 48hours. Both probiotics increased TGP significantly in GS butnot in MS. There was no difference in total VFA production,however GS with and without probiotics produced signifincantly more propionic acid and less butyric acid then MSwith and without probiotics. The addition P2 numericallyreduced the total methane production per gOM between4-6% in both MS and GS. These results showed that i) thereis alignment between the two tested laboratories and ii)the P2 DFM shows potential to reduce methane productionwithout affecting organic matter degradation.

M3 - Conference abstract in proceedings

SP - 48

BT - 2nd International Conference on Microbial Food and Feed Ingredients

ER -