Evaluation of the microbial population in ruminal fluid using real time PCR in steers treated with virginiamycin

https://doi.org/10.17221/74/2009-CJASCitation:Guo T.J., Wang J.Q., Bu D.P., Liu K.L., Wang J.P., Li D., Luan S.Y., Huo X.K. (2010): Evaluation of the microbial population in ruminal fluid using real time PCR in steers treated with virginiamycin. Czech J. Anim. Sci., 55: 276-285.
download PDF
The objective of the present study was to investigate the effects of virginiamycin (VM ) supplementation on ruminal fermentation and microbial populations in steers. Four ruminally cannulated Chinese Luxi steers (BW 559.4 ± 30.1 kg) were used in a crossover design experiment with an experimental period of 28 days. The forage to concentrate ratio of the basal diet was 35:65 on dry matter basis. The experiment consisted of control treatment and treatment with control diet plus VM at a dose of 30 mg/kg concentrate (DM basis). Rumen fluid was collected at 07:30 prefeeding, at 11:30 and 17:30 postfeeding on day 27 and 28. A part of the pooled sample from rumen fluid was transferred to anaerobic culture by a roll-tube technique and analysed for species-specific real-time PCR quantification. The remaining pooled rumen fluid sample was analyzed for pH, VFA, ammonia N and l-lactic acid. The results showed that VM increased the ruminal pH (6.70 vs. 6.63; P < 0.05), but it decreased ammonia nitrogen (4.94 vs. 6.19 mg/100 ml; P < 0.01) and mean counts of amylolytic bacteria and proteolytic bacteria (P < 0.01) as compared to the control. The additive VM did not affect the l-lactic acid concentration (1.39 vs. 1.26 mmol/l) in rumen fluid. Compared to the control, the steers receiving VM have altered a trend of quantification of Selenomonas ruminantium, Anaerovibrio lipolytica, Ruminococcus albus and Streptococcus bovis in rumen fluid (0.05<p<0.1) as compared to the control. However, VM had no significant effect on Lactobacillus spp. (P = 0.41), Butyrivibrio fibrisolvens (P = 0.35), on the genus Ruminococcus (P = 0.25), Ruminococcus flavefaciens (P = 0.52), Prevotella ruminicola (P = 0.54), on the genus Prevotella (P = 0.67) and Megasphaera elsdenii (P = 0.97). In this study, we found that VM had selective effects on ruminal bacteria and influenced ruminal fermentation by changing a part of the specific ruminal bacteria populations.
download PDF

© 2019 Czech Academy of Agricultural Sciences