Transcript Chapter 41: animal nutrition

Chapter 41:
Animal Nutrition
By Camilo Tapia-Urdaneta, Elena
Lam, and Xoujun
Animals
An animals diet must supply chemical energy, organic raw
materials, and essential nutrients.
Herbivores mainly eat plants.
carnivores eat other animals.
omnivores eat plants and other matter.
There are many aquatic animals that are suspension feeders,
sifting small particles from the water. Substrate feeders
tunnel through their food, eating as they go. fluid feeders
suck nutrient-rich fluids from a living host. Most animals are
bulk feeders eating as they go.
Extra tip: if you were to jog a mile a few hours after lunch,
which stored fuel would you probably tap?
> You would tap the muscle and liver glycogen
Homeostatic Mechanisms
glucose regulation:
Vertebrates store excess calories as
glycogen in the liver and muscles and
as fat. These energy stores may be
tapped when an animal expends more
calories than it consumes. Blood
glucose level is maintained within a
relatively narrow range by a negative
feedback mechanism.
caloric imbalance:
undernourished animals have diets
deficient in calories. Overnourished
animals consume more calories than
they need. Obesity is a very serious
problem In the united states, where
lack of exercise and fattening foods
make an unhealthy combination.
Obesity is strongly determined by
genes. The problem of maintaining a
healthy weight partly stems from our
evolution past, when fat hoarding may
have been important for survival.
Extra info: individuals who’s diet consists
of primarily of corn would likely
become malnourished
Supplying Carbon Skeletons and
Essential Nutrients
Carbon skeletons are required in biosynthesis. Essential nutrients must be supplied in
preassembled form. Malnourished animals are missing one or more essential
nutrients in their diet. Something that is required for nutrition is vitamins. Vitamins
are organic molecules required in small amounts, They are either water-soluble or
fat-soluble. Minerals are also very important for nutrition, they are inorganic
nutrients, usually required in small amounts.
nutrients required
=
healthy body
Extra tip: the symbiotic microbes that help nourish a ruminant live mainly in specialized
regions of the stomach
Main Stages of Food Processing:
Ingestion, Digestion, Absorption, and
Elimination
Food processing in animals involves
ingestion (act of eating), digestion
(enzymatic breakdown of the
macromolecules of food into their
monomers), absorption (the uptake of
nutrients by body cells), and
elimination (the passage of undigested
materials out of the body in feces).
 Digestive compartments
In intracellular digestion, food particles
are engulfed by endocytosis and
digested within food vacuoles. Most
animals use extracellular digestion,
with enzymatic hydrolysis occurring
outside cells in a gastrovascular cavity
or alimentary canal.
Extra tip: which of the following organs is
incorrectly paired with its feeding
mechanisms?
> Large intestine – bile production.

Mammalian Organs and Functions
The stomach stores food and secretes gastric juice, which converts a meal to acid
chyme. Gastric juice includes hydrochloric acid and the enzyme pepsin.
Small intestine is the major organ of digestion and absorption. Acid chyme from the
stomach mixes in the duodenum with the intestinal juice, bile, and pancreatic juice.
Diverse enzymes complete the hydrolysis of food molecules to monomers, which are
absorbed into the blood and lymph across the lining in the small intestine. Hormones
help regulate digestive juice secretion.
The large intestine aids the small intestine in reabsorbing water and houses bacteria,
some of which synthesize vitamins. Feces pass through the rectum and out the anus.
oral cavity, pharynx, and esophagus: food is lubricated and digestion begins in the
oral cavity, where teeth chew food into smaller particles that are exposed to the
salivary amylase, initiating the break down of glucose polymers. The pharynx is the
intersection leading to the trachea and esophagus. The esophagus conducts food
from the pharynx to the stomach by involuntary peristaltic waves.
Extra tip: the mammalian trachea and esophagus both open into the rectum.
Extra tip: which of the following enzimes has the lowest pH optimum? >trypsin
Evolutionary Adaptation Association
With Diet




dental adaptations: a mammals dentition is generally correlated with its diet. In
particular, mammals have specialized dentition that best enables them to ingest their
usual diet.
Stomach and intestinal adaptations: herbivores generally have longer alimentary
canals then carnivores, reflecting longer time needed to digest vegetation.
Symbiotic adaptations: many herbivore animals have fermentation chambers where
symbiotic microorganisms digest cellulose.
Extra info: our oral cavity, with its dentition, is most functionally analogous to an
earthworm’s gizzard
The end