Feed Intake & Regulation

Question 1

what part of the brain controls the food intake?

Answer 1

• lateral hypothalamus (hunger center)
• ventromedial hypothalamic nucleus (safety center)

Question 2

appetite

Answer 2

• instinctive desires necessary to keep up
  organic life; THE DESIRE TO EAT

Question 3

hunger

Answer 3

• The physical sensation of desiring food.
• physiological state

Question 4

satiety

Answer 4

lack of desire to eat

Question 5

appetite vs specific appetite

Answer 5

appetite: drive to eat foods with specific
flavors or sensory characteristics

specific appetite: drive to eat foods
that provide certain nutrients and/or
energy

Question 6

what are the list of factors affecting food intake?

Answer 6

• Palatability of the feed
• Dietary energy density
• Individual preference for animal
• Function, Age, or Size of animal
• environmental condition
• Availability of the clean/free choice water
• Other management and facility stressor

Question 7

palatability

Answer 7

• acceptance and relish of a feed or agreeable to taste of the feed
• l in the process of locating and
  consuming food
• dependent on:
  
  • properties of the food: physical & chemical

Question 8

higher energy intake vs lower energy intake

Answer 8

higher energy intake = lower feed intake

lower energy intake = higher feed intake

Question 9

what happens if the nitrogen requirements are not met?

Answer 9

• diet rate of passage is reduced
• varies with CHO digestabilibty

Question 10

forage availability & quantity

Answer 10

• quality & quantity influence intake
• forced to consume plants with a slower rate of digestion
• Increase the concentration of feed that requires significant digestion reduces the rate of passage and physical fill
  becomes limiting

Question 11

feed intake between breeds?

Answer 11

• feed intake occur between selected lines and between
  breeds and between different crosses.

example: Duroc pigs tend to eat more then most pig breeds

Question 12

other factors of feed intake

Answer 12

• poor feed intake:
  
  • post-weaning
  • social & physiological
  • environment
  • dietary stress
• Total daily intake is limited by digestive
  tract capacity = rate of increase must decline as the animal
  grows

Question 13

what are the 5 theories of feed intake control mechanisms

Answer 13

1. glucostatic theory
2. thermostatic theory
3. lipostatic theory
4. aminostatic theory
5. lonostatic theory

Question 14

glucostatic theory

Answer 14

• inverse relationship between level of blood glucose and voluntary feed intake
• The hypothalamus has centers to detect blood glucose = in turn regulate feed intake

Question 15

thermostatic theory

Answer 15

• the loss of body heat drives the mammal to converse body heat & consume food
• relationship between environment & feed intake

Question 16

lipostatic theory

Answer 16

• Feedback from fat stores to the brain for long-term regulation of feed intake
• technique force feeding

Question 17

aminostatic theory

Answer 17

• Balance of amino acids influences food intake
• imbalances:
  
  • decreased food intake = decreased concentration of
    limiting AA in blood = suppressing appetite

Question 18

lonostatic theory

Answer 18

• Extracellular role of Na+ and Ca++ ions within the brain =
  effects upon body temp and feed intake

proposed: body temperature is controlled by Na and Ca ion ratio

Question 19

pica

Answer 19

mineral deficiency = eating unwanted food requirements, not considering to be food

example: pigs eating dirt