Unit 1 Nutrition

Dry Matter

Non-water component of feed/food

Dry matter vs As Fed

Without water (%) vs. with water (%)

Why is it important to put things on a DM basis?

COST and Nutrient value

• people don’t want to pay for water

What does food/feed processing do?

Increases surface area

Increases digestibility

( ↑ surface area = ↑ digestability)

Grain Elevators

store bulk grain harvested by farmers and keep it nice and dry

Feed Mills

process those grains and other ingredients to create animal feed

• increase surface area and dry

Conversions:

100mg / 1 g

1 ton = 907.18 kg

454 g / 1 lb

2.2 lb / 1 kilo

Fermentation

Microorganism + Glucose = VFA/Lactate/alcohol + CO2

Process of transforming carbohydrates(sugars and starches) into alcohol and CO2 or organic acids through yeast, bacteria, or a combination of the two.

Types of Fermentation

1. Rumen and hind gut fermentation

   • via microorganisms

2. Alcohol fermentation

   • via microorganisms

3. Lactic acid fermentation - in oxygen deprived muscle cells

4. Bread making

   • via microorganisms

What animals eat the entire plant? (stalk, leaf, and seed)

Ruminants:

• cows

• beef

• sheep

• goats

Equine

What animals eat the seed of the plant?

Monogastrics:

• pigs

• chickens

• dogs

• equine

• human

• etc.

Ruminants:

• feed lot beef

Goal of a plant

• reach reproductive maturity

• develop and protect viable seeds

• not be consumed

Goal of ruminant farmer

• harvest high quality

• harvest adequate tonnage

Goal of ruminant

• extract energy from starch

• extract energy from fiber

Plant Cell Structure

Pectin

Non-structural carbohydrate - potentially digestible

Key roles in plant growth, development, and defense against stress

Cellulose

Structural Carbohydrate - potentially digestible

a strong, rigid, carbohydrate molecule that forms the primary structural component of plant cell walls

Hemicellulose

Structural Carbohydrate - potentially digestible

Support by cross-linking with cellulose and lignin

Lignin

Structural carbohydrate - INDIGESTIBLE

providing structural support

(↑ maturity = ↑ lignin = ↓ digestability)

Components of Feed: Carbohydrates

Forage quality over time

Plants vs Animals

Plants: Photosynthesis to get energy

Animals: Amino Acid Synthesis from inorganic N to get energy

Photosynthesis

The uptake of nutrients occurs at both the roots and the leaves

• roots absorb water and minerals from the soil

• Carbon dioxide diffuses into leaves from the surrounding air through stomata

__% of Dry matter in plansts are organic substance while the other —% is inorganic substance.

95% organic substance (carnohydrate, cellulose in cell walls)

5% inorganic substance

Classes of Plant feeds

• Forages

• Grains

• Roots, Tubers

• Byproducts

Concentrates

often the seed of the plant

• contain high “concentration” of digestible energy per unit weight and volume

Roughages/Forages

Leaves and stems of grasses (incl. cereals), legumes, brassicas

Defined by the fraction of cell wall

• As cell wall increases, feeds become bulkier: requires greater volume to hold equal weight of substance

Cereal Grains

Produced by plants of the GRASS family, grown primarily for their seeds

• Production has been increasing over the years

EX. Wheat, Barley, Rice, Maize, Millet, Rye, Oats, Triticale, Sorghum

Grains fed to US livestock

Corn, Sorghum, Oats, Barley

Grain Structure

Nutrient Contect of cereal Grains

Generally Highly digestible

Seed Hulls:

• Heavy Hulls (barley and oats) known as rough grains

• Rice hulls almost totally indigestable because of high lignin and silica content.

Types of Corn

Dent: “field corn” - feeding and industrial products

Flint: “indian corn” - hard exterior, grown in central and south america, decorative

Sweet: human consumption, more sugar at same maturity

• 50% of sugar converted to starch in 24 hours… Eat fresh!

Flour: soft kernel, easy to grind

Popcorn: type of flint corn, very hard hull

• moisture inside kernel turns to steam and builds pressure to pop

Corn is reffered to as ____ in other countries

maize

Corn will produce more _____ per unit of land than any other grain crop

Digestible energy

It is a very digestible, palatable feed

Roots, Tubers

Turnip

Byproducts

Cereal seed coats, oilseed meals

Two families of cultivated forages

Grasses & Legumes

Grasses

creating seeds that have a lot of starch

bluegrass, ryegrass, bermudagrass, fecue, timothy grass, foxtail, sorghum, bromegrass, orchardgrass, quackgrass, and canarygrass

Legumes

Nitrogen fixation plants

have long roots rich in proteins and minerals

alfalfa, vetch, sainfoin, birdsfoot trefoil, clover

Nitrogen fixation

Enrich the soil by forming a symbiotic relationship with nitrogen-fixing bacteria, such as Rhizobia (within root nodules), which convert atmospheric nitrogen into usable forms.

• plants require ammonia or nitrate to synthesize amino acids, but lack ability to convert atmospheric N2 into ammonia (NH3)

• Symbiotic relationships between plants and bacteria evolved

• Nirtogen-fixing bacteria supply nitrogenous minerals in the soil by converting N2 to NH3 via nitrogen fixation

Parts of plants: leaves

• more nutritious

• higher in non- structural carbohydrate and protein

• lower in structural carbohydrate

Parts of plants - Stems

• less nutritous

• higher in sturctal carbohydrates = less digestable

• vascular tissue

Parts of Plants - inflorescence (flowering part)

less important as a feed component

Parts of plants - Fruit

• Cereal grain (starch-rich)

• Oilseed (protein and lipid rich)

Parts of plant - Roots

generally unimportant except in few cases

Forage nutritive value

Composite of of:

• nutrient density

• digestibility

Apparent digestibility (%) =

Apparent digestibility

Not all nutrients that ‘disapeared’ were utilized by animl

• microbial utilization and synthesis

GIT secretions

• digestive enzymes (proteins)

GIT epithelium turnover

Generalized fecal composition

Factors affecting nutritive value:

Maturity: increased maturity = increased lignin = decreased digestibility

Leaf-Stem Ratio: high leaf stem ratio is desirable because leaves contain more nutrients and less structural carbohydrates

• decreases with maturity

• fiber in leaves is more digestible than in stems

Stressors

Temp

• high temp = increase lignification & increased activities of lignin synthetic enzymes

Light Intensity

• low light = decrease lignification

Moisture deficit

• delayed plant maturity = increased digestibility

Moisture excess

• delayed plant maturity = increased digestibility

Soil fertility

• lignification generally lower if low soil fertility

Assessment of quality attributes

• crude protein

• fiber

• some assessment of digestibility

used to partially determine cost of feedstuff

Forage quality and animal performance

Laboratory Assessment of feed

1. chemical evaluation

   • Detergent System

2. In vitro digestion

Chemical evaluation: Detergent system

NDF

A neutral detergent that dissolves plant pectins, proteins, sugars and lipids; leaving fiber parts behind (cellulose, lignin, and hemicellulose)

Residual (or insoluble) remains include:

• Cellulose, hemicellulose, lignin

Considered a close estimate of total fiber constituent feedstuff

Why do plants produce NDF?

Protection

• “exoskeleton” on seeds

• Once barrier breached, bacteria and fungi infiltrate and produce mycotoxins

Structure

• plant grow to sunlight and oppose gravity

Metabolic function

• lignan “exoskeleton” reduces the loss of water

• drought resistant plants have increased NDF

• drought stress stimulates lignin production

ADF

Acid detergent recovers cellulose and lignin, and removes hemicellulose

• includes the least digestible portion of forage (lignin and cellulose)

• Feeds with ADF are lower in digestibility

ADF is often used to calculate _______ _______ of feed... because:

Energy Content

because energy content of feed is related to it’s digestibility

Van Soest System

In vitro vs in vivo

In vivo: in life, experiment preformed in living organism

In vitro: preformed in lab

In vitro digestion:

Simulates:

• Rumen digestion (48 h incubation in rumen fluid at 39˚ C)

• Gastric digestion (48 h incubation in pepsin solution at pH 2)

Dacron Bag

to measure the digestibility and degradation of feedstuffs in the rumen.

Small, porous bags containing feed samples are placed into the rumen for a set period, removed, and the amount of feed material that has disappeared is measured to determine its degradability.

Animal Assessment 3 major approaches

1. Digestion Trial

2. Balance Trial

3. Production (growth, lactation) trial

Digestion Trial

Requirements:

Individual feeding

• Need to know diet chemical composition

• need to know how much feed each animal consumes

Quantitative feces collection, separated from urine

• need chemical composition of feces

Adequate # of animals (>5)

Adequate sampling period (>7d)

Minimal disruption of feed intake

measure what is intaken vs what is shit out

Balance Trial

Requirements same for digestion trial, PLUS measurement of urinary losses

N balance = N intake - (fecal N + urinary N)

Production Trial

Applications

1. Titrate maximal or optimal responses to:

   1. total feed intake

   2. intake of specific nutrients

2. Compare the nutritional value of different feed ingredients fed at the same level

Production Trial: Efficiency of feed utilization

Nutrition involves processes of:

Ingestion - apprehension of feed, chewing, and swallowing to the initial digestive organs

Digestion - reduction of food to utilize form; physical and chemical processing of ingested food

• pre-ingestion processing of feed starts the digestive process

Absorption - active transport and passive diffusion

Metabolism - post-absorptive utilization of nutrients

Essentail Nutrient vs Nonessential nutrient

Essentail Nutrient: a nutrient an animal’c body cannot make, they need to eat it

Nonessential nutrient: nutrient that the body can make sufficient quantities of

Essentail nutrients:

Macronutrient

A nutrient that is provided (not necessarily required) in large amount in diet

• carbohydrates

• proteins

• lipids

• water

Micronutrient

A nutrient that is needed in relatively small amounts in diet

• vitamins

• minerals

The GIT does not absorb ________ because __________________.

Macronutrients because they are too large

Must break down the macros into simplest building blocks through digestion

Dietary Categories

Feeding Mechanisms

Anatomical Classification

Significance of fermentative digestion

ALL mammals have some fermentative capsity

Importance is directly related to fiber consumption

3 vial fatty acids

Make ~25 ATP through microorganisms/fermentation

Fiber digestion differences

Pregastric fermenters - Ruminants

1. Fermentation in thr umen comes before the stomach

2. Food is processed (digested) by microorganisms; carbohydrates are fermented to volatile fatty acids (VFAs)

3. VFAs are absorbed straight through rumen walls - this is how ruminants get their energy

4. True stomach (acidic or glandular) is used to digest microorganisms - this is how ruminants get their protein

Ruminants - pregastric fermenters

Pre-gastric germenters - nonruminants

Take advantage of sacculated stomach

• allows for some fermentation capacity

• not as extensive as a rumen

• animals must select more digestible forages

Non-ruminant: pregastric fermenter

Shows sacculated stomach

Post-gastric (hind gut) fermenters

1. Fermentation chambers come after the stomach and the small intestine

2. microorganisms can ferment what is not digested in small intestine

3. VFAs are abosrbed through hindgut epithelia

4. Excess microorganisms are defecated

   1. Hind gut fermenters miss out on microbial protein!

Cecal Fermenters - most of fermentation occurs in the cecum

Colon Fermenters - most of fermentation occurs in colon

Can see sacculated colon

Colon fermenters - most of fermentation occurs in colon

Has unsacculated colon - likely carnivore/ eats highly digestible foods

Adaptations to feed sources

1. Prehension, Mastication, & Deglutition

2. Gastric Capacity and structure

3. Intestional length and functions

Prehension

Seizing and conveying feed into mouth

Mechanisms vary with behavior and diet

• Forelimbs (primates, raccoon)

• Snout (elephant, tapir)

• Tongue (anteater, cow, sheep)

• Lips (horse, sheep, rhinoceros

• Beak (birds

• Drinking varies as well (suction, ladle tongue)

Mastication (or chewing)

To crush the food, increase surface area, and allow enzymes to act on molecules

• carnivores only to reduce size of particle to small enough to swallow

• herbivores chew continuously

• Adaptations with teeth

Mechanical digestion

Physical breakdown of food

• teeth & grinding increase surface area (allows for easier digestion

• Bacetria living in mouth feed off nutrients sticking to teeth (cause tooth decay)

Deglutition (swallowing)

Swallowing: reflux initiated by presence of food in pharynx

• Propulsion of food to stomach by esophageal peristalsis

• varies little with diet

Quantity and composition of saliva varies considerably

Functions of saliva

• moisten feed (salt and water)

• Lubrication (aids swallowing)

• Starch and lipid digestion (amylase and lipase): species dependant

Salivation comparison

Gastric capacity and structure

• Capacity greatest in pre-gastric fermenters; stomach = reservoir

• small stomach in carnivores related to nutritive density of diet

• distribution and composition of epithelial lining varies between species and dietary adaptations

Sphincters

Circular muscles that control the movement of food into and out of the stomach

Intestinal length and functions: Small intestine

less variable - but generally shorter in carnivores

• meat more digestible = shorter length (carnivores)