NUT 115 E2

Why do we feed protein?

So it gets digested and absorbed as Amino Acids, which the body rebuilds into peptides, to be used for milk, tissues, hormones, enzymes [Body, Secretory, Functional Proteins]

Amino Acid is the requirement not protein. There are essential (cannot be synthesized in sufficient amounts) and non-essential

What determines Essentiality of Amino Acids?

Physiological status, species, Age.

Conditionally Essential Arginine, Glutamine, Glycine, Taurine

Essentiality: Taurine

Taurine is essential for cats as two enzymes in the pathway are deficiently low. Requirements set by AAFCO in mg/100kcal units. 25 in dry and 50 in canned food.

Eessentiality Arginine

Lactating animals, used by mammary gland to support synthesis of NE-AA and other functions, used by the animal so there’s more in the mammary glands than milk protein

Essentiality: Glycine, Glutamine

These can help support diseased animals or animals in early neonate or elderly life stages

Which amino acid isomer is used by the body

tRNA only recognizes L-AA,

exception D-Met can be converted to L-Met by the body

What makes up Crude protein?

The sum of True Protein + NPN

True protein is composed of AA like Beta-Casein

Non protein nitrogen is N found in other sources like Urea

How do we measure crude protein?

We measure the total nitrogen using two different methods, we calculate crude protein by assuming every protein is 16% Nitrogen, soo Nitrogen % x 6.25 = Crude Protein %

What is the assumption about crude protein?

That every protein is 16% Nitrogen, which really depends on the protein. Ex: Milk is 6.38.

Protein Quality

How efficiently can that protein be turned into proteins the body uses

Digestibility + Composition of amino acids

(Some amino acids are wasted and excreted in urine or feces.)
Can be determined using cannulas

Supplemental Amino Acids

Synthetic AAs are fed to animals, made in lab.

Ruminants can utilize NPN as the microbes can convert NPN → NH3 → AA from Urea into Microbial Protein. Can also convert low quality protein to high quality

In ruminants synthetic AA need to be rumen protected so the microbes cannot digest them. For example, Arginine should be supplemented and Ruminally protected. Can coat with fatty acids, polymers or lignin

Review: How do I convert Nitrogen Content of Corn (1.4%) and Soybean Meal(8.5%)

N * 6.25 soo 1.4 → 8.8% and 8.5→ 53.1%

Digestion of proteins in Hindgut-ferms and Monogastrics

Proteins degraded by pepsin and HCl → peptides degraded by Peptidases/proteases → amino acids → absorption,

Use of NPN in these feedstuffs is rare.

Protein Digestion in Ruminants

Undegradable protein passes to Abomasum and Small Intestine Microbes break down protein and NPN to create microbial protein, then that microbial protein can be digested by the animal in the Abomasum and Small intestine.

Amino Acid Profile

A measure of protein quality in the feedstuff, the first limiting AA are going to limit production of protein, typically essential AA

AA can be limiting because:

Corn is low in Lysine, Soybean meal is low in methionine.
Can also be due to how quickly an amino acid gets used up. Like methionine gets used up super fast for metabolism, synthesis of antioxidants feathers, wool,

How do we measure Limiting AA?

Comprise a study that measures what happens when we remove one amino acid, in the pig study when lysine was removed we saw a decrease in gain:feed ratio.

What happens to excess amino acids

Get catabolized into carbon skeletons for synthesis of NE-AA, Nitrogen turns into urea, can also turn into energy, glucose, and FFA.

AA and Animal Behavior

Animals can detect large imbalances of AA, either selectively choosing feeds to fixing imbalances or eating less to not exacerbate it.

Saw that AA profile was tied to tail-biting behavior in piglets.

Review: Would a Pig or Dairy Cow diet contain more NPN?? What type of protein rich feed would be for cows but not swine?

Cow!! Alfalfa Hay!!

Review: Swine Diet Contains 25% soybean meal and 70% corn grain, Whats the first limiting AA?

Corn is low in Lysine so it is the first limiting AA. Soybean meal is low in Methionine so it would be the second limiting AA

Review: The cow diet contains 50% corn silage, 15% ground corn, and 15% rumen-protected soybean meal – what might be the first limiting amino acid(s) in this diet?

Lysin???? check later on 4/28 lecture

Review: What would be a key difference between the synthetic amino acids potentially found in the cow v. swine diets?

Lipid classification

Lipids are a broad category or nonpolar organics
Fats are Solid Triglycerides at room temp
Oils are Liquid Triglycerides at room temp
Fats/Oils are the primary storage form of energy. Fat yields 2.25x more energy than carbohydrates and proteins

Simple Lipids

Fats/Oils
Glycerides made out of Glycerol and Fatty Acids

Compound Lipids

Phospholipids, Glycolipids, usually utilize fatty acids.

Functional lipids for metabolic proecesses → lipid transport, parts of cell membranes

Derived Lipids

Usually cyclic and not derived from Fatty Acids
Steroids, Sterols, Carotenoids

Fatty acid structure

Begin with a methyl group and end with a carboxyl group, different chain lengths and # of unsat bonds
C#:# where first # is length and second is number of bonds
w (omega) number is what atom is the first unsat bond in the chain from the methyl side (the end)

Fatty acid composition

Saturated Fats are more solid at room temperature like tallow, or meat fat

Unsat fats are liquid at room temp because molecules can pack together as tightly

Essential Fatty Acids and their C#:#

Linoleic C18:2
Linolenic C18:3
Arachidonic C20:4 (only essential in Cats)

Purposes of fats

Double the energy storage of carbs and protein
Essential Fatty acids
FatSol vitamins carrier
Dust Control
Palatability
Omega-3/DHA
Antiinflammatory properties

Importance of Linoleic & Linolenic acid

They are the beginning of pathways towards other important PUFAs. They cannot be synthesized in the body. Omega3s are anti inflammatory, While Omega6s are Proinflammatory. Linoleic Acid and Arachidonic acid are W-6, Alpha-Linolenic Acid and DHA are W-3.

Cats do not have Delta-6-desaturase to make DHA or AA.

Fat Sources in feedstuffs

Base fat in forage and grain (Not much but something)

Byproducts like whole cottonseed, distillers grains, solubles, fish meal.

Oil from oilseeds like canola, soybean, sunflower

Oil palms, palm fat, palm oil

rendered fat like tallow, lard, fishoil

How are oilseeds produced?

We extract oil from soybean and canola by pressing and then extracting. The leftover seeds are called “meal/cake” and are fed to animals like canola meal. Rich in protein.

Fatty Acid Profile in Grains, Byproducts, Forages

Like proteins, different fat sources have different measures of quality.

Palmitic and Linoleic acid is quite common in all our grains and our cottonseed byproduct.

Alfalfa Hay is special that it is high in linolenic acid (w-3) but low in Oleic acid (still has decent linoleic acid (w-6).

Fatty Acid Profile in Common Oils and Animal fats.

Animal fats have less Unsaturated fats, have more stearic acid. Soybean, Canola and Sunflower Oil are lower in Linolenic acid as unsaturated Fatty acids are prone to spoiling.

How are Fatty acids digested in Monogastrics/Hindgut ferms.

Gastric Lipase breaks down TAG into smaller chunks, Bile Salts will dissolve TAG so that pancreatic lipase can break them down into FFAs (in the small intestine)

How are fatty acids digested in the Rumen?

Rumen Biohydrogenation, Unsat fatty acids fed become Saturated Fatty Acids in the rumen due to microbial activity. And then its the same as monogastric.

C16:0 Palmitic acid is supplemented to dairy cows to increase milk fat, energy supply, doesn’t get effected by biohydrogenation

Fatty Acid in Chain Length and Bonds Digestibility

Shorter and Unsat chains are more digestible than longer sat chains. Less impurities means higher energy value, Impurities arise during fat extraction process

Fat Analysis

Determined by solvent, ether extract, content, sometimes refined with acid hydrolysis. Nonnutritive lipids are also included in crude fat content.

Lately Fatty Acids themselves are measured by converting them to methyl esters

Fat Inclusion levels in animal nutrition.

Fat inclusion is low, generally around 5%. because fat is energy dense and can negatively impact digestion

Mineral Classification

Naturally occuring inorganic elements. Ca, Cl, Mg, P,K, Na, S are macrominerals, present at high levels in the body or very needed in diet. Ca and P are highest with 50% and 25% of total body mineral.

Trace minerals are present at low levels in the body or have a low requirement. <0.01% of diet.

What do minerals do?

99% of Ca and 80% of P are in bones and teeth,

Important for blood clotting. Sulfur containing S, Regulatory effects, enzyme cofactors, maintain osmotic balance and blood pressure, nerve signaling, and muscle contractions.

Importance of Ca:P ratio

More Calcium than phosphorus. They both inhibit eachother. Compete for uptake.
Dairy cattle need a little extra as they produce milk, secrete 50g a day. 95% of eggshells are calcium carbonate so laying hens need 6:1

Considerations for trace minerals

Range of supplementation and tolerance is narrow. Lots of feed like algae can absorb too many trace minerals. It depends on species consuming feed too. Many trace minerals compete with eachother for absorption.

Surplus of minerals

Accumulate in Liver. ex: copper
Zn and Fe inhibit Cu absorption and release in Liver, Mo and Sulfate form an insoluble Cu complex in the tract, removing Cu.
Cu poisoning occurs when accumulated Cu is released from the liver. Diets with excess Cu or Low Levels of Cu antagonists can result in subclinical and eventual clinical Cu Toxicity.

Cu can get suddenly released from the liver randomly and cause slow subclinical toxicity quickly becoming clinical

Sheep absorb Cu from Large and small intestine really fast. (Large intestine absorption only seen in sheep

Sources of minerals

Alfalfa Hay is very rich in Ca, Ca helps buffer gut from acidosis or ulcers.
Meat and Bone meal is rich in Ca and P.
Cereal grain is high in P but low in Ca
Most P in plants is stored in Phytic Acids. Its not easily accessible to animals. Feed must be treated with Phytase to make it more available. Microbes in the rumens can handle phytic acid.

Regional differences in plant and mineral content in US.

Soils in NE US tend to have more selenium. Mineral supplements are fed depending on where crops are grown.

Supplementing Minerals

Should be used to balance diet based on content and availability of minerals in specific diets.
Oyster shells and Limestone high in Ca
Dicalcium Phosphate, Meat and Bone meal high in Ca and P
Monosodium phosphatte can also be supplemented.
Salt is added to diet, can be a salt lick,

Ranches can throw mineral supplements on ground. done for pasture cattle.

Perfomance animals need more to recover for stress.

Trace Minerals premixes

Typically added to complete diet, if a supplement is just bought. typically you add carriers like rice hulls, soy flour, protein meals.

Trace mineral forms

Hydroxy form for microbe resistance
Amino Acid Chelates increase absorption in non-ruminants
Sulphate forms generally cheaper and lower absorption, not as efficient.

Review: A farm with Sheep and Laying hens, what would be differences in mineral supplements

Sheep need to have low copper levels, hens needs lots of calcium supplementing. Poultry need phytase added to mineral supplement to breakdown phytic acid to get phosphorus outta supplements. Sheep supplements need to be in hydroxy forms as they need protection from microbial degredation in the rumen.

Vitamins definition and categories

Organics that are not use for synthesis, structure or energy.
Used for Enzyme precursors or coenzymes in various metabolic processes,
Fat Sol: ADEK, Store in liver, deficiencies occur slowly, toxicity can occur
Water Sol: B and C, toxicity is rare, but deficiencies occur quickly because no storage

Vitamin Bioactivity considerations

Vitamins have precursors and different forms and can contribute to the function of the vitamin even if they arent the active form.
VitA is Retinol in Active form but can be constructed from Beta-Carotene, both are vitamin A.
Not every animal converts to bioactive form as easily.
Vitamins are not easy to estimate optimal intake.

Vitamin A

Retinol, Retinal, Retinoic Acid, Beta-Carotene.
Plays a role in vision, bone teeth development and growth, reproduction, maintenance of epithelial cells, antioxidant pathways, immune response;
Needs to be supplemented more in Animal based feeds.

Vitamin D

Group of compounds that regulate Ca and P metabolism. D2 from plants and D3 from meat must be converted into Calcitriol active form in the body.

Vitamin E

Alpha Tocopherol is main form
Most talked about antioxidant, works as a preservative for food products ans it protects damage from free radicals. improves palatability, protects from rancidity.

Vitamin K

Quinone, K2 from only gut bacteria, K1 from plants. Important for blood clotting

Vitamins Bs

Group of coenzymes for energy metabolism and pathways for cellular maintenance. Ruminants get them from bacteria.

Vitamin C

Ascorbic Acid, Important for normal cell function, growth, development, antioxidant properties, neuromodulation, protection, collagen biosynth. Only required for guinea pigs and primates, other animals can synthesize it from glucose.

Sources of Vitamins Fat Sol

Fat sol come from:
Immature forages are high in Beta Carotene
Egg yolks, organ meats, fatty fish, cod liver oil, plant oil, are high in D3, E and K2
Plants (give vitamin K) and suncured forages and hay are good sources of Vitamin D.
Bacteria in Rumen can synth Vitamin K

Sources of vitamins for Water Sol

Cereal Grains are high in thiamine, Niacin present in cereal grains is in a bound form and not biologically available unlike niacin from animal sources, all B vitamins supplemented as a safety net

Bacteria in rumen synth B vitamins

Interactions in minerals and vitamins

Vit. E and Se work together in antioxidant pathways so usually supplemented together.

Vitamin digestion and absorption

In such low concentrations they are absorbed due to diffusion, fat sol will be in micelles.

Vitamin Units

mg/kg or ug/kg for Bs and C vitamins
mg/kg or IU/kg for fat sol vitamins.
IU is the standardization of biological effect you can expect from a given substance, relates to bioactivity of vitamins in its various forms and precursors.
Varies on species bioactivity.

Vitamin tolerance

Most vitamins are supplemented into complete diets, animals are much more tolerant to excess vitamins. Sometimes added extra to feed to improve food quality. Pregnancy and lactation increase requirements like choline, biotin, folic acid.

Review: Why is Vitamin A listed on Rosie the Cat’s diet? What does IU mean? What compounds contribute?

Cats cannot convert Vitamin A from precursors, IU includes bioactivity of vitamin and precursors, Retinoids, Beta carotene.

What is nutrient requirement defined as?

Daily amounts, concentrations for maintenance, growth, reproduction. Relevant to age, body weight, production sstate

What questions impact nutrient requirements?

Age? Size? Physio State? BW changes? Thermoneutral zone? Activity level?

Maintenance v. Production

Maintenance requirements

Nutrients required for basal metabolic processes, breathing, necessary movement, digestion, bw, temp, repairing tissues, measured at rest. Baseline.

Related more to metabolic size than live bodyweight.

Live weight includes whole body weight including digestive tract fill. Metabolic body weight is the amount of metabolically active tissue in the body.
BW^0.75 is the factor used.

Production requirements

Growth, increase in size of animals, cells can change chemical composition. Wool is considered growth not synthesis.
Synthesis: fetus, milk, eggs, making stuff not a part of the body.
Activity: Animals performing, work, play, sport, or dealing with stress

Energy Requirements in feed

Decides which nutrients will be used to provide energy. Thinking about digestion and metabolic efficiency of protein,carbs and fats in the diet.

Indirect calorimetry purpose

measuring respiration, feces, and urine to estimate losses.

Dynamics of nutrient Requirements

We formulate diets for an average animal at the certain point of time.
Each indiviudal has different requirements depending on age, injury, physio state, activity, production

Discrepancy increases with increasing heterogeny in the herd.

How much should we feed?

Balance between nutrient density, capacity of intake, feed behavior intake, about 3%~ of their body weight

Body size is major factor determining intake, but also age, activity etc. We offer food, animal consumes it, we dont force feed intake

Feed intake regulation

Meal Size is limited by stomach stretch receptors and sensors in the portal blood veins. Hormonal and neural signals (leptin, grehlin, insulin, cck) indicate animals nutritional status.

Temporal Short term regulation of food

Start and end of feeding events, signaled by satiety mechanisms. Stretch receptors and hormones

Temporal long term food regulation

prevents animal from increasing body condition (getting to obese), main signal is secretion of leptin from fat depots, and insulin regulation.

Orexigenic response

Depletion-Repletion hypothesis, feedback based around nutrient setpoint,

When nutrient is low you increase intake, mobilization, decrease oxidation

Anorexigenic response

When nutrient pool is high you decrease intake, increase nutrient storage and oxidation

Gut Fill

More fiber means lower DM intake and less protein consumed. Vice versa

Feed intake regulation and control

These signals are motivations not compulsions, they can be overridden by centers in the brain, nutrient balance also impacts feed intake

Regulation: Physiology and behavior

Dogs will eat as much as they physically can because wolves deal with feast or famine food availability, they are unsure when the next meal is coming.

Dogs can prefer people food because the dog needs to perform food seeking behaviors (contrafreeloading)