Mouth (see monogastric)
1. Food acquisition
2. Mechanical breakdown - mastication
3. Saliva
Esophagus - transportation
Stomach (see monogastric)
Small Intestine (enzymes from SI and Pancreas) – See Monogastric
Large Intestine
Cecum ~same as rumen, a pocket off of the LI
CP – already digested and Absorbed
Starch - already digested and Absorbed
Cellulose – VFA produced and some absorbed
B vitamins synthesized, but not absorbed in cecum
L.I. = H2O absorption (minor mineral and H2O soluble vitamins)
Pre-gastric VS. Post-gastric digestion of cellulose
Poultry Digestion/Absorption
Mouth (beak)
1. Food acquisition – no teeth
2. Poorly developed salivary gland
Esophagus - transportation
Crop – part of esophagus – ingesta holding and moistening, some species have a little fermentation
Proventriculus – ingesta passes through quickly
Gastric juice produced - HCl & pepsinogen
Ventriculus = Gizzard – very muscular to contract for physical ¯ particle size
Contains stones (grit) to assist in this physical breakdown
No enzymes, but HCl and pepsin from Proventriculus
Small Intestine – see monogastric
Enzymes ?? Lactase??
Ceca – 2 "cecums" – same as in horse, but not as extensively used
Large Intestine – see monogastric
Feces and urine (uric acid) are both excreted through same opening (vent)
The Pancreas
Two types of tissue
Acini
= secrete the various digestive enzymesIslets of Langerhans
= secrete hormones – two types of islet cellsa
= secrete glucagonb
= secrete insulinglucagon and insulin are antagonistic, play key roles in blood glucose concentration
The Liver
Gland:
largest and probably the most important gland in the bodyFunctions:
Bile synthesis
Glucose regulation (blood)
Glycogen
Gluconeogenesis
– synthesis of glucoseDeamination of AA
= remove amino group from aa, be used for energy – N goes to Urea cycleFatty Acid synthesis
– from CHO and proteinFormation of ketones
Formation of lipoproteins, phospholipids, & cholesterol
Storage
= Vit. A, ~D, B12 , FeDetoxification
= first place nutrients from SI go to via blood, toxins detoxified (hopefully)Formation of plasma proteins
= fibrinogen, prothrombin, (blood clot formation)Degradation and Excretion of Hormones
= steroid hormones, cholesterol
Bile
Produced
= continuously by the liverStored
= gall bladderSecreted
= into SI as ingesta enters from the stomach (cholecystokinin)Functions
Fat Emulsification
Fat Absorption
= fat and fat soluble vitamin absorption**Increase fat solubility in water
Digestive Enzymes
Enzymes:
catalysts for normal spontaneous reactions (slow rate). Catalysts are not permanently affected by the reaction. Enzymes act as organic catalysts. All physiological function intimately linked to enzymes. (digestion, kidney excretion, muscle contraction, tissue growth/breakdown ® turnover, cellular respiration)Nature & Characteristics:
Protein:
Produced:
by living cellsHeat Labile:
destroyed by heatSpecificity:
a. 1 bond 1 molecule
b. >1 bond 1 molecule
- lipasec. cross boundaries??
- No crossing of boundaries, ie. Lipase will not work on CHO or CPpH:
- most have optimum pH: slower (less active) at ¯ or pHexample: pancreatic amylase optimum pH is ~7.0 (neutral). If stomach contents not neutralized, amylase activity would be slow therefore incomplete starch digestion.
Temperature:
- like pH, optimum temperature. Temperature is usually constant in warm-blooded animals (98.6 to 102 oC)Activity:
Secreted form:
Co-"?":
some need help from "other" factors to be activeCofactor
= if enzyme requires a mineral, then the mineral is a cofactorCoenzyme
= if an enzyme requires a vitamin, the vitamin is a coenzymeMechanism of Action:
Substrate:
Active Site:
lactation on the enzyme where it attaches to the substrateProduct:
the released result of the reactionMaltose acted on by maltase to form 2 glucose
Amylose acted on by amylase to form X glucose
Protein acted on by pepsin to form oligopeptides
Fact acted on by lipase to form fatty acids