Effects of Different Fiber Substrates on In Vitro Rumen Fermentation Characteristics and Rumen Microbial Community in Korean Native Goats and Hanwoo Steers

Abstract

Korean native goats (Capra hircus coreanae) (KNG) and Hanwoo (Bos taurus coreanae) are indigenous breeds inhabiting Korea. This study compared the in vitro rumen fermentation characteristics, dry matter (DM) degradation, and ruminal microbial communities of Korean native goats and Hanwoo steers consuming rice hay (RH) and cotton fiber (CF). The pH, ammonia-nitrogen (NH3-N), and total volatile fatty acids (VFAs) production significantly differ (p < 0.05) across species in all incubation times. After 24 h, the pH, NH3-N, and total VFAs production were higher in Korean native goats than in Hanwoo steers. Total gas, molar proportion of propionate, and total VFAs were higher (p < 0.05) in RH than in CF for both ruminant species. DM digestibility of both substrates were higher (p < 0.05) in Hanwoo steers than in KNG. Both treatments in KNG produced higher (p < 0.01) microbial DNA copies of general bacteria than those in Hanwoo steers. Butyrivibrio fibrisolvens and Fibrobacter succinogenes had significantly higher DNA copies under RH and CF in Hanwoo steers than in Korean native goats. B. fibrisolvens, Ruminococcus albus, and Ruminococcus flavifaciens after 24 h of incubation had a higher abundance (p < 0.05) in RH than in CF. Overall results suggested that rumen bacteria had host-specific and substrate-specific action for fiber digestion and contribute to improving ruminal functions of forage utilization between ruminant species.