Nutrients of practical value Flashcards by Aimee Supinski

Is sampling an important variable in feed analysis

Yes

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Most common methodology to assess feed nutrients

Proximate analysis (wet lab analysis)

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Proximate analysis is an estimation of

Feed components, not necessarily nutrients

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Feed is made up of _________ & ____________ (1st division)

Moisture & Dry Matter

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Dry matter is made up of ________ & _________

Inorganic material & organic material

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Feed inorganic material

Called Ash, made up of minerals

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Organic material of feed is made up of ___________& __________

Protein & non-nitrogenous residue

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Protein is also called

Crude protein (CP)

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Non-nitrogenous residue is made up of _______ & __________

Ether Extract & Carbohydrates

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Ether extract is

Fat

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Carbohydrates of feed are made up of _____ & ______

Nitrogen Free Extract & Crude Fiber

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Crude Fiber is made up of ______ & _______

Neutral Detergent Fibre (NDF) & Acid Detergent Fibre (ADF)

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What is Nitrogen-Free Extract

Soluble carbohydrates (like starch, etc)

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All components of proximate analysis are determined analytically except

NFE, which is determined mathematically

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How to determine DM of a feed

Moisture content = loss in weight that results from drying a known weight of feed (wet weight) from an amount of time at 55 or 105 °C , then measuring the weight after drying (dry weight)

Moisture content = dry weight / wet weight x 100%

make sure u don’t include container weight in ur calculations

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_________ is the most important part of a feed / ingredient as it contains all the nutrients

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Determining DM or moisture content in a feed is critical for

Formulating animal diets

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Water dilutes _____ & ______ in feed

Energy & nutrients

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Moisture content modifies

Feed intake and performance

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Increased water in feed means

Increased weight which means increased transport costs

Procedure of water and DM determination for samples that contain large amounts of volatile substances (eg VFAs & essential oils)

Dry at low temperature (55 °C) or freeze dry

What has high VFA

Silage

On a DM basis, do nutrients increase or decrease

Increase, as water is no longer diluting them

Crude protein measures the amount of ________ in feed

Nitrogen

How to determine CP of a feed

Kjeldahl method or Dumas Technqiue

On average, protein in feed contains around _______% Nitrogen

16% N

100% (total protein) / 16% (Nitrogen) =

6.25 - a constant that is used for CP calculations

CP% =

Total NItrogen (Kjeldahl) x 6.25

Limitation of CP calculations

CP% includes true protein and non-protein nitrogen (free amino acids, amides, nitrates, nitrites, nucleic acids, UREA) Urea = 46% N so CP would be 288% - however, it was my impression that we just don’t care? If someone got another impression pls let me know

EE made up of

Lipids, organic acids, alcohol, pigments, fat-soluble vitamins, and carotenoids but also plant waxes, essential oils, resins

How to find EE

Dried and ground feed sample continuous extraction (4h, 40-60°C) in a solvent (petroleum or diethyl-ether) & then you evaporate the solvent, and reside is EE

EE is often referred to as

Crude Fat

EE% =

EE residue weight / sample weight x 100%

More sensitive EE methodologies

Gas chromatography & HPLC

Crude Fibre - how to figure out the old fashioned way (sorry about this one it sucks)

Sample (A) of defatted EE residue is sequentially boiled in weak acid (H2SO4) and alkali (NaOH) solutions to stimulate digestion. Residue is washed (Hal & ether), filtered, dried and weighed (B). B is burned in a furnace at 550°C and resulting ash weighed (C) CF% = (B - C)/ A x 100%

Is finding CF tedious and not highly repeatable

Yes

What was the old CF system replaced with

The detergent Fiber system

How does the detergent Fiber system work

Digest feed with neutral detergent - breaks feed into cell contents and residue (hemicellulose, cellulose, & lignin) - NDF Digest NDF with acid detergent - hemicellulose filtered out and left with cellulose & lignin - ADF Digest ADF with 72% sulfuric acid - cellulose filtered out and lignin is left

High ADF means the diet is

Highly indigestible

What is Ash

Inorganic material in the feed (minerals)

Ash is determined by

Ignition of a known weight of feed at 550°C until all organic material has burned away (5-6 hours)

Dm - Ash =

Organic matter (OM)

Newer, more sensitive methodologies for Ash %

Spectroscopy - can give individual mineral components

Nitrogen Free extract

Elements without nitrogen and non extract either - everything left - supposedly represents more digestible CHO

How to calculate NFE

% NFE = 100 - (% EE + % CF + %CP + % Ash)

What is alternative feed analysis

Near infrared Sceptropscopy (NIRS) or Chromatograpy

What is NIRS

Near Infra-Red Spectroscopy which does rapid and non-destructive analysis of feeds and mixed diets Detects reflection of near-IR light (absorption and reflection) of OH/CH/NH groups (proteins, lipids, fibre, moisture, minerals)

REVIEW DM to AS FED AND AS FED TO DM

REVIEW ASSIGNMENT FOR CALCULATION EXAMPLES!

YES