Macronutrients

A wild animal is:

• Undomesticated

• Not living under human control

• Untamed

A domesticated animal:

• Has direct ancestors that have undergone a domestication process

• Is managed by humans

Domestication is an evolutionary process during which humans establish control over:

1. Living space

2. Care and welfare

3. Selection of mating partners

4. Reproduction

5. Diet

Tame animal

A tame animal is:

• An animal that has been familiarized with humans

• Tractable = easy to control or influence

⚠ Tame can apply to both:

• Wild animals

• Domesticated animals

A feral animal:

• Lives in the wild state

• BUT its ancestors have undergone domestication

➡ Feral ≠ wild

• Wild = never domesticated

• Feral = descended from domesticated animals but now living wild

Mammals

• Monotremes - may lay eggs

• Marsupials - pouched animals

• Placentals - carries placenta

• Birds, Reptiles, Amphibians, Fish

Nutrients are:

Organic and inorganic chemical compounds used by an animal to support maintenance, growth, and reproduction.

6 categories of nutrients:

1. Water

2. Carbohydrates

3. Proteins

4. Lipids

5. Vitamins

6. Minerals

Carbohydrates

• Made up of monosaccharides

• Example: Glucose

Lipids

• Made up of fatty acids

• Example: Palmitic acid

Proteins

• Made up of amino acids

• Example: Lysine

Energy

⚠ Energy itself is NOT a nutrient.

Instead:

• Energy is derived from certain nutrients

• Energy-yielding nutrients include carbohydrates, lipids, and proteins

ATP production:

• Energy from nutrients is used to produce ATP

• The lecture asks: “What’s missing from here to enable production of ATP?” ; water

Organic nutrients

Organic nutrients:

• Contain carbon (C) in their structure

• Have C–C or C–H bonds

Inorganic nutrients

Inorganic nutrients:

• Do not contain carbon (C) in their structure

• And/or do not have C–C or C–H bonds

1. Free Water

Water obtained directly from the environment, such as:

• Drinking water

• Ponds

• Rivers

• Lakes

• Puddles

➡ This is water that the animal directly consumes.

2. Dietary Water

Water contained in food.

Examples:

• Fresh grasses: ~75% water

• Lean tissue/meat: ~70% water

• Other foods vary:

  • Seeds: ~10% water

  • Fruits: ~70–90% water

➡ The amount of water an animal gets from its diet depends on the water content of the food.

3. Metabolic Water

Metabolic water is: something that you make from digesting food

• Water produced during oxidation of energy-yielding nutrients

During oxidation:

Energy-yielding nutrients → water + CO₂ + energy (ATP)

➡ Therefore, oxidation produces:

• Water

• CO₂

• Energy in the form of ATP

Monosaccharides

• Single sugar building blocks of carbohydrates

• These are absorbable units

Types:

• Pentoses = 5 carbons

  • Example: Ribose

• Hexoses = 6 carbons

  • Examples:

    • Glucose

    • Fructose

    • Galactose

Disaccharides

• Two monosaccharides joined by a glycosidic bond

Examples:

• Sucrose = glucose + fructose

• Lactose = glucose + galactose

• Maltose = glucose + glucose

Oligosaccharides

• Chain of 3–10 monosaccharides

• Considered short-chain carbohydrates

Polysaccharides

• Chain of 10+ monosaccharides

• Considered long-chain carbohydrates

• Most abundant carbohydrates found in food

Plant-based polysaccharides

• Cellulose → structural component of plant cell walls

• Hemicellulose → structural component of plant cell walls

• Lignin → structural component of plant cell walls

• Starch → energy storage; long-term

Animal-based polysaccharides

• Glycogen → energy storage; short-term

• Chitin → structural component

Protein

• A macromolecule composed of 1 or more polypeptide chains

Amino acids

• Building blocks of proteins

• There are 20 standard, genetically coded, proteinogenic amino acids

• Amino acids are absorbable units

Peptide

• Two or more amino acids joined by a peptide bond

Dipeptide

• A pair of amino acids linked by a peptide bond

• Absorbable unit

Polypeptide chain

• A long, unbranched peptide chain

Amino Acids

Amino acids are required for:

1. Building and maintaining tissue

Examples:

• Muscle

• Bone

• Skin

• Hair

• Hooves

• Feathers

2. Synthesizing enzymes

3. Synthesizing blood constituents

• Example: Glycine → precursor for heme

4. Synthesizing hormones

5. Synthesizing secondary metabolites

Example: Tryptophan → precursor for serotonin

6. Yielding energy

• Amino acids can also be used as a source of energy.

Peptide Formation

A peptide bond forms through a reaction between:

• The carboxyl group of one amino acid

• The amino group of another amino acid

This reaction:

• Forms a peptide bond

• Produces 1 molecule of water (H₂O)

Essential amino acids

Amino acids that:

• Cannot be synthesized at all by the animal (or by microorganisms within the animal)

OR

• Cannot be synthesized in sufficient quantities to meet the animal's requirements

Therefore:

• Essential amino acids must be present in sufficient quantities in the diet

Terminology

• Essential nutrients = indispensable

• Non-essential nutrients = dispensable

Essential

amino acids (PHILL M T VAT... fill empty vat)

P Phenylalanine

H Histidine

I Isoleucine

L Leucine

L Lysine

M Methionine

T Threonine

V Valine

A Arginine*

T Tryptophan

Conditionally Essential Amino Acids

Examples include:

• Phenylalanine → Tyrosine

• Methionine → Cysteine → Taurine

  • Taurine is essential for all felids

• Arginine

Lipids

• Hydrophobic biomolecules

• Hydrophobic = tend to not mix with water

Lipids are comprised of:

• Fatty acids → absorbable unit

• Fatty acid derivatives

• Monoglycerides → absorbable unit

• Diglycerides

• Triglycerides (fats)

• Phospholipids

• Waxes

• Sterols

  • Example: Cholesterol

General Fatty Acid Structure

A fatty acid has:

1. Carboxyl group

• Located at one end

• COOH

2. Linear hydrocarbon chain

• Made of hydrogen (H) and carbon (C)

3. Methyl group

• Located at the other end

• CH₃

Linear hydrocarbon chain

• Most fatty acids have an even number of carbon atoms

Fatty Acid Nomenclature

Fatty acids are described based on:

1. Hydrocarbon chain length

2. Degree of saturation

   • Number of double bonds

3. Position of double bonds in the chain

4. Orientation of hydrogen atoms around double bonds

   • Cis

   • Trans

Saturated fatty acids

• Have 0 double bonds

• Examples/sources:

  • Butter

  • Animal fat

Unsaturated fatty acids

• Have 1 or more double bonds

• Examples/sources:

  • Oils

  • Plant-based fats

Monounsaturated fatty acids

Have 1 double bond

Polyunsaturated fatty acids (PUFAs)

• Have 2 or more double bonds

Fatty Acid Structure Factors

Fatty acids can vary based on:

• Carbon chain length

• Whether the carbon chain has an odd or even number of carbons

• Number of double bonds

• Whether double bonds are cis

Triglycerides (TAG)

Fats are stored as triglycerides (TAG).

TAG consists of:

• 3 fatty acids

• 1 glycerol

➡ 3 fatty acids + 1 glycerol = triglyceride (TAG)

Fatty Acid Synthesis and Modification

Most mammals

• Can sufficiently synthesize saturated fatty acids

Fatty acid synthesis

• Saturated fatty acids can be synthesized by the animal.

Elongate

add 2 carbons at a time to the fatty acid chain.

➡ Most mammals can elongate and desaturate fatty acids to form PUFAs.

Desaturate

add a double bond to the fatty acid chain.

➡ Most mammals can elongate and desaturate fatty acids to form PUFAs.

Essential Fatty Acids

Most mammals require certain fatty acids in their diet.

1. Linoleic acid

• 18:2 n6

• Omega-6

• Plant-based

2. Alpha-linolenic acid

• 18:3 n3

• Omega-3

• Plant-based

3. Arachidonic acid

• 20:4 n6

• Omega-6

• Animal-based

⚠ Arachidonic acid is only required for strict carnivores, such as felids.