Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
*Corresponding author: shenjunshi@njau.edu.cn
Online published on 4 November, 2017.
This study was conducted to investigate the effects of bacitracin (B) and bacitracin zinc (BZ) on in vitro fermentation, methane and ammonia production, and select microbial populations of the rumen. Both B and BZ were added at 3 doses, namely 10 (low), 30 (medium), and 90 (high) mg/l of in vitro fermentation medium. Results showed that B and BZ had similar effects on rumen fermentation characteristics and microbial populations. Low dosage of B or BZ addition reduced (P<0.05) methane and ammonia production, while had no adverse effects (P>0.05) on total VFA concentration and feed digestibility. The population of total bacteria was unaffected (P>0.05) by low B and BZ doses, but was significantly (P<0.05) decreased by high B and BZ doses. All B and BZ doses lowered (P<0.05) the populations of Firmicute, Bacteroidetes, methanogens, Clostridium aminophilum and Clostridium sticklandii. However, B and BZ addition had no influence (P>0.05) on the populations of protozoa and fungi. Results indicated that optimum B or BZ addition could reduce methane and ammonia production, with no adverse effects on total VFA concentration and feed digestibility. Further, these effects are probably associated with the variation of rumen functional microbial populations.
Ammonia, Bacitracin zinc, Methane, Microbial population, Rumen fermentation
