Comparative aspects of plant tannins on digestive physiology, nutrition and microbial community changes in sheep and goats: A review

Authors: Min, Byeng Ryel; SOLAIMAN, SANDRA - Tuskegee University

Submitted to: Journal of Animal Physiology and Animal Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/16/2018
Publication Date: 7/24/2018
Citation: Min, B., Solaiman, S. 2018. Comparative aspects of plant tannins on digestive physiology, nutrition and microbial community changes in sheep and goats: A review. Journal of Animal Physiology and Animal Nutrition. 102(5):1181-1193. https://doi.org/10.1111/jpn.12938.
DOI: https://doi.org/10.1111/jpn.12938

Interpretive Summary: Sheep and goat production in the U.S. has increased in recent years because of the dietary preferences of certain ethnic and religious groups whose population has increased in the past two decades. The nutritional aspects of goats and sheep are not as well studied as beef and dairy cattle. Plants contain a group of natural compounds collectively known as plant tannins. However, the effects of tannins on goat and sheep performance are poorly understand. Therefore, scientists from ARS (Bushland, Texas) and Tuskegee University (Tuskegee, Alabama) reviewed the potential benefits of tannin-containing diets for sheep and goats and specie differences in their response to plant tannins. This review is of interest to goat and sheep producers, especially those in the southeast U.S., and to people who advise such producers.

Technical Abstract: Comparative aspects of plant tannins on digestive physiology, nutrition and microbial community in sheep and goats are discussed in the context of differences due to feed intake, digestibility, utilization of nutrients and microbial community. The purpose of this review was to present an overview of the potential benefits of tannin-containing diets for sheep and goats and specie differences in their response to tannins. It is well established that moderate level of tannins in the diet (3%–4% tannins DM) can precipitate with soluble proteins and increase protein supply to the sheep, but comparative aspects of tannin-containing diets in sheep and goats on animal performance, digestive physiology, rumen microbial changes and potential benefits to sustainable animal production by those compounds have received little attention. In addition, developing plant-based tannin-containing diets for control of rumen microbiota and rumen fermentation (e.g., methane gas) would be expected to have a greater impact on the ruminant health, productivity and emission of greenhouse gasses. The positive impacts of the plant tannin compounds mainly depend on their influence on the gut microbiome diversity and ability to generate fermentation end products (short-chain fatty acids) that have diverse biological roles. Diets which contain optimal levels of tannins have potential benefits for sustainability of small ruminant production systems. However, there is a need for an improved understanding of the utilization of tannin-containing forages to improve their management. This implies investigations of animal responses to tannin-containing forages or browse species and, in particular, a better understanding of the interactions that can arise between sheep and goats on digestion, DMD, rumen fermentation and microbial community changes. This knowledge could help to improve current feeding systems in terms of efficiency of feed use and environmental impacts (reduce methane gas production) and thus contribute to the development of a sustainable sheep and goat production.