Toksikologi Pakan: Tannins
Transcript of 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
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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
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- 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.
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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
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- High light intensity
- High temperature
- Severe drought
- Tissue damage
Increase tannin
levels
B. Structure
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Condensed tannin (CT)
Hydrolysable tannin (HT)
Diversity of tannin structures
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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
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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
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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
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- 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
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- 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
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Toxicity problems
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Prevention of bloat
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Protection of
protein from
rumen
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rumen
degradation
Mitigating methane emission
• Global warming
• Loss of energy
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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
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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
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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
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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
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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
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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
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Source: Vasta et al. (2010)
Appl. Environ. Microbiol. 76, 2549-2555
Containing 6.4% tannins
from quebracho powder
Inhibition of phenolics on lipase activity
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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
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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.
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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.
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