L20&21- Fermenters (#3) Flashcards
Carbohydrate digestion generates__?
Glucose
Glucose fermentation generates?
Volatile Fatty Acids
Methane production allows___ to continue
Glycolysis
VFAs are used to make ____ aka ( __ )
Glucose (gluconeogenesis)
VFA are used to make ____________ as well (other than glucose)
FA
Most forgut fermenters are ________
ruminants
Ruminant stomach is divided into 4 compartments:
- Rumen
- Reticulum
- Omasum
- Abomasum
____ is the largest of the compartments and functions as a fermentation vat
Rumen
Ruminants secrete copious amounts of ____ which is rich in _____ and ______ (needed to buffer acids produced during fermentation, ____ (antifoaming agent), and ___ which helps supply nitrogent for microbial AA synthesis)*
- Saliva.. bicarbondate and phosphate
- Mucus (antifoaming agent)
- Urea
Contents are mixed by ____ of the rumen pillars and wall- how many per minute?
Contractions- 1-3 contractions per minute
During _____, a bolus of fibrous material is formed at the base of the esophagus and regurgitated so that animal can rechew the dietary fibers*
Rumination
Fermentation products, VFAs, are absorbed from the rumen via _____
Papillae
______ allows the ruminant to expel the volumes of gas generated during fermentation*
Eructation
What is the significance of papillae?*
Increase SA of the rumen
Ruminants are divided into 3 cateogories based on dietary preference- what are they? Also give example animals of each
- Grazers (cattle, sheep, buffalo, etc)
- Browsers (deer, moose, giraffe)
- Intermediate feeders (goats, reindeer, elk, etc)
What are the main differences btwn grazers and browsers?*
GRAZERS: have a large rumen allowing for maximal fiber digestion and requiring long fermentation times- their diet is HIGH in fiber and LOW in easily digested carbs
BROWSERS: have a less developed rumen, with short fermentation times- their diet is HIGH in more soluble, easily digested carbs and LOWER in fiber
What are some major differences between grazers and browsers with respect to RUMEN SIZE?** [+/- too]
Grazer (+): Very large, needed to accommodate high-fiber diet
Browser (-): Smaller, deit is lower in fiber, higher in soluble carbs which are more rapidly digested and fermented
What are some major differences between grazers and browsers with respect to RUMEN PILLARS?** [+/- too]
Grazer (+): Well-developed musculature needed to mix bulky, fibrous diet
Browser (-): Musculature is less well-developed bc of lower-fiber diet
What are some major differences between grazers and browsers with respect to RUMEN PAPILLAE?** [+/- too]
Grazer (-): Less extensive, VFA are produced at a mod pace, so do not need to be rapidly absorbed
Browser (+): Very extensive. Allows for the rapid absorption of VFA resulting from rapidly fermented soluble carbohydrates
What are some major differences between grazers and browsers with respect to OMASUM?** [+/- too]
Grazer (+): Well developed. Omasum keeps undigested fiber from entering abomasum
Browser (-): Less developed. Less fibrous diet
What are some major differences between grazers and browsers with respect to SALIVARY GLANDS?** [+/- too]
Grazer (-): Moderate (cow prod 100-150 L/day)
Browser (+): Well developed (3 to 4 times the amnt of grazer). Saliva buffers the rapidly produced VFA and glands secrete tannin binding proteins. Copious saliva washes easily digested food directly into abomasum
What are some major differences between grazers and browsers with respect to RAFT OR MAT FORMATION?** [+/- too]
Grazer (+): High fiber diet leads to mat formation
Browser (-): Low fiber diet decreases tendency to form mat
What are some major differences between grazers and browsers with respect to FERMENTATION TIME?** [+/- too]
Grazer (+): Very long. Long time needed to digest and ferment the high-fiber diet
Browser (-): Shorter time. Low-fiber, high-soluble carb diet, is fermented more rapidly
What are some major differences between grazers and browsers with respect to BIOHYDROGENATION?** [+/- too]
Grazer (+): Extensive hydrogenation bc of long fermentation time and need to dispose of hydrogens generated during fermentation. Fewer PUFA in body fat of ruminant
Browser (-): Less hydrogenation. Higher cc of PUFA are incorp in body fat
What are some major differences between grazers and browsers with respect to GLUCOSE TRANSPORTERS?** [+/- too]
Grazer (-): Fewer glucose transport proteins in SI
Browser (+): Present. Some readily available carbohydrates (RAC) are swept out of the rumen because of the large volume of saliva and are digested and absorbed in the SI
What are the 2 major categories of carbs in forage?* Describe
- Cell contents or solubles carbs- easily digested and make up a larger percentage of the carbs in the diet of the browser
- Cell wall components- are more resistant to digestion and make up the majority of the carbs in the forage of grazers
_____ is composed of linear chain of glucose with B-1,4 linkages- several chains will aggregate to form microfibrils- what is exclusive about mammalian enzymes with the B-1,4 linkages?
Cellulose
- No mammalian enzymes can hydrolyze it
____ has a random structure with many diff sugards besides glucose such as xylose, manose, etc
Hemicellulose
____ is a branched polysaccharide rich in galacturonic acid which fnctions as a glue to hold neighboring plant cells together
Pectin
____ is highly insoluble phenolic polymer crosslinked to the hemicellulose and pectins. _____(repeat) adds rigidity to the plant cell walls
Lignin
Lignification increase with plant ____ and decreases both _____ and ___ of forage
- Plant age
- Digestibility and palatability of forage
3 types of rumen microorganism (RMO) are?
- Bacteria
- Protozoa
- Fungi
____ are the ultimate specialists
Bacteria
What do protozoa engulf? (3 things)
Fiber fragments, starch granules and fiber-digesting bacteria
Digestion of the plant cell walls is carrid out by a __________ of several bacterial species- what does this mean?
Consortium
- Alone one species would be unable to digest but coming together to form a consortium of several species, they can digest cell wall fiber to glucose
What is termed a “readily available carb” (RAC) in contracst to cellulose and hemicellulose which are NOT easily digested and their glucose is NOT therefore readily available?
Starch
What happens ot the glucose obtained from the digestion of carbs from cattle feed?
Fermented by RMO in 2 steps:
- Primary fermentation
- Secondary fermentation
What is primary fermentation?
Uses glycolysis to convert glucose to pyruvate
What is secondary fermentation?
Converts pyruvate to a variety of VFA mainly (acetate, pripionate, and butyrate and some gases)
What are the endproducts of rumen fermentation*? (4)
- VFA (acetate, propionate, and butyrate)*
- Gases (CO2, CH4, H2, HS)
- Heat of fermentation
- Microbial cell mass (princip source of protein for ruminants)