Growth Flashcards
What must newborns do after birth?
Make a number of major adaptations since many things were being taken care of by their mother.
ex. temperature regulation (newborns have a lower TNZ)
What is brown adipose tissue?
Brown adipose tissue (BAT) is tissue that helps keep newborns warm.
It is comprised of many fat droplets with abundant mitochondria that can oxidize their own fatty acids and synthesize ATP.
BAT is effective at converting nutrients to heat, and is stimulated by the sympathetic nervous system.
ex. pigs need heating lamps because they do not have BAT
It was originally thought that levels of BAT decreased as an animal ages, but now it is thought that some may be associated with deep muscle tissue.
Describe the ETC
NADH passes e- through a series of proteins to oxygen
This pumps H+ into the intermembrane space
H+ flows back into the matrix through ATP synthase, turning the enzyme and making ATP
Describe the relationship between TCA cycle and heat production
When TCA increases, heat production increases (use of ATP)
When TCA decreases, heat production decreases
Describe BAT and uncoupling protein 1
Uncoupling protein 1 in BAT allows H+ to flow back into the mitochondrial matrix without making ATP.
This is called non-shivering thermogenesis
H+ does not flow through ATP synthase, and the TCA continues to run and generate heat
How is carb metabolism modified for a newborn animal?
Dietary source of carbs is lactose
Gluconeogenesis is needed
Liver glycogen is mobilized immediately after birth (it beaks before birth)
How is lipid metabolism modified for a newborn animal?
Blood free fatty acids increases rapidly from fat cells after birth
Milk fat becomes an important dietary source of lipids
Body fat deposition accelerates in the neonatal period
How is protein metabolism modified in a newborn animal
Rapid rates of lean growth and tissue protein synthesis
Milk protein is high in essential amino acids (EAA), which have high biological value
Early growth has the fastest and highest rate of protein synthesis
Describe the generic trend in an animals growth
Rapid growth in early life that slows over time
What is composition of gain affected by?
Age, breed, genetics, and gender
Energy and protein intake (homeorhesis and nutrient prioritization)
Muscle grows rapidly first, bone grows steadily, fat grows slowly then increases
Describe the composition of proteins
Proteins are nitrogenous compounds of nutritional importance
- all proteins contain nitrogen
- true proteins are chains of amino acids (AA)
- non-protein N includes ammonia and urea, they are not AA or true proteins (NPN can be utilized by rumen microbes to make protein)
What roles do proteins play in the body
Proteins are the principal component of organs and lean tissue
They have a great functional diversity:
- cell membrane structure
- mechanical support
- nutrient transport
- enzymes
- hormones
- antibodies
Describe protein levels on a fat free basis
Proteins are constant or consistent in the body on a fat free basis
Where are the majority of the body’s proteins found?
Body fluids
it is available for breakdown if an animal is not eating enough protein; muscle can also be broken down but this is not ideal
What affects a protein’s deposition in a day?
The difference between protein synthesized and protein degraded. (futile cycle)
Why do proteins and AA have high turnover rates?
The high turnover rate enables a change in protein composition and ensures that proteins are functional. Constant turnover also allows adaptation.
Turned over AA are recycled and 75-80% are reutilized for new protein synthesis. The remaining 20-25% have their amino groups removed, their C skeletons are metabolized, and the ammonia is detoxified.
Over time, proteins can misfold or breakdown, so they must be replaced; high turnover ensures replacement
Proteins needed by the animal now can be made and they can then be broken down later for future proteins
What are the steps of protein synthesis?
expression of mRNA for the protein, and then synthesis of the protein on a ribosome
What determines the protein a cell utilizes?
The gene that is transcribed
Describe the relationship between increasing protein yield and protein requirement of an animal.
The amount of protein made by an animal is regulated by their cells. If an animal’s protein requirement is met, the only way to increase its protein yield would be to enhance the genes that code for it.
The animal will not make more protein if they’re deficient and you feed them more protein.
If an animal is at its protein requirement, it will not make more protein if you fed it more protein; this relates to the broken stick model, the system cannot be pushed
Describe the rate of protein synthesis in the body including specific locations
The rates of protein synthesis varies in different tissues and is high in the liver because the number of enzymes made there and in the gut because of rapid cell loss/turnover.
Rate of protein synthesis is lower in muscles than in the gut or liver.
What does net protein synthesis depend on?
Rate of synthesis vs. rate of degredation
Where is protein synthesis the most efficient?
Milk and egg production
It is less efficient in meat production because there is an associated cost of maintaining muscle protein after it is made
How can changes in protein deposition be made?
By different combinations of changes in synthesis and degredation
What are some general properties of amino acids?
- contain 15-18% nitrogen
- have primary, secondary, tertiary, and quaternary structures
- 20-25 AA are found in common dietary protein
- they are chemically diverse, but have a common general formula
- mostly water soluble
all amino acids contain an amino group, and central carbon atom, a carboxyl group, and a defining side chain (often labeled “R”)
Describe AA as isomers
AA are optically active (except for glycine); 2 optical isomers
L (levo-rotational)
D (dextro-rotational)
