Nutritional requirements for calcium, phosphorus, and vitamin D in growing pigs

Pedro Urriola and Jerry Shurson

Department of Animal Science

Introduction

Nutritional management of Ca, P, and Vitamin D has 4 objectives:

Lean growth Bone strength

Diet cost Environment

Overview

• Dietary requirements for P and Ca are dynamic, but poorly defined for vitamin D

• Concentrations and digestibility of P and Ca vary among and within feed ingredients

• Premixes are formulated to contain generous amounts of vitamin D: – uncertainty of requirements– low content in other diet feed ingredients

Introduction• Previous mentioned issues of

mortality and lameness were linked to hypovitaminosis D

• However, not all events may necessary be due to low vitamin D

• Interplay of 3 nutrients on requirements and nutrient concentration

• Therefore, a review of the requirements is necessary

Ca

P

Vit D

Objectives

• Review NRC (2012) approach for determining Ca and P requirements for swine

• Review usefulness of models of digestion and metabolism

• Review requirements of Vit D in bone growth and health management

CONCENTRATIONS IN FEED INGREDIENTS

Nutritional requirements for calcium, phosphorus, and vitamin D in growing pigs

Form of Ca and P in feed ingredients• About 60% of P in cereal grains is

present as phytate

• Pigs cannot digest phytate

• Phytase enzymes are added to feed to release P from phytate– Phytase activity is defined as FTU and

varies among commercial products– Reduces the need for inorganic

supplementation– Reduces P excreted in manure

How do we measure the concentration and utilization of Ca and P in diets for pigs?

• Total P• Available P• Apparent total tract

digestible • Standardized total tract

digestible

Concentration, availability and digestibility of Ca, P, and phytate (%, as-fed basis)

  Ca P Phytate Avail. of P1 STTD of P2

Corn 0.02 0.26 0.21 - 34.0

Soybean meal 0.33 0.71 0.38 - 48.0

DDGS 0.12 0.73 0.26 - 65.0

Dical-P 24.8 18.8 - 49.5 81.4

Monocal-P 70 16.9 21.5 - 68.9 53.4

1Availability of phosphorus2Standardized ileal digestibility of phosphorus

Availability P system was used to measure P in feed ingredients

0.5 1 1.5 2 2.5 3 3.5 4 4.5

-1

-0.5

0

0.5

1

1.5

f(x) = 0.25 x − 1R² = 1

f(x) = 0.5 x − 1R² = 1

Standard Ing.Linear (Standard Ing.)Test Ing.Linear (Test Ing.)

Inclusion level or intake

Bo

ne

stre

ng

th

Slope 1 standard = 0.5Slope for test = 0.25Ratio = 0.25/0.5 = 0.5

Test ingredient 50%

Availability system reduces total diet P while meeting the animals requirement

C-SBM 100 g/kg DDGS 200 g/kg DDGS

Total P Total P Available P Total P Available P

Ingredient g/kg as fed

Corn 615.2 540.2 540.7 465 466.1

DDGS 0 100 100 200 200

Soybean meal 332.1 305.6 305.4 279.1 278.8

Dical phosphate 10.8 9.4 8.8 8.1 6.3

Limestone 7.2 8.2 8.6 9.2 10.5

Calculated nutrient concentration (g/kg DM)

Total phosphorus 6.3 6.3 6.1 6.3 5.9

Available P 3.4 3.6 3.4 3.8 3.4

Hanson et al. (2012)

Formulation of diets on an available P basis reduces total P intake when using DDGS

CSB 10D-TP 10D-AP2 20D-TP3 20D-AP43.05

3.15

3.25

3.35

3.45

3.55

P intake, g/d

Hanson et al. (2012)

Formulation of diets on an available P basis reduces P excretion when using DDGS

CSB 10D-TP 10D-AP2 20D-TP3 20D-AP40.8

0.85

0.9

0.95

1

1.05

1.1 P excretion, g/d

Hanson et al. (2012)

Digestibility system account for undigested P and adopted NRC (2012)

• Apparent• Standardized

– Endogenous losses

• True

𝐴𝑇𝑇𝐷 ,%=( 𝐼𝑛𝑡𝑎𝑘𝑒−𝐸𝑥𝑐𝑟𝑒𝑡𝑖𝑜𝑛)

𝐼𝑛𝑡𝑎𝑘𝑒

Stein et al. (2007)

Basal

Specific

Intake, g/kg

Out

flow

, g/

kg D

MI

Undigested

But not all P excreted in feces comes from the diet → endogenous losses

Fernandez (1995); Stein et al. (2007)

𝐴𝑇𝑇𝐷 ,%=( 𝐼𝑛𝑡𝑎𝑘𝑒−𝐸𝑥𝑐𝑟𝑒𝑡𝑖𝑜𝑛)

𝐼𝑛𝑡𝑎𝑘𝑒

The STTD digestibility system accounts for endogenous losses of P

• Apparent (ATTD)• Standardized (STTD)

– Endogenous losses

• True (TTTD)

𝑆𝑇𝑇𝐷 ,%=( 𝐼𝑛𝑡𝑎𝑘𝑒−𝐸𝑥𝑐𝑟𝑒𝑡𝑖𝑜𝑛−𝐸𝑛𝑑𝑜𝑔𝑒𝑛𝑜𝑢𝑠 𝑙𝑜𝑠𝑠𝑒𝑠)

𝐼𝑛𝑡𝑎𝑘𝑒

Stein et al. (2007)

Use of the STTD system reduces the amount of inclusion of monocal phosphate

Item Diet 1 Diet 2 STTD of P, %

Ingredient composition, %      

Corn 64.5 43.7 26

SBM 32.6 13.2 39

DDGS - 40 65

Monocal phosphate 1.07 0.4 83

Nutrient composition      

Total P, % 0.61 0.64 51

STTD of P, % 0.31 0.31 48

Fangzu et al. (unpublished data)

What about vitamins in diets?

Bioavailability is used to measure vitamin activity in feed ingredients and synthetic sources

0.5 1 1.5 2 2.5 3 3.5 4 4.5

-1

-0.5

0

0.5

1

1.5

f(x) = 0.25 x − 1R² = 1

f(x) = 0.5 x − 1R² = 1

Standard Ing.Linear (Standard Ing.)Test Ing.Linear (Test Ing.)

Inclusion level or intake

Ou

tco

me

vari

able

(B

W)

Slope 1 standard = 0.5Slope for test = 0.25Ratio = 0.25/0.5 = 0.5

Test ingredient 50% bioavailability

Concentration of vitamin D is expressed as international units (IU)

• The IU of VitD = biological activity of 0.025 μg of cholecalciferol

• Another prominent form is ergocalciferol (vitamin D2) found in plant materials.

Concentration of vitamins in premixes and diets• Factors that affect the bioavailability and degradation of

vitamins in premixes:– Humidity– Sun light exposure– Heat– pH– Presence of oxidative agents– Type of inorganic trace minerals (Shurson et al., 2011)

• Under practical applications, concentrations provided by premixes are at levels several times (2 to 3x) greater than recommended levels in the final diet (Richert, 2012).

USE OF MODELS TO ESTIMATE DIETARY REQUIREMENTS

Nutritional requirement for calcium, phosphorus, and vitamin D in growing pigs

Dietary requirements of Ca and P are dynamic

• There is no standard recommendation (NRC 2012), rather is calculated

• Optimal lean growth can be obtained with 85% of P for optimal bone growth

• Observe impact of dry matter intake

𝑆𝑇𝑇𝐷 𝑃𝑟𝑒𝑞 (𝑔/𝑑𝑎𝑦)=0.85×[𝑚𝑎𝑥𝑊𝐵𝑃 𝑟𝑒𝑡𝑒𝑛𝑡𝑖𝑜𝑛

0.77+0.19×∗𝑫𝑴𝑰 +0.007×𝐵𝑊 ]

No all phytase enzyme have the same effect of apparent total tract digestibility of P, %

0 200 400 600 800 1000 12000

10

20

30

40

50

60

13.318.4

32.1

13.3

29.7

39.6

13.3

47.452.7

13.3

22.8

36.3

NatuphosOptiphosPhyzymeRonozyme

Phytase units,

AT

TD

of

P,

%

Kerr et al. (2012)

DIETARY REQUIREMENT OF VITAMIN D

Nutritional requirement for calcium, phosphorus, and vitamin D in growing pigs

Nutritional recommendations of vitamin D (NRC, 2012)• Sow:

– Changed from 200 to 800 IU/kg diet• Growers:

– 220 IU/kg• Finishers:

– 150 IU/kg

Vitmanin D receptor

1, 25-OH-D325-OH-D3

7-dehydrocho

lesterol

Nutritional recommendations of vitamin D (NRC, 2012)

Age BW, kg NRC, IU/kg

Serum 25(OH)D, ng/mL

0 40k IU1 Outdoors2

Birth 1.5 - 2-3 4 -

Day 10 3 - 8-9 60-80 -

At weaning 5-6 200 5-6 20-30 58.5

Grower 25-70 150 15-20 - 61.0

Finisher 70-140 150 28 - 86.0

1Toussignant et al. (2013), Jang et al. (2012).2Abbot and Madson (2012).

Criteria for establishing vitamin D required intake• Bone strength:

– Ricketts– Osteoporosis

• Health:– Antibody production

Supplementation increases serum 25(OH)D3, but it doesn’t mean greater growth

Birth d10 Weaning0

10

20

30

40

50

60

70

Control 40K Vit D

Se

rum

25

(OH

)D3

Sometimes it improves BW of pigs after 40,000 IU of Vit D

21 28 470

2

4

6

8

10

12

14

5.436.06

12.28

5.646.37

12.67

Control40 K Vit D

Tousignant et al. (2013)

…but it is inconsistent

Birth d10 Weaning d14 postwean0

50100150200250300350400

Control 40K Vit D

AD

G,

g/d

Jang et al. (2012)

Ergocalciferol or Cholecalciferol

25-hydroxy-D3

1, 25-hydroxy-D3

Intestine

Calcium absorption

Phosphorus absorption Immune functions

Skeletal

Bone mineralization

Conclusion

• Dietary requirements for Ca, P, and VitD are dynamic

• Constant monitoring and adjustment in diet formulations

• Nutritional models are a useful tool for determining objective and dynamic requirements

• New parameters need to account for differences in animal health

Thanks…

Mechanistic model of P fate in GIT of pigs

Létourneau-Montminy et al. (2011)

Phosphorus flows stomach (STO) and the proximal (PSI) and distal (DSI) small intestine PP = phytate P; a = animal, pl = plant, min = mineral origen.PPns = nonsol PP; PPs = sol PP; NPPs = sol NPP; NPPns = nonsol NPP; Pendo = end P

Synthesis of vitamin D

Vitmanin D receptor

1, 25-OH-D325-OH-D3

7-dehydrocholesterol

Recommended requirements

• Humans:– Indoor and high latitude– IOM (2011) serum 25(OH)D:

• Estimated average requirement: 40 nmol/L• Recommended daily intake: 50 nmol/L

• Swine:– Indoor reared– NRC (2012)

Parameters of P metabolism in growing pigs with medium and high P intake (g/d)

H = high P intake (g/d)

M = medium P intake (g/d)

Fernandez (1995)