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116 Cards in this Set

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Ingestion
consumption/act of taking food into the body/stomach
Mastiation
process of chewing
Digestion
Material subjected to chemicals/enzymes with resultant change/decomposition of physical/chemical nature of that substance
Absorption
passage of nutrients and other materials to blood, lymph, and cells of allimentary tract (digestive tract)
Metabolism
all chemical processes of the body involved in the miantenence of life
Excretion
removal of waste porducts in the body, mainly in the form of feces/urine
Why study nurtrition?
1. Feed costs- comprise 40-70% of total production costs

2. Nutrition affects health and performance- many diseases nutrition related

3. Feed industry is a major employer- 20-30% animal sci/ag. graduates get jobs as nutritional/management consultants

4. Better informed consumers- interpritation of food/feed labels, terminology is important, evaluation of fad diets
Disciplines involved in nurtition
1. Chemistry- Antioine Lavoisier: "father of nutrition"- developed theory of combustion and related it to how the body actually burns nutrients through cellular oxidation. Inventions: metric system, analytical balance, thermometer, bomb calorimeter

2. Biochemistry

3. Physiology

4. Microbiology- microbes that live in digestive tract and aid in digestion and silage making process. Some microbes live on feedstuffs and produce toxins.
Other disciplines in nutrition
Immunology- nutrition relationship to immune function

Genetics- certain nutritional disorders genetically inherited

Math- algebra needed for ration balancing

Stats- interpritation of research data

Physics- radioactively tagged nurtients for research and their fate following digestion

Economics- least cost ration balancing
Nutrient
Any chemical/compound in diet that supports normal reproduction, growth, lactation, or maintenance of life processes
Ration
Amount of feed consumed by an animal in 24 hours (daily amount)
Diet
Feed ingredient or mix of ingredients (including water) consumed by animals
Balanced Diet
diet that supplies required nutrients in correct amounts and proportions to nourish target animal for specific purpose of production
Food/Feed
Edible material that provides nutrients. Can be natural or artificial. used for purpose of sustaining animals.

(Feed-animal food, Food- human food)
Foodstuff/Feedstuff
Any material made into or used as food/feed
Water
Cheapest and most abundant nutrient:
65-85% of animal body weight at birth and 45-65% of body weight at maturity.

Percentage of body weight decreases with age- inverse relationship with body fat

90-95% blood, 70-90% tissues

Various Functions:
transport nutrients and aid in excretion

medium that allows chemical reactions

regulate body temp.

lubricate joints and organs in body cavities
Carbohydrates
By % molecular weight: C (77%), H (12%), O (11%)

Includes sugar, starch, cellulose, and gum

serve as structrual components in plants

very little occurs as carbs in animal body

source of energy and bulk to keep digestive tract working smoothly *Glucose*
Lipids
By % molecular weight: C (77%), H (12%), O (11%)

Insoluble in water, soluble in organic solvents (ex. ether)

most energy dense nutrient

produce ~2.25 times more energy than carbs
Proteins
By % molecular weight: C (55%), H (72%), O (23%), N (16%), S&P (<1%)

Principle constituent of organs and soft tissue

Complex molecules containing various amino acids. (22 comonly found in proteins)

Essential Amino Acids (10)- body can't sythesize fast enough to meet its requirements
Minerals
Inorganic, solid, crystalline chemical eliments. total mineral content= ASH

Comprise 3-5% of animal's dry body weight. (Ca- 1/2 total body minerals, P- 1/4 total body minerals)

Macrominerals: essential, required in large amounts (Ca, P, Na, Cl, Mg, K)

Microminerals: trace elements required in small amounts (Ca, Cu, F, I)
Vitamins
Organic components of natural food, but distinct from carbs, fat, protein, and water.

Present in food in minute amounts and effective in body in small amounts

Essential for developement of normal tissue; necessary for metabolic activity, but don't enter structural portion

When absent from diet or not absorbed/ utalized properly disease/syndrome may result
Proximate Analysis
1. Heat feed above bp of water to get %DRY MATTER

2. Burn in muffle furnace to get ASH (estimate total meneral content- does not tell about individual minerals)

3. kjeldahl process to find amount of N in sample. Nx6.25= CRUDE PROTEIN (based on protein containing 16% protein. 100/16=6.25)

4. Extract with ether. Loss of weight after drying= FAT

5. Boil extracted sample in dilute acid, then weak alkali to determine CRUDE FIBER. (remove starches, protein, sugar)

6. 100%- water-ash-protein-fiber-fat=NITROGEN FREE EXTRACT. (soluble carbs., sugars, and starches)
Classes and Proximate Analysis
Water- dry matter

Carbohydrates- NFE/Crude fiber

Fat- Crude fat/ether extract

Protein- Crude protein (Nx6.25)

Minerals- Ash

Vitamins- water soluble (B) and fat soluble (A, D, E, K)
General uses of Nutrients
1. Maintain body- energy needed for normal processes, activity, and warmth. Cells must always be replaced

2. Build the body

3.Egg production- protein and calcium

4. Production of young (gestation)

5.Production of milk- sale/nourishment of young

6.Work- pleasure/draft horses
Prehension
Taking feed/ water into the mouth
Deglutition
Act of swallowing
Regurgitation
Casting up of undigested material
Digestion
Breakdown of feed particles into suitable products for absorption.

May include:
Mechanical forces- chewing

Chemical action- acidity of stomach (pH 2-3)

Enzymitic Activity- hydrolysis; catalysts for biochemical reactions

Microbial Fermentation- pre/post gastric
Absorption
Transfer of nutrients from GIT to circulating blood/lymph system
Anabolism
Growth/building process (synthesis)
Catabolism
Breakdown/destructive reactions (degredation)
Metabolism
Combination of anabolic and catabolic reactions occuring in the body with liberation of energy
Excretion
Removal of waste products
Carnivores
Feed almost entirely on flesh of other animals

Short, simple GIT- rapid passage

Rich diet, easily digested except for hairs, feathers and other types of resistant proteins

Must have strong protein digesting enzyme systems
Herbavores
Depend entirely on plants for food (cows, horses)

long, complex GIT, slower passage, many compartments, some large for long term storage and fermentation of fiber aided by microbes
Ominivores
Consume plants and flesh (dog, hog, poultry, humans)

Medium length and complexity of GIT
Monogastrics (Nonruminents)
Pig/horse/cat/avian- Single compartment stomach

Make poor use of fibrous feeds

Microbial fermentation in cecum and large intestine allows horse to utalize fibrous feeds effectively.
Ruminants
Cow/sheep/goats/deer- multicompartmental stomach

By means of microbial fermentation processes of the rumen these animals can:
make effective use of high fiber feed

utalize nonprotein N to make microbial protein (ex. urea)

synthesize B-vitamins in ruman reducing requirement for these vitamins
Digestive Tract of a Pig
Oe- eshophagus
S-stomach
D-duodenum
I-intestine
Ca- caecum
Co-colon
Re- rectum
An- anus
Tounge (pig)
Prehension, mixing, and deglutition
Mouth (pig)
proximal organ of the gastrointestinal tract that contains three accessory organs: Tounge, teeth, salivary glands
Teeth (pig)
Paired glands that secrete saliva
Components of Saliva (pig)
Water- moistens consumed feed and aids in taste mechanisms

Mucin- lubrication/ aid in deglutition

Inorganic salts- in form of bicarbonate which acts as buffer to regulate pH of the stomach

Amylase- initiates carbohydrate breakdown *not found in all species
Esophagus (pig)
Hallow muscular tube that transports ingesta from the mouth to the stomach.

Material moved by waves of contractions of muscles that encircle esophagus and referred to as PERISTALTIC WAVES or PERISTALISIS

Valve exists (cardiac sphincter) at the junction of stomach and esophagus (allows ingesta to enter stomach)
Stomach (pig)
Hallow, pear-shaped muscular digestive organ.
Functions:
1. Storage- ingested feed stored temporarily in form of CHYME (thick semi-fluid material) or partially digested contents

2.Muscular Contractions- causes movement and mixing of the chyme

3. Secretions- various digestive juices are secreted including:
HCl: strong acid that lowers pH of digesta to ~2.0. Ideal pH for enzymes in stomach to function.

MUCUS- covers the entire stomach to protect it from the acidic environment

PEPSIN- a protease enzyme that hydrolizes/digests protein
*pepsinogen (zymogen)--HCl--->pepsin
*protein--pepsin-->polypeptides and peptides

RENNIN- protease enzyme that converts:
Milk casein to curdled /coagulated casein
*slow rate of passage to prevent diarrhea

No carbohydrate digestion in stomach. Fat moves slowly through stomach. Fat presence in stomach slows action of pyloric sphincter to hold fatty food in stomach longer for m ore effiicient digestion.
Why is the Stomach Acidic? (pig)
Acidity:
-bacterial effect ( kills bacteria)
-breakdown/digest food components and makes protein more suseptable to enzymatic digestion
-activates pepsinogen conversion to pepsin
-provides proper environment for pepsin to work
-chyme that leaves stomach and enters small intestine stimulates various secretions from the small intestine
Cardiac Shincter of Pig Stomach
muscle that opens and closes to allow food in
Esophageal Region of Pig Stomach
nonglandular area surrounding cardia
Fundic gland region of pig stomach
contains cells that provide gastric secretions needed for initial stages of digestion

*parietal cells- produce HCl
*chief cells- produce enzymes/precursers of enzymes
Pyloric gland region of pic stomach
contains cells that produce mucus and some proteolytic enzymes
Pylorus of pig stomach
beginning of small intestine (duodenum)
Pyloric sphincter of pig stomach
located in pyloris- controls passage of chyme out of stomach
Small Intestine (pig)
long, narrow tibe that is the most active digestion and nutrient absorption site.
*in market pig: >50ft long!
Duodenum (first section of pig stomach)
site of active enzyme secretions from duodenum lining and pancreas.

bile secreted from liver into gall bladder, then secreted into stomach
Jejunum (middle section of pig stomach)
active in nutrient absorption
Ileum (last section of pig stomach)
active in nutrient absorption

pH of small intestine ~6-7 (much more BASIC than the stomach)
Pig liver secretions
BILE produced by liver and stored in gall bladder and is comprised mostly of water and alkaline salts that help neutralize acidic chyme (From 2-->7).

Bile secreted into small intestine when needed- important in fat digestion: include bile acids that activate pancreatic lipase and emulsifies fat.
Pig pancreas secretions
pancreatic juice is secreted by the pancreas into the duodenum through the pancreatic duct:
1.WATER

2.ALKALINE- strongly alkaline; raises pH from 2 to 7

3. PROTEOLYTIC ENZYMES- trypsin, chymotrypsin, carboxypeptidases; all aid in digestion.
*Zymogen- Trypsinogen--enterokinase-->trypsin

4.AMYLASE- breakdown starch- attacks 1,4 glucan links in starch and glycogen

5.LIPASE- digest fat:
tryglycerol converted to monoglycerol
Pig intestinal wall
1.WATER

2. ALKALINE- neutralize strong stomach acidity

3. CARBOHYDRATES- catalyze final steps of carbohydrate digestion. Disaccharidases are produced by villi that line the intestinal wall:

sucrase digests sucrose ---> glucose+fructose

lactase digests lactose--->glucose+galactose

maltase digests maltose--->glucose+glucose

4. AMINOPEPTIDES AND DIPEPTIDES- catalyze final steps of protein digestion and work on intermediates from protein digestion.

5.ENTEROKINASE- Converts trypsinogen (zymogen) to trypsin
Movement of digesta in pig GIT
Peristalisis- contractions of smooth intestinal muscles, stimulated by presence of ingesta, especially fiber.
Absorption in pig GIT
transfer of material from lumen (inside) of GIT to the cells
Active absorption
requires energy and can occure against concentration gradient.
Passive absorption
movement of materials across cell membrane by simple diffusion; automatically by physical principles.
Effect of suface area on absorption
smooth lining for fixed area absorption

VILLI- small projections extending from wall of lumen to increase surface area for more efficient absorption
*each villus has microvilli (brush border) and arteriole and venule, together with drainage tube of lymphatic system, a lacetal. Venules ultimately drain into protal blood system, which goes directly to the liver.
Blood vs lymph absorption
most nutrients are absorbed into the blood.

*lipids absorbed into lymphatic system, then into the blood.

*lymph- clear, water, liquid, white and red blood cells; remove protein from tissues
Absorption location
most absorption takes place in the small intestine

very little absorption in stomach

some absorption in large intestine
Pig large intestine
larger diameter and volume than small intestine, but shorter.

nearly all amino acids and monosaccharides absorbed prior to this point and only fiber remains
Sections of pig's large intestine
1. Caecum- first section, little functional significance

2.Colon- middle section, largest part

3.Rectum- last section
Functions of pig's large intestine
Site of water reabsorption- recycling water is critical funcion to avoid dehydration

secretion of some mineral elements such as calcium

storage resevoir of undigested GIT contents (feces)

Bacterial fermentation- synthesis of some water soluble vitamins and vitamin K; some breakdown of fiber that reamins in GIT (acetate, buterate, propionate-->volitlie fatty acids)

No villi- limited absorption from large intestine of nutrients from feedstuffs or from microbial origin

peristalic movements in large intestine cause slow movement- need time for water removal

defication- expulsion of waste material through anus
Differences in horse digestive system (compared to the pig)
1. saliva contains no enzymes


2. never vomits

3. no gall bladder

4. greatly enlarged large intestine
-both caecum and colon greatly enlarged.
-bacteria turns fiber into volitile fatty acids (acetate, propionate, butyrate) that are absorbed and used as energy.
*less fiber digestion in the pig
Horse mouth
prehensive agents include:teeth, upper lip, and tounge

upper jaw is wider than lower jaw- mastication occurs on only one side of the mouth at a time

saliva-contains no enzymes; mature horse may secrete up to 10gallons/day
Horse esophagus
50-60 inch long tube from mouth to stomach on left side of neck.

ONE WAY peristalic movements TOWARD STOMACH- horse doesn not regurgitate
Horse stomach
smaller stomach than other animal species (3-4gallons)

the stomach does not have extensive muscular moement activity as other species like the pig-ingesta tend to arrange themselves in layers
*causes the horse to be more prone to disorders
Hosre small intestine
similar anatomy and function to the pig but no gall bladder

*bile secreted directly from liver to duodenum
Horse large intestine
Accounts for large part of GIT capacity (over 60%)

divided into caecum, large colon, small colon, and rectum
Caecum and colon of the Horse
contain active microbial population similar to that of a rumen. The bacteria can:
-breakdown cellulose and other carbohydrates to produce volitile fatty acids
-synthesize water soluble vitamins (not many reabsorbed into system)
-synthesize protein- N+carbohydrate (structural unit of protein/energy)
*some absorption of VFA occurs from caecum because protein and other large molecules originating in caecum and colon are not subjected to digestive juices- of limited use to the horse
Small Colon of horse
primary area of water reabsorption from intestinal contents

*because large intestine usually expanded with ingesta material, impaction can easily occur.
Order of AVIAN digestive tract
esophagus
crop
proventriculous
gizzard
pacrease
liver
small intestine
ceca
colon
cloaca
vent/anus
Avian mouth
no teeth- rigid and attached tounge, poorly developed salivary glands

has a beak- adapted to rapidly pick up small particles (reduce particle size)

saliva- contains salivary amylase
Avian crop
enlarged area in esophagus; functions include:
-ingesta holding/moistening reservoir (cotrol flow rate through GIT)
-allows breakdown reactions of salivary amylase
-some microbial activity so fermentation ocurs in some species
Avian proventriculus
site of gastric juice production (HCl and pepsin)

pH = ~4

ingesta passage rapid ~14 sec
Avian gizzard
Thick muscular walled area- physically reduce particle size of ingesta by mixing and grinding (similar to mastication)

Contains grit (small stones or hard particles)- aids in grinding ingested seed and grain

no secretions of enzymes-HCl and pepsin work from proventriculus in gizzard
Avian small intestine
pH slightly acidic

absorption similar to mammals

most enzymes found in mammalian species ARE present in avian small intestine
Differences in avian small intestine from the pig
1.Bile and pancreatic ducts enter the small intestine near the end of the duodenum

2.no lactase-milk not part of avian diet; lactase not necessary

3.villi contain no lacetals- not lymphatic drainage-fat absorbed directly into blood

4.hormone enterogastrone-not present in birds, which affects fat absorption
Differences in avian ceca and colon from pig
1. two ceca- "blind pouches" mammals and some birds only have 1

2.Colon is very short- 2-4in. and empties into cloaca where fecel material excreted through vent/anus

3.feces and urine excreted together- birds produce uric acid and mammals produce urea. Bird urine dumped into lower large intestine, moves back to ceca for water reabsorption, then emptied through vent
Functions of avian ceca and colon
water reabsorption

some fiber digestion and water soluble vitamin synthesis in ceca because of bacterial fermentation, but much lower levels than in most mammals
Cow mouth
no upper incisors- only upper dental pad

molar teeth (upper and lower)- shaped so animal can chew on one side of jaw at a time

saliva production relatively continous- can produce 25 gallons/day in adult cows and 2gallons/day in adult sheep

no enzymes in saliva- provides N (urea), P, and Na to microbes

saliva highly buffered to buffer pH in rumen so microbes can exist
Cow stomach
esophagus openeing is common to both reticulum and rumen compartments
Reticulum (honeycomb)
walls lined with mucus membrane containing many intersecting ridges that subdivides the surface into honeycomb like compartments.

wall arrangement traps hardware (nails, wire) so it won't pass to lower GIT and cause problems

walls secrete NO ENZYMES

functions in moving ingested feed into rumen or omasum and in regurgitation of ingesta during rumination
Rumen
large muscular compartment that almost entirely fills the left side of the abdominal cavity.

walls contain projections called papillae

NO enzymes

functions:
storage
soaking
physical mixing and breakdown
fermentation chamber: moist, warm (~38C), anaerobic, desireable pH, and continual infusion of substrate and removal of end products of digestion.

*ideal environment for microbes
Pregastric fermentation in cows
bacterial synthesis of water soluble vitimins and vitamin K

bacterial synthesis of amino acid and protein (N+carb--->microbial protein)

breakdown of fibrous feeds (high in cellulose)- rumanents produce CELLULASE
fibrous feeds--->VFAs (energy)
Omasum
spherical organ filled with muscular laminae (leaf structure)

walls secrete NO ENZYMES

Functions:
reduce particle size of ingesta before it enters the abomasum
absorbs water
Abomasum
"true/glandular stomach"

first glandular protion of the ruminant GIT

**WALLS SECRETE ENZYMES**

In general, corresponds to gland regions in simple stomach of nonruminents
Cow small and large intestine
similar in structure and function to those of the pig.
Esophegeal (or reticular groove)
passageway that extends from the cardia to the omasum, which can close to direct ingesta from the esophagus into the omasum directly, or open and permit ingesta to enter rumen/reticulum

Functions:
allow milk consumed to bypass reticulorumen and excape bacterial fermentation

*groove not functional in adult animals
Rumination
process that allows an animal to ingest feed rapidly, the complete the chewing at a later time.
Steps:
1. Regurgitation
2. Remastication
3. Resalivation
4. Reswallowing
Eructation
belching of gas

microbial fermentation in rumen results in large amounts of carbon dioxide and methane which must be eliminated.

BLOAT: common problem in which gas can't escape. Froth/foam produced in rumen which interferes with normal belching and gas accumulates. Control measures must prevent foam or break it rapidly after it has formed.
Carb fermentation in horse vs cow
starch-advantage to horse, rumen less efficient

fiber-advanage to ruminent, total fermentation greater in ruminent compared with hindgut of horse
Protein fermentation in horse vs. cow
dietary protein quality more important to the horse

microbes in rumen alter dietary protein (make it higher quality)
Vitamin fermentation in horse vs. cow
vitamins produced by microbes in rumen are available for absorption in small intestine, and in horse they are not.

B vitamin supplementation in diet is less important for rumenents
Fat fermentation in horse vs. cow
become saturated by microbes in rumen
Saliva digestion in mouth
SALIVARY AMYLASE- starch-->maltose
*none in rumenents or horse, of little importance in other species
Gastric digestion in stomach
PEPSIN- protein-->polypeptides

RENNIN- milk curdling/ protein denaturation

LIPASE- fat splitting, minor activity compare dto pancreatic digestion
Pancreas digestion in duodenum and upper small intestine
TRYPSIN- protein-->peptides and amino acids

CHYMOTRYPSIN- protein-->peptides and amino acids

CARBOXYPEPTIDASE- protein-->peptides and amino acids

AMYLASE- undigested carbs to sugars

LIPASE- fat splitting: fats-->fatty acid and glycerol

BUFFERS- bicarbonates to neutralize stomach acids
Liver digestion
no enzymes produced, but produces BILE SALTS important in lipid metabolism and emulsifies fat, giving enzyme (lipaese) greater access/surface area to react. Bile salts also aid in maintaining pH of small intestine
Intestine digestion
AMINOPEPTIDASES- proteins-->peptides and amino acids

DIPEPTIDASE- dipeptides-->amino acids

NUCLEASES- nucleoproteins-->purines and pyrimidines

MALTASE- maltose-->glucose+glucose

LACTASE- lactose-->glucose+galactose

SUCRASE- sucrose-->glucose +fructose
Saliva digestion in mouth
SALIVARY AMYLASE- starch-->maltose
*none in rumenents or horse, of little importance in other species
Gastric digestion in stomach
PEPSIN- protein-->polypeptides

RENNIN- milk curdling/ protein denaturation

LIPASE- fat splitting, minor activity compare dto pancreatic digestion
Pancreas digestion in duodenum and upper small intestine
TRYPSIN- protein-->peptides and amino acids

CHYMOTRYPSIN- protein-->peptides and amino acids

CARBOXYPEPTIDASE- protein-->peptides and amino acids

AMYLASE- undigested carbs to sugars

LIPASE- fat splitting: fats-->fatty acid and glycerol

BUFFERS- bicarbonates to neutralize stomach acids
Liver digestion
no enzymes produced, but produces BILE SALTS important in lipid metabolism and emulsifies fat, giving enzyme (lipaese) greater access/surface area to react. Bile salts also aid in maintaining pH of small intestine
Intestine digestion
AMINOPEPTIDASES- proteins-->peptides and amino acids

DIPEPTIDASE- dipeptides-->amino acids

NUCLEASES- nucleoproteins-->purines and pyrimidines

MALTASE- maltose-->glucose+glucose

LACTASE- lactose-->glucose+galactose

SUCRASE- sucrose-->glucose +fructose
Saliva digestion in mouth
SALIVARY AMYLASE- starch-->maltose
*none in rumenents or horse, of little importance in other species
Gastric digestion in stomach
PEPSIN- protein-->polypeptides

RENNIN- milk curdling/ protein denaturation

LIPASE- fat splitting, minor activity compare dto pancreatic digestion
Pancreas digestion in duodenum and upper small intestine
TRYPSIN- protein-->peptides and amino acids

CHYMOTRYPSIN- protein-->peptides and amino acids

CARBOXYPEPTIDASE- protein-->peptides and amino acids

AMYLASE- undigested carbs to sugars

LIPASE- fat splitting: fats-->fatty acid and glycerol

BUFFERS- bicarbonates to neutralize stomach acids
Liver digestion
no enzymes produced, but produces BILE SALTS important in lipid metabolism and emulsifies fat, giving enzyme (lipaese) greater access/surface area to react. Bile salts also aid in maintaining pH of small intestine
Intestine digestion
AMINOPEPTIDASES- proteins-->peptides and amino acids

DIPEPTIDASE- dipeptides-->amino acids

NUCLEASES- nucleoproteins-->purines and pyrimidines

MALTASE- maltose-->glucose+glucose

LACTASE- lactose-->glucose+galactose

SUCRASE- sucrose-->glucose +fructose