Hydrogen is an important intermediate in the rumen, which may be associated with dissolved hydrogen, as elevated hydrogen may inhibit electron flow in the rumen. The removal of molecular hydrogen (H₂) by methanogenesis is postulated to eliminate the inhibitory effect of H₂ on the microbial degradation of feed material. Different fibre structures in forages can alter fibre digestibility and influence fibrolytic microorganisms in the rumen, which may be associated with ruminal dissolved H₂ (dH₂) concentration.

Researchers from China Agricultural University and the Institute of Subtropical Agriculture (ISA) of the Chinese Academy of Sciences investigated the relationship between dissolved hydrogen and fiber digestion in beef cattle fed with two types of forages (napier grass and corn stover) with different fiber structure. The study provides evidence that fiber of corn stover silage can be more easily degraded and utilized by rumen microorganisms than that of napiergrass silage, leading to greater DM intake and average daily gain. Fiber of corn stover silage provides more sites for colonization of rumen microorganisms, and thus had greater degradation and utilization by rumen microorganism than that of napier grass silage. Cattle fed with corn stover silage diet increased methanogen population and dissolved methane concentration in corn stover silage treatment decreases dissolved hydrogen concentration, which facilitates the growth of hydrogen-producing or fiber-degradation microorganisms, leading to the enhancement of fiber digestion.

The research was supported by the National Key Research and Development Program of China (Grant No. 2018YFD0501800 and 2016YFD0500504), National Natural Science Foundation of China (Grant No. 31561143009 and 31472133), State Key Laboratory of Animal Nutrition(Grant No. 2004DA125184F1705), China Agriculture Research System (Grant No. CARS-36), Youth Innovation Promotion Association CAS (Grant No.2016327), CAS President's International Fellowship (Grant No. 2018VBA0031), and the Major Project for Science and Technology of Hunan Province (Grants No. 2017NK1020).

The study entitled "Increased fibre degradation is associated with decreased rumen dissolved hydrogen in growing beef bulls fed by two types of forages" has been published in British Journal of Nutrition, more details could be found at https://doi.org/10.1017/s0007114520002962.

Contact: Rong Wang

E-mail: rongwang@isa.ac.cn

Institute of Subtropical Agriculture, Chinese Academy of Sciences

Figure. 1. Scanning electron microscopy images(scale bar = 100 μm) of napier grass(A and C) or corn stover(B and D) silage before(A and B) and after(C and D) 48-h in vitro ruminal incubation.