Chapter 41 - Animal Nutrition

Question 1

Describe the nutritional criteria diets must have.

Answer 1

1. Provide fuel for cellular processes.
2. Provide raw materials for biosynthesis.
3. Proivde essential nutrients.

Question 2

What raw materials are required for biosynthesis, and what do they provide?

Answer 2

• Lipids
  
  • Fats & oils
  • Unsaturated vs. saturated (unsaturated has 1+ double bonds)
• Carbohydrates (source of carbons)
  
  • Sugars & starches
  • Simple vs. complex
• Proteins (source of nitrogen)
  
  • From amino acids

Question 3

Describe essential vs. nonessential nutrients.

Answer 3

Necessary nutrients cannot be synthesized by the body. Some are universal, others are species specific.
Including:

• Amino acids
• Fatty acids
• Vitamins (organic)
• Minetrals (inorganic)

Nonessential nutrients are those nutrients that can be made by the body, they may often also be absorbed from consumed food.

Question 4

Describe malnutrition and its forms.

Answer 4

“Failure to get sufficient nutrition”

• Nutrient deficiency
  
  • Protein deficiency most common
• Undernourishment
  
  • deficient in calories
  • draws on stored energy (first glycogen, then fat, then proteins)
• Overnourishment
  
  • Excessive caloric intake
  • Causes obesity

Question 5

Describe the stages of food processing.

Answer 5

1. Ingestion
   
   • Mechanical digestion (chewing!)
2. Digestion
   
   • Chemical digestion (enzymes)
3. Absorption
   
   • Nutrient molecules enter body cells
4. Eliminaton
   
   • Undigested material

Question 6

Describe extraceullar vs. intraceullar digestion.

Answer 6

• Extracellular digestion
  
  • Occurs in digestive tract
  • Uses digestive enzymes which are very acid.
    
    • Specialized compartments protect against self-digestion.
  • Digestive tract is incomplete or complete
• Intraceullar digestion
  
  • Occurs intraceullarly using lysozomes

Question 7

Describe incomplete vs. complete digestive systems.

Answer 7

• Incomplete:
  
  • “Simple in = out”
• Complete:
  
  • “Specialized one-way”
  • Can ingest while digesting

Question 8

Describe the mammalian digestive system and where each stage of processing occurs.

Answer 8

• Mouth (ingestion)
  
  • Teeth, tongue, salivary glands
• Esophagus (ingestion)
  
  • both striated & smooth muscle; waves of muscular contraction (peristalsis) move bolus of food to stomach
• Stomach (digestion)
  
  • Stretchy, mucus-lined
  • HCl & pepsinogen (enzyme) → acid chyme (semifluid mass of partly digested food)
  • Helicobacter pylori (bacteria) & ulcers
• Small intestine (digestion & absorption)
  
  • Liver & gallbladder, pancreas
  • Villi & microvilli (increase surface area) with capillaries & lacteals (lyhmpatic capillary)
• Large intestine (absorption & elimination)
  
  • Full of microorganisms (gas & vitamins)
  • Leads to rectum
• Anus (elimination)

Question 9

Describe the modes of ingestion.

Answer 9

• Suspension/ Filter Feeders:
  
  • Filter particles from the environment (ex: baleen whales, sponges)
• Fluid Feeders:
  
  • Suck fluids from host (ex: bees, mosquitos)
• Substrate Feeders:
  
  • Live on or in food source (ex: termites, earthworms)
• Bulk feeders:
  
  • Ingest large pieces (ex: giraffe, wolves)

Question 10

Describe feeding patterns.

Answer 10

• Herbivores
  
  • Eat primary producers
• Carnivores
  
  • Eat other animals
• Omnivores
  
  • Eat everything
  • Most are opportunistic

Question 11

Describe dental adaptions in carnivores, herbivores, and omniovres.

Answer 11

• Carnivore
  
  • Large, pointed incisors & canines “rip & cut”
  • Jagged premolars and molars “crush & shred”
• Herbivore
  
  • Broad, ridged premolars and molars “grind” tough plant material
  • Modified incisors & canines “bite off” vegetation
    
    • May be absent
• Omnivore
  
  • Human’s teeth not good at specializing at anything

Question 12

Describe homodonts vs. heterodonts.

Answer 12

• Homodonts: Teeth are all about the same shape
  
  • Most vertebrates
• Heterodonts: Teeth are specialized for different functions
  
  • Ex: snake’s fangs, anteater, etc.

Question 13

Describe stomach & intestinal adaptations in carnivores vs. herbivores.

Answer 13

• Carnivore
  
  • Large, expandable stomachs adapted for gorging with lengthy periods between meals
• Herbivore
  
  • Longer intestinal tracts to ferment and process vegetation.

Question 14

Describe symbiotic adaptions and some examples.

Answer 14

• Some animals have microorganisms in fermentation chambers to hydrolyze cellulose.
  Location varies on species:
  
  • cecum, crop, stomach
• Rodents & lagomorphs (bunnies):
  
  • symbionts located in large intestine
  • use coprophagy to extract extra nutrients

Question 15

Describe glucose homeostasis.

Answer 15

Homeostasis defined as certain level (70-100 mg) of glucose per 100 mL of blood. Maintained by insulin & glucagon from pancreas via negative feedback:

• Stimulus: Blood glucose level rises after eating.
• Response: Pancreas secretes insulin.
• Action: Transport of glucose into body cells & storage of glucose as glycogen.
• Result: Homeostasis!
• Stimulus: Blood glucose level drops below set point.
• Response: Pancrease secretes glucagon.
• Action: Breakdown of glycogen and release of glucose into blood.
• Result: Homeostasis!