Assessing Lipid Quality and Effects on Swine Health and Performance

G.C. Shurson1, B.J. Kerr2, and A.R. Hanson3

Department of Animal Science, St. Paul, MN1

USDA-ARS, Ames, IA2

Swine Vet Center, St. Peter, MN3

WE NEED TO IMPROVE CALORIC EFFICIENCY OF FEED INGREDIENTS TO ACHIEVE THIS!

Rising feed ingredient prices requires focusing on caloric and nutritional efficiency

Ingredient Mcal NE/kg

$/MT (2005)

$/100 Mcal (2005)

$/MT (2012)

$/100 Mcal (2012)

% Increase

Corn 2.67 65 2.7 298 12.3 456

Soybean meal 2.09 200 10.5 606 32.1 306

Corn DDGS 2.34 50 2.4 309 14.5 604

Wheat middlings 2.12 60 3.1 287 14.9 481

Fat – A-V blend 7.23 300 4.6 936 14.3 311

Source: Woyengo et al. (2014)

• High energy sources that improve G:F

• Help maintain energy intake under heat stress

• Improve palatability

• Improve pelleting

• Reduce dust

• Supply essential fatty acids and fat soluble vitamins

Azain (2001)

Lipids are an important component of swine diets

We need to improve CALORIC EFFICIENCY in pork production systems

• Energy – Most expensive diet component

• Lipids– Most expensive energy source– Highly variable fatty acid content, quality, and energy value

• Feed conversion– Not a good predictor of caloric efficiency

Our Goal - Improve caloric and nutritional efficiency of pork production

2005 2006 2007 2008 2009 20105,0005,5006,0006,5007,0007,5008,0008,5009,0009,500

10,000

Caloric Efficiency, Kcal/kg gain

Source: National Pork Board Industry Productivity Report (2011)

Challenges for optimizing energy value of lipids• Nutritionists want predictability and consistency of feed ingredients

– We need accurate ME/NE values to minimize risk of:

• Over-feeding energy and nutrients

– Lost opportunity to capture full economic value

• Under-feeding energy and nutrients

– Sub-optimal animal performance

– We need to prevent ME/NE losses by:

• Reducing lipid peroxidation before animal consumption

• Reducing metabolic oxidative stress from lipids after consumption

General categories of feed lipids

• Animal fat– Rendered fats from beef or pork by-products

• Titer > 40 = tallow• Titer < 40 = grease• Low titer indicates a higher proportion of unsaturated fatty acids

• Poultry fat

• Blended feed fat– Includes blends of tallow, grease, poultry fat, and restaurant grease– Most restaurant grease is hydrogenated soybean oil blends

• Blended animal and vegetable fats– Includes blends of feed grade animal, poultry, vegetable oils, and/or restaurant grease

but may also contain soap, chemical, and other industrial by-products

• Vegetable soap stock– Includes free fatty acids removed from oil during refining

Challenges with evaluating feed lipids• Price is often not related to energy value

• Composition is highly variable among sources

• Quality of feed lipids is…– Poorly defined relative to energy and feeding value– Highly variable

• Are animal fats a biosecurity concern for swine farms?

How is lipid quality evaluated in the market?

• General trading standards– Titer (minimum)

– Free fatty acids (maximum)

– Moisture, insolubles, unsaponifiables (maximum)

– Color

• Other considerations– Pass the AOM stability test at 20 hrs and peroxide value < 5

– Certified to have NO PCB and pesticide residues

– Contain trace concentrations of heavy metals or other contaminants

– May include specifications for minimum or maximum iodine value

Old and Inaccurate• Titer

• MIU

• FFA

• Color

New and Accurate• ME (kcal/kg)

• Susceptibility to peroxidation

• Predictive tests

• Extent of peroxidation

• Indicator tests

• Fatty acid profile

Are we using the most accurate measures to determine the true value of feed fats and oils?

These are used to establish ingredient price in the market

These should be used to determinenutritional and economic value in swine diets

There is a disconnect between lipid price and value!

Factors that affect ME content of lipids

• Age of pig

• Unsaturated:saturated fatty acids (IV) content

• Free fatty acid (FFA) content

• Fatty acid chain length

• Fatty acid position on glycerol

• MIU content

Fatty acid composition is highly variable among lipid sources

Corn Soybean Lard Palm Tallow0

10

20

30

40

50

60

70

80

90

100

11 10

24

4425

2 4

14

5

19

27 23

4139 36

5451

1010

3

C22:6C22:5C20:5C20:4C22:1C20:1C18:3C18:2C18:1C16:1C22:0C20:0C18:0C16:0C14:0C12:0C10:0C8:0C6:0

Kerr et al. (2015)

Fatty acid composition is highly variable among lipid sources

Soybean Corn Lard Tallow Palm0

50

100

150

200

250

14 1339 48

7881 82

56 4413

132 125

6244

13

Iodine ValueU:S RatioTotal UnsaturatedTotal Saturated

NRC (2012)

ME value of various fats and oils for swine

7,400

7,600

7,800

8,000

8,200

8,400

8,600

8,800

ME, kcal/kg

TallowChoice white greasePoultry fatLardRestaurant greaseCorn oilSoybean oilCanola oilCottonseed oilSunflower oilPeanut oilAnimal-Veg Blend

NRC (2012)

Distillers corn oil use in swine diets

• Significant amounts of distillers corn oil are being used in swine diets– Competitive pricing vs. other feed lipids– Higher ME content vs. other feed lipids– PEDv in the U.S. swine industry

• caused some shift away from using animal protein and fat ingredient sources toward plant based ingredients

• Free fatty acid (FFA) content ranges from < 5% to 15%

• Previous research results suggest that as FFA content increases, ME content decreases for swine

Energy content of distillers corn oil (DCO) with variable free fatty acid (FFA) content for swine

NRC (2012)

Refined Corn Oil

DCO (4.9% FFA)

DCO(12.8% FFA)

DCO(13.9% FFA)

Corn Oil(93.8% FFA)

MIU, % - 1.53 1.91 3.94 2.25 5.60

GE, kcal/kg - 9,423 9,395 9,374 9,263 9,156

DE, kcal/kg 8,754 8,814a 8,828a 8,036b 8,465ab 8,921a

ME, kcal/kg 8,579 8,741a 8,691a 7,976b 8,397ab 8,794a

ATTD of EE2, % - 93.2 94.0 95.0 91.7 92.7

1Apparent total tract digestibility of ether extracta,bMeans within treatment comparisons with different superscript differ (P ≤ 0.05).

Kerr and Shurson (2015)

DE content of fats and oils for swine can be estimated based on FFA and U:S fatty acid content

Constant Young Old

A 36.898 37.890

B - 0.005 - 0.005

C - 7.330 - 8.200

D - 0.906 - 0.515

DE (MJ/kg) = A + B × FFA + C × eD(U/S)

DE (kcal/kg) = A + B × FFA + C × eD(U/S)

0.004184 MJ/kcal

Powles et al. (1993)

Oxidative Stress

AntioxidantsReactive Products

Cellular &Tissue Damage

Lipid peroxidation occurs at several levelsStorage Processing

Ingredient

Dietary

G. I. Tract

Physiological

Metabolic oxidative stress, reduced immune function, energy and nutrient utilization efficiency

↓ PUFA↓ Vitamin E↑ Peroxidation

e.g vitamin E, A, C, and S-amino acidsExogenous Antioxidants

e.g glutathione, vitamin C, and enzymesEndogenous Antioxidants

Hanson (2014)

Range in peroxidation of feed fats and oils used in the feed industry (> 500 samples)

Lipid Peroxide value (meq/kg) TBA (ppm MDA)

Soybean oil < 1 to 80 < 0.1 to 7.2

Palm oil < 1 to 56 0.2 to 7.9

Animal-vegetable blend < 1 to 313 0.2 to 16.5

Animal fat < 1 to 65 0.3 to 11.8

Fish oil 1 to 295 0.4 to 105

Source: Kemin Industries, Inc.

Feeding peroxidized lipids reduces growth performance and metabolic oxidative status

of pigs

Literature summary of the effects of feeding peroxidized lipids on swine growth performance

• Data from 17 published studies– Compared feeding peroxidized lipids vs. unoxidized lipids to swine

• Evaluated only supplemental feed fats and oils– Excluded lipids from feedstuffs (e.g. meat and bone meal, fish meal, etc.)– Diets were isocaloric

• Variables of interest included:– Diet PV meq/kg– Diet MDA meq/kg– ADG, ADFI, and G:F – Serum TBARS and α-tocopherol

• Dependent variables are reported as a % relative to unoxidized lipids (control)

Hanson (2014)

Swine0

20

40

60

80

100

120

% R

elati

ve to

Die

ts C

onta

inin

g U

nox-

idiz

ed Li

pid

11.2% Reduction

Unoxidized lipid = 100%

Growth rate is reduced when feeding peroxidized lipidsto swine

Hanson (2014)

Swine0

20

40

60

80

100

120

% R

elati

ve to

Die

ts w

ith U

noxi

dize

d Li

pid

7.5% Reduction

Unoxidized lipid = 100%

Feed intake is reduced when feeding peroxidized lipidsto swine

Hanson (2014)

Swine0

20

40

60

80

100

120

% R

elati

ve to

Die

ts C

onta

inin

g U

nox-

idiz

ed Li

pid

4.3% Reduction

Unoxidized lipid = 100%

Gain efficiency is reduced when feeding peroxidized lipidsto swine

Hanson (2014) • Serum α-tocopherol 46.3% relative to controls• Serum TBARS 19.7% relative to controls

0.00 5.00 10.00 15.00 20.00 25.00 30.000.0

20.0

40.0

60.0

80.0

100.0

120.0

Dietary PV (mEq/kg) and ADGSwine

PV (mEq/kg diet)

ADG,

% re

lativ

e to

cont

rols

r = - 0.16 P = 0.55

Dietary PV is not correlated with reduced ADG of pigs

TBARS is negatively correlated with reduced ADG of pigs

0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.00

20

40

60

80

100

120

TBARS, mg malondialdehyde eq/kg diet

ADG,

% re

lativ

e to

cont

rols r = - 0.63 (P = 0.05)

The science behind lipid peroxidation

Lipids can be easily peroxidized under common processing and storage conditions

Heat

Light

Oxygen

Oxidizing Minerals

Lipid sources high in unsaturated fatty acids are most susceptible to peroxidation

• Most vulnerable fatty acids– Oleic acid (C18:1)– Linoleic acid (C18:2)– Linolenic acid (C18:3)

• Rate of peroxidation increases with the degree of unsaturation– Oleic = 1 × rate– Linoleic = 10 × rate– Linolenic = 100 × rate

Adapted from: Bartosz and Kolakowska (2007)

Peroxidization yields numerous compounds that can have undesirable effects to animals

L• LOO•

LH (new PUFA)

LOOH

O2

→ Products: aldehydes & ketones, ↓

acids & polymers

Modifications of: DNA (e.g. 8-OH-deoxyguanosine) Protein (e.g. carbonyl adducts)

PUFA→Initiation

Propagation

Termination

Many peroxidation products are produced and decomposed at different rates and time points

Peroxides Aldehydes Acids Polymers

Time

Rela

tive

num

eric

al v

alue

0h12h, 87C12L/m

Cano

la o

ilCo

rn o

il

24h, 93C12L/m

36h, 95C12L/m

48h, 95C12L/m

60h, 95C12L/m

72h, 94C12L/m

Color is not a reliable indicator of peroxidation.

Color changes of corn and canola oil during lipid peroxidation

Indicative TestsPeroxide value

Thiobarbituric acid reactive substances (TBARS)

p-Anisidine valueConjugated dienes

TOTOX valueCarbonylsHexanal

2,4-decadienal (DDE)4-hydroxynonenal (HNE)

Triacylglycerol dimers and polymersOxiranes

Non-elutable material

Many analytical procedures can be used to measure SOME of the peroxidation products

Predictive TestsActive oxygen method

Oil stability indexOxygen bomb method

corn oil canola oil

poultry fat

beef tallow

0

50

100

150

200

250

300

Peroxide ValueTBARSAnisidine Value

Chan

ge re

lativ

e to

uno

xidi

zed

lipid

corn oil canola oil

poultry fat

beef tallow

Peroxide ValueTBARSAnisidine Value

96° C for 72 h 185° C for 7 h

Peroxidation measures are influenced by lipid fatty acid composition and heat treatment

Liu et al. (2012)

Which peroxidation measures should we use?

• None of the current analytical procedures provide a complete and accurate assessment of peroxidation

• Rate and amount of peroxidation varies with:

– heating conditions (time and temperature)

– depends on fatty acid composition of lipids

Are we doing enough to protect the value of feed fats and oils?

Impact of antioxidants on lipid peroxidation of DDGS and distiller’s corn

oil stored under extreme temperature and humidity conditions

Hanson et al. (2015)

Adapted from: Bartosz & Kolakowska (2007)

Antioxidants inhibit chain reactions of lipid peroxidation

LOO• + LOOHα - T•

α – tocopherol (Vitamin E) Vit. C

LOH

GPX

GSH

GSSG

GPX = glutathione peroxidase• selenium

GSH = glutathione• cys, glu, gly

GSR = glutathione reductase• riboflavin

GSR

Low oil (RO) DDGS5% crude fat18 batches

High oil (HO) DDGS13% crude fat

18 batches

DCO (DCO-HI)MIU = 1.76%18 batches

DCO (DCO-LO)MIU = 1.31%18 batches

No Antioxidant

n = 6

Rendox-CQ® (TBHQ)

1000 ppm fatn = 6

Santoquin-Q4T®

(ethoxyquin + TBHQ)1500 ppm fat

n = 6Each batch split into 3

subsamples for analysis on day 0, 14, and 28

Storage conditions:38⁰ C

94% Relative humidity

Series105

10152025

HO-DDGSRO-DDGSDCO-HIDCO-LO

PV m

eq/k

g oi

lPeroxide value, TBARS, and anisidine value

increased during storage at 38⁰C

Series10

5

10

15

TBAR

S m

g M

DA e

q/kg

oi

l

d 0 d 14 d 2802468

AnV

Time effect (P < 0.01)Ingredient effect (P < 0.01)Ingredient × time interaction (P < 0.01)

Peroxide valueTBARS

Anisidine valueincreased over

time

Hanson et al. (2015)

PV, meq/kg fat TBARS mg MDA eq/kg fat

0.001.002.003.004.005.006.007.008.009.00

HO-DDGSRO-DDGSDCO-HIDCO-LO

Ingredient effect (P < 0.01)a,bMeans with different letters differ (P < 0.05)

Amount of peroxidation varied among ingredients

a b a b a b a b

Hanson et al. (2015)

PV, meq/kg fat TBARS mg MDA eq/kg fat

AnV0.00

2.00

4.00

6.00

8.00

10.00

12.00

CONRENSAN

Antioxidant effect (P < 0.01) a,bMeans with different letters differ (P < 0.05)

Antioxidants reduced peroxidation in distiller’s corn oil and DDGS

a b c a b b

a b c

Hanson et al. (2015)

Effects of feeding increasing amounts of peroxidized corn oil on growth

performance and antioxidant status of nursery pigs

Hanson et al. (2015)

Experimental procedures

• Refined corn oil was heated at 185⁰C for 12 hrs with 12 L air/min (rapidly peroxidized)

• 128 barrows (BW = 6.3 ± 0.6 kg) were fed 1 of 4 isocaloric diets containing 9% corn oil

• Measured ADG, ADFI, and G:F for 5 wks

• Determined liver and serum selenium and vitamin E concentrations

Hanson et al. (2015)

Diet 1 2 3 4

Unheated corn oil 9 6 3 0

Peroxidized corn oil 0 3 6 9

Measure Unoxidized Rapid Oxidized

PUFA, % 54.9 49.3

Vitamin E, IU/100 g 27.7 23.3

OSI, h at 110⁰C1 10.8 2.2

TBARS, mg MDA eq/kg2 48.3 26.7

Peroxide value meq/kg 1.7 5.7

Anisidine Value 5.3 138.01OSI = oil stability index2TBARS = thiobarbituric acid reactive substances

Analyzed characteristics of corn oil

Hanson et al. (2015)

0 3 6 9 0 3 6 90 3 6 90.00.10.20.30.40.50.60.70.8

kgGrowth performance responses from feeding increasing concentrations of peroxidized corn oil

Linear P = 0.10

Linear P = 0.03

Error bars represent PSEM

8%

4%ADG ADFI Gain:Feed

9 6 3 0

0 3 6 9

9 6 3 0

0 3 6 9

9 6 3 0

0 3 6 9

Unoxidized, %

Peroxidized, %

Caloric efficiency declined linearly (P = 0.03) from 2.4 to 4%

Hanson et al. (2015)

Serum metabolic oxidative status indicators

α-Tocopherol Selenium TBARS

0 3 6 90.00.20.30.50.60.80.9

ug/m

L

0 3 6 90.000.020.040.060.090.110.13

ug/m

LLinear

P = 0.11

0 3 6 90.0

0.2

0.4

0.6

0.8

1.0

uM

Linear P = 0.05

Cubic P = 0.005

Data represent least squares means on day 14 and 35TBARS = thiobarbituric acid reactive substancesError bars represent PSEM

55% 8% 8%

9 6 3 0

0 3 6 9

9 6 3 0

0 3 6 9

9 6 3 0

0 3 6 9

Unoxidized, %

Peroxidized, %

Hanson et al. (2015)

How do we connect measures of lipid peroxidation to predict animal growth performance?

• What measures do we use?

• What is the threshold of peroxidation that reduces animal performance?– Varies by species?– Varies by lipid source?

• Are there long-term metabolic consequences of feeding peroxidized lipids not observed by changes in growth performance?

• Are supplemental antioxidants needed?

Common physiological measures of metabolic oxidation status

• Peroxidation products in biological samples– Hydrogen peroxide (rapidly catabolized)– TBARS and conjugated dienes (non-specific)– MDA, HNE, protein carbonyls, 8-hydroxy-deoxyguanosine, isoprostanes (concern thresholds have not been

established)• Liver damage

– Serum transaminase enzymes • Endogenous antioxidants in serum and liver

– α-tocopherol– Vitamin A– Glutathione– Vitamin C– Glutathione peroxidase– Catalase– Superoxide dismutase

• Increased liver size relative to body weight• Changes in gut barrier function• Changes in gene regulation (PPARα)

– Controls expression of fatty acid oxidative metabolism in many waysKEY POINTS:Multiple measures must be used.Relative importance of individual measures is poorly understood.Limited information on using these measures to predict utilization of lipids in animals.

• Lipids containing high amounts of PUFA are most susceptible to peroxidation

• We need to use different peroxidation measures for different types of lipids due to differences in fatty acid composition

• Peroxidation indicators are affected by time and temperature of heating– PV, DDE, and AnV may be acceptable at low temperatures (95⁰C)– HNE, hexanal, and TBARS are good indicators of peroxidation at high

temperatures (185⁰C)– PV, TBARS, and AnV increased in distiller’s corn oil and DDGS stored at 38⁰C

• Commercial antioxidants are effective in reducing peroxidation by ~50%

Conclusions

• Feeding peroxidized lipids reduces growth performance and increases metabolic oxidation in pigs– Peroxide value is a poor predictor of reduced ADG of pigs

• Feeding increasing levels of peroxidized corn oil linearly reduces ADG and Gain:Feed of nursery pigs– Effects are dose dependent– Caloric efficiency declined 2.4 to 4% with 3 to 9% rapidly peroxidized corn oil

Conclusions

• We need to better understand if changes in metabolic antioxidant indicators relate to reduced growth or compromise animal health over time.– Dietary thresholds for maximum lipid peroxidation need to be established

• How do we relate negative biological effects of peroxidized lipids to price or value?

Conclusions