Effect of slowly digested

starch and coccidiosis

vaccination on broiler

performance

R. K. Savary*, J. A. Fricke, A. G. Van Kessel and H. L. Classen

NSERC-IRC AGM

June 9, 2016

Introduction

• Starch is the most important energy source in

poultry

• Factors affecting rate and extent

of starch digestion include:

▫ Size of the granule

▫ Degree of crystallinity

▫ Amylose:amylopectin ratio

▫ Encapsulation (Parada & Aguilera, 2011)

http://polysac3db.cermav.cnrs.fr/

Starch Classification

Ileum

RDS SDS RS

(Englyst & Hudson, 1996)

RDS: Rapidly digested starch SDS: Slowly digested starch RS: Resistant Starch

Duodenum

Jejunum

Energy for Ileal Enterocytes

Fermentation

Undigested Nutrients

Gut microbiota

Protein

Starch Fibre

NH3

Polyamines

SCFA, ↓ pH

Protein

Synthesis

Reduced enteric disease and zoonotic organisms

Barrier Function – Normal

Epithelial

Cell

Barrier

Proteins

Epithelial

Cell Epithelial

Cell

Blood Stream

Gut Lumen

Bacteria

Barrier Function - Inflammation

Epithelial

Cell

Epithelial

Cell

Epithelial

Cell

Blood Stream

Gut Lumen

Barrier

Proteins

Bacteria

Why Coccidiosis Vaccination?

• Differences in rate and extent of starch

digestion may provide nutrients to the end of

the ileum and caeca

▫ Direct ‘feeding’ of cells

▫ Fermentation to SCFAs

• The benefits provided may be subtle.

▫ Greater potential for improvement under the

stress of a disease challenge

Why Coccidiosis?

• What is Coccidiosis? ▫ A parasitic infection of the intestinal tract caused by coccidian protozoa

• Economically important species in chickens

include: • Eimeria acervulina • Eimeria maxima • Eimeria tenella • Eimeria necatrix

• Chickens can be infected by more than one

species at a time

www.link.vet.ed.ac.uk

Eimeria Life Cycle

The Eimeria sporozoites

invades the host’s

intestinal epithelial cells

After 2-6 cycles the

sporozoites develop into an

oocyst.

Non-infectious

oocysts are shed in

the excreta

Oocyst sporulate in the

environment and are

consumed by the chicken

Diagram: Tim Fiss

Eimeria acervulina and mivati

Reid and Long (1979)

Eimeria maxima

Reid and Long (1979)

Eimeria tenella

Reid and Long (1979)

Why Coccidiosis? • Subclinical coccidiosis can negatively affect:

▫ Body weight gain

▫ Feed consumption

▫ Feed:gain ratio

• Clinical infections can additionally result in:

▫ Watery droppings

▫ Death (in severe cases)

• Easy variables to measure, ensures disease

challenge is “working”

An Update From Last Year

Objectives

• To develop a disease challenge model which

is capable of:

▫ Causing intestinal damage in chickens

▫ Does not result in high mortality rates

▫ Can be used at the U of S Poultry Centre

▫ Can be used to detect subtle nutritional

benefits

Materials and Methods

• 288 male Ross 308 chicks

• Housed in 48 cages, 6 birds per cage

• Fed commercial wheat/soybean meal based

grower diet

• Gavaged with one of 4 doses of Coccivac-B

at 15 days of age

▫ 0, 10, 20 or 30 times the label dose

Gavaging at 15 Days of Age

Prepare Birds for Gavaging Gavage

Results

• No change in performance parameters

• Decrease in AMEn

• Increase in weight and length of intestinal

tract sections

•What happened?

Trouble-Shooting

• Viability of the vaccine

▫ Little to no oocysts in caeca (microscopy)

▫ Vaccine close to expiry data

• Gavaging method

▫ Some birds sounded “wheezy”

▫ Problem with gavaging technique?

Gavaging Method

Repeater Pipette Results

Trachea

Air Sacs

Gavaging Method

Gavaging Needle Results

Esophagus

Crop

Results of Repeat Trial

• Decrease in production performance!

• Decrease in AMEn!

• Increase in intestinal length and weight!

• No “wheezy” birds!

• Selected 30x label dose to use in future

trials!

Vaccine Change

Coccivac-B Coccivac-B52

Retest 0 and 30x with 12 cages of 6 birds each

Objectives

• To develop a disease challenge model which

is capable of:

▫ Causing intestinal damage in chickens

▫ Does not result in high mortality rates

▫ Can be used at the U of S Poultry Centre

▫ Can be used to detect subtle nutritional

benefits

Objectives

• Under coccidiosis disease challenge

conditions to:

▫ Evaluate graded levels of slowly digested

starch on production performance

▫ Evaluate graded levels of slowly digested

starch on gut parameters

▫ Determine a ratio of slowly:rapidly digested

starch that optimizes gut health

Materials and Methods

• 480 male Ross 308 chicks

• Housed in 96 cages, 5 birds per cage

• Fed commercial wheat/soybean meal based

grower diet or one of 5 starch diets

Materials and Methods

Ingredient 0 SDS 25 SDS 50 SDS 75 SDS 100 SDS

Starch source total 55.96 55.96 55.96 55.96 55.96

Wheat starch 44.77 33.58 22.38 11.19 0.00

Pea protein 5.04 3.78 2.52 1.26 0.00

Pea fibre 6.16 4.62 3.08 1.54 0.00

Pea starch 0.00 13.99 27.98 41.97 55.96

Wheat Starch + Pea Protein + Pea Fibre = Pea Starch

Materials and Methods

Ingredient Starch Diets Control Diet

Starch Component/Wheat 55.96 58.83

Soybean Meal 27.71 31.80

Porcine Meal 5.00 -

Oat Hulls 3.00 -

Canola Oil 3.79 4.97

Titanium Oxide (Ti2O2) 0.30 0.30

Econase GT P (Xylanase) - 0.01

Other 3.74 4.10

Materials and Methods

• Gavaged with 30 x label dose of Coccivac-

B52 at 18 days of age

▫ Commercially available vaccine

▫ Live oocysts

▫ Four Eimeria species

E. acervulina

E. maxima

E. mivati

E. tenella

▫ Two strains of

E. maxima

Gavaging at 18 Days of Age

Step 1: Weigh and wing

band bird

Step 2: Prepare bird for

gavaging

Step 3: Gavage

Data Collection

• Variables measured

▫ Body weight

▫ Body weight gain

▫ Feed consumption

▫ Feed:gain ratio

• Measured on:

▫ 0, 7, 14, 18 and 25

days of age

Data Collection

• Oocyst per gram (OPG) counts

Data Collection

• Intestinal tract weight and length

• pH

• Ileum and caeca

Oocyst Per Gram Counts

Oocysts Per Gram of Excreta

Production Performance

0–18 Day Feed Intake (g/bird)

891

b

a

a

ab ab ab

18–25 Day Feed Intake (g/bird)

857

0–18 Day Body Weight Gain (g/bird)

695

a a

a a

b

ab

18–25 Day Body Weight Gain (g/bird)

560

0–18 Day F:Gm (g feed/g gain)

ab

ab

ab

a

b

b

18–25 Day F:Gm (g feed/g gain)

Relative Intestinal Weights and

Lengths

Empty Proventriculus (g/kg)

a

ab

b b b

b

Empty Gizzard (g/kg)

b

a a a a

a

Empty Duodenum (g/kg)

a

b

ab

ab

ab

ab

Empty Intestinal Tract Weight (g/kg)

a

a

a

a

a

a b b

b

b

b b

Intestinal Tract Length (cm/kg)

a

a

a

a

b b

b b

Intestinal pH

Ileal pH

ab

bc bc

a a

c

ab

bc

ab

bc

ab

bc

Ileal and Caecal pH

a

b

Caecal pH

Accessory Organs

Pancreas Weight (g/kg)

ab

b

a

ab ab

ab

Pancreas and Spleen Weight (g/kg)

b a

b

a

Preliminary Conclusions

• Successful coccidiosis disease challenge

• During the challenge period:

▫ There was no clear change in performance

with increasing slowly digested starch (SDS)

levels

▫ Coccidiosis decreased ileal pH less as slowly

digested starch increased

▫ Slowly digested starch decreased caecal pH,

indicating fermentation of starch had

occurred

Take Home Message

• Results are preliminary

• Disease challenge model successfully

created a disease situation

• Decreasing ileal and caecal pH indicate

fermentation of starch had occurred

• Further analysis is required to determine the

extent of this effect on gut health

Next Steps

Starch Protein

Develop

Model

Starch +

Protein

Finalize results and

develop model

Apply nutritional

treatments to

disease challenged

birds

Combine nutritional

treatments

Next Steps

Starch Protein

Develop

Model

Starch +

Protein

Finalize results and

develop model

Apply nutritional

treatments to

disease challenged

birds

Combine nutritional

treatments

NSERC IRC Sponsor Organizations

Acknowledgements

Collaborators:

• Dr. Jenny Fricke

• Dr. Andrew Van Kessel

Dawn Abbott

Michael Kautzman

Graduate Students

Poultry Centre Staff

Thank you.

Questions?