Effect of inoculated corn silage on rumen fermentation and lipid metabolism in an artificial rumen (RUSITEC)

Abstract

Effects of providing substrates containing corn silage (12 g of DM/day) and lucerne hay (3 g DM/day) to an artificial rumen (RUSITEC) in which the whole plant corn was not inoculated (CS, control), or inoculated with Lactobacillus plantarum CCM 4000 (CS + LP), Lactobacillus fermentum LF2 (CS + LF) or Enterococcus faecium CCM 4231 (CS + EF) on rumen metabolism was examined. The inoculants were promising probiotic- and bacteriocin-producing strains. The substrates were fermented in fermentation vessels for 11 days, which included a stabilization period of 5 days. The counts of inoculants decreased during ensiling of corn, and at the end of ensiling (105 days), their counts were less than 1.0 log 10 cfu/g; probably for lower pH (3.44–3.54). Organic matter and neutral detergent fibre degradabilities were increased in inoculated CS compared to control. Ammonia N production was decreased in all inoculated substrates. From other fermentation parameters, only total VFA production, production of acetate, n-butyrate (mmol/day) significantly increased during fermentation of CS + LP and CS + LF substrates compared to control. The inoculated CS substrates influenced the efficiency of microbial protein synthesis ( P<0.001). Biohydrogenation of C 18:1, C18:2 and total C18 FA increased in all inoculated CS substrates in fermentation fluid in RUSITEC. The concentration of trans 11 C18:1 (TVA) was unchanged in inoculated CS substrates and the concentration of cis 9, trans 11 C18:2 (CLA) were decreased ( P<0.05) compared in CS. All inoculants of whole plant corn were not effective for increasing CLA and TVA concentration in fermentation fluid and for decreasing of rumen biohydrogenation of C18 fatty acids in RUSITEC.