Effects of dietary supplementing tannic acid on methane production, rumen fermentation, rumen microflora and nutrient digestion of Liuyang black goats

yun, ying; Liu, Ting; Liu, Hui hui; Zhang, Hui; Pan, Faming; An, Lijing; Wang, Xinji; Xu, Guoyan; Gu, Qiangwen; zheng, chen

doi:.0.0.0

Article

https://doi.org/10.5713/ab.25.0114 [Accepted] Published online September 30, 2025.

Effects of dietary supplementing tannic acid on methane production, rumen fermentation, rumen microflora and nutrient digestion of Liuyang black goats

ying yun¹

, chen zheng^1,*

¹College of Animal Science and Technology, Gansu Agricultural University, Lanzhou China, China
²Gansu Provincial Health Commission, Lanzhou 730000, P. R. China, Lanzhou, China
³Institute of Animal & Pasture Science and Green Agriculture of Gansu Academy of Agricultural Science, Lanzhou 730070, P. R. China, Lanzhou, China
⁴Animal Husbandry and Veterinary Station of Nawu Town, Hezuo, Gannan Tibetan Autonomous Prefecture 747000, P. R. China, Hezuo, China
⁵Animal Husbandry and Veterinary Workstation of Minqin County, Minqin 733399, P. R. China, Minqin, China
⁶Animal Husbandry and Veterinary Workstation of Datan Town, Minqin County Agriculture and Rural Bureau, Minqin 733399, P. R. China, Minqin, China
⁷Animal Husbandry and Veterinary Workstation of Heli Town, Gaotai 734300, P. R. China, Gaotai, China

Correspondence: chen zheng, Tel: +86-13919351538, Email: mazh_7853@hotmail.com

Received: 21 February 2025 • Revised: 25 May 2025 • Accepted: 18 September 2025

Abstract

Objective
This study investigated the effects of dietary tannic acid on methane production, nutrient digestibility, rumen fermentation, and rumen microbiota in Liuyang black goats.
Methods
Twelve adult goats were randomly assigned to two groups: a control group (CON) and a treatment group (TAN) that received 2 % tannic acid in their diet. The experiment had two stages, each with a 10 - day adaptation and a 5 - day sampling phase. Methane emission was measured using a mobile open-circuit respirometry system, while rumen fluid samples were analyzed for volatile fatty acids (VFAs), ammonia nitrogen, and microbial composition via 16S rRNA sequencing.
Results
The results indicated that the tannic acid significantly reduced overall methane emission (p < 0.05), methane per voluntary feed intake (VFI, p < 0.05), dry matter intake (DMI, p < 0.05), acid detergent fiber intake (ADFI, p < 0.05), and neutral detergent fiber intake (NDFI, p < 0.05). Microbial analysis showed increased relative abundance of Firmicutes (p < 0.05) and decreased Methanobrevibacter and Prevotella. Tannic acid also improved ADF digestibility (p < 0.05) and altered VFA profiles by increasing acetic acid to propionic acid ratios and valeric and butyric acids (p < 0.05). Tannic acid supplementation also increases the ratios of acetic acid to propionic acid, as well as valeric and butyric acids (p < 0.05), while increasing the digestibility of ADF (p < 0.05).
Conclusion
Dietary tannic acid effectively reduced methane emission and enhanced feed efficiency in Liuyang black goats by modifying rumen fermentation and microbial activity. These findings suggest tannic acid's potential as a sustainable feed additive for ruminants, although long-term impacts on health and productivity require further investigation.

Keywords: tannic acid; methane; nutrient digestion; rumen microorganism; rumen fermentation