ANIMAL NUTRITION EXAM 1

Nutrition

Applied biochemistry and physiology

Diet Formulation

Application of nutrition and economics

Nutrient Allocation

The most effective way to use a source of nutrients

Nutrients***

Carbohydrates, proteins, minerals, vitamins, and water

Carbohydrates

End product of photosynthesis

Base energy source

Nonstructural carbohydrates

NCHO

Easy to digest

Includes starches and sugars

Structural carbohydrates

CHO

Resistant to digestion

Includes cellulose

Not digestible by mammalian enzymes

Minerals

Rocks, inorganic

Macrominerals

Needed in large quantities

Ca, P, Na, Cl, K, Mg, S

Microminerals

Usually in ppm or ppb

Mn, Zn, Fe, Cu, Se, Co, Mo, I, Cr, F

Vitamins

Fat soluble: A, D, E, K

Water soluble: B, C

Water

Needed clean and abundant

Hot (water requirement)

Access is necessary, prevents overheating

Cold (water requirement)

Access difficult (turns to ice)

DMI

Dry matter intake

Enzyme

Biological catalyst that increases the rate of reactions (PROTEINS!)

Increases biochemical reactions by interacting with reactants and products to increase likelihood of reaction occuring

Proenzymes (zymogens)

Enzymes produced in an inactive form, must be activated to work

Metabolism

Sum of biochemical reactions in the body

Anabolism

Biosynthesis, building complex molecules

Requires the INPUT of ENERGY

Catabolism

Degradation of complex molecules (break down)

Yields/produces energy

Digestive physiology

Diet selection

Dietary strategies

Animal's ability to derive nutrients from feedstuff

Mammalian Digestion

Autoenzymatic

Autoenzymatic

Animal synthesizes the enzymes

Microbial digestion

Alloenzymatic

Alloenzymatic

Microbes in the GI tract provide energy (such as VFA production in ruminants)

Monogastrics

Humans, pigs, horses, dogs, cats

Oral cavity purposes

Mechanical breakdown of food (chewing/mastication)

Decrease particle size of food for enzyme access (increase digestion)

Mixing of feed and saliva for lubrication

Saliva

Lubrication of food, oral health

Contains enzymes and buffers

Esophagus

Transports food from the mouth to the stomach

Stomach

Storage

Controls flow of digesta to the small intestine

Rate of Passage (kP)

How fast digesta moves

Rate of digestion

How fast digesta is digested

Increased Kd

Increased digestion

Increased Kp

Decreased digestion

Extent of digestion

Kd/(Kd+Kp)

Mixing

Physical processing of digesta

Secretion

Enzymes, acid and buffer

Acid

Denatures proteins and kills microbes

Enzymes

Zymogens produce enzymes

Buffer

HCO3

Increases pH, close to the surface of the stomach

Mucus + buffer

Prevents acid and enzymes from damaging the stomach surface

Gastric ulcers

Damage to the stomach surface

Caused by Nonsteroidal anti-inflammatory drugs, Stress, and H. Pylori (bacterium)

Digestion

Chemical, acid

Denatures proteins

Activates zymogens

Enzymatic; Hydrolytic (adding water) breaks down molecules into smaller molecules

Absorption by stomach

Water, alcohol, Cu, F, Mo, Aspirin

Monogastric stomach regions

Esophageal: No glandular sections

Cardiac: Secretes mucus and buffer

Gastric/Peptic: Secretes acid, mucus, enzymes (pepsin)

Pyloric/Antrum: Secretes acid, mucus, endocrine secretions (gastrin, somatostatin)

Pyloric sphincter

Determines Kp (Rate of passage)

Is regulated hormonally to avoid overloading the digestive capacity of the small intestine

3 Layers of the stomach muscle

Longitudinal (Vertical)

Circular (horizontal)

Oblique (Diagonal)

LCO-VHD

Lazy Cats Oppose Vigorous Human Demands

Rugae

Folds in the stomach that allow the stomach to stretch

Gastroesophageal sphincter

Separates the esophagus from the stomach

gastroesophageal reflux disease (GERD)

Backflow of contents of the stomach into the esophagus

Endocrine

Into body (Secretes internally)

Exocrine

Out of body (sweat)

Small intestine

Primary site of digestion and absorption

Small intestine functions

Digestive, absorption, secretion, high immune function

Digestion

Preparation of ingested food for absorption

Hydrolysis

Cleavage of a molecule by water

Typically involves hydrolytic enzymes

Absorbed in small intestine

NCHO, Protein, Lipids

NCHO Hydrolization

Monosaccharides

Protein Hydrolization

Amino acids and small peptides

Lipids hydrolization

Monoacylglycerides and fatty acids

Aerobic Respiration

Requires oxygen

Stomach digestion products

Uses mammalian enzymes

Creates glucose

Glucose + O2 -> 6CO2 + 6H2O + >= 34 ATP

Fermentation

Anaerobic respiration

Microbial utilization

Takes place in the reticulorumen and large intestine/cecum

Fermentation of starch and cellulose

Starch and Cellulose are broken down through microbial enzymes to produce VFAs, CO2, and CH4.

Microbes in fermentation

Microbes receive 1-4 ATP (energy loss)

ATP absorbed by the mammal

Products of fermentation

VFAs, Methane (CH4), CO2, Microbial Crude Protein, Microbial phospholipids, Vitamins, and Ammonia (NH3)

Microbes being digested by the mammal

MCP and MPL

MCP: Source of amino acids and energy

MPL: Source of fatty acids and energy

Both are absorbed in the SMALL INTESTINE.

CANNOT BE ABSORBED IN THE LARGE INTESTINE!

True/False: If fermentation chamber is after small intestine, MCP and MCL can be absorbed

False; MCP and MCL are absorbed in the small intestine; therefore, they would not be absorbed.

Sources of energy in the animal and where can it be digested

VFAs are the main source of energy and can be digested in the large intestine.

They are usually absorbed from the location of fermentation (rumen, cecum, etc.).

3 VFAs

Acetate (A): CH3COO-

Propionate (P): CH3CH2COO-

Butyrate (B): CH3CH2CH2COO-

Foregut Fermenters

Ruminants, microbial digestion prior to small intestine

Benefits of ruminants

Animal benefits from all products of fermentation

-MCP ferments in to amino acids and is absorbed in the S.I.

-MPL is absorbed in the S.I.

-Vitamins are absorbed in the S.I.

-VFAs and NH3 are absorbed in the reticulorumen

Downside of ruminants

Easily digestible nutrients are fermented (energy loss due to microbes, CH4 and CO2)

Hindgut fermentation

Horses, humans, etc. (Cecum fermentation)

Microbial digestion occurs after the small intestine

Benefits of monogastrics

Mammal has first access to easily digestible nutrients (no energy loss)

Downside of monogastrics

VFAs are absorbed in the cecum, but MCP, MPL, and Vitamins are excreted in feces (poor utilization