ruminants 2 :)

describe true symbiosis

• between ruminant and its rumen microbes

• microbes depend on essential condition

what are microbes essential for

digestion and fermentation of fibrous feedstuffs that cant be used for nutrients

• ruminant provides habitat and microbes provide end products of fermentation

explain the rumen characteristics

• low oxygen environment

• anaerobic microbes

• dry matter varies from 6-18%

what is the oxygen environment contents in the rumen and atomosphere

rumen: 65% CO2, 7% N2, .6% O2

atmosphere: Trace CO2, 78% N2, 21% O2

what does it mean when the rumen is very fluid

it facilitates microbial interactions and enzymes with feed

what is the rumen supported by

substrates, eating feed, and a large holding capacity

what does capacity aid in when referring to the rumen

retention of complex diet components, allowing degradation and fermentation

what is the rumen rich in

carbohydrates; cellulose and other polysaccharides make up the feed

what happens to large particles in the rumen

they are retained until sufficient degradation occurs

explain rate of passage in the rumen

it is the amount of liquid and particles that flow OUT of the rumen per unit of time

• k_p

• 8%/h

what is bacteria’s role in the rumen

• digestion and fermentation of feed

• 10^10 - 10^11/mL bacteria

• 0.3-50µm

what is protzoas role in the rumen

• slow rate of pH decline

• 10^4-10^6 / mL ciliated bacteria

• 20-200µm

what is fungis role in the rumen

attachment site for bacteria

• 10² - 10^4 / mL fungal zoospores

what is the substrate of cellulolytic

cellulose

what is the substrate of hemicellulolytic and pectinolytic

hemicellulose and pectin

what is the substrate of amylolytic

starch

what is the substrate of proteolytic

proteins

what is the substrate of ammonia producing

amino acid deaminators

what is the substrate of lipolytic

lipase producers

what is the substrate of intermediate acid utilizers

lactate, succinate, formate

explain rumen protozoa

• majority ciliated, some flagellates

• comprise 40% of microbial N and 60% of fermentation products

• contributes to fermentation; starch, sugar, pectin, hemicellulose

• predators of bacteria; consumed for protein

explain anaerobic fungi

• attach and found in plant fragments

• contribute to degradation of cellulose and other polysaccharides

explain intermediate cross feeding

intermediates being metabolites are produced through cell processes.

• shared between species

• end products of one become substrate of another

whats an example of intermediate cross feeding in microbial independence

• S. ruminantium cant use cellulose but B.succinogenes does

  • B.succinogenes produces succinate and S. ruminantium can be used to produce succinate

• lactate can be used by M. elsdenii to produce propionate

what are the VFA requirements

• sharing VFA among non-celluloytic and celluloytic bacteria

• production of branched chain VFA from deamination of branched chain amino acids by non-cellulolutic bacteria

• prodvide carbon skeletons

for VFAs what do carbon skeletons do

helps synthesis of amino acids

• allows for synthesis of microbial fatty acids with branched or odd numbered chains

explain interspecies hydrogen transfer

• H2 producing and H2 utilizing species

• H2 used to produce methane for CO2

• H2 transferred to methane producers to encourage more H2 production

• H2 producers are associated with great energy production

what are substrates

• not lipids apparently

• hydrolyzed to free fatty acids and glycerol backbone, but not fermented

• some protein/amino acid utilization

• carbohydrates

in carbs, several sugars are found where

hemicellulose

what are carbs

• sugars in feed or produced by polysaccharide hydrolysis

• starch

• pectins (structural polysaccharides of plant cell wall)

explain variable fermentation rates in order

1. soluble CHO fermented first

2. pectin

3. structural CHO

4. cellulose last

why are variable fermentation rates in the order that they’re in

its easier to attack or hydrolyze substrates earlier and faster than harder to attack substrates

what does fermentation follow

hydrolysis

what is pyruvate converted to in fermentation

VFAS through pathways.

• first to acetyl-CoA

  • acetyl converte to acetate propinate

what are the 3 main pathway propinate production

• succinate

• acrylate

• propanediol

what is butyrate produced from in fermentation

butyryl-coA which is derived from 2 molecules of acetyl-coA

what is butyrate’s short chain fatty acid

2 hexose → 2 butyrate +4H2 + 4CO2

what is propionate short chain fatty acid

3 hexose → 4 propionate + 2 acetate + 2CO2 + 2H2O

what is acetate short chain fatty acid

hexose + 2H2O → 2 acetate + 4H2 + 2CO2

what is the molar ratio in short chain fatty acid

acetate : propionate : butyrate → 70:20:10

what is the summation of methane

hexose → 2 acetate + CO2 + CH4

what is the summation of acetate from CO2

Hexose → 3 acetate