Importance of Phosphorus

1
Importance of Phosphorus

• One of the most important minerals required by
  livestock and poultry.
• Complexes with calcium to give rigidity to bones.
• An integral part of many organic compounds
  plays important roles in energy and protein
  metabolism.
• Almost every biochemical reaction that occurs in
  muscle, blood and other soft tissues involves
  phosphorus.
• Affects protein synthesis, lean deposition in
  growing animals.

2
Phosphorus Requirements

• Best source of unbiased information on
  requirements is the nutrient requirement
  publications of the National Research Council
  (NRC).
• NRC is part of the National Academy of Sciences
  a private organization established 140 years ago
  by President Abraham Lincoln to advise the nation
  on issues of science and technology.
• The Committee on Animal Nutrition of the NRC has
  established guidelines for feeding animals for
  past 75 years.

3
Nitrogen and Phosphorus in Animal Manures

• 
  
• N
  P
• 
  ( of DM)
• Manure from
• Swine 4.71 2.97
• Poultry 5.13 1.62
• Beef 3.96 1.07
• Dairy 3.75 0.79
• Sheep 3.89 0.56
• Sweeten (1992).

4
Swine and Poultry Manure High in Phosphorus -
Why?

• Diets (especially swine diets) generally tend to
  be oversupplemented with phosphorus.
• Grains, oilseed meals in swine and poultry diets
  are high in phytate phosphorus.
• Pigs and poultry are unable to degrade phytase
  and utilize the phosphorus - no phytase in their
  digestive tract.
• As a result, most of dietary phosphorus from the
  natural ingredients is excreted in the feces.

5
Phytic Acid The Culprit
6
Phytate Phosphorus
7
Phytate Phosphorus Content of Cereal Grains,
Byproducts, and Oilseed Meals

• 
  Phytate Phosphorus
• of total P
  of total P
• Barley 56 Wheat bran 70
• Oats 56 Wheat middlings 74
• Corn 66
• Wheat 67 Soybean meal 61
• Grain sorghum 68 Cottonseed meal 70
• Sesame meal 81
• Nelson et al. (1968).

8
Nutritional Strategies to Reduce Phosphorus in
Swine Manure

• Feed diets that are not excessive in phosphorus.
• Formulate diets on an available phosphorus
  basis.
• Use feedstuffs that are low in phytate or that
  have endogenous phytase.
• Wheat, wheat byproducts, triticale, barley.
• Reduce dietary phosphorus and supplement with
  phytase.
• Use low-phytate cereals and oilseed meals.

9
Model-Predicted P Excretion (kg) in
Growing-Finishing Pig Fed Corn-Soy Diet from 20
to 120 kg
79 More P Excreted
10
Phytase What Does it Do?

• Increases phytate digestibility - increases
  bioavailability of P in cereal grains and oilseed
  meals.
• Reduces the amount of supplemental inorganic P
  needed to maximize growth and bone
  mineralization.
• Markedly reduces fecal P excretion.
• Increases the absorption of Ca, Mg, Zn, and other
  divalent cations.
• May improve the utilization of dietary protein
  and energy.

11
Low-Phytate Corn

12
Forms of Phosphorus in Germ of Normal and Mutant
lpa1 Corn
Other Organic P
Inorganic P
Phytic Acid P
Raboy et al. (1990)
13
Soluble Carbohydrates in Soybean
Sucrose