Animal Nutrition

Nutrition & Feeding

• Food Processing:

  • Taken in

  • Taken apart

  • Taken up

• Feeding Strategies:

  • Opportunistic feeders: Eat whatever food is available.

  • Herbivore: Eats plants.

  • Carnivore: Eats other animals.

  • Omnivore: Eats both plants and animals.

Dietary Needs

• Chemical energy: For cellular processes.

• Organic building blocks: For biosynthesis.

• Essential nutrients: Substances an animal cannot synthesize and must obtain from its diet.

• 4 Classes of Essential Nutrients:

  • Essential amino acids

  • Essential fatty acids

  • Vitamins

  • Minerals
    2.1 Essential Amino Acids

  • Requirement: 20 amino acids required for protein synthesis.

  • Animals synthesize ~½ from their diet.

  • Remaining essential amino acids: Must be consumed in preassembled form.

  • Protein Sources:

  • Complete proteins: Provide all essential amino acids (e.g., meat, eggs, cheese).

  • Incomplete proteins: Most plant proteins are incomplete; vegetarians need a variety of plant sources to get all essential amino acids.
    2.2 Essential Fatty Acids

  • Must be obtained from the diet.

  • Includes certain unsaturated fatty acids.

  • #### Omega 3 (per week)

    • Importance: Great for brain and heart health.

  • Sources: Seeds, grains, vegetables.
    2.3 Essential Vitamins

  • Humans: Require 13 essential vitamins.

  • Fat-soluble vitamins: A, D, E, K.

  • Must be consumed with lipids for absorption.

  • #### Vitamin A

    • Function: Helps maintain healthy skin, teeth, and vision.

    • Sources: Canned carrots, spinach, apricots, mangoes, and eggs.

    • Recommended Daily Allowance: 800 mcg.

  • #### Vitamin D

    • Function: Essential for healthy bones.

    • Sources: Canned sardines, salmon, mackerel, and egg yolk.

    • Recommended Daily Allowance: 5 mcg.

  • #### Vitamin E

    • Function: A primary fat-soluble antioxidant that supports normal cell division and muscle function.

    • Sources: Canned tuna, salmon, almonds, prawns, and sunflower seeds.

    • Recommended Daily Allowance: 12 mg.

  • Water-soluble vitamins: (e.g., C, B vitamins).

  • #### Riboflavin

    • Function: Great for reducing fatigue, maintaining healthy skin, and boosting the immune system.

    • Sources: Canned rice pudding and asparagus.

    • Recommended Daily Allowance: 1.1 mg.

  • #### Vitamin C

    • Function: Provides natural protection against free radicals, promotes healthy skin, nails, hair, and joints.

    • Sources: Canned strawberries, blackcurrants, asparagus, tomatoes, pineapples, and baked potatoes.

    • Recommended Daily Allowance: 200 mcg.

  • #### Folic Acid

    • Function: Helps form healthy blood cells and is particularly beneficial in pregnancy.

    • Sources: Canned broad beans, kidney beans, chickpeas, black-eyed peas, and brown rice.

    • Recommended Daily Allowance: 1.1 mg.

  • #### Thiamin

    • Function: Helps the body turn carbohydrates, fat, and protein into energy.

    • Sources: Canned chili con carne, kidney beans, spinach, peas, peanuts, and bran flakes.
      2.4 Minerals

  • Small, inorganic molecules.

  • Required in small amounts.

  • Ingestion of large amounts can upset homeostasis.

  • Example: Mineral blocks for animals.

  • #### Iron

    • Function: Good for red blood cell production and supports energy utilization.

    • Sources: Canned corned beef, baked beans, lentils, red kidney beans, meatballs in tomato sauce, and cashew nuts.

    • Recommended Daily Allowance: 14 mg.

  • #### Calcium

    • Function: Keeps both bones and teeth strong; good for the nervous system, too.

    • Sources: Canned spinach, almonds, sardines, custard, and white bread.

    • Recommended Daily Allowance: 80 mg.

Deficiencies

• Malnutrition: A diet lacking in one or more essential nutrients.

• Implications:

  • Grazers: May need concentrated sources of certain nutrients.

  • "Golden rice": Engineered to produce \u03b2-carotene, a precursor to Vitamin A, addressing xerophthalmia (night blindness).

• Specific Deficiencies:

  • Vitamin A: Xerophthalmia

  • Vitamin C: Scurvy

  • Vitamin D: Rickets

• Malnourishment (Undernutrition): Diet does not provide enough chemical energy.

• Consequences:

  • Body uses stored fats and carbohydrates.

  • Breaks down body proteins, leading to loss of muscle mass.

  • Suffering protein deficiency of the brain.

  • Can lead to death or irreversible damage.

Assessing Needs

• Insights from epidemiology and genetics.

• Hemochromatosis: Iron buildup even with normal intake (genetic condition).

• Neural tube defects: Can be caused by folic acid deficiency (e.g., Spina bifida).

Food Processing

• Four Stages:

1. Ingestion: Taking food in.

2. Digestion: Breaking food down.

3. Absorption: Taking up nutrients.

4. Elimination: Passing undigested material.
   5.1 Feeding Mechanisms (Categories of Ingestion)

• Filter feeders: Sift particles from medium.

• Substrate feeders: Live in or on their food source.

• Fluid feeders: Suck nutrients from a living host.

• Bulk feeders: Eat large pieces of food.
  5.2 Digestion

• Mechanical digestion: Increases surface area of food.

• Chemical digestion: Breaks food into smaller molecules.

• Involves enzymatic hydrolysis.

• Specialized Compartments:

  • Intracellular digestion: Food vacuoles (e.g., via phagocytosis).

  • Extracellular digestion: Compartments continuous with the outside environment.

  • Gastrovascular cavity: Single opening (e.g., Cnidarians).

  • Alimentary canal: Complete digestive tract.
    5.3 Alimentary Canal

• A digestive tube with two openings (mouth & anus).

• Can have specialized regions for stepwise digestion & absorption.
  5.4 Mammalian Alimentary Canal (GI Tract)

• Main Organs: Mouth, esophagus, stomach, small intestine, large intestine.

• Accessory Glands: Secrete digestive fluids through ducts.

  • Salivary glands

  • Pancreas

  • Liver

  • Gallbladder

• Peristalsis: Wave-like muscle contractions move food.

• Sphincters: Muscular valves regulating passage of material.

Vertebrate Adaptations

• Variations on a common plan, reflecting diet. 6.1 Dentition

  • Teeth: Modified to capture, tear, cut, or grind food.

  • Epidermal teeth: Hard, cornified epidermal ridges.

  • Dermal teeth: Most vertebrates.

  • Types of Dentition:

  • Homodont: All teeth are the same.

  • Heterodont: Four different types of teeth (mammals).

    • Incisors: Cutting.

    • Canines: Tearing flesh.

    • Premolars: Grinding.

    • Molars: Grinding.
      6.2 Alimentary Canal Adaptations

  • Carnivores: Have an expandable stomach to hold large, infrequent meals.

  • Herbivores: Typically have a longer alimentary canal to allow more time for plant matter digestion.
    6.3 Mutualistic Adaptations

  • Fermentation chambers: Host microorganisms digest cellulose.

  • Ruminants (e.g., cows): Have four compartments in their stomach; microorganisms produce volatile fatty acids.

  • Cecal digesters (e.g., rabbits, horses): Fermentation occurs in the cecum.

Regulation of Digestion 7.1 Storage Regulation

• Glycogen: Stored in liver and muscle cells (short-term energy).

• Triglycerides: Stored in adipose tissue (long-term energy).

• Glucose homeostasis: Regulated by hormones.

• Insulin: Lowers blood glucose.

• Glucagon: Raises blood glucose.

Over-nourishment

• Causes obesity.

• Associated with:

  • Type II diabetes

  • Colon & breast cancer

  • Heart attacks & strokes

• Appetite Regulation:

  • Hormones regulate appetite.

  • Satiety center in the brain.

  • Leptin studies: Leptin is a hormone that signals satiety.

Obesity & Evolution