Chapter 7: Proteins and Amino Acids (Oct 18 Lec)

Question 1

Absorbed amino acids are used by the ____ (usually as fuel)

Answer 1

enterocyte

Question 2

describe what happens to absorbed amino acids

Answer 2

they enter the portal blood supply, taken to live for metabolism

• used in current form to synthesize proteins:
  
  • albumin (the major plasma protein)
  • clotting factors
  • acute phase proteins (inflammatory response)
  • many other proteins

deamination and/or transamination

• synthesize non-essential AA
• convert C skeleton to glucose, lipids, or energy

Removal of ammonia from body

Question 3

do animals have protein requirements?

Answer 3

no!

need amino acids

Question 4

What “protein requirements” do monogastrics have?

Answer 4

the necessary indispensable AA, in the proper amount
AND
amino N (usually in the form of protein) to synthesize dispensable AA

Question 5

What “protein requirements” do ruminants have?

Answer 5

• can rely entirely on microbial protein synthesis

- high producing animals need preformed dietary AA as well as microbial protein

Question 6

T/F

microbes in ruminants can synthesize all 20 amino acids

Answer 6

true!

Question 7

when is amino acid requirement highest?

Answer 7

at birth (declines with age)
- related to growth rate (higher for growth than for maintenance)

Question 8

T/F

amino acid requirement is always higher for males in all livestock species

Answer 8

False
not always- but usually
- sometimes will be higher for females (eg producing milk).
- usually higher for males b/c of larger body size, faster growth rate

Question 9

Liebig’s Law of the Minimum

Answer 9

” a crop’s yield is restricted by the lack of a single element, even though there may be sufficient quantities of all other essential nutrients”.
Can be extended to animals and their resources (eg a single trace mineral can be the limiting factor)

Question 10

protein synthesis cannot occur beyond the level of the ____ ____ ___

Answer 10

limiting amino acid

Question 11

if protein synthesis is limited b/c of a deficiency of one amino acid, what happens?

Answer 11

other amino acids are broken down

Question 12

Amino acid imbalance=

Answer 12

the dietary proportions of indispensable AA do not meet the needs of the animal (1 or more AA are limiting)

Question 13

give an example of amino acid antagonism

Answer 13

Lysine and arg because they share a transporter

eg. if lysine is in excess, supplement arginine

Question 14

T/F

toxicity of an AA can be overcome but supplementing another amino acid

Answer 14

false