Phenolics are ubiquitous in all plant organs and integral part of animal and human foods. Phenolic acids, flavanoids and tannins are the most common phenolic compounds. Fruits and vegetables are rich source of polyphenols for humans. Whereas, tree leaves in tropical countries are potential sources phenolic compounds for animals. Researchers have become more interested in polyphenols due to their potent antioxidant properties and credible effects in the prevention of cardiovascular, neurodegenerative diseases and cancer. Condensed tannins (CT) and flavanoids have the ability to modify the rumen fermentation towards reduced methanogenesis by altering rumen microbial community and their supplementation reduces nitrogen excretion in ruminants by improving its utilization efficiency. Improvement in feed intake, growth rate, wool production, reproduction and milk production in ruminants fed CT containing diets were observed in a dose dependent manner. In ruminants, most proteins are rapidly solubilised and release 56- 65% N in the rumen during mastication; consequently large losses of N (25-35%) occur as ammonia absorbed from rumen. CT from tree leaves could be used as organic protectant of proteins to improve protein utilization by ruminants and reduce environmental pollution by minimising N losses through urine. Supplementation of CT through leaves of Artocarpus heterophyllus, Ficus infectoria, Ficus bengalensis and Ficus glomerata at 1.5- 2.0% levels was observed to reduce the rumen degradability of groundnut cake to 60-75 per cent from the normal value of 92 per cent. Controlling gastro-intestinal parasites by supplementation of CT through F. infectoria, Psidium guajava and Ficus bengalensis was effective to ameliorate drug resistance. Feeding study to lambs and crossbred cows with supplementation of CT (1.5%) either through F. Infectoria and F. bengalensis leaves was found to increase feed efficiency, growth rate, milk yield, fat yield, antioxidant status and immunity of animals. Flavanoids and tannin-rich feeds could reduce or inhibit rumen biohydrogenation of vaccenic acid to stearic acid, resulting in the accumulation of conjugated linoleic acids (CLA) in milk and meat which has hypolipidaemic and anti carcinogenic effects in humans. Judicious application of plant phenolics could improve overall health and production performance of animals.
Plant phenolics in animal health and methane mitigation. avijit dey
1. Plant Phenolics in Animal Health and Methane
Mitigation
Dr. Avijit Dey
Senior Scientist
ICAR- Central Institute for Research on Buffaloes, Hisar- 125 001
*avijitcirb@gmail.com
2. What are Plant Phenolics ?
Phenolics: compounds possessing one or more aromatic
rings with one or more hydroxyl groups
Most abundant:
1. Phenolic acids: Gallic, coumaric, caffeic, ferulic acids
2. Flavanoids: Flavones, flavonols, flavanols, flavanones,
isoflavones, and anthocyanins
3. Tannins: Hydrolysable and condensed tannins
Less common:
Stilbenes and Lignans
5. Total phenolics and tannin fractions of
some common tropical tree leaves
Leaves Hindi
name
TPh NTPh TTPh CT
Acacia nilotica Desi babool 4.9 1.1 3.8 1.7
Artocarpus heterophyllus Kathal 24.2 1.3 23.0 19.1
Azadirachta indica Neem 2.9 1.3 1.7 0.6
Eugenia jambolana Jamun 8.5 1.1 7.4 4.2
Ficus bengalensis Bargad 19.6 3.5 16.1 12.6
Ficus glomerata Gular 17.5 1.4 16.2 12.1
Ficus infectoria Pakar 19.4 5.5 13.9 9.4
Grewia oppostifolia Bhemal 2.7 1.4 1.3 0.2
Mangifera indica Aam 5.8 1.4 4.4 0.9
Morus alba Tut 2.1 1.4 0.7 0.2
Musa paradisiaca Kela 1.7 0.8 0.9 0.6
Populus fastigiata Popler 4.6 1.1 3.5 1.1
Quercus incana Oak 15.4 2.1 13.3 7.2
6. Phenolics as Antioxidants
Oxidative stress
Reactive oxygen and/or nitrogen species (ROS/RNS,
e.g., superoxide anion, hydrogen peroxide, hydroxyl
radical, peroxynitrite)
>Endogenous antioxidant capacity
Leading to oxidation of a varieties of bio-molecules,
such as enzymes, proteins, DNA and lipids
Development of chronic degenerative diseases
including coronary heart disease, cancer and aging
8. Erythrocytic antioxidant indices of lambs fed
graded levels of F. infectoria leaf meal (FILM)
Attributes Treatments SEM
CON FILM-I FILM-II FILM-III
Catalase (mK/g Hb) 9.5 a 10.1b 10.7 b 10.4 b 0.12
SOD (mmol MTT formazon formed/g
Hb)
1.5 a 1.7 ab 2.0 b 1.9 b 0.11
LPO (nmol MDA/g Hb) 73.9 b 65.2 a 63.9 a 60.8 a 1.11
GSH (mol/g Hb) 9.7 a 10.8 a 11.6 b 11.8 b 0.34
T-SH (mol/ml PRBC) 40.1a 46.0 b 46.1b 48.3 b 0.82
NP-SH (mol/ml PRBC) 4.4 4.4 4.6 4.6 0.12
P-SH (mol/ml PRBC) 35.6 a 41.6 b 41.5 b 43.7 b 0.62
a,b Mean bearing different superscript within a row differ significantly (p<0.05)
10. Effect of condensed tannins supplementation
through F. bengalensis leaves on erythrocytic
antioxidant indices in cows
Attributes Treatments SEM
CON FBLM
Catalase (mK/g Hb) 9.8 a 10.9 b 0.16
SOD (mmol MTT formazon formed/g Hb) 1.7 a 2.3 b 0.21
LPO (nmol MDA/g Hb) 74.6 b 64.6 a 1.32
GSH (µmol/g Hb) 9.9 a 11.8 b 0.31
T-SH (µmol/ml PRBC) 39.4a 45.7b 0.86
a,b Mean bearing different superscript within a row differ significantly (p<0.05)
15. Phenolics in GI Parasitism
• Resistance of gastrointestinal parasites (GIP) to
chemotherapeutic drugs have stimulated to search the potential
of plant secondary metabolites as an alternative GIP control
strategy.
• Plant CT may have direct or indirect effects on GIP.
Direct: 1. CT-nematode interactions, thereby affecting
physiological functioning of GIP
2. Decrease the viability of the larval stages of several
nematodes
3. Interfering with parasite egg hatching and
development to infective stage larvae
Indirect: 1. Improving protein utilization
2. Improving host immune and antioxidant status
16. •Feeding of CT (1-2%) to goats through a leaf meal mixture (Ficus infectoria, Psidium guajava
and Ficus bengalensis; 70:20:10) decreased faecal egg counts with improvement in feed
efficiency and immune response.
17. •Inhibition of different developmental stages of Haemonchus contortus in sheep with
improvement in nutrient utilization was observed by supplementation of CT (1.5% of DM)
through a leaf meal mixture of Ficus infectoria and Psidium guajava
18. •The potential benefit of tannins on GIP also depends on nature of
CT, their source and dose levels to animals. Type of parasites
present in GIT, their habitat and degree of worm load also determine
the efficacy of condensed tannins to GIP
20. Cont..
Tannin-rich feeds could reduce or inhibit biohydrogenation of
vaccenic acid to stearic acid, resulting in the accumulation of
vaccenic acid (Priolo and Vasta, 2010) which has been reported to
hypolipidemic (Jacome-Sosa et al., 2010) and anti carcinogenic
effects in humans (Miller et al., 2003).
Rana et al. (2012) observed an increase (47% to 58%) in Δ9-
desaturase activity by condensed tannin supplementation, resulting
in an enhancement of total CLA content in muscle by indirectly
regulating the Δ9-desaturase expression in tissues through changes
induced in the profile of fatty acids absorbed.
Supplementation of quebracho tannins, flavonoids (genistein and
hesperidin) improves meat quality by increasing colour, pH and
water holding capacity (Kamboh and Zhu, 2013).
21. Phenolics in Methane Mitigation
•Two modes of action of tannins on methanogenesis (i) a direct effect on ruminal
microbes and (ii) an indirect effect on fiber digestion to decrease production of
hydrogen which is a substrate for methanogens
23. Cont..
• Linear decrease in methane production with increasing
(0.2- 2% of DM) levels of CT from different plant sources in
the diet of ruminants (Tan et al., 2011; Cieslak et al., 2012)
without hampering rumen fermentation.
• Some reports suggest that tannins have no effect on rumen
methane production (Oliveira et al., 2007; Beauchemin et
al., 2007).
• Effects of tannins on rumen protozoa, bacteria, fungi and
methanogens, thereby methane production are variable
and mostly depend on the type of tannins, their origin and
supplementation levels.
28. Conclusion
• Natural phenolics have the ability to improve antioxidant status and
immunity of humans and animals.
• Plant phenolics especially condensed tannins can improve animal
production by improving bioavailability of protein in the rumen and
overcoming effects of gastro-intestinal nematodes.
• Potential of plant phenolics in reducing ruminal methanogenesis have
attracted special attention for development of feeding strategy for
reducing greenhouse gas from livestock sector.
• The manipulation of milk and meat quality, particularly with respect to
fatty acid composition by feeding of plant phenolics, is an active area
of research, which may result in human health benefit.
• Plant phenolics may indeed be beneficial for animal health and
production, there is need for more animal study for identification of
source and dose of phenolics for maximum advantage.
