Overview of utilization of enzymes in diets for growing pigs

Pedro. E. UrriolaDepartment of Animal Science

University of Minnesota, St. Paul

Digestion and breakdown nutrients for absorption

What are enzymes, how they work?

Enzymes modify activation energy to accelerate chemical reactions

Key-lock specific activity of enzymes

Types on digestive and exogenous enzymes

• Proteases: pepsin, trypsin, chymotrypsin, carboxypeptidases, keratinase

• Carbohydrases: amylase, maltase, xylanases or β-glucanase

• Lipases: pancreatic lipase• Esterases: ferulic acid esterase, acetyl-xylan esterase• Phosphatases: alkaline phosphatase, phytase-3 or

phytase-6

Pigs can’t digest all nutrients in feed

Corn

Whe

at

Barley

Soybea

n meal

Rapes

eed m

eal

Palm ke

rnel m

eal

Cottons

eed m

eal

Copra m

eal

DDGSc0

20

40

60

80

100

AT

TD

of D

M, %

ATTD of DM: apparent total tract digestibility of dry matter

Feed ingredients with high concentration of dietary fiber are less digestible

Rice Corn Peas Barley Soybean meal

Oats Corn DDGS

0

200

400

600

800837

680

432

585

60

466

3522108

192 221 233298 323

Starch Total dietary fiber

g/kg

DM

Bach Knudsen et al. (2013)

Even within the same ingredient (corn) digestibility of nutrients vary

ATTD of DM ATTD of N ATTD of P0.0000.1000.2000.3000.4000.5000.6000.7000.8000.9001.000

12345

Jeong et al. (2015)

Apparent total tract digestibility of DM decreases with dietary fiber

78.0 80.0 82.0 84.0 86.0 88.0 90.0 92.00.9050.9100.9150.9200.9250.9300.935

f(x) = − 0.00122790522752915 x + 1.024754268522R² = 0.306976306882285

ATTD of DMLinear (ATTD of DM)

Neutral detergent fiber, g/kg

Dig

estib

ility

coef

ficie

nt

Jeong et al. (2015)

Exogenous enzymes enhance digestibility of nutrients• The global feed enzyme market is today worth in excess of

$550 million • Saves the global feed producers an estimated $3 to 5 billion

per year– Phytase (60%) – Non-phytase (40%) mainly carbohydrases

Adeola and Cowieson (2011)

Phytase increases digestibility of phosphorus

• Approx. 60% of P in cereal grains is present as phytate

• Pigs cannot digest phytate• Phytase are enzymes added to feed to

help release P from phytate• Decrease of run off phosphorus

Phytase releases P, but also other nutrients

Plant carbohydratesClassification based on location in the plant cell:Intracellular carbohydrates: Cell wall carbohydrates:

Classification based nutritional or physiological impact:Organic acids Sugars Starch Oligo

Poly-fructans Β-glucan Cellulose Lignin

PhenolsPectins & gums Hemicellulose

Classification of plant carbohydrates

Corn fiber:-Arabinoxylans-Cellulose-Ferulic and coumaric acid

Classification of plant carbohydrates

Corn fiber:-ArabinoxylansL-arabino-D-xylane-Cellulose-Ferulic and coumaric acid

D-xyloseL-arabinose

Corn fiber vs. wheat fiber:-Wheat fiber contains greater amount of soluble arabinoxylans

Corn cDDGS Wheat Barley0

50

100

150

200

250

300

350

Tota

l die

tary

fibe

r, g/

kg

DM

Cereal grains and co-products contain different fibers-Soluble arabinoxylans

Corn cDDGS Wheat Barley0.000

0.100

0.200

0.300

0.400

0.500

0.600

0.700

SDF:

IDF

SDF:IDF = soluble vs. insoluble dietary fiber ratios

Xylanases are a group of enzymes that degrade hemicellulose

McKee et al. (2012)

GH = glycoside hydrolase

Type of DDGS Enzyme type Change in production of physiological parameter

Wheat DDGS1 xylanase + glucanase + cellulose ↑ 6.5% AID of CP;↑ 12.3% ATTD of GE; ↑ 6.6% ADG; ↓ 1.3% ADFI

  xylanase + glucanase + cellulase (dose 2X) ↑ 9.6% AID of CP;↑ 12.6% ATTD of GE; ↑14.4% ADG; ↓1.6% ADFI

Corn DDGS4 xylanase and phytase ↑ 4% AID of CP; ↑6% ATTD of GE

Corn DDGS5 α-Galactosidase + galactomannanase + β-glucanase + xylanasegalactomannanase + XylanaseXylanase

↓ 2.4% ADG; ↓5.6 ADFI ↓ 7.2% ADG; ↓9.1% ADFI↑ 1.8% ADG; ↑1.6% ADFI

Wheat and Corn DDGS6

phytase and xylanase ↑ 13% of ATTD of phosphorus

Corn DDGS7 xylanase and phytase ↑ 9.5% diet ME

Corn DDGS8 xylanase and phytase No effect on growth performance

Corn DDGS9 xylanase, β-glucanase, pentosanase, hemicellulose, and pectinase.

↑2.4% ADG

Factors that affect the activity of exo-enzymes in swine feed Availability of substrate

StructureSolubility

Interaction among nutrients Thermal stability

Pellet diets Interaction among enzymes

Arabinoxylans

Carbohydrase enzymes improve energy digestibility in low energy diets

2750 2800 2850 2900 2950 3000 3050 3100 31500123456

f(x) = − 0.00929147595885498 x + 29.5127900486405R² = 0.708171091948177

Diet Metabolizable Energy, kcal/kg

% im

prov

emen

t in

diet

M

E

Adapted from Zhou et al (2009)

TDF ATTD of TDF0

20

40

60

80

100

31.223.4

42.1 43.746.355.0

%

Min.Mean Max.

Min.

MeanMax.

Content and digestibility of fiber varies among sources of DDGS

Urriola et al. (2010)

Digestible TDF, g/kg 0

50100150200250300

73

184

255

% .

Substrate availability varies among sources of corn distillers dried grains with solubles

Urriola et al. (2010)

1. Enzymes may have greater activity on low digestible fiber

2. Enzymes may have greater activity in highly digestible fiber

Factors that affect the activity of exo-enzymes in swine feed

In vitro

Enzyme• Nutrient

release• Increment in

fermentation

Substrate• Trapped

nutrients• Extent of

fermentation

Stomach and small intestine 2-6 h

Enzyme• Nutrient release• Degrade anti-nutr

Substrate• Entrapped nutrients• Anti-nutr

Large intestine 18-28 h

Enzyme• Beneficial fermentation products (VFA)• Harmful fermentation products

Substrate• Resist fermentation

Arabinoxylans

Dietary fiber increases secretion of mucins and number of goblet cells

Huang et al. (2015)

Goblet cell area (% of mucosa) of growing pigs fed:- Corn and soybean meal,- Wheat straw (WS)- Corn distillers dried

grains with solubles (DDGS)

- Soybean hulls (SBH)- All diets contained 17%

total dietary fiber

In summary• Efficiency of feed utilization can be increased with addition

of exogenous enzymes to diets of pigs– Carbohydrases degrade non-starch polysaccharides– Phytase degrades phytic acid, increases digestibility of

phosphorus• Effects vary according to dietary and pig digestive conditions

as well as availability of substrate