toksikologi pakan: tannins

Toksikologi Pakan: Tannins

Anuraga Jayanegara

Outline

A. Introduction

B. Structure

C. Interaction

D. Analytical methods

E. Biological effects

F. Treatments/processing methods

Department of Nutrition and Feed Technology

A. Introduction

Plant secondary compounds

- Do not function in primary metabolism such as biosynthesis,

biodegradation and other energy conversions of intermediary

metabolism

- Do have diverse biological activities ranging from toxicity to hormonal

mimicry

- May play a role in protecting plants from herbivory and disease


- May play a role in protecting plants from herbivory and disease

- Examples: alkaloids, terpenes, phenolics

Tannins, definition

Water-soluble phenolic compounds that have ability to precipitate

proteins

Classification

Condensed tannin (CT, proanthocyanidins): oligomers of two or more

flavan-3-ols such as catechin, epicatechin, or gallocatechin.

Hydrolysable tannin (HT): consisting of a central core of carbohydrate to

which phenolic carboxylic acids are bound by ester linkage.



Why plants produce phenolics?

A strategy adopted by plants to deter attack by microorganisms,

insects and higher animals.

Factors affecting tannin levels:

- Nutrient stress (N, P, K, S deficiencies)

- High light intensityIncrease tannin


- High light intensity

- High temperature

- Severe drought

- Tissue damage

Increase tannin

levels

B. Structure


Condensed tannin (CT)

Hydrolysable tannin (HT)

Diversity of tannin structures


Source: Mueller-Harvey (2006)

J. Sci. Food Agric. 86, 2010-2037.

Multiple hydroxyl groups: enable phenolics to form complexes

with proteins, polysachharides and minerals.

Tannin-protein complex:

C. Interaction


Tannin-protein complex:

1. Hydrogen bonds: free phenolic hydroxyl groups

2. Hydrophobic bonds: aromatic ring structures

3. Covalent bonds: polymerization reactions due to heating,

exposure to UV radiation and the action of polyphenol

oxidase

Illustration of protein precipitation by tannins


Marangon et al. (2010)

Analytica Chimica Acta 660, 110-118

D. Analytical methods

- Categorized into: (1) chemical methods, (2) protein precipitation

methods, (3) gravimetric assays, (4) tannin bioassay, (5) Others.

- Chemical assays:

- Total phenols and total tannins: Folin-Ciocalteu (oxidation-reduction),

ferric chloride (metal-complexing property of phenolics)

- Condensed tannins: vanilin assay, butanol-HCl assay

- Hydrolysable tannins: rhodanine method, HPLC


- Hydrolysable tannins: rhodanine method, HPLC

- Protein precipitation assays: ninhydrin assay, BSA method, radial

diffusion assay

- Gravimetric methods: ytterbium acetate, PVPP

- Tannin bioassay: in vitro gas production + PEG (e.g. Jayanegara &

Sofyan, 2008)

More detailed methods ....

E. Biological effects

Negative effects:

- Decreasing nutrient utilization, in particular protein utilization

- Decreasing feed intake

- Toxicity and death of animals

Positive effects:

- Prevention of bloat


- Prevention of bloat

- Protection of protein from rumen degradation

- Mitigating methane emission

- Modulation of PUFA biohydrogenation in the rumen

- Controling of gastro-intestinal nematode parasites

Decreasing nutrient utilization


Toxicity problems


Prevention of bloat


Protection of

protein from

rumen


rumen

degradation

Mitigating methane emission

• Global warming

• Loss of energy


Source: Morgavi et al. (2010)

Animal 4, 1024-1036

Evidences:

- Jayanegara et al. (2009), Animal Feed Science and Technology 150, 230-

237

- Jayanegara et al. (2009), Media Peternakan 32, 120-129

- Jayanegara et al. (2010), Sustainable Improvement of Animal Production

and Health (Odongo, N.E., Garcia, M., Viljoen, G.J. (Eds.)), FAO, Rome,

pp. 151-157


pp. 151-157

- Jayanegara et al. (2011), Animal Feed Science and Technology 163, 231-

243

- Jayanegara et al. (2012), Journal of Animal Physiology and Animal

Nutrition 96, 365-375

- Jayanegara et al. (online first), British Journal of Nutrition


Source: Bhatta et al. (2009)

J. Dairy Sci. 92, 5512-5522 Phenolics and microbial population

Ruminal methanogens attached to protozoal

species � interspecies H transfer

Protozoa-associated methanogens contribute

up to 37% of total rumen methane emissions

Removal of protozoa from the rumen


Protozoa colonized by

methanogens

Removal of protozoa from the rumen

(defaunation) � may ↓ CH4 emission

α-Linolenic acid

Linoleic acid

• Reduce the risk of

cardiovascular disease

• Lowering plasma

cholesterol level

Modulation of PUFA biohydrogenation


Source: Chilliard et al. (2007)

Eur. J. Lipid Sci. Technol. 109, 828-855

Rumenic acid

Vaccenic acid

Stearic acid

• Prevent cancer

proliferation

•Decrease atherosclerosis

• Improve immune system


Source: Khiaosa-ard et al. (2009)

J. Dairy Sci. 92, 177-188

CH: grass-clover hay (control)

TF: dried sainfoin (7.9% CT)

TH: CH + A. mearnsii extract (7.9% CT)

SH: CH + Y. schidigera extract (1.1% saponins)

Condensed tannins (CT)

Influence of tannins on biohydrogenating bacteria


Source: Vasta et al. (2010)

Appl. Environ. Microbiol. 76, 2549-2555

Containing 6.4% tannins

from quebracho powder

Inhibition of phenolics on lipase activity


Source: Van Ranst et al. (2011)

Animal 5, 512-521

Other evidences:

- Jayanegara et al. (2011), Animal Production Science 51, 1127-1136

- Jayanegara et al. (2012), Livestock Science 147, 104-112

- Palupi et al. (online first), Journal of the Science of Food and Agriculture


F. Treatment methods

- Wood ash: a good source of alkali; 10% solution of oak wood ash

decreased the content of TP, CT and protein precipitation capacity by 66,

80 and 75% in oak leaves, respectively.

- Urea-ammoniation: 4% urea in fresh leaves.

- Drying: but not effective.

- Chemicals: extraction with organic solvents (30% acetone, 50%

methanol, 40% ethanol) removed ca 70% tannins from oak leaves.


methanol, 40% ethanol) removed ca 70% tannins from oak leaves.

- Solid-state fermentation: biodegradation of tannins using white-rot

fungi.

- Addition of tannin-binding polymers: PEG (polyethylene glycol)

incorporation, PVPP.

Department of Nutrition and Feed Technology Department of Nutrition and Feed Technology

Thank you for your attention!Thank you for your attention!

Department of Nutrition and Feed Technology Department of Nutrition and Feed Technology

toksikologi pakan: tannins

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