Energy Flashcards
The bulk of dietary dry matter weight is used for fulfilling an animal’s need for _____.
Energy
Provision energy is the…..
Provision energy is the primary cost of feeding animals.
What are the primary sources of dietary energy?
Dietary carbohydrate, fat, and protein
Why do animals eat?
Animals eat for energy and with a few exceptions, NOT for a sensed deficiency of other nutrients like protein, minerals, or vitamins.
What will determine whether the concentration of a nutrient in a diet is adequate, too low, or too high?
Energy density
1 Kilocalorie is how many calories?
1 kcal = 1000 calories
Define gross energy and what does gross energy represent?
Gross energy is the energy value of a diet or foodstuff that is estimated from the heat released from combustion in an oxygen atmosphere. Gross energy represents the MAXIMAL POSSIBLE energy that could be obtained by an animal from a foodstuff.
The gross energy of a food gives little information on….
The actual energy available to an animal. This is because not all the chemical energy released on combustion can be used by an animal.
Digestible energy
- The concept of digestible energy corrects for overestimation of gross energy contributed by undigested and unabsorbed material in food passed to feces. 2. Digestible energy is defined as the gross energy of food minus gross energy of feces: DE = GEfood - GEfeces
Digestible energy is sometimes termed….
“apparent digestible energy” because feces contain more than undigested food. Feces contain excreted products, such as mucus, desquamated gut epithelial cells, and digestive enzymes. These substances add gross energy to undigested food.
How to calculate DE per gram of the food
DE/g = (Gross energy of food - gross energy of feces)/amount of food (grams)
How to calculate DE expressed as percentage of the gross energy
DE% = (GE of food - GE of feces)/GE of food x 100
All of the energy in food that is digested and absorbed cannot be used in metabolic processes. This is because….
- Some chimcal bond energy is lost in urine
- Some energy in food is fermented by gastrointestinal microbes
- Substantial microbial fermentation occurs in ruminants and species with extensive post-gastric fermentation
- For simple tomached animals, energy loss in combustible gases is small
What is the nitrogenous waste product in mammals, birds, and aquatic animals?
- Urea is the nitrogenous waste product in mammals
- Uric acid is the nitrogenous waste product in birds
- Ammonia is a substantial nitrogenous waste of aquatic animals
What is metabolizable energy defined as?
The gross energy in food minus the gross energy in feces, urine and combustible gases:
ME = GE food - (GE feces + GE urine + GE gases)
ME = DE - (GE urine + GE gases)
Besides using gross energy to calculate metabolizable energy, metabolizable energy of foods also can be estmated from….
Protein, fat, and carbohydrate content indicated from a proximate analysis
For calculation of meatbolizable energy in dogs and cats, the following formular is used by pet food manufacturers:
ME (kcal/kg) = 10 [(3.5 x crude protein) + (8.5 x crude fat) + (3.5 x NFE)]
What are the metabolizable energy values assigned to crude protein, crude fat, and NFE (carbohydrate)?
Crude protein ME = 3.5
Crude fat ME = 8.5
NFE ME = 3.5
Gross energy of crude protein value is determined by…
The difference between gross energy in dietary protein and gross energy in nitrogen containing compounds lost in urine
What system of expressing the energy value of foods provides an energy value index for deits for herbivors that considers digestibility?
Total Digestible Nutrient system
What system of expressing the energy value of foods was developed for estimation of energy requirement in growing animals, particularly cattle?
The Net energy (NE)
Net energy excludes energy loss of what that other systems of expressing the energy value of foods do not exclude?
Net energy excludes energy loss in heat associated with digestion and assimilation of food - the “heat increment”
Heat increment is also called “specific dynamic action” and varies with physiological state so net energy varies with physiological state
Gross Energy (GE) can be divided into:
