7 - Animal Nutrition

• 6 classes of nutrients

  • Carbohydrates
  • Fats
  • Proteins
  • Water
  • Vitamins
  • Minerals
• 3 main classes of nutrients

  • Proteins
  • Carbohydrates
  • Fats
• Fibre


  Not really a nutrient, as it is not absorbed into the body; it just passes straight through the digestive system and is passed out in the faeces
• The amount of energy used depends on age, sex, and what job you do
• Age: Child


  More energy required
• Age: 50s-60s


  Less energy needed as metabolism slows down
• Sex

  Generally, males use up more energy than females
• Pregnant women need extra calcium and iron
• Breastfeeding mothers need extra energy to produce milk
• Menstruating women need more iron
• Importance of nutrients - Carbohydrates

  • For energy release and energy storage in animal and plant cells
  • Starch is found in staple foods (potatoes, wheat, rice, maize)
  • Glucose is found in sweet foods (fruit, vegetables, honey, milk, and malt products)
  • Lack of carbohydrate: weight loss, hypoglycemia (low blood glucose, easily tired)
• Importance of nutrients - Fats

  • Needed for energy and to make cell membrane (phospholipid)
  • Store excess fat/oil under the skin in Adipose Tissue
  • Form layer around organs (kidney - provide mechanical protection)
  • Sources include cooking oils, meat, eggs, dairy products, oily fish
  • Too much saturated fats can lead to coronary heart disease and heart attack
• Foods with saturated fats

  • Milk
  • Cream
  • Butter
  • Cheese
  • Animal fats
• Foods with unsaturated fats

  • Vegetable oil
  • Fish oils
  • Polyunsaturated spreads
  • White meat (chicken)
• Importance of nutrients - Proteins

  • Needed for growth, repair, and fighting disease
  • Kwashiorkor due to lack of protein
  • Sources include animal products like meat, fish, cheese, milk, and eggs
  • Vegetable sources include soya-bean products, legumes, and nuts
• Importance of nutrients - Vitamins

  • Citrus fruit - vit C
  • Butter, egg yolk - vit D
  • Milk, cheese, dairy products - Ca
  • Liver, red meat, dark veggies - Fe
  • Veggies and fruits - Fibre
• Fibre contains cellulose
• Dental decay and gum disease are caused by bacteria
• Acid released by bacteria
• Types of teeth

  • Incisors
  • Canines
  • Premolars
  • Molars
• Mechanical digestion


  Breakdown of food into smaller pieces
• Chemical digestion

  Breakdown of large, insoluble molecules into small, soluble molecules
• Functions of enzymes

  • Amylase
  • Maltase
  • Lipase
  • Pepsin
  • Trypsin
• Hydrochloric acid in the stomach
• Bile is an alkaline mixture
• Organs of the digestive system

  • Mouth
  • Oesophagus
  • Stomach
  • Small intestine (duodenum and ileum)
  • Large intestine (colon, rectum, anus)
  • Salivary glands
  • Pancreas
  • Liver
  • Gall bladder
• Ingestion


  The taking of substances, e.g. food and drink, into the body
• Digestion


  The breakdown of food
• Absorption


  The movement of nutrients from the intestines into the blood
• Assimilation


  Uptake and use of nutrients by cells
• Egestion


  The removal of undigested food from the body as faeces
• The alimentary canal is a long tube from mouth to anus
• Large insoluble molecules are broken down into small soluble molecules
• The movement of small food molecules and ions occurs
• Undigested food is removed from the body
• Absorbed nutrients are used for energy
• Teeth structure

  Enamel is the hardest but can be dissolved by acids; dentine is softer and contains living cytoplasm; pulp contains nerves and blood vessels; cement attaches tooth to the jawbone
• How to avoid tooth decay

  • Eat less sugar
  • Use fluoride toothpaste regularly
  • Regular and thorough brushing
  • Regular visits to the dentist
• Mechanical digestion is the breakdown of food into smaller pieces
• Chemical digestion is the breakdown of large, insoluble molecules into small, soluble molecules