monogastric stomach

what is gluconeogenesis

synthesis of glucose from non-carbohydrate sources

where does gluconeogenesis occur

cytosol of cell

what enzyme steps are irreversible

• pyruvate carboxylase

• PEPCK

• fructose 1,6 bisphosphatase

• glucose 6 phosphatase

ruminants use what produced from fermentation of carbs in the rumen

propionate; no glucose absorbed from small inestine

propionate is converted to

succinyl-coA

what happens to succinyl-coA

it goes through the TCA cycle to oxaloacetate to enter gluconeogenesis

what can be used as carbon skeletons for gluconeogenesis

amino acids

what controls gluconeogenesis

hormones

which hormones control gluconeogenesis

• insulin; inhibits

• glucagon; promotes

• cortisol; stimulated

what influences the structures of the digestive tract in simple stomach animals

diet feedstuff composition

digestable diets require

less digestive capacity

plant based diets with more fiber require

more digestive capacity and complexity in the GI tract to facilitate digestion

what is important in fiver digestion in ruminants

retention

what is important in plant fiber digestion

capacity

fermentation improves what in non-ruminants

plant fiber digestion

where does fermentation occur in non-ruminants

hindgut- large intestine

fermentative capacity is greatest in which animal

cattle

caarbs go from the small intestine to what in regular animals

large intestine

what byproduct gasses are produced by fermentation by bacteria

CO2 and H2

explain herivore diets

• forages

• consume grass and legumes from pastures or harvested

• supplementation with concentrates (proteins or energy)

explain omnivore diets

• swine and poultry have their digestion based on enzymes of GI tract

• low in fiber

• energy concentrates

• protein concentrates

explain carnivore diets

• dogs have teeth with premolars and molars that help with crushing

• can use plant products in diet

• energy concentrates

• protein concentrates (meat meal, fish meal)

proteins that contain essential amino acids are

high quality

what are methods of raking proteins besides amino acid profile

digestibility and biological value

what is biological value

it evaluates how well a protein is used for productive functions; how well it supplies essential amino acids

what aids in digestion

enzymes

enzymes have what characteristics

• heat stability

• free flowing for handling ease

• stability for storage and feeding

xylands are a type of

hemicellulose- non starch polysaccharide that contains pentose xylose sugars

xyans contribute to

the cell wall of a plant

what are xylans associated with

rye, wheat, triticale

what do xylanses break down

xylans

beta glucanase are a type of

plant cell wall carbohydrate; not digestible

what are beta glucanases associated with

barley and oats

beta glucanse enzymes break down what

beta glucans

in poultry and swine, non-structural carbs can make

digesta viscous, which interferes with digestion

what is phytate

• inositol hexaphosphate

• storage form of phosphorus

chelates binds

metal ions like zinc and calcium

chelation of metal ions limits

their bioavailibility

with phytate phosphorous poor digested diets, what can help meet requirements

additional inorganic sources like dicalcium phosphate. this increases total phosphorus with phytate phosphorus lost in manure

what can be a pollutant

phosphorus and nitrogen

animals lack what enzyme

phytate, but bacteria and fungi produce it

isolating phytase genes does what

improves the bioavailability of phosphorus from feedstuffs

phytase (does or does not) liberate all phosphorus from phytate

does not

because phytase doesnt liberate all phosphorus, what happpens

• bioavailability is improved of phosphorus and minerals

• total phosphorus is reduced from inorganic sources

brush border peptidases are what

enzymes that include a mineral ion in the catalytic portion of the enzyme responsible for enzyme activity

does phytase improve or decrease protein digestibility

improve

TDN is what

• energy system applied to ruminants and swine

• similar to DE

• expressed as weight or precent

• able to be converted to energy values

how do you calculate TDN

digestion trials.

• either extract and nitrogen free extract

what are some problems with TDN

• Is calculated from digestibility experiments, an old method

• intake levels low in experiments

• feeds are variable in quality