Nicole Wagner Animal Nutrition

Table of Contents Nutritional Requirements Food Types Feeding Mechanisms Overview of Food Processing (Click on topics to access slides)

Nutritional Requirements Animals are heterotrophs that require food for fuel, carbon skeletons, and essential nutrients. By definition a heterotroph is an organism that obtains organic food molecules by eating other organisms or their by-products.

A nutritionally adequate diet satisfies three needs: Fuel , chemical energy; for the cellular work of the body. Organic Raw Materials in the form of carbon skeletons used in biosynthesis Essential Nutrients which are substances that the animal cannot make for itself from any raw material and must be obtained from food in a prefabricated form

Food Types Animals fit into one of three dietary categories: Herbivores, animals that eat mainly autotrophs (plant and algae) Carnivores, animals that eat other animals Omnivores, animals that regularly consume animals as well as plant or algal matter However, most animals are opportunistic feeders; eating foods that are outside their main dietary category when these foods are available. (Click on highlighted words for links to web resources)

Feeding Mechanisms Diverse feeding adaptations have evolved among animals. Four main groups of mechanisms by which animals ingest food: Suspension-feeders: many aquatic animals that sift small food particles from the water. Substrate-feeders (deposit-feeders): animals that live in or on their feed source, eating their way through the food Fluid-feeders: animals that survive by sucking nutrient-rich fluids from a living host Bulk-feeders: animals that eat relatively large pieces of food

Overview of Food Processing The four stages of food processing: Ingestion: the act of eating Digestion: enzymatic breakdown of the macromolecules of food into their monomers Absorption: body cells take up nutrients such as amino acids and simple sugars from the digestive system Elimination: occurs as undigested material passes out of the digestive system as feces