Feed additives and feed efficiency in the pork industry

F.R. Dunshea1,2

1CRC for High Integrity Pork; 2Department of Agriculture and Food Systems, Melbourne School of Land and Environment,

The University of Melbourne, Parkville, VIC 3010;

We need technology

https://www.elanco.com/Content/pdfs/2011_11068_Three-Rights-White-Paper-Revision_AI11224.pdf

Some technologies

Porcine somatotropin (pST, Reporcin)

β-agonists (ractopamine, Paylean)

Dietary additives

Cysteamine

Chromium

Betaine

Neuroleptics

Immunization against GnRF (Improvac)

Beta agonists (ractopamine, Paylean)

Orally active metabolic modifier

Metabolic modifiers

Porcine somatotropin (pST, Reporcin)Recombinant peptide hormone

Daily (or less frequent) injectable

Beta agonists (ractopamine, Paylean)Orally active metabolic modifier

Introduction

Wray-Cahen et al. 1998

Daily pST injections increases daily gain (data 16 farms across Australia)

0

200

400

600

800

1000

Gilt Gilt Boar Boar

Dai

ly g

ain

(g

/d)

ControlpST

Dunshea 2005

Daily pST injections decreases FCR(data 16 farms across Australia)

Dunshea 2005

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Gilt Gilt Boar Boar

Fee

d:g

ain

(g

/g)

ControlpST

MWF pST injections decreases FCR

Hellams et al 2000

2.00

2.20

2.40

2.60

2.80

3.00

0 20 40 60 80

Dose of pST (mg/week)

FC

R

Daily

MWF

Metabolic modifiers

Beta agonists (ractopamine, Paylean)Orally active metabolic modifier

Ractopamine increases daily gain (5 ppm for 14 d followed by 10 ppm for 17 d)

0

200

400

600

800

1000

1200

Gilt Gilt Boar Boar

Dai

ly g

ain

(g

/d)

ControlRactopamine

Rikard-Bell et al. (2009a)

Ractopamine decreases feed:gain (5 ppm for 14 d followed by 10 ppm for 17 d)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Gilt Gilt Boar Boar

Fee

d:g

ain

(g

/g)

ControlRactopamine

Rikard-Bell et al. (2009a)

2.0

2.2

2.4

2.6

2.8

Boars Gilts

Fee

d co

nver

sion

rat

io

Control Ractopamine Ractopamine + pST

Effect of feeding ractopamine for 4 weeks without or with daily pST for last 2 weeks on FCR

Rikard-Bell et al. (2009b)

Paylean for 4 weeks plus 4 pST injections over last 2 weeks decreases feed:gain

Paylean for 4 weeks plus 4 pST injections over last 2 weeks decreases feed:gain

van Barneveld et al. (2009)

Introduction

Wray-Cahen et al. 1998

Introduction

Wray-Cahen et al. 1998

Cysteamine

Cysteamine

• Cysteamine hydrochloride (CSH) increases ST secretion in rats

• Mechanism appears to be through inhibition of somatostatin (SRIF) secretion

• Responses are not as pronounced as pST and may be transitory

• Further work is required to optimise the dose and timing as high doses may blunt the response more rapidly through inhibition of gherelin

Cysteamine at 70 ppm increases ADG

600

700

800

900

Control 70 ppm CSH

Dai

ly g

ain

(g

/d)

Dunshea 2007

Liu et al 2009

Response to Cysteamine (70 ppm) is not as great as pST

600

800

1000

1200

Control Cysteamine pST

Dai

ly g

ain

(g

/d)

Dunshea 2007

Cysteamine (70 ppm) and pST decrease fat

Dunshea 2007

0

3

6

9

12

15

P2 Shoulder fat

mm

or

% Control

Cysteamine

pST

Cysteamine

• Cysteamine hydrochloride (CSH) increases ST secretion in rats

• Mechanism appears to be through inhibition of somatostatin (SRIF) secretion

• Responses are not as pronounced as pST and may be transitory

• Further work is required to optimise the dose and timing as high doses may blunt the response more rapidly through inhibition of ghrelin

Introduction

Wray-Cahen et al. 1998

GRF (GHRH) and other neonatal manipulations

0.400.450.500.550.600.650.700.750.80

Untouched 0.25nmol GHRH 0.50nmol GHRH Handled

Neonatal Treatment

AD

G fr

om d

ays

0-15

0 (k

g/da

y)

Female Male

Gallagher 2000

Dunshea (unpublished)

0

2

4

6

8

Saline pST/GHRH pST

Liv

ewei

gh

t (k

g)

Weaning

Weaning + 7 d

Neonatal treatment with pST can increase weaning weight and subsequent growth

Dunshea (unpublished)

Neonatal treatment with pST can increase slaughter and carcass weight

60

70

80

90

Saline pST/GHRH pST

Wei

gh

t (k

g)

Carcass

Slaughter

Introduction

Wray-Cahen et al. 1998

Chromium

Chromium

• Chromium is an essential element that improves insulin activity

• The digestibility and availability of Cr is low and variable (0.5-2% for inorganic Cr and 10-25% for organic)

• Responses to dietary Cr have been variable, possibly because of poor and variable digestibility

Dietary Cr increases ADG but the response is variable (31 studies)

Sales and Jancik 2011

Nano- and micro- chromium

• Chromium is an essential element that improves insulin activity

• The digestibility and availability of Cr is low and variable (0.5-2% for inorganic Cr and 10-25% for organic)

• Responses to dietary Cr have been variable, possibly because of poor and variable digestibility

• Reducing the Cr particle size may improve responses

Dietary Cr increases carcass weight

60

62

64

66

68

70

72

Control CrPic micro CrPic nano CrPic

Carc

ass w

eig

ht

(kg)

Hung et al. 2011

Dietary Cr reduces backfat in very lean pigs

6.0

7.0

8.0

9.0

Control CrPic micro CrPic nano CrPic

P2

bac

k fa

t (m

m)

Hung et al. 2011

Dietary nano CrPic increases the expression of muscle PI3K (an insulin signalling gene)

0

50

100

150

200

Control nano CrPic

Rel

ativ

e ex

pre

ssio

n (

%)

Low fatHigh fat

Hung et al. 2011

Betaine

• Betaine is an osmoregulator that reduces maintenance energy requirements

• Improved pigs can be limited by DE intake

• Responses to metabolic modifiers may be limited by DE intake

• Betaine may provide additional energy for protein deposition in pigs

Betaine and pST have additive effects on daily gain in boars fed 80% ad libitum

0

200

400

600

800

1000

1200

1400

Control Betaine

Dai

ly g

ain

(g

/d)

Control

pST

Betaine P=0.049

pST P<0.001

ab

cc

Suster et al. (2006)

Betaine and xylanase have additive effects on daily gain in gilts fed 80% ad libitum (2.7 kg/d)

700

800

900

Control Betaine

Dai

ly g

ain

(g

/d)

Control

Xylanase

Dunshea (unpublished)

Dietary neuroleptics may improve growth of boars

• Performance of group-housed entire males over the late finishing period is less than potential, possibly because of aggressive and sexual behaviours

• Dietary neuroleptics (and immunization against GnRF) offer a means of reducing sexual and aggressive behaviours

Dietary neuroleptics may increase carcass growth

Dunshea et al. 2011

• Physical castration of male pigs results in reduced feed efficiency and lean deposition and excess deposition of fat

• Performance of group-housed entire males over the late finishing period is less than potential, possibly because of aggressive and sexual behaviours

• Immunization against GnRF offers a means of reducing boar taint and negative behaviours and improving growth performance over that of both entire and physically castrated males

Immunological castration (Improvac)

0

200

400

600

800

0 30 60 90 120 150

Lea

n t

issu

e d

epo

siti

on

(g/d

)

Age (days)

Suster et al. (2006)

Entire males deposit more lean than physically castrated barrows during finishing

Entire

Barrow

0

10

20

Fat mass (kg) Fat % P2 (mm)

kg, %

or

mm

Entire

Barrow

Physically castrated barrows are fatter than entire males at 150 days of age

Suster et al. (2006)

0

1

2

3

4

Study 1 Study 2 Study 3 Study 4

Fee

d:g

ain

Entire

Barrow

Physically castrated barrows are less efficient than entire males (ca. 11%) from weaning to market

I Smell Boar Taint!

GnRFHypothalamus

Pituitary

LH & FSH

steroids such astestosterone & androstenone

boar taint & sexual & aggressive activities

Testes

Sexual development in the boar

GnRFHypothalamus

Pituitary

LH & FSH

steroids such astestosterone & androstenone

boar taint & sexual & aggressive activities

Anti-GnRF

Testes

Immunization against GnRF (with Improvac) arrests/reverses sexual development in the boar

Immunocastration reduces testes size

60.0

80.0

100.0

120.0

140.0

14 16 18 20 22 24

Age (weeks)

Tes

tes

wid

th (

mm

)

Boar Improvac Dunshea et al. (2001)

Primary Secondary

0

2

4

6

8

10

12

0 2 4 6 8

Weeks after secondary immunization

Tes

tost

ero

ne

(ng

/mL

)Boar

Improvac

Dunshea et al. (2008)

Plasma testosterone declines rapidly and remains low for upto 8 weeks

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 2 4 6 8

Weeks after secondary immunization

Fat

an

dro

sten

on

e (µ

g/g

)Boar

Improvac

Dunshea et al. (2008)

Fat androstenone declines rapidly and remains low for upto 8 weeks

0.0

0.1

0.2

0.3

0.4

0.5

0.0 0.5 1.0 1.5 2.0 2.5

Androstenone (µg/g fat)

Ska

tole

(µ

g/g

fat

)Boar ImprovacBarrow

Castration and immunocastration eliminate boar taint

Dunshea et al. (2001)

Dunshea et al. (2011)

Moore et al. (2011)

Immunization agaisnt GnRF decreases the lysine requirement beyond 3 weeks after secondary immunization

0

200

400

600

800

1000

1200

1400

1600

Boar Boar + pST

Dai

ly g

ain

(g

/d)

Control

Improvac

pST and Improvac combine to increase daily gain

Oliver et al. (2001)

0

200

400

600

800

1000

1200

Boar Boar + Ractopamine

Dai

ly g

ain

(g

/d)

Control

Improvac

Ractopamine and Improvac combine to increase daily gain

Moore et al. (2008)

Conclusions

• We have some excellent metabolic modifiers (eg. pST and ractopamine) and we need to advocate their use while we continue to identify other technologies

• Dietary additives offer a means of manipulating growth performance but can be variable and inconsistent and further research is needed to identify the circumstances under which they are most effective.

• There may be opportunities to manipulate the somatotrophic/IGF/insulin axis with dietary additives (although responses will likely not match pST)

• Immunization against GnRF offers a means of improving feed efficiency through making use of entire males without the risk of boar taint