Transcript Lecture 5: Animal Nutrition II

Animal Nutrition III (Ch. 41)
Keywords
• Ruminant digestion
• Symbiosis
– Definition
– Algal-invertebrate
– Chemoautotrophinvertebrate
• Hydrothermal vent
• H2S (sulfide)
• chemoautotrophy
Basic parts of alimentary canal
Mechanical
digestion
mouth
storage
absorption
anus
Structure of cellulose
Cecum
• Allows breakdown of
cellulose in
herbivores
• One opening and exit
- lower oxygen,
slower passage
• Digested cellulose
must be reintroduced
to digestive system
Ruminant digestion
Ruminant 4 chambered stomach
• Rumen and reticulum - where symbiotic
bacteria and protists break down cellulose
• Cow rechews food
• Omasum - where water is absorbed
• Abomasum - further digestion by cow’s
enzymes
Symbiosis
Autotroph-invertebrate symbiosis
• Symbionts are algae
• Algae photosynthesize and provide
molecules such as sugars to the host
• Hydra, anemones, giant clams, corals
Examples
Chemoautotroph-invertebrate
symbiosis
• Symbionts are chemoautotrophic bacteria
• Bacteria use hydrogen sulfide as an energy
source and provide molecules such as
sugars to host
• Tubeworms, clams, mussels
Where do we find these
organisms?
Life at a vent
O2
H2S
Respiratory surface of tubeworm
H2S
O2
Hb
Oxygen and sulfide are
transported to the bacteria
Chemoautotrophy: Bacteria
oxidize sulfide and use the
energy for carbon fixation
H2S + O2
SO4=
ADP
CO2
ATP
carbohydrate
Calvin-Benson
Cycle