herbivore digestive anatomy student handout...herbivory α-1,4 linkages and maltose α-1,6 linkages...
TRANSCRIPT
Herbivore Digestive Anatomy
Integrated Rangeland Management REM 456
Spring 2013Sergio Arispe, Ph.D.
http://www.lelylife.com http://horsetrailerworld.com
OverviewComparative Digestive Anatomy
Herbivory
Digestive Systems
Anatomy
Digestive End-Products
Foregut Fermenters
Comparative Digestive Anatomy
http://yr11-biology-revision.wikispaces.com
Fraction of Primary Production Consumed By Various
HerbivoresFRACTION VEGETATION TYPE HERBIVORE
GRASSLANDS INVERTEBRATES30-60% GRASSLANDS
GRASSLANDS (AFRICA)
UNGULATES20-90% TUNDRA
GRAMINOIDSTALLGRASS PRAIRIE BIRDS (GRANIVORES)58% SALT MARSH
(Modified from Crawley, 1983)
Herbivory
Cellulose
β-1,4 linkages
Herbivory
α-1,4 linkages and α-1,6 linkagesMaltose
Amylose
Digestive Systems
The major purpose of the digestive system is to provide for the assimilation of nutrients required for biological functions including maintenance, growth, lactation, and reproduction
Digestive SystemsNon-cellulose digestors Hindgut or Post-gastric FermentersForegut or Pre-gastric FermentersArchitecture of GIT
Location, size, and shape
Nature and location of the digestive agentsEnzymes and digestive juices, fermentation
Chemical nature of the end products of digestionAmino acids, Volatile Fatty Acids (VFA’s), Monoacylglycerol (MAG), Free Fatty Acids (FFA)
Gastrointestinal Tract (GIT) Functions
Diet
Esophagus
Stomach
Large IntestineAnus
Origins of Simple Stomach Animals
(Van Soest, 1994)
Non-cellulose Digestors
Simple stomach animals (Monogastrics)
E.g., Humans, swine, reptiles
Cellulose is not an energy source
(Van Soest, 1994)
Cellulose DigestorsHindgut Fermentors
Foregut Fermentors
www.tamu.edu
Hindgut FermentersDiet
MouthEsophagus
Stomach
Small Intestine
Large Intestine
AnusColon
Cecum
Hindgut FermentersCecal Fermenters
E.g., Rabbits, Guinea Pigs, Rat
http://www.rabbitfood.org.uk(Stevens, 1977)
Hindgut FermentersCecal Fermenters
Rabbits, Guinea Pigs, RatDiet
MouthEsophagus
Stomach
Small Intestine
Large Intestine
FecesColonCecum
http://www.rabbitfood.org.uk
Hindgut FermentersColon Fermenters
Horse, Elephant, Rhino
ADM Alliance Nutrition®
http://www.mi-feed.com.au/past_nutrition.php?page=Mar2006
Hindgut Fermenters
Location Substrate Digestive Agent End Product
Stomach Pepsin Amino Acids
Small Intestine
Carbohydrates
Proteins Trypsin, Carboxypeptidase
Lipase
Glucose, Maltose
MAG’s, FA’s
Large IntestineMicrobes VFA’s
Mineral & Water absorption
Origins of Simple Stomach Animals
(Van Soest, 1994)
Gastrointestinal Tract (GIT) Functions
Diet
MouthEsophagus
StomachSmall Intestine
Large IntestineAnus
Foregut FermenterKangaroo
(Van Soest, 1994)
Foregut FermenterRuminants
Sheep, cattle, goats, elk, white-tailed deer
(Van Soest, 1994) http://www.youtube.com/watch?v=cWg1u1bUKNc
Feed Prehension Mastication & deglutition (swallowing) & salivation
Anterior rumen or reticulum
Mixed in Rumen, Fermented
Small Particles
Abomasum Small Intestine Feces
No, Small ParticlesYes
No, Larger particles than
rumination
Nursing
RumenPurpose
Major site of anaerobic fermentation
Mixes rumen contents
Mucosa
Filiform and foliate
Increase surface area
Layers in Rumen
cm scale
454 g
Marker
1362 g
MinutesC
entim
eter
s
10203040
1 2 3
Gas
(Van Soest, 1994)
ReticulumPurpose
Distributes feed tot he omasum
Origin of primary rumen contractions
Some VFA absorption
Mucosa
increase surface area
Traps small particles
Omasum
Purpose
Pump food to the abomasum
Some VFA and H2O absorption
Mucosa
Arranged on muscular laminae
AbomasumPurpose
Produces HCl
Secretes proteolytic enzymes
pH 2-3.5 to prepare food for lower GIT
Mucosa
Arranged in folds
RuminantsLocation Substrate Digestive Agent End Product
Reticulo-rumenProtein
CarbohydratesLipids
Microbial ProteinVFA’s
TAG, FFA’s
Omasum Water & Mineral absorption
Abomasum Pepsin Amino Acids
Small Intestine
Carbohydrates
Proteins
Lipids
Amylase, Glucosidase
Trypsin, Carboxypeptidase
Amino Acids
MAG’s, FFA’s
Large IntestineCarbohydrate Microbes
Approximate relative capacity of ruminant stomach compartments
(Acker & Cunningham, 1991)
Compartment At birth At 4 months At maturity
Rumen 25% 75% 80%
Reticulum 5% 5% 5%
Omasum 10% 9% 7%
Abomasum 60% 11% 8%
Total 100% 100% 100%
SummaryThe architecture of the GIT and the agents of digestion are of utmost importance to determine digestive function
Ruminants and hind-gut fermentors have well developed fermentation sites
Hind-gut fermentors have greater rate of passage and can survive on lower quality food
Ruminants can eat lower quality forage but must retain food for a longer period of time