Energy

Question 1

The bulk of dietary dry matter weight is used for fulfilling an animal’s need for _____.

Answer 1

Energy

Question 2

Provision energy is the…..

Answer 2

Provision energy is the primary cost of feeding animals.

Question 3

What are the primary sources of dietary energy?

Answer 3

Dietary carbohydrate, fat, and protein

Question 4

Why do animals eat?

Answer 4

Animals eat for energy and with a few exceptions, NOT for a sensed deficiency of other nutrients like protein, minerals, or vitamins.

Question 5

What will determine whether the concentration of a nutrient in a diet is adequate, too low, or too high?

Answer 5

Energy density

Question 6

1 Kilocalorie is how many calories?

Answer 6

1 kcal = 1000 calories

Question 7

Define gross energy and what does gross energy represent?

Answer 7

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.

Question 8

The gross energy of a food gives little information on….

Answer 8

The actual energy available to an animal. This is because not all the chemical energy released on combustion can be used by an animal.

Question 9

Digestible energy

Answer 9

1. 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

Question 10

Digestible energy is sometimes termed….

Answer 10

“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.

Question 11

How to calculate DE per gram of the food

Answer 11

DE/g = (Gross energy of food - gross energy of feces)/amount of food (grams)

Question 12

How to calculate DE expressed as percentage of the gross energy

Answer 12

DE% = (GE of food - GE of feces)/GE of food x 100

Question 13

All of the energy in food that is digested and absorbed cannot be used in metabolic processes. This is because….

Answer 13

1. Some chimcal bond energy is lost in urine
2. 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

Question 14

What is the nitrogenous waste product in mammals, birds, and aquatic animals?

Answer 14

1. Urea is the nitrogenous waste product in mammals
2. Uric acid is the nitrogenous waste product in birds
3. Ammonia is a substantial nitrogenous waste of aquatic animals

Question 15

What is metabolizable energy defined as?

Answer 15

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)

Question 16

Besides using gross energy to calculate metabolizable energy, metabolizable energy of foods also can be estmated from….

Answer 16

Protein, fat, and carbohydrate content indicated from a proximate analysis

Question 17

For calculation of meatbolizable energy in dogs and cats, the following formular is used by pet food manufacturers:

Answer 17

ME (kcal/kg) = 10 [(3.5 x crude protein) + (8.5 x crude fat) + (3.5 x NFE)]

Question 18

What are the metabolizable energy values assigned to crude protein, crude fat, and NFE (carbohydrate)?

Answer 18

Crude protein ME = 3.5

Crude fat ME = 8.5

NFE ME = 3.5

Question 19

Gross energy of crude protein value is determined by…

Answer 19

The difference between gross energy in dietary protein and gross energy in nitrogen containing compounds lost in urine

Question 20

What system of expressing the energy value of foods provides an energy value index for deits for herbivors that considers digestibility?

Answer 20

Total Digestible Nutrient system

Question 21

What system of expressing the energy value of foods was developed for estimation of energy requirement in growing animals, particularly cattle?

Answer 21

The Net energy (NE)

Question 22

Net energy excludes energy loss of what that other systems of expressing the energy value of foods do not exclude?

Answer 22

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

Question 23

Gross Energy (GE) can be divided into:

Answer 23