Nutrition lecture 3 - energy

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dmandrus
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249572
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Nutrition lecture 3 - energy
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2013-11-28 21:16:49
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Nutrition lecture energy
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Nutrition lecture 3 - energy
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  1. Is energy a nutrient?
    Nope a property
  2. What 3 nutrients have energy?
    • Protein
    • fat
    • carbs
  3. Do vitamins and minerals have energy?
    No
  4. Bomb calorimetry measures?
    Gross energy of a feedstuff
  5. Eneergy during bomb calorimetry is obtained via?
    Combustion or oxidation of the nutrients containing energy
  6. 4 parts of a bomb calorimeter?
    • Bomb which should be pressurized
    • Bucket which contains a known amount of water
    • water jacket surrounding bomb which picks up heat produced
    • Thermocouples to measure heat
  7. What do we do to feed before we burn it in a bomb calorimeter?
    Pellet because dusty feed sucks
  8. Why would we pressurize the bomb with O2
    So thatthe feedstuff and not O2 is limiting in the reaction
  9. What are the 3 units of measuring eneergy?
    • Calorie - Amount of energy to raise temp of 1 g of water 1 degree celcius
    • British thermal unit -  amount of energy to raise temp of 1 lb of water 1 degree farenheit
    • Joule - Work done by 1 newton exerted over a distance of 1 meter
  10. how many joules in a calorie?
    4.184
  11. Why a lump of coal has a good GE hwo is its DE?
    Extremely low or 0
  12. Define gross energy?
    Amount of heat released when a substance is completely oxidized in a bomb calorimeter
  13. GE is synonyous with?
    HEat of combustion
  14. Ge while giving us the total energy in the feed it does not tell us?
    How much of the energy is accesible or can even be utilized
  15. What is often the single biggest loss of energy from thje food?
    Feces losses
  16. How do we test energy in the feces?
    Bomb calorimeter it
  17. Formular for DE?
    =  GE - Feces energy
  18. Composition of GE that DE takes up in pigs reminants on concentrate and ruminants on roughage
    • 80
    • 70
    • 50-60
  19. What does metabolizable energy take into consideration?
    • Urinary losses
    • Gaseous losses
  20. What is the main gaseous loss of digestion?
    Methane
  21. Can you combust urine?
    Yes
  22. Where do urine losses come from?>
    End products of protein metabolism such as urea and uric acid
  23. What is the range for urinary energy loss in animals?
    2-5%
  24. Where do most gaseous losses come from?
    Bacterial fermentation
  25. 3 main gases lost from metabolism?
    • Methane
    • Hydrogen sulfide
    • Carbon monoxide
  26. Do monogastrics have high energy loss due to gas?
    No not even 1%
  27. How do you measure gas loss in a cow
    Measure gas produced during flatulence and eructation
  28. What is the usual conversion to go from DE to ME?
    ME = DE *0.82
  29. What type of energy do we use to formulate diet in pigs? Poultry? Cows?
    • Digestible energy , losses in urine and gas are low
    • ME although urinary is small, urine and feces are together....
    • ME energy loss of urine and gas is too large to ignore and could be even as high as 10-15%
  30. What is taken into account to get net energy?
    Heat incremenet or the heat loss
  31. While NE is ideal why isnt it often used?
    Super intensive to get data for
  32. Formula for NE?
    = ME - heat incremenet
  33. So define net energy?
    The part of the feed that is completely useful to the animal to maintain itself or produce meat milk or eggs
  34. 2 componenets of net energy?
    • Maintenance component - basal metabolism, heat for body warmth, voluntary maintenance activity
    • Production componenet - growth, fat deposition, repro, milk, work, eggs
  35. 2 ways to measure heat loss?
    • Direct calorimetry - measure heat loss directly, very sophisticated and expensive, very few labs
    • Indirect calorimetry - uses gas exchange  to estimate. primarily O2 and CO2
  36. What was used prior to the bomb calorimeter to estimate energy content?
    Total dirgestible nutrients (TDN) - uses proximate analysis to estimate energy content
  37. What is the formular for TDN?
    = Digestible crude protein + digestible crude fiber + digestible nitrogen free extract +digestible ether extract *2.25
  38. How is TDN usually expressed?
    As a % of the ration
  39. Does water contribute any TDN?
    Nope acts a diluent
  40. IS TDN general or species specific?
    Should be species specific as different animals can access different fractions
  41. What are 5 factors affecting TDN?
    • % dry matter
    • Digestibility of dry matter
    • Amount of fat
    • Amount of ash
    • Species fed
  42. What form of energy does TDN roughly estimate?
    DE
  43. 1 kg of TDN is equal to how much DE?
    4.4kcal DE
  44. How does a 76% TDN translate into a tonnage ration feed?
    760kg/tonne

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