Symbiotic association between different microbes in rumen

1. phD Scholar
LUVAS HISAR

2.  Establishment of microbes in young ruminant is
primarily dependant upon its exposure to an adult
animal .
 Major portion of microbial population consists of
 Anaerobic bacteria
 Ciliate protozoa
 Anaerobic fungi

3.  Counting can be done in strained rumen fluid
 Concentration of rumen protozoa can be significantly
lower in rumen fluid than in whole rumen contents by a
factor depending on time and method used to separate the
fluid fraction.
 Increased percentage of solids acted as a filter mat
retaining more of the protozoa

4.  Grooming to young animals by mother
 Salivation on feed or even pasture followed by ingestion
of the contaminated material by a young animal leads to
faunation
 Airborne water droplets
 Rumen pH is quite acidic in young due to rapid
fermentation of milk sugars so the sequence of
establishment of protozoa is Entodinium first followed by
Diplodinium and then Holotrichs.

5.  Modification in physiology of the animal host i.e. changes
in rumen motility, rumen wall absorption capacity ,
salivary secretion etc. May cause a temporary
disappearance of rumen ciliates.
 Well established bacterial flora and rumen pH is necessary
for establishment of rumen ciliates.

6.  Diurnal variation :
 Chemotactic response: migration of Isotrichidae primarily
Isotrachia and Dasytricha into rumen contents at feeding
time followed by abrupt decrease as a result of
sequestration .
 As the storage polysaccharide in the cells increased after
feeding they sequester by settling in ventral rumen as the
polysaccharide utilized the levels falls below a
chemotactic threshold within 10-12h and if animal is fed,
the isotrichids will migrates in response to soluble sugars

7.  Diet : when amount of available energy increased in ration
protozoan concentration increased , ration containing 40-
50% roughage will support maximal protozoan numbers
with a diverse fauna containing species of most of genera .
 Increased concentrates above 60% corresponding decrease
in minimal rumen pH results in protozoan concentration,
shifts towards Entodinium ,or completes defaunation

8.  Intake: protozoan number were inversely proportional to
particle size and rate of passage of feed through the rumen
 Frequency: feeding the same quantity of feed four times
daily instead of once a day resulted in doubling of protozoan
concentration because multiple feeding prevents the drastic
fluctuations in rumen pH which can be inhibitory to
protozoa

9.  Seasonal differences : hot to cold or wet to dry both
inhibit or slow down plant growth and results in a
decrease energy available to the animal

10.  Geographical location
 Difference in diet
 Origin of animals
 Isolation from others ruminants
 Specificity of rumen ciliates
 Antagonism between species

11.  Host specificity : in the animal itself by some unknown
physiological factors could influence the genera and
species which establish in its rumen these includes type
and amount of feed ,rate of consumption, saliva production
,rumen pH, rate and type of fermentation , osmolality,
particulate matter.
 Protozoan specificity :on the basis of races existing within
a given species.

12.  Antagonism between species : the type of fauna
established in a given animal can be influenced by
antagonistic relationship which appears to exist
between certain rumen ciliates species.

13.  Non photosynthetic microorganism containing chitin in
their vegetative cell walls and are fibrolytic in nature for
maximum production of these organism they require pH
6.5 and 39°C, presence of CO2 and absence of O2.
 Ability to grow under low redox potential
 Vegetative stage are called as zoospore
 Rapid increase in number shortly after feeding resulted
from stimulation of reproductive body by haem or haem
containing compounds on a vegetative phase of the
organism which differentiated and liberated the flagellates.

14.  Young preruminants rely upon their mother milk for
nutrition, with lactose as major CHO most of anaerobic
fungi can utilize this lactose as carbon source and thrive
in low redox potential developed by anaerobic bacteria so
plant fibre is not essential for their establishment .
 Can be transferred by grooming, by feeding at same site,
coprophagy and they are not host specific.

15.  Diets rich in forage such as hay and silage or silage based
diets with a long ruminal transit time , consistently results
in development of high population densities of anaerobic
fungi
 Fungi normally grow on highly lignified tissue and in the
pelleted ration or supplemented with soluble sugar the
transit time is low resulted in high wash out of infected
particles and low ruminal pH also reduces the fungal
population

16.  Appearance of a bacterial population would not dependent
on feed composition but composition of microflora depends.
 Bacterial population established in rumen with in few days
after birth creates suitable environment for establishment
and growth of cellulolytic species

17.  The concentration of total rumen bacteria decreased after
feeding , increased slowly to maximum and then
gradually decreased until the next feeding
 Concentration pattern reflects an initial dilution by feed,
water and saliva and increase in growth rate in response
to incoming nutrients which exceeds the dilution rate and
finally a depletion of nutrients with a corresponding
decrease in growth rate

18.  Diet : high concentrate diet increases bacterial
concentration however feeding frequency, feeding level
and sampling time and individual animal variation all
appear to influence bacterial concentration.
 Animal fed on pasture: counts are lowest in winter and
highest during summer this reflect the low nitrogen
content in winter herbage
 Antibiotics: they inhibit the gram positive bacteria,
with a corresponding enrichment of gram negative
bacteria

19.  As a result propionate production is increased, protein
degradation and methane in rumen is depressed
 Interrelationships: major nutritional effects of rumen
protozoa is upon the protein/energy ratio of nutrients
available for absorption in small intestine affecting animal
growth rate, feed intake and feed digestibility exerting a
levelling or buffering effect on the rumen

20.  When fungus are eliminated by feeding chemically
treated barley straw the digestibility of fibre was
depressed
 Bacterial population found to be much higher in
defaunated than in faunated animal and decrease
markedly following faunation
 The fermentation of feedstuffs is taken over by increased
bacterial population

21.  Zoospore and sporangia concentration found to be increased
in defaunated animals
 Different levels of energy intake would be expected to
support different amounts of total microbial biomass.