ANS230 Lecture 22/23 : Net Energy - Thermodynamics, Calorimetry & Bioenergetics

Where do animals get glucose from?

Plants

Where do plants get glucose from?

Photosynthesis

What do plants DO during photosynthesis?

They fix carbon from CO2

What is the formula for Cellular Respiration?

C6H1206 + 602 → 6 C02 + 6 H2O + ATP + Heat

During cellular respiration, does the generation of heat have a negative or positive connotation?

Negative

What is energy defined as?

Energy is defined as the capacity to do work

Where is energy contained?

It is contained within the chemical bonds of nutrients

How is energy converted?

Cells convert chemical energy from feed into mechanical, electrical, or heat energy.

What percentage of feed energy is used for maintenance (basal metabolism)?

Over 50%

What did Antoine Lavoisier equate animal metabolism to and why?

A Flame, because both consume Oxygen and produce heat

What is the first law of thermodynamics?

Energy can neither be created nor destroyed

What is the second law of thermodynamics?

Entropy always increases; no energy transformation is 100% efficient

How does Einstein’s Theory of Relativity (E = MC²) relate to animal nutrition?

Because we can covert mass or feed into measures of energy (calories)

What does direct calorimetry measure?

Measures heat production directly

What does indirect calorimetry measure?

Estimates heat produced indirectly from oxygen consumption, carbon dioxide production

What does basal metabolsim represent?

Energy required to maintain life

Who fathered both indirect and direct calorimetry?

Antoine Lavosier

What is gross energy?

The total energy released as heat when a substrate is fully oxidized, often measured in a bomb calorimeter

How much energy is in a gram of Carbohydrates?

4-4.1 kcal/g

How much energy is in a gram of protein?

5.4 kcal/g

How much energy is in one gram of fat?

9 kcal/g

Why does it make sense that fats have more energy than carbs and proteins?

This is because there are more carbons and hydrogens in fat molecules than there are in carbs and proteins

How is Digestible Energy determined?

Gross energy minus fecal loss

How is metabolizable energy determined?

Gross energy minus losses in feces, urine, and gas

What is the heat increment in bioenergetics?

Heat increment is the amount of heat that is generated from fermentation and nutrient metabolism

What are the three categories of net energy?

Maintenace, Gain, and Lactation

Is energy transfer 100% effiicient?

No

True/ False, Heat Increment is why energy transfer is not 100% efficient

True

Heat is lost at ________

every step during digestion and metabolism.

HI is heat loss above ________

maintenance

What are the four sources of heat increment?

• Digestion

• Fermentation

• Waste Product Formation

• Nutrient Metabolism

What is the difference in digestion and fermentation?

Digestion is Enzymatic Breakdown, Fermentaion is microbial breakdown

Heat is produced via:

• Basal metabolism (maintenance)

• GI Microbes

• HI of Feeding

What formula do we use for the body size and surface area for animals to accommodate variety in metabolic heat production?

BW^0.75

Different tissues have different ______ rates

metabolic

What is the biggest difference between the GI tract of ruminants and non-ruminants?

Microbes

What has a higher HI, ruminants and non-rumintans? Why?

Ruminants; bc of all the fermentation the microbes do

Why is improving efficiency of dietary energy essential?

• Reduce costs of animal production

• Minimize nutrient waste

How do ruminants primarily transform energy?

Use microbes to transform energy into fermentation products.

How do non-ruminants primarily transform energy?

Use Oxidation and Reduction potential to transform energy for their use