Animal Nutrition Exam 1 - Protein Nutrition

Proteins

What is the most abundant biological macromolecule?

Protein

_____ are the most abundant biological macromolecules. Present in all cells and all parts of cells.

• Great variety, ranging in size and biological diversity

• Name is derived from the Greek language, “proto” meaning FIRST

expensive

Protein is often the most ____ dietary ingredient → therefore it is socially and economically important

Amino Acids

______ = The “Building Blocks” of Protein

Stereoisomers

Amino Acid Structure

• ______ (Isomeric Molecules)

  • Groups of isomers in which the atoms are linked in the same order but differ in spatial arrangement.

L-Form

Enantiomers are Mirror Images. When we synthesize proteins you get L and D forms of Amino Acids, which one is present/use in biological proteins?

L-Amino Acids

L vs D Amino Acids

______

• Most abundant form of amino acids and is found in all proteins in plants and animals

D-Amino Acids

L vs D Amino Acids

______

• Amino Acids that are not commonly seen in animal or plant protein.

• May come from microbial population → are of microbial origin (produced during microbial protein synthesis in the GIT)

Hydrophobic

Chemical Characteristics of Amino Acids

1. _____

• Nonpolar, aliphatic R groups

• Aromatic R groups

Hyrdrophilic

Chemical Characteristics of Amino Acids

2. _____

• Polar, uncharged R groups

Very Hydrophilic

Chemical Characteristics of Amino Acids

3. ______

• Positively & Negatively charged R groups

Chemical Characteristics

Amino acids with similar ______ are more inclined to compete for similar sites of absorption within the small intestine

Absorption

If you feed similar amino acids in excess they will compete for _____

Biologically

_______ Essential Amino Acids

• Amino Acids that are required for specific biological pathways to function within the body

Essential Amino Acids

Biologically Essential Amino Acids Include:

_______

• Amino Acids that are produced in an inadequate supply in the body. Therefore, they must be supplemented in the diet.

Nonessential Amino Acids

Biologically Essential Amino Acids Include:

________

• Amino acids that are produced in adequate amounts by the body.

• Do not need to consume them

Quality

Protein ____

• Determined by a combination of both AA sequence and AA digestibility

• Type of amino acids present in protein

Nutritionally Essential

Biologically Essential Amino Acids → all have biological functions in the body: some of them are ________ because the does not produce enough to meet the requirements

Protein Synthesis

Limiting Amino Acids

1st Limiting Amino Acids: amino acid that limits ________

Defecient

Limiting Amino Acids

• Protein synthesis stops

• Will not grow because some amino acids are ____

Urine

Limiting Amino Acids

• Excess Amino Acids: wasted in _____ (high in Nitrogen)

Limiting Amino Acids

______: An amino acid that is first to limit protein synthesis. It varies among species, physiological stage, and dietary conditions.

Amino Acids

Animals have specific requirements for _____, not proteins

Primary Structure

Protein Structures

Secondary Structure

Protein Structures

Tertiary Structure

Protein Strcutures

Quaternary Structure

Protein Structures

Configuration

Modification of Protein

*Changing the ______of proteins

• Denature by heat: ex → egg yolks turning from clear to white

• Changing the chemical properties of the protein

Review

Review

• It is remarkable how much protein is being produced everyday

Crude Protein (CP)

_______

• A crude way to estimate protein content of a material based on Nitrogen alone.

• Nitrogen only comes for protein.

Nitrogen

Crude Protein

An estimation of protein within a sample based on _____ content

6.25

Crude Protein = Nitrogen content x _____

Crude Protein

Most proteins contain 16% nitrogen. Therefore if you multiply the N content by 6.25 you will get the ____ value.

Review

Review

Review

Review

*Tip: If given a specific N content of a specific protein in a sample, you will more than likely be required to calculate the actual conversion factor of said protein

Protein

Crude Protein is not 100% accurate because not all proteins have the same Nitrogen content. In addition to this, there are also components that have Nitrogen but are not ____ (ex. NPN)

Amino Acids → want to know exact amino acid profile and quantity

• Different amino acids have different internal concentrations of amino acids

If you wanted a better entity (term) to describe protein content over Crude Protein, what would it be?

Diets

Crude Protein is not 100% accurate

• However….

  • CP is simple to calculate

  • CP is widely used

• Easy to compare _____, even though you really don’t know the amino acid composition

Non Protein Nitrogen (NPN)

_______ is the portion of nitrogen within a sample that does not come from protein

Urea

For milk, urine, and livestock feed ____ is the most abundant component of Non Protein Nitrogen

Urea

_____

• Found in fertilizer

• Found in urine (main source of the excertion of Nitrogen)

Nitrogen

• Dog urine contains urea with too much ____ for the grass → Kills the grass but fertilizes the soil around it (causing grass to grow)

Protein

Nonprotein Nitrogen (NPN)

• However, it is important to recognize that other molecules such as free amino acids, peptides, nitrate, amides, creatine and creatinine can be present (ARE NOT ______)

Mitochondria - Urea Cycle

Where in the body do we make urea?

Body

You cannot feed urea to dairy cows although it is produced in the ____

Rumen

Urea Utilization

• Urea is degraded in the ____ by microbial urease (enzyme) forming NH3 (ammonia) and CO2 (carbon dioxide)

Rumen

Where is urea degraded?

Urease

What microbial enzyme degrades urea forming NH3 and CO2?

Amino Acids

Urea Utilization

• Microbial populations within the rumen then utilize NH3 (ammonia) to synthesize microbial _____

NH3

High vs. Low Nitrogen Intake

• Within ruminants, increased intake of Nitrogen from the feed with result in an increased concentration of ____ being absorbed through the rumen epithelium

Flow

High vs. Low Nitrogen Intake

• As you increase Nitrogen intake, the size of the pools (except the urine) does not change. Instead, the ___ of Nitrogen throughout various organs changes

• This is seen in changes in the amount of urine produced and excreted

Ex: the amount of nitrogen in the feces doesn’t change that much

Protein

Young animals require more ____ because they are still growing

Urea

Older animals no longer require growth, thus if you overfeed (such as feeding puppy food) protein, the flow of _____increases and puts strain on the liver and kidneys

• The liver produces urea

Urea

What organ produces urea?

Ammonia

Urea is a normal component of bodily fluids and is not toxic. However, ____ is, especially in high concentrations

Nonruminants

You should not feed urea to _______

Urea

Microbes can use ____ to make microbial amino acids

Blood pH

Under the circumstances that no organic acids are available, which can be seen in low starch diets NH3 builds up in the blood → This causes an increase in ____ which can result in death if not treated. (need to aclimate animals when feeding urea)

• Ammonia (pH = 9)

Consume

You want to make NOT ____ urea if you are not a ruminant

Small Amounts

Urea Toxicity

• Horses, pigs, and other monogastrics can tolerate ______ of urea

Crude Protein

Urea Toxicity

• Cattle can tolerate up to ~25% of their _____ as urea (~1/2% urea in the total diet), all essential amino acids can be formed in the rumen if sulfur, phosphorus, and iron are present.

Symptoms

Urea Toxicity

_____ of Toxicity

• Convulsions, Excess salivation, and death → Means ammonia is already in the blood

Acid Infusion

Urea Toxicity

• What to do if toxicity symptoms appear?

  • _______ (50% vinegar solution) to prevent ammonia absorption

    • Acidifies the rumen and converts NH3 to NH4+ → slower absorption through rumen wall trapping NItrogen in Rumen thus slowing the amount of NH3 reaching the bloodstream

Urease

Urea Toxicity

• What to do if toxicity symptoms appear?

  • Cold water also reduces ____ activity → enzyme that breaks down urea into ammonia, reducing ammonia concentration

Protein Digestibility

_________: The amount of protein that can be converted into a form that can be absorbed by an animal

Rumen Undegraded Protein (RUP)

____________: Dietary protein fraction that is not degraded in the rumen. (escape vs. bypass protein)

• The more the animal eats the greater this fraction.

• Protein from diet not degraded in the rumen, micobes will not have access to it as microbes are in the rumen

Rumen Degraded Protein (RDP)

____________: Dietary fraction that is degraded in the rumen.

• We want this unless we are feeding TOP NOTCH proteins → as we want specific amino acids and not microbial amino acids

In Situ

RDP and RUP Measurements

• _______

  • Live animals experiments with cannulated animals. Mobile bag technique → put food in tea bag, put inside animal

In Vitro

RDP and RUP Measurements

• ______ (in the glass)

  • Experimental laboratorial approaches

Computer Models

RDP and RUP Measurements

• ______

  • Combination of all experimental approaches (combines data from multiple experiments)

In Vivo

RDP and RUP Measurements

• ______ (live animals) THE BEST***

  • Live animal experiments with cannulated animals

    • takes a long time

    • Very expensive

    • Labor intensive

    • Large number of animals

Degraded

In Situ Limitations

• Assumes that proteins, peptiles and AA in the soluble fraction are completely _______

  • Leaving the bag does not inherently mean it was degraded could just be soluble

Physical Restrictions

In Situ Limitations

• Reduced access to feed by the microbial populations due to __________ imposed by the use of mobile bags

Contamination

In Situ Limitations

• Imprecise quantification of microbial contamination of the undigested residues

  • Presence of microbes within the bag itself, ____ of sample.

Liquids

____ go faster through the GI tract

Protein Solubility

• _________

  • How well a particular protein mixes with water in the rumen

Protein Degradability

• _______

  • How much of particular protein is broken down in the rumen.

    • Urea is immediately degraded

    • Strach is degraded slowly to provide more energy for a longer period of time → it eventually becomes sugar in tthe blood (longer lasting energy slower degradable)

Soybean Meal

What is the most common protein source in the United States?

For HIGH PRODUCING ANIMALS

• Slow digestion to stay longer in the GI tract, more opportunities for it to be digested.

TQ: When would you want something to be highly degradable but not highly soluble?

• The more soluble, the quicker it passes through the GI tract

Review

Review

Passage Rate

Factors Affecting Protein Digestion

• _____

  • Inversely related to retention time. → goes fast through the GI tract → less digested (not as much time for the enzymes)

  • With increased Kp overall digestibility will decrease → Retention time is slower if you eat too much : will pass through your body faster

Diet

Factors Affecting Protein Digestion

• _____(Forage vs. Grain)

  • Grains help improve microbes allowing the animal to better digest cellulose

Less

**The more you consume the ___ chance for digestion as it leads to a lower retention time and faster passage rate

Synchronization

Factors Affecting Protein Digestion

• Carbohydrate and Nitrogen _______

  • Necessary to provide microbes with necessary energy source to digest protein

Dry Matter Intake

Factors Affecting Protein Digestion

• _______ Intake (DMI)

  • Increase in DMI leads to a decrease in overall digestibility

  • Increased consumption → decreased digestibility

Diet Processing

Factors Affecting Protein Digestion

• ________

  • Examples:

    • Maillard Reaction

    • Tannins

    • Formaldehyde

    • Acid Treatment

    • Rumen Protected Amino Acids

Maillard Reaction

Diet Processing

_________ (Browning Reacting) → Toast, Heat Reaction

• Named after French chemist Louis-Camille Maillard, in 1912 while attempting to reproduce biological protein synthesis. The reactive carboxyl group of the carbohydrates reacts with the nucelophilic amino group of AA, and forms a complex mixture of molecules responsible for a range of odors and flavors.

Tannins

Diet Processing

______ (Reduce Digestibility)

• Polyohenolic compounds that bind and precipitate proteins and AA.

• Hydroxyls and carboxyls groups form strong bonds with proteins and AA

• Combined with plants that are usually highly degradable in the rumen → protects protein

• Binds with proteins and makes proteins less digestible

Formaldehyde

Diet Processing

___________ (add in tiny amounts to preserve cells)

• preserves tissues or cells by cross linking primary amino groups in proteins with other nearby nitrogen atoms in protein ot DNA through alpha CH2 linkages.

Acid Treatment

Diet Processing

______

• Variety of reactions that denature (structural change) protein

  • Citric acid: common additive to food

Protected Amino Acids

Diet Processing

________

• pH, temperature, or physical sensitive

• Protection of AA from microbial attacks to ensure the essential Amino Acids are absorbed in the small intestine

Trypsin Inhibitors

Diet Processing

__________(Reduces digestibility)

• Decrease the activity of protein hydrolyzing enzymes in the small intestine (trypsin and chymotrypsin)

• Decreases protein digestibility

• Heat treat will also destroy inhibitors (this is why we feed roasted soybeans to destroy inhibitors)

• Commonly found in soybean protein

Trypsin

Enzyme is small intestine that digests protein

Stomach

Protein Digestion

1. No chemical digestion takes place in the mouth, it begins in the _______

Pepsin

Protein Digestion (Stomach)

2. Monogastrics: Hydrochloric acid denatures protein and also converts pepsinogen (produced in walls of the stomach) to _____

Peptides

Protein Digestion

3. Pepsin breaks the protein down into ____ of various lengths and some amino acids

• Trypsinogen

• Chymotrypsinogen

Protein Digestion

1. In response to a drop in pH (due to release of HCl in the stomach), the pancreas makes ______ and ______ (zymogen)

• This signals that the protein has arrived within the small intestine

Small Intestine

Protein Digestion

2. These zymogens will be activiated (by some form of cleavage) and be secreted into the _________ in the for of trypsin and chymotrypsin

Peptides

Protein Digestion

3. These proteases break down polypeptides into smaller ______ (very few peptides have to be broken down at this stage)

Small Intestine

What is the main site of digestion and absorption?