This document discusses methods to improve microbial protein efficiency in ruminants to reduce feed costs. It describes rumen ecology and the microbes involved in fermentation, including bacteria, protozoa and fungi that break down plant fibers and synthesize microbial protein. Key factors that influence microbial protein production are discussed, such as nutrient synchrony and feed additives. The goal is to optimize rumen conditions and maximize microbial protein synthesis to meet protein needs of ruminants while minimizing costly protein supplements.

1. Improving microbial protein efficiency –
A method to reduce feed cost in ruminants
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Dr. Jasmine Rani K.
2018-DVM-005
Department of Animal Nutrition
College of Veterinary and Animal Sciences, Mannuthy

2. Outline
• Introduction
• Rumen and its microbes
• Nitrogen metabolism and microbial protein synthesis
• Factors influencing microbial protein synthesis
• Conclusion
• Future prospective
• References
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3. Introduction
 Production potential of animal Heredity
 Optimum nutrition is essential
 Major constraint of livestock production is increasing feed
cost
 Protein is one of the costliest nutrient in the feed
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4. Introduction contd…..
 Microbial protein can act as a major source of protein for
ruminants (Thirumalesh and Krishnamoorthy, 2013)
 Augmentation of rumen microbial protein production can
reduce the level of protein in the feed
 Reduce carbon losses in the form of CH4
(Clemmons et al., 2018)
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5. Four compartments of ruminant stomach
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Rumen
 Reticulum
 Omasum
 Abomasum
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6. Rumen Ecology
 Rumen- large fermentation vat
 Reticulo-rumen provides continuous culture system for anaerobic
bacteria, protozoa and fungi
 pH 6.5 – 6.8
 Temperature 38 °C - 42 °C
 Anaerobic condition
 Redox potential (Eh) -250 to - 450mV
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7. 8/12/2020 7Department of Animal Nutrition
Microbes Bacteria Protozoa Fungi
Cells/ml 1010–1011 104–106 103–105
% of mass 50 40 5-10
Generation
interval
20 min 8-36 h 24h
(Orpin, 1981; Kamra, 2005)
Rumen microbes

8. Microbial types
 Classification of rumen bacteria
Energy source/ substrate utilized
• Cellulolytic bacteria
• Amylolytic bacteria
• Proteolytic bacteria
• Ureolytic bacteria
• Methanogenic archaea
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9. Cellulolytic bacteria
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Species Description Energy source
End products
Fibrobactor succinogenes Gram -ve rods Cellulose Acetate, succinate,
formate
Ruminococcus flavifaciens Gram -ve cocci Cellulose
Acetate, succinate,
formate, lactate, CO2,
H2
Ruminococcus albus Gram -ve cocci Cellobiose
Acetate, formate
CO2, H2
(Nagaraja, 2016) www.sciencephoto.com

10. Amylolytic bacteria
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Species Description Energy source
End products
Streptococcus bovis Gram +ve
cocci
Starch and sugar Acetate, formate,
lactate, CO2
Bacteroides ruminicola Gram –ve
rods
Xylan, Starch,
sugar
Acetate, formate,
propionate,
succinate
(Nagaraja, 2016)
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11. Proteolytic bacteria
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Species Description Energy source
End products
Prevotella ruminicola Gram -ve rods Starch, xylan, pectin,
protein
Acetate, succinate,
formate,
propionate
Bacteroides amylophilus Gram -ve rods Starch, protein
Acetate, succinate,
formate, lactate
Selenomonas ruminantium Gram -ve rods
Sugar, starch, pectin,
xylan
Lactate,
propionate,CO2,
H2
(Nagaraja, 2016)

12. Methanogenic archaea
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Species Description Substrate
End products
Methanobrevibacter
ruminantium
Rods CO2, H2 CH4
Methanobacterium
formicium
Rods CO2, H2 CH4
Methanomicrobium
mobile
Rods CO2, H2 CH4
(Nagaraja, 2016) www.sciencephoto.com

13. Rumen protozoa
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Family Genus Description Substrate End
products
Isotrichidae Isotricha
Dasytricha
Cilia over entire
body
Cellulose
Hemicellulose
Starch
Xylan
Protein
Acetate,
propionate,
butyrate,
lactate, H2
Ophryoscolecidae Entodinium
Diplodinium
Epidinium
Ophryoscolex
Cilia in the mouth
region
Cellulose
Hemicellulose
Starch
Xylan
Protein
Acetate,
propionate,
butyrate,
lactate,
H2,CO2
(Nagaraja, 2016)www.sciencephoto.com

14. Rumen fungi
Species Description Substrate End products
Neocallimastix frontalis Polyflagellate
Cellulose
Hemicellulose
Xylan
Acetate, fumarate,
lactate, malate, CO2,
Ethanol
Caecomyces communis Uniflagellate Cellulose
Hemicellulose
Xylan
Acetate, fumarate,
lactate, malate, CO2,
Ethanol
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15. Environmental niches for microbes
Adhered to feed particles – 80 %
Free-living in the liquid phase
 Attached to rumen epithelium –
Epimural bacteria
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16. Digestion of protein in the rumen
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(Nagaraja, 2016)

17. Protein utilization in ruminants
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Ruminal ammonia N concentrations : 50 to 85 mg/L

18. End products of rumen fermentation
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MCP
80-
100%
Contribution of Protein
(Thirumalesh and Krishnamoorthy, 2013)
 Volatile fatty acids (VFA)
 Microbial protein
 CO2
 Methane

19. Properties of microbial protein
Good quality protein BV-80%
Amino acid content is similar to milk or
meat
More methionine and lysine than oil seed
cake
Digestibility: 80% (Bacteria-70-80% and
Protozoa 76-85%)
Metabolisability: 65%
Efficiency: Maintenance 100%; Lactation-
67% and Growth 60%
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20. Comparison of the amino acid composition of the
microbial proteins, milk, meat and soya bean meal
Amino acids,
AA
Microbial
protein, g AA/
100 g protein
Milk,
g/ 16 g N
Muscle,
g/ 16 g N
Soya bean meal
g/ 16 g N
Leucine 8.0 ± 0.8 10.2 8.0 8.0
Isoleucine 5.8 ± 0.7 5.6 5.1 5.0
Lysine 9.2 ± 1.8 8.2 9.1 6.4
Methionine 2.5 ± 0.6 2.9 2.7 1.2
Phenylalanine 5.3 ± 0.7 5.4 4.5 5.0
Arginine 5.3 ± 1.0 4.0 6.7 7.5
Histidine 2.1 ± 0.5 3.0 3.7 2.5
Threonine 5.7 ± 0.8 5.0 4.6 3.9
Tryptophan 1.5 ± 0.8 1.4 1.3 1.3
Valine 5.8 ± 0.9 7.4 5.3 5.01
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(Orskov, 1992)

21. Microbial yield
• Proportion of substrate energy fixed into microbial cells
Determines
 The microbial protein available to the animal
 Potential for the use of non protein nitrogen
 FME- Fermentable metabolisable energy
 Y- 9 at maintenance, 10 for growth, 11 for lactation
 DMCP- Digestible mirobial crude protein
 DUP- Truly digestible un degraded true protein(ICAR,2013; NRC, 2001)
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Microbial crude protein yield, MCP(g)= FME X Y
Metabolisable protein (g/kg DM) = DMCP+ DUP

22. Expression of microbial efficiency
 Y glucose : Microbial cells (g)/ mole glucose
 Microbial cells (g)/100 g of fermented feed
 Microbial cells (g)/mole of ATP
 MCP(g)/MJ ME
 MN(g)/kg DOMR
 MN(g)/kg TDOM
 MCP(g)/kg TDOM (Thirumalesh and Krishnamoorthy, 2013)
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23. Feed source Range Mean
Purified diets 150-500 337
Forages 160-490 303
Concentrates 130-260 211
Mixed diets 100-470 251
Silage diets 110-310 189
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Microbial Protein yield (g/kg TDOM)
(Van Soest, 1994)

24. Methods for quantification of MCP
1.Protein free purified diet
2. Use of microbial markers
Diaminopimelic acid (DAPA)
Amino ethyl phosphoric acid (AEPA)
35S, 32P or 15N
3. Prediction of microbial-N flow to the duodenum
4. Quantification of purine derivatives in urine
5. Total purine quantification (RNA equivalent)
6. Partitioning factor (PF)
(Blummel et al., 1997, Krishnamoorthy and Srinivas, 2010)
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25. Efficiency of rumen microbial growth
Organism
Efficiency(g microbial DM /mol ATP)
% Theoretical
maximum
% Actual
maximum
Mixed rumen microbes, in vivo 34–66 11–21
Mixed rumen microbes , in vitro 23–52 7.5–16.7
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(Thimothy and Firkins, 2015)

26. Energy needs of microbes
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Bucket model of energy spilling
(Thimothi and Firkins,2015)

27. Factors influencing MCP synthesis efficiency
Animal factors
 Species
 Age
 Physiological
state
Microbial factors
 pH
 Redox potential
 O2 concentration
 Protozoal predation
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Feed factors
Quality of nutrients
N and energy synchrony
Feed additives
(Srinivas and Krishnamoorthy, 2016)

28. Conclusion
 Microbial protein (MCP) plays a pivotal role in ruminant nutrition
 80-100% of protein requirement can be met from MCP
 Factors influencing MCP- animal, microbial and feed
 Adequate carbon and nitrogen supply
 Nitrogen and energy synchrony - Total mixed ration
 Frequency of feeding
 Feed additives
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29. Conclusion
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Maximize ruminal fermentation
Maximize microbial protein synthesis efficiency
Reduce costly protein supplements
Minimize nitrogen excretion
Sustain and improve the animal health and production

30. Future Prospective
• Newer feed evaluation models should be developed
• Research should be done to understand the association between
nutrient supply and efficiency of MCP synthesis
• DNA sequencing technologies and bioinformatics to study of the
microbial diversity
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31. References
• AFRC. 1992. Technical committee on responses to nutrients. Nutritive requirements of
ruminant animals,835p.
• Aguerre, M.J., Capozzolo, M.C., Lencioni, P. 2016. Effect of quebracho-chestnut tannin
extracts at 2 dietary crude protein levels on performance, rumen
fermentation, and nitrogen partitioning in dairy cows. J Dairy Sci. 99: 1- 11.
• ARC, 1984. The Nutrient Requirement of Ruminant Livestock. Agricultural Research
Council, CAB, Farham Royal, UK.612p.
• Ashwin, K., Paladan., Sandeep, U., Sahoo, J.K., Perween, S., Gupta, M. and Singh, A.
2018. An update on B vitamin nutrition for cattle. Int. J. Curr. Microbiol. Appl.Sci.
7: 188-192.
• Ashwin, K. and Srinivas, B. 2015. Effect of vitamin supplements on in vitro
fermentation, in vivo microbial protein synthesis and milk production in Deoni
cows. M. V. Sc., dissertation project, Southern Regional Station, National Dairy
Research Institute, Bangalore.
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32. References
• Beauchemin, K.A., Colombatto, D., Morgavi, D.P. and Yang, W.Z. 2003. Use of
exogenous fibrolytic enzymes to improve feed utilization by ruminants. J. Anim.
Sci. 81. 2: 37–47
• Blummel, M. and Lebzien, P. 2001. Predicting ruminal microbial efficiencies of dairy
rations by in vitro techniques. Livestock Produ. Sci. 68: 107-117.
• Brock, F.M., Forsberg, C.W. and Buchanan-Smith, J. G. 1982. Proteolytic activity of
rumen microorganisms and effects of proteinase inhibitors. Appl. Environ.
Microbiol. 44:561–569.
• Chandrasekharaiah, M., Thulasi, A. and Sampath, K.T. 2011. Microbial protein
synthesis, nitrogen capture efficiency and nutrient utilisation in sheep fed on
finger millet straw (Eleucine coracana)-based diet with different rumen-
degradable nitrogen levels. J. Sci. Food and Agric. 91: 1505-1510.
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33. Questions?
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