Animal Nutrition and Digestion PDF

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Principles of Nutrition and Digestion Ecology: study of animals and they environment Nutritional Ecology: how animals adapt to their environment by developing dietary habits and physiologica mechanisms that allow them to exploit available food sources in their habitats Very few animals are absolutely restricted to one diet

Feeding strategies: Continuous Feeders (grazing animals) Horses, deer Most common in animals that consume either or both: Low quality foodstuff (grass) Foodstuff that are scattered in small quantities across large areas Discontinuous Feeders (Meal Eaters) Humans, carnivores, cats, animals in agriculture Most common in animals that eat high quality foodstuff all at once (fruit, eggs, other animals) Eat foodstuffs that are commonly available in bulk

Modes of Feeding: Hunter Wolves, cats eagles, whales, alligators

Grazer (foragers) Sheep goats, deer, pigs, squirrels Scavengers Hyena, vultures, raccoons

Dietary Habits: Herbivores- Plants Omnivores- Plants & Animals Carnivores- Animals Insectivore - Insects Frugivore - Fruits Mucivore – Mucus/Sap

Granivore - Seeds Ossivore - Bones Piscivore - Fish Ovivore - Eggs Detritivore - Dead things Folivore – Leaves Fungivore – Fungi Planktivore – Plankton Sanguivore - Blood "Harvesting Equipment”: Different animals have different dietary habits and so their bodies have undergone Specialized Adaptations Teeth and Upper Palate

Herbivores: crowns on their teeth are designed to be grinned down throughout their life because they eat grass, front teeth have been adapted to grab and cut grass Ruminants: no upper incisor, only dental pads ("no front teeth”) Carnivores: pointed incisors and jagged molars & canines Mouth (teeth, tongue, lips, muzzle) Used for acquiring food, grinding food, mixing food w/ saliva Pigs: noses are strong so they can dig/ root in the dirt to explore their environment an find food Horses: lips to grasp food like fingers, Prehensile (grasping) mechanism, and a stereotypy is Cribbing for stress, nibbling on wood or posts prehensile= Capable of grasping Cows: prehensile mechanism of cows is with their tongue; tongue rolling, oral stereotypy, cows being in an environment where they can’t express its natural foraging behavior, indicating that they’re stressed Cats: tongue has small hooks to grasp, whiskers help understand environment

Anatomical Classification of Digestive Tracts Anatomy: the study of the structure or internal workings of a body An animal digestive anatomy depends on its specialized diet Herbivores: need lots of bacteria to break down cellulose Omnivores/ Carnivores: simpler digestive tracts because meat is easy to break down

Hind-Gut Fermenters ( large intestine ) Sacculated

Un-sacculated

Cecal

Colonic

Pre-Gastric Fermenters ( stomach ) Ruminant

Unsacculated

Sacculated

Non-Ruminant

Fermentation: Chemical breakdown of a substance by bacteria, Yeast, or other micro-organisms All mammals have some fermentative capacity Pre-Gastric Fermenters: Have some bacteria in stomach Ruminants Have only 1 stomach but 4 compartments

Grazing herbivores: Cattle, sheep Selecting Herbivores/ Folivores/ Frugivores: deer, antelope, camel

1. Rumen- Largest Compartment of stomach, where most fermentation happens 2. Reticulum- works closely with rumen (reticulorumen) to sort particles of food based on degree of digestion 3. Omasum- water absorption 4. Abomasum- has acid and enzymes to break down food further Non-ruminants

Selective Herbivores: colobine Monkey, Hamster, Vole Grazing and selective Herbivores: Kangaroos, hippopotamus Folivores: Hoatzin Hind-gut Fermenters: have bacteria in Large Intestine Cecal digesters Cecum: a pouch that is found at the beginning of the large intestine) Cecum is a major site of fermentation of cellulose Most fiber digestion happens here, bacteria is able to digest cellulose In horses, the microbes that are needed to break down cellulose are located in the cecum Grazer: Capybara (largest cecum known so far), horse Selective Herbivores: Rabbit (lemming) Omnivores: Rat, Mice Colonic Digesters Limited Cellulose (fiber) digestion, bacteria to break down cellulose are located in the large intestine only Sacculated (L.I. has lots of bumps/sacks/grooves) Grazers: Elephant horse, zebra Folivores: new world monkeys Omnivores: Pig, humans Unsacculated (LI has smooth lining) Herbivores: panda Carnivores: dogs, cats Identifying a type of digester: 1. Look at stomach Weird/misshaped= ruminant simple= non ruminant 2. Look at Cecum v.s. Large Intestine which ones bigger? Cecum bigger?= cecum digester LI Bigger?= hind-gut digester 3. Look at Large Intestine Grooves/folds= sacculated More smooth patter= unsacculated

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