Environmental Nutrition to Reduce Nutrient Excretion and Air Emissions

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Environmental Nutrition to Reduce Nutrient
Excretion and Air Emissions
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Nutrient excretion

• Nutrients excreted
• Nutrient ingested - Nutrients digested
• Therefore, excretions represent an inefficiency

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Nutrient excretion dependent on

• Quantity of endogenous losses (function of
  maintenance)
• Amount of dietary nutrient consumed relative to
  nutrient needs (excesses)
• Efficiency of nutrient utilization and retention
• Interrelationships of nutrients

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Precision nutrition

• Meeting nutrient needs while minimizing nutrient
  excesses

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Challenges to precision feeding

• Determining nutrient needs
• Stage of growth
• Genetic-specific
• Management-dependent
• Estimation of nutrient digestibility/bioavailabili
  ty
• Variation in feed ingredient composition

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The key understanding inefficiencies in
nutrient utilization

• Many steps are involved in the utilization of
  nutrients.
• Each step has inefficiencies associated with it.
• The key to reducing waste is to understand where
  utilization can be influenced.

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Feed Waste an expensive waste of nutrients

• Feed waste
• Adherence pigs take 1.5 g feed away from feeder
  60 times per day ( 4 of intake)
• Portion may be returned
• Spillage pigs push feed out of feeder (in
  practice, range 1.5 to 20)

-Rooting Dairy cows pick through their feed
refusing as much as 10 of what is offered
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Feeder management

• Traditional guidelines
• Proper feeder care and adjustment can reduce feed
  waste drastically
• Bottom of feeder should be 50 covered with FRESH
  feed
• Pig needs to exert effort to eat
• Feeders should be inspected at least weekly
• Clean and adjust where necessary

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Present feed in most palatable form

• Feed should be pelleted
• Reduces feed waste 5
• Dry feed is not very palatable
• Pigs move back and forth from feeder to waterer
  while eating
• Augments feed waste

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Present feed in most palatable form (continued)

• Wet-dry or liquid feeders
• Back and forth motion is prevented
• Reduces feed waste
• Increases feed intake
• Increases gain

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Enzymes required for digestive process contribute
to waste through catabolism
Feed provided
Waste
Feed waste

• Upon consumption, the animal excretes proteins
  and enzymes, e.g., during chewing
• Equals to 30 of protein intake

Feed consumed
Inefficiencies
Intestinal secretions (enzymes, cells)
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Enzymes required for digestive process contribute
to waste through catabolism (continued)

• During synthesis, inefficiencies occur
• Protein is catabolized
• N is excreted (mainly in urine)

As much as 10 of dietary N may be excreted
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Enzymes required for digestive process contribute
to waste and not all are reabsorbed

• Approximately 25 of the enzymes secreted are not
  reabsorbed in the small intestines
• Are fermented in large intestines
• Contribute to odor
• Remains are excreted
• Contribute to waste

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Feed quality affects enzyme production and thus
catabolism

• Factors augmenting enzyme secretions
• Anti-nutritional factors such as trypsin
  inhibitor
• Found in (underprocessed) soybean meal
• Protein content of the diet
• Overprocessed ingredients?

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Enzymes open opportunities

• Fiber-degrading enzymes
• Wheat/barley/rye as major ingredients
• Xylanase/beta-glucanase improve digestibility 2
  to 9
• Corn-soy diets
• Alpha-galactosidase, proteases, etc. may prove
  effective

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Phytase has a major effect on P availability

• Plants contain a large portion of P in the form
  of phytate
• Pigs cannot digest phytate
• Most plant phosphorus is thus unavailable
• Phytase can break down phytate, releasing the P
• The availability of P increases from 30 to 50
  in typical diet
• 30 reduction in P excretion

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Phytase to reduce P excretion

• Some research has demonstrated added performance
  with phytase
• Potential to increase critical amino acid
  digestibility
• May increase zinc and other trace mineral
  absorption
• Diet costs are typically not increased

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Nutrient DigestibilityAvailable nutrients
absorbed - expenses

• Ileal digestible nutrients
• Estimate of availability
• Available nutrients are destined for
• Maintenance
• Growth

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Nutrient Digestibility

• For a typical diet, 8 of protein and 70 of
  phosphorus is not digested
• Indigestible proteins are fermented in large
  intestines
• Contributes to odor
• Remains are excreted
• Contributes to waste

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Reduce the indigestible fraction by selecting
highly digestible ingredients
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New crops offer solutions as well

• De-germed, de-hulled corn

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Processing can improve nutrient digestibility

• Grinding
• Grind feed to uniform particle size of 600
  microns.
• Pelleting
• Improves protein digestibility 3.7.
• Expanding/extruding
• Improves pellet quality.
• Effects on digestibility very diet-dependent.
• Effects can be negative!
• Flaking/rolling/cracking
• Improves digestibility by gt10

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Mineral bioavailability

• 30 improvement in bioavailability of organic
  mineral sources (chelates) compared to inorganic
  sources (Leeson et al., 2003)

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Maintenance, although essential, results in waste

• Maintenance is obligatory
• Basic function of life
• Nutrients used for maintenance are ultimately
  catabolized (broken down)
• Maintenance requirement depends on size of animal

Feed provided
Waste
Feed waste
Feed consumed
Inefficiencies
Intestinal secretions (enzymes, cells)
Undigested feed and secretions
Nutrients absorbed
Maintenance
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Maintenance, although essential, results in
waste (continued)

• Five-lb pig
• Lysine 2.6 of requirement
• Threonine 6.1 of requirement
• 250-lb pig
• Lysine 8.8 of requirement
• Threonine 19.4 of requirement

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Maintenance-linked waste cannot be reduced

• By improving daily lean gain, maintenance waste
  becomes relatively less important
• Optimize production
• Optimize management
• Optimize animal health
• Optimize nutrition, etc.

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Absorbed nutrients can be used for maintenance,
followed by growth, presuming the profile matches

• Nutrients are required in specific ratio for
  growth
• The most limiting nutrients sets the upper limit
  for growth
• Excesses for other nutrients are catabolized
  and/or excreted
• For a typical diet,
• 30-35 is mismatched

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Ideal protein concept
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Protein requirements
Theory for lowering protein

• All excess protein above requirements have no
  value
• Excess protein is absorbed at the small
  intestine
• Protein is deaminated in the liver
• Urea is subsequently excreted in urine at the
  kidney

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Protein requirements (Continued)

• Urea is rapidly converted to ammonia following
  deposition Therefore,
• feeding less protein leads to less urea
  excretion
• reduced urea excretion should decrease ammonia

• A 1 point reduction in dietary protein results
  in a 10 decrease in N excretion and ammonia
  emission

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The more ingredients used, the better the match!

• Major portion of nutrients in feed is wasted
  because diet is not ideal
• Contributors to this problem
• Small number of ingredients
• Limits flexibility in matching animal-specific
  profile

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Theoretical Reduced N Excretion
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Diets should be optimally matched to the
animals requirement

• Nutritional requirements change with
• Maintenance requirement (affected by sex, age,
  and weight).
• Gain and composition of gain.
• Product yield and composition.
• Health status, environmental conditions, and
  activity.

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Diets should be optimally matched to the
animals requirement (continued)

• Temperature outside of thermo-neutral zone.
• Energy used for thermo-regulation.
• Increase energy-to-protein ratio.

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Phase feeding reduces waste

• Nutritional requirements change continuously
• Protein to energy ratio of feed decreases with
  age
• Diet should be adjusted to match this decrease
• Phase feeding

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Diets should be optimally matched to the
animals requirement (continued)

• Examples of nutritional strategies
• Grouping for production, stage of growth, or
  weight range
• Split-sex feeding
• Barrows require more energy for maintenance than
  gilts
• Increase energy to protein ratio of the feed for
  barrows

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Inefficiencies occur when the diet provides more
nutrients than the animal needs More
phases/groups less waste
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Phase-feeding diets are also cheaper, but the
extra hassle may outweigh the benefits

• More phases/groups less waste and cheaper
  diets
• But also more hassle
• Compromise between number of phases/groups and
  benefits achievable
• In-line mixers/liquid feeding systems allow for
  continuously changing the diet composition
  without increasing hassle

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Precision nutrition is further hindered by feed
manufacturing problems

• Feed manufacturing problems
• Variation in ingredient quality
• Somewhat compensated for by over formulating (
  more waste)
• Weighing errors
• Mixing problems

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Inefficiencies are linked to tissue accretion

• Inefficiencies occur in the production of tissues
• A portion of the nutrients is broken down
• Remnants are excreted
• N Mainly in urine
• Responsible for excretion of 10 of dietary N

Feed provided
Waste
Feed waste
Feed consumed
Inefficiencies
Intestinal secretions (enzymes, cells)
Undigested feed and secretions
Nutrients absorbed
Maintenance
Nutrients available for growth
Mismatch
Nutrients used for growth
Inefficiencies
Growth
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Improving the efficiency of tissue accretion
requires pharmacological interventions

• Difficult to improve through nutritional means
• Compounds such as the beta-agonists
  (Ractopamine), improve the efficiency of nutrient
  utilization
• Offer great potential for reducing nutrient waste

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Potential reductionExamples
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P Intake, Retention and Excretion
Agristats, 1999 (control) IndustryPhy
17.1g P
12.2 g
17.0g P
12.2g
13.8 g
17.1g P
19.3
13.8 g P
26 g
6.38 lb bird 1.93 feed to
gain 49 days of age RA0109
exp results
36.2g P
30.8g P
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P Intake, Retention and Excretion
Agristats, 1999 (control) UMD Rcmd
17.1g P
12.2 g
16.9g P
12.2g
13.8 g
17.1g P
22.5
14.8 g P
26 g
6.38 lb bird 1.93 feed to
gain 49 days of age RA0109
exp results
36.2g P
31.7g P
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P Intake, Retention and Excretion
Agristats, 1999 (control) UMD RcmdPhy
17.1g P
12.2 g
16.9g P
12.2g
13.8 g
17.1g P
30.5
11.9 g P
26 g
6.38 lb bird 1.93 feed to
gain 49 days of age RA0109
exp results
36.2g P
28.8g P
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P Intake, Retention and Excretion
Agristats, 1999 (control) UMD RcmdPhy25OHD3
17.1g P
12.2 g
16.8g P
12.2g
13.8 g
17.1g P
41.5
10.0 g P
26 g
6.38 lb bird 1.93 feed to
gain 49 days of age RA0109
exp results
36.2g P
26.8g P
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-22
-33
-48
Plt0.0001
Powers et al., 2004 (unpublished)
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Where does all of the waste end up?

• Feces contain the remnants of the digestive
  process
• Undigested feed
• Endogenous losses
• Odor
• But also excess zinc and copper
• Excreted through bile and excreted as feces
• Uptake of calcium and phosphorus is regulated
• Excess is excreted as feces

Manure pit
Feed waste
Undigested feed and secretions
Feces

Maintenance
Inefficiencies enzyme prod. tissue accretion
Urine
Mismatch
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Where does all of the waste end up? (continued)

• Urine contains the remnants of metabolism
• Urea from protein breakdown
• Some diverted to feces
• Excess potassium, sodium, and chlorine

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Odor compounds fermentation products of
remnants of the digestive process

• Undigested feed endogenous losses
• Subject to fermentation in the large intestines
• Fiber and carbohydrates
• Volatile fatty acids (e.g., butyric acid)

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Odor compounds fermentation products of
remnants of digestive process (continued)

• Proteins
• Volatile fatty acids
• Phenolics (para-cresol, skatole)
• Mercaptans (hydrogen sulfide, methyl mercaptan)
• Amines (putrescine, cadaverine)
• Sulfur
• Mercaptans

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Diets can be formulated to yield less odor

• Odor emission is difficult to study
• Data on effects of feed digestibility on odor are
  circumstantial
• But theoretically effect should be strong
• Low-protein diets proven to reduce odor
• Low-sulfur diet proven to reduce odor

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Sulfur converts to mercaptans

• Methionine, cysteine, and taurine are
  sulfur-containing amino acids
• Upon catabolism, they can contribute to sulfur
  odor.
• Many minerals are fed as sulfur salts
• High bio-availability with relatively low cost
• Impact on odor has been ignored

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Urea in urine major source of ammonia

• Urea, the form in which nitrogen is excreted, is
  not stable
• Urease (of bacterial origin) converts urea to
  ammonia
• Ammonia is volatilized from urine/manure based on
• Surface area
• Temperature
• Air flow across manure surface
• pH
• Ammonia concentration