Use of tannic acid to protect barley meal against ruminal degradation

Abstract

The inefficiency of starch utilisation by ruminants fed readily fermentable cereal grains, such as barley, decreases the metabolic potential of such feeds and can cause serious dysfunctions related to acidosis or pre-acidosis status in animals with higher energy requirements. The rate and extent of ruminal disappearance of grain dry matter (DM) are determined largely by the morphological features of the seed endosperm, but the presence of polyphenols may also constitute a limiting factor in ruminal hydrolysis. To assess the impact of tannins on the rate and extent of ruminal fermentation of barley grain, commercial grade tannic acid (TA) was included at 0, 1.0, 2.5 or 5.0% (wt/wt, DM basis) with ground barley grain in incubation in situ, and disappearance of DM and crude protein were monitored over 48 h. A dose-dependent effect of TA on in situ degradation of barley meal was observed; significance was attained (p < 0.05) at the 5% treatment level. Scanning electron microscopy revealed limited microbial hydrolysis of endosperm cell walls in TA-treated samples, although TA did not prevent microbial attachment to or hydrolysis of starch granules. Tannins may be effective for slowing ruminal disappearance of barley to improve starch utilisation by ruminants.

Seaweed extract stimuli in plant science and agriculture

“…Phlorotannins from brown seaweeds are chemically less complex than tannins from terrestrial plants which are well known to interfere with rumen fermentation of starch and fiber leading to poorer overall performance of ruminants (McAllister et al 1994;Martinez et al 2005). Extracts of A. nodosum enriched in polymeric polyphenols and sulfated polysaccharides are potent inhibitors of α-glucosidase in vitro, lower blood glucose in mice, stimulate glucose uptake in adiposites, and modulate nitric oxide production by macrophages (Zhang et al 2006).…”

Influence of tannic acid application on alfalfa hay: in vitro rumen fermentation, serum metabolites and nitrogen balance in sheep

“…Due to its availability, cost and relative purity, tannic acid has been used widely to study the effect of tannins on rumen fermentation (Driedger et al, 1969;Nishimuta et al, 1974;Murdiati et al, 1992;Zhu and Filippich, 1992;Plumlee et al, 1998;Hervas et al, 2000;Santos et al, 2000;Frutos et al, 2004;Martinez et al, 2005 and. The objective of this study was to assess the influence of spraying tannic acid (TA) on chopped alfalfa hay on in vitro rumen fermentation of dry matter (DM) and N retention by sheep fed alfalfa hay.…”

Peculiarities of Enhancing Resistant Starch in Ruminants Using Chemical Methods: Opportunities and Challenges

“…Only a few experiments were conducted under in situ and in vivo conditions in ruminant nutrition so far [24,25,26,79,80], hence there is scarcity of information and further studies are warranted.…”

“…Tannins, naturally occurring secondary plant constituents, are also suggested as a means to slow down ruminal starch degradation [26]. Barley grain was milled to pass a 2 mm sieve and was subsequently soaked in 0 (served as control), 1%, 2.5%, and 5% of tannic acid (TA) for 20 min.…”

“…However, their relevance with regards to the modulation of starch degradation and the metabolic effects of feeding RRS in ruminants are not discussed. In addition, during the last few years, the use of some new chemical methods that utilize weak organic acids [23,24,25] or tannic acid [26] to confer the starch resistance against amylolytic degradation has been proposed, but there is no report summarizing the available data. The present article attempts to summarize the most important achievements in the chemical processing methods used to generate RRS, and review the advantages and challenges of feeding RRS to ruminants, including its effects on rumen health and metabolism.…”