Overview of Animal Nutrition and Ingestion
- Nutrition: process of consuming and using food and nutrients
- Nutrient: any substance consumed by an animal that is needed for survival, growth, development, tissue repair, or reproduction
- All organisms require nutrients to survive
What Do Animals Require?
- Five categories of organic nutrients
- Carbohydrates
- Proteins
- Lipids
- Nucleic acids
- Vitamins
- Inorganic nutrients
Essential Nutrients
- Essential amino acids: in order for protein synthesis to occur in human adults, eight amino acids must be available simultaneously and in the correct relative amounts.
- Can be obtained from meat.
- Essential fatty acids: important for phospholipid membrane; and principal storage compound.
- Vitamins: organic molecules in small amounts; serve as coenzymes
- Water soluble and fat soluble
- Minerals: inorganic molecules in small amounts
Dietary Categories
Herbivores: mainly eat plants and algae
- Gorillas, cows, hares, snails
Carnivores: eat other animals
- Sharks, hawks, spiders, snakes
Omnivores: consume animals, plants, and algae
- Roaches, crows, bears, raccoons, humans
Most animals are opportunistic: eating food
that are outside their main dietary category
Strategies for Obtaining Food
- Ways in which an animal obtains its food are related to its environment
- Suspension feeding: filter organic matter out of water
- Bivalve molluscs, sea squirts, baleen whale
- Bulk feeding: they use many modified body parts like tentacles, beaks, claws, pincers, etc.
- Fluid feeding: lick or suck fluid from plants or animals
- Do not need teeth except, perhaps, to puncture an animal’s skin
Passive or Active Absorption
- Nutrients must be absorbed by the epithelial cells lining the digestive tract
- Three ways:
- Passive diffusion
- Facilitated diffusion
- Active transport