JOURNAL OF ANIMAL AND FEED SCIENCES, cilt.33, sa.1, ss.88-100, 2024 (SCI-Expanded)
The aim of the study was to assess the impact of potential probiotic strains of lactic acid bacteria (LAB), Apilactobacillus kunkeei EIR/BG-1 isolated from the gut of honeybees, and Enterococcus hirae EIR/CM-2 isolated from cow's milk, on rumen fermentation parameters and microbial population in a high-concentrate diet using a rumen simulation technique (Rusitec). The experiment consisted of 7 days of adaptation and 7 days of data collection. The dietary treatments were as follows: no additives (control), addition of 1 ml/fermenter (10(8) CFU) of Al. kunkeei EIR/BG-1, and addition of 1 ml/fermenter (10(8) CFU) of E. hirae EIR/CM-2. Alongside rumen fermentation characteristics, rumen microbial composition was investigated using real-time PCR. Supplementation with LAB strains did not affect ruminal pH, production of methane, and total and individual short chain fatty acids, ammonia-N concentration, dry matter digestibility and total protozoa. However, the abundance of Ruminococcus flavefaciens increased in the Al. kunkeei EIR/BG-1 treatment (P < 0.05). Moreover, the size of R. flavefaciens population in E. hirae EIR/CM-2 was comparable to that in the Al. kunkeei EIR/BG-1 treatment. Selenomonas ruminantium was more abundant in the Al. kunkeei EIR/BG-1 treatment compared to the E. hirae EIR/CM-2 treatment (P < 0.05). The abundance of Streptococcus bovis and Megasphaera elsdenii decreased with both Al. kunkeei EIR/BG-1 and E. hirae EIR/CM-2 supplementations (P < 0.05). In conclusion, Al. kunkeei EIR/BG-1 and E. hirae EIR/CM-2 exhibited beneficial effects on some members of the rumen microbial population, although these effects did not manifest in significant alterations in ruminal fermentation. Further research is required to clarify the probiotic potentials of these LAB strains as feed additives for ruminant rations.