Post on 19-Jan-2016
Chapter 41 Animal Nutritionand
Digestion
Need to Feed• Dietary categories
CarnivoreHerbivoreOmnivore
• Animals are truly opportunistic eaters meaning occasionally they will eat something out of the norm when resources are scarce
• 3 nutritional needs1. Fuel (chemical energy)2. organic raw materials for biosynthesis3. essential nutrients
Management of Energy Budget• Nearly all an animal’s ATP generation is based on the oxidation of
energy rich organic molecules – CHO, proteins, and fats• Severe problems occur if budget is out of balance for long periods
undernourishment – chronic deficiency in calories- stores of glycogen and fat are used up - body begins breaking down proteins- muscular atrophy- brain can become protein deficientovernourishment – excessive food intake- obesity is increasing problem- fat stores are compounded instead of being used for fuel- inheritance is a factor in obesity- hormone leptin may be a regulatory checkpoint to combat
obesity
Animal’s Diet• In order build complex molecules it needs to grow, maintain itself, and
reproduce, animals must obtain organic precursors (carbon skeletons) from its food
• Essential nutrients – must be obtained in preassembled form because animals’ cell cannot make them from raw materials
Ex: Vitamin Cmalnourishment – missing one or more essential nutrients4 classes of essentials:1. essential amino acids – 20 in diet; 10 naturally made2. essential fatty acids – rarely deficient3. vitamins water soluble – B complex, Folic acid, Cfat soluble – A, D, E, K4. minerals - calcium, phosphorus, iron, iodine, sodium
Stages of Food Processing• The 4 stages of food processing:
1. Ingestion – eating; brings in large polymers that need to broken down for use2. Digestion – mechanical and chemical break down
of polymers into monomers the body can absorb*enzymatic hydrolysis- adding water to break bonds of macromolecules in food
3. Absorption – uptake of small molecules into bloodstream
4. Elimination – passing of undigested material out of body
Digestive System• Peristalsis – rhythmic waves of contraction that moves food
down esophagus; smooth muscle control• Sphincters – ring like valves that act as junctions between
specialized regions of digestive tube• Accessory glands in digestion:
a. Salivary glands – digestive enzymesb. Pancreas – digestive enzymes and bufferc. Liver – production of biled. Gallbladder – storage and release to bile to break
up fats• Accessory to digestion because no food passes through these
organs
Digestive System• Mouth
- will mechanically and chemically break down food particles- Food in mouth will stimulate a reflex that causes saliva to be released by salivary glands
Saliva contains –- mucin- glycoprotein that coats the lining of mouth- buffers to prevent tooth decay- antibacterial agents - Amylase that hydrolyzes starch and
glycogen
Digestive System
• Mouth pharynx – region of throat that is the
junction between trachea and esophagusepiglottis- cartilaginous flap that covers
the opening to trachea• Esophagus – connects the mouth to stomach
no digestion takes place; peristalsis
Ingestion
Digestive System
• Stomach- stores food and begins digestion- elastic walls expand when food enters- mechanical action of smooth muscles
churn contents or chyme- gastric juice (HCl) mixes and dissolves
food particles; kills bacteria present with food- pepsin – enzyme in gastric juice that will hydrolyze proteins
Early Digestion
Digestive System
• Small Intestine3 sections:
1. Duodenum – mixes juices and bile from pancreas, liver, and gallbladder
2. Jejunum – absorption of nutrients
3. Ileum – absorption of nutrients and water
Enzymatic digestion
Digestive System
• Large Intestine- cecum is a pouch like extension of
intestine - contains appendix- dispensible organ contains white blood cells that may aid in immunity/ microbial breakdown
*Main function of colon is absorption of water and any useful remaining nutrients
• Rectum – terminal portion of colon
Evolutionary Adaptations
• Dentition, or assortment of teeth, has greatly contributed to success of vertebrate class
- utilization of different shaped teeth for particular types of food or modes of nutrition
• Expandable stomachs allowing large portions of food and long periods between meals
• Symbiotic bacteria in alimentary canals• Ruminants – 4 chambered stomach for digestive of
herbivorous material*rumen, reticulum, omasum, & abomasum
Adaptations